This is in preparation for subsequent patches that add support for PWM
capture to this driver.
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
In the original code the clock rate was only obtained during
initialisation; however, the rate may change between then and
its use. This patch ensures the correct rate is acquired just
before use.
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Exciting functionality is on the way to this device. But
before we can add it, we need to do some basic housekeeping
so the additions can be added cleanly.
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This is to bring the terminology used in the STi PWM driver more
into line with the PWM subsystem.
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The lpc-18xx driver currently manipulates the pwm_device struct directly
rather than using the pwm_set_chip_data() function. While the current
method may save a clock cycle or two, using the explicit function call
makes it more obvious that data is set to the local chip data pointer.
Signed-off-by: Olliver Schinagl <oliver@schinagl.nl>
Reviewed-by: Ariel D'Alessandro <ariel@vanguardiasur.com.ar>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Add support for the PWM controller found in the Amlogic SoCs. This
driver supports the Meson8b and GXBB SoCs.
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Tested-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Tested-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
From pwm_samsung_calc_tin(), there is routine to find the lowest divider
possible to generate lower frequency than requested one. But it is
always possible to generate requested frequency with large enough
modulation bits except on s3c24xx, so this patch fixes to use lowest div
for the case. This patch removes following UBSAN warning:
UBSAN: Undefined behaviour in drivers/pwm/pwm-samsung.c:197:13
shift exponent 32 is too large for 32-bit type 'long unsigned int'
[...]
[<c0670248>] (ubsan_epilogue) from [<c06707b4>] (__ubsan_handle_shift_out_of_bounds+0xd8/0x120)
[<c06707b4>] (__ubsan_handle_shift_out_of_bounds) from [<c0694b28>] (pwm_samsung_config+0x508/0x6a4)
[<c0694b28>] (pwm_samsung_config) from [<c069286c>] (pwm_apply_state+0x174/0x40c)
[<c069286c>] (pwm_apply_state) from [<c0b2e070>] (pwm_fan_probe+0xc8/0x488)
[<c0b2e070>] (pwm_fan_probe) from [<c07ba8b0>] (platform_drv_probe+0x70/0x150)
[...]
Cc: Tomasz Figa <tomasz.figa@gmail.com>
Signed-off-by: Seung-Woo Kim <sw0312.kim@samsung.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Remove all pm_runtime_get_sync() and pm_runtime_put_sync() call as well
as the dummy pm_ops from the pwm-tipwmss driver. No registers are being
modified. The runtime PM still needs to be enabled, so that the runtime
PM framework can take care of enabling/disabling the PWMSS clock when
submodules of PWMSS (ECAP or EHRPWM) call runtime PM APIs. With this
change PWMSS clock goes to idle when none of the submodules are in use.
Signed-off-by: Jyri Sarha <jsarha@ti.com>
Signed-off-by: Vignesh R <vigneshr@ti.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
While the particular usage in question is likely safe (struct
cros_ec_command is 32-bit aligned, followed by <= 32-bit fields), it's
been suggested this is not a great pattern to follow for the general
case -- for example, if we follow a 'struct cros_ec_command' (which is
32-bit- but not 64-bit-aligned) with a struct that starts with a 64-bit
type (e.g., u64), the compiler may add padding.
Let's add __packed, to inform the compiler of our true intention -- to
have no padding between these struct elements -- and to future proof for
any refactorings that might occur.
Signed-off-by: Brian Norris <briannorris@chromium.org>
Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Use the mtk_pwm_data struction to define different registers
and add MT2701 specific register operations, such as MT2701
doesn't have commit register, needs to disable double buffer
before writing register, and needs to select manual mode
and use PWM_PERIOD/PWM_HIGH_WIDTH.
Signed-off-by: Weiqing Kong <weiqing.kong@mediatek.com>
[thierry.reding@gmail.com: use of_device_get_match_data()]
[thierry.reding@gmail.com: parameterize more consistently]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This patch adds suspend-to-RAM support to the Berlin PWM driver.
Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Exported pwm channels aren't removed before the pwmchip and are
leaked. This results in invalid sysfs files. This fix removes
all exported pwm channels before chip removal.
Signed-off-by: David Hsu <davidhsu@google.com>
Fixes: 76abbdde2d ("pwm: Add sysfs interface")
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The current TWL6030 code for the TWL PWM driver does not reliably disable the
PWM output, as tested with LEDs. The previous commit to that driver introduced
that regression.
However, it does make sense to disable the PWM clock after resetting the PWM,
but for some obscure reason, doing it all at once simply doesn't work.
The TWL6030 datasheet mentions that PWMs have to be disabled in two distinct
steps. However, clearing the clock enable bit in a second step (after issuing a
reset first) does not work.
The only approach that works is the one that was in place before the previous
commit to the driver. It consists in enabling the PWM clock after issuing a
reset. This is what TI kernel trees and production code seem to be using.
However, adding an extra step to disable the PWM clock seems to work reliably,
despite looking quite odd.
Signed-off-by: Paul Kocialkowski <contact@paulk.fr>
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This set of changes improve some aspects of the atomic API as well as
make use of this new API in the regulator framework to allow properly
dealing with critical regulators controlled by a PWM.
Aside from that there's a bunch of updates and cleanups for existing
drivers, as well as the addition of new drivers for the Broadcom iProc,
STMPE and ChromeOS EC controllers.
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Merge tag 'pwm/for-4.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm
Pull pwm updates from Thierry Reding:
"This set of changes improve some aspects of the atomic API as well as
make use of this new API in the regulator framework to allow properly
dealing with critical regulators controlled by a PWM.
Aside from that there's a bunch of updates and cleanups for existing
drivers, as well as the addition of new drivers for the Broadcom
iProc, STMPE and ChromeOS EC controllers"
* tag 'pwm/for-4.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm: (44 commits)
regulator: pwm: Document pwm-dutycycle-unit and pwm-dutycycle-range
regulator: pwm: Support extra continuous mode cases
pwm: Add ChromeOS EC PWM driver
dt-bindings: pwm: Add binding for ChromeOS EC PWM
mfd: cros_ec: Add EC_PWM function definitions
mfd: cros_ec: Add cros_ec_cmd_xfer_status() helper
pwm: atmel: Use of_device_get_match_data()
pwm: atmel: Fix checkpatch warnings
pwm: atmel: Fix disabling of PWM channels
dt-bindings: pwm: Add R-Car H3 device tree bindings
pwm: rcar: Use ARCH_RENESAS
pwm: tegra: Add support for Tegra186
dt-bindings: pwm: tegra: Add compatible string for Tegra186
pwm: tegra: Avoid overflow when calculating duty cycle
pwm: tegra: Allow 100 % duty cycle
pwm: tegra: Add support for reset control
pwm: tegra: Rename mmio_base to regs
pwm: tegra: Remove useless padding
pwm: tegra: Drop NUM_PWM macro
pwm: lpc32xx: Set PWM_PIN_LEVEL bit to default value
...
Driver updates for ARM SoCs.
A slew of changes this release cycle. The reset driver tree, that we merge
through arm-soc for historical reasons, is also sizable this time around.
Among the changes:
- clps711x: Treewide changes to compatible strings, merged here for simplicity.
- Qualcomm: SCM firmware driver cleanups, move to platform driver
- ux500: Major cleanups, removal of old mach-specific infrastructure.
- Atmel external bus memory driver
- Move of brcmstb platform to the rest of bcm
- PMC driver updates for tegra, various fixes and improvements
- Samsung platform driver updates to support 64-bit Exynos platforms
- Reset controller cleanups moving to devm_reset_controller_register() APIs
- Reset controller driver for Amlogic Meson
- Reset controller driver for Hisilicon hi6220
- ARM SCPI power domain support
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Merge tag 'armsoc-drivers' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc
Pull ARM SoC driver updates from Olof Johansson:
"Driver updates for ARM SoCs.
A slew of changes this release cycle. The reset driver tree, that we
merge through arm-soc for historical reasons, is also sizable this
time around.
Among the changes:
- clps711x: Treewide changes to compatible strings, merged here for simplicity.
- Qualcomm: SCM firmware driver cleanups, move to platform driver
- ux500: Major cleanups, removal of old mach-specific infrastructure.
- Atmel external bus memory driver
- Move of brcmstb platform to the rest of bcm
- PMC driver updates for tegra, various fixes and improvements
- Samsung platform driver updates to support 64-bit Exynos platforms
- Reset controller cleanups moving to devm_reset_controller_register() APIs
- Reset controller driver for Amlogic Meson
- Reset controller driver for Hisilicon hi6220
- ARM SCPI power domain support"
* tag 'armsoc-drivers' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (100 commits)
ARM: ux500: consolidate base platform files
ARM: ux500: move soc_id driver to drivers/soc
ARM: ux500: call ux500_setup_id later
ARM: ux500: consolidate soc_device code in id.c
ARM: ux500: remove cpu_is_u* helpers
ARM: ux500: use CLK_OF_DECLARE()
ARM: ux500: move l2x0 init to .init_irq
mfd: db8500 stop passing around platform data
ASoC: ab8500-codec: remove platform data based probe
ARM: ux500: move ab8500_regulator_plat_data into driver
ARM: ux500: remove unused regulator data
soc: raspberrypi-power: add CONFIG_OF dependency
firmware: scpi: add CONFIG_OF dependency
video: clps711x-fb: Changing the compatibility string to match with the smallest supported chip
input: clps711x-keypad: Changing the compatibility string to match with the smallest supported chip
pwm: clps711x: Changing the compatibility string to match with the smallest supported chip
serial: clps711x: Changing the compatibility string to match with the smallest supported chip
irqchip: clps711x: Changing the compatibility string to match with the smallest supported chip
clocksource: clps711x: Changing the compatibility string to match with the smallest supported chip
clk: clps711x: Changing the compatibility string to match with the smallest supported chip
...
Use the new ChromeOS EC EC_CMD_PWM_{GET,SET}_DUTY commands to control
one or more PWMs attached to the Embedded Controller. Because the EC
allows us to modify the duty cycle (as a percentage, where U16_MAX is
100%) but not the period, we assign the period a fixed value of
EC_PWM_MAX_DUTY and reject all attempts to change it.
This driver supports only device tree at the moment, because that
provides a very flexible way of describing the relationship between PWMs
and their consumer devices (e.g., backlight). On a non-DT system, we'll
probably want to use the non-GENERIC addressing (i.e., we'll need to
make special device instances that will use EC_PWM_TYPE_KB_LIGHT or
EC_PWM_TYPE_DISPLAY_LIGHT), as well as the relatively inflexible
pwm_lookup infrastructure for matching devices. Defer that work for now.
Signed-off-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
When disabling a PWM channel, the PWM clock was being stopped
immediately after writing to PWM_DIS. As a result, the disabling
of the PWM channel did not complete properly, and the PWM output
might be left at the wrong level.
Fix this by waiting for the channel to be effectively disabled
(by checking the PWM_SR register) before disabling the clock.
Signed-off-by: Guillermo Rodriguez <guille.rodriguez@gmail.com>
Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Tegra186 has multiple PWM controllers with only one output instead of
one controller with four outputs in earlier SoC generations.
Add support for Tegra186 and detect the number of PWM outputs using
device tree match data.
Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
duty_ns * (1 << PWM_DUTY_WIDTH) could overflow in integer calculation
when the PWM rate is low. Hence do all calculation on unsigned long long
to avoid overflow.
Signed-off-by: Hyong Bin Kim <hyongbink@nvidia.com>
Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
To get 100 % duty cycle (always high), pulse width needs to be set to
256.
Signed-off-by: Victor(Weiguo) Pan <wpan@nvidia.com>
Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Add reset control of the PWM controller to reset it before
accessing the PWM register.
Signed-off-by: Rohith Seelaboyina <rseelaboyina@nvidia.com>
Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The former is much longer to type and is ambiguous because the value
stored in the field is not the (physical) base address of the memory-
mapped I/O registers, but the virtual address of those registers as
mapped through the MMU.
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This macro is used to initialize the ->npwm field of the PWM chip. Use a
literal instead and make all other places rely on ->npwm.
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The PWM_PIN_LEVEL bit is leave unset by the kernel PWM driver.
Prior to commit 08ee77b5a5,
the PWM_PIN_LEVEL bit was always clear when the PWM was disable
and a 0 logic level was apply to the output.
According to the LPC32x0 User Manual [1],
the default value for bit 30 (PWM_PIN_LEVEL) is 0.
This change initialize the pin level to 0 (default value) and
update the register value accordingly.
[1] http://www.nxp.com/documents/user_manual/UM10326.pdf
Signed-off-by: Sylvain Lemieux <slemieux@tycoint.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This adds a driver for the PWM block found in chips of the STMPE 24xx
series of multi-purpose I2C expanders. (I think STMPE means ST
Microelectronics Multi-Purpose Expander.) This PWM was designed in
accordance with Nokia specifications and is kind of weird and usually
just switched between max and zero duty cycle. However it is indeed a
PWM so it needs to live in the PWM subsystem.
This PWM is mostly used for white LED backlight.
Cc: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Implement the ->apply() function to add support for atomic update.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Brian Norris <briannorris@chromium.org>
Tested-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The current logic will disable the PWM clk even if the PWM was left
enabled by the bootloader (because it's controlling a critical device
like a regulator for example).
Keep the PWM clk enabled if the PWM is enabled to avoid any glitches.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Reviewed-by: Brian Norris <briannorris@chromium.org>
Tested-by: Brian Norris <briannorris@chromium.org>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Implement the ->get_state() function to expose initial state.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Reviewed-by: Brian Norris <briannorris@chromium.org>
Tested-by: Brian Norris <briannorris@chromium.org>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The current implementation always round down the duty and period values,
while it would be better to round them to the closest integer.
These changes are needed in preparation of atomic update support to
prevent a period/duty cycle drift when executing several times the
'pwm_get_state() / modify / pwm_apply_state()' sequence.
Say you have an expected period of 3.333 us and a clk rate of
112.666667 MHz -- the clock frequency doesn't divide evenly, so the
period (stashed in nanoseconds) shrinks when we convert to the register
value and back, as follows:
pwm_apply_state(): register = period * 112666667 / 1000000000;
pwm_get_state(): period = register * 1000000000 / 112666667;
or in other words:
period = period * 112666667 / 1000000000 * 1000000000 / 112666667;
which yields a sequence like:
3333 -> 3328
3328 -> 3319
3319 -> 3310
3310 -> 3301
3301 -> 3292
3292 -> ... (etc) ...
With this patch, we'd see instead:
period = div_round_closest(period * 112666667, 1000000000) *
1000000000 / 112666667;
which yields a stable sequence:
3333 -> 3337
3337 -> 3337
3337 -> ... (etc) ...
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Reviewed-by: Brian Norris <briannorris@chromium.org>
Tested-by: Brian Norris <briannorris@chromium.org>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Add support for the PWM controller present in Broadcom's iProc family of
SoCs. It has been tested on the Northstar+ bcm958625HR board.
Signed-off-by: Yendapally Reddy Dhananjaya Reddy <yendapally.reddy@broadcom.com>
[thierry.reding@gmail.com: bunch of coding style fixes, cleanups]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
There is no need to check each time if the clk_rate defined or not when we call
pwm_lpss_config(). Move the check to ->probe() instead.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Intel Edison has 4 PWM channels on the die with the same IP as in
Broxton. Enable it.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
If duty_ns is large enough multiplying it by 255 overflows and results
wrong duty cycle value being programmed. For example with 10ms duty when
period is 20ms (50%) we get
255 * 10000000 / 20000000 = -87
because 255 * 10000000 overlows int. Whereas correct value should be
255 * 10000000 / 20000000 = 127
Fix this by using unsigned long long as type for on_time_div and changing
integer literals to use proper type annotation.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The base_unit calculation applies an offset of 0x2 which adds
significant error for lower frequencies and doesn't appear to be
warranted - rounding the division result gives a correct value.
Also, the upper limit check for base_unit is off-by-one; the upper
nibble of base_unit is invalid if >=128 according to the Table 88
in the Z8000 Processor Series Datasheet Volume 1 (Rev. 2).
Verified on UP Board (Cherry Trail) and Minnowboard Max (Bay Trail).
Signed-off-by: Dan O'Donovan <dan@emutex.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The PWMSS local clock gating registers have no real purpose on OMAP ARM
devices. These registers were left over registers from DSP IP where the
PRCM doesn't exist. There is a silicon bug where gating and ungating clocks
don't function properly. TRMs will be update to indicate that these
registers shouldn't be touched.
Therefore, all code that accesses the PWMSS_CLKCONFIG or PWMSS_CLKSTATUS
will be removed by this patch with zero loss of functionality by the ECAP
and EPWM drivers.
Signed-off-by: Franklin S Cooper Jr <fcooper@ti.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
When using the old eCAP and ePWM bindings for AM335x and AM437x the clock
can be retrieved from the PWMSS parent. Newer bindings will insure that
this clock is provided via device tree.
Therefore, update this driver to support the newer and older bindings. In
the case of the older binding being used give a warning.
Signed-off-by: Franklin S Cooper Jr <fcooper@ti.com>
[thierry.reding@gmail.com: rewrite slightly for readability]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
booting.
This driver has been unusable with multiarch because of the hardware
timer access. With the recent PWM changes, we can finally fix the
driver for multiarch and device tree support. And naturally there
is no rush for these for the -rc cycle, these can wait for the
merge window.
The PWM changes have been acked by Thierry. For the media changes
I did not get an ack from Mauro but he was Cc'd in the discussion
and these changes do not conflict with other media changes.
After this series we can drop the remaining omap3 legacy booting
board files finally.
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Merge tag 'omap-for-v4.8/ir-rx51-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap into next/drivers
Merge "omap ir-rx51 driver fixes for multiarch for v4.8 merge window"
from Tony Lindgren:
Fix a long time regression for ir-rx51 driver for n900 device tree
booting.
This driver has been unusable with multiarch because of the hardware
timer access. With the recent PWM changes, we can finally fix the
driver for multiarch and device tree support. And naturally there
is no rush for these for the -rc cycle, these can wait for the
merge window.
The PWM changes have been acked by Thierry. For the media changes
I did not get an ack from Mauro but he was Cc'd in the discussion
and these changes do not conflict with other media changes.
After this series we can drop the remaining omap3 legacy booting
board files finally.
* tag 'omap-for-v4.8/ir-rx51-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap:
ir-rx51: use hrtimer instead of dmtimer
ir-rx51: add DT support to driver
ir-rx51: use PWM framework instead of OMAP dmtimer
pwm: omap-dmtimer: Allow for setting dmtimer clock source
ir-rx51: Fix build after multiarch changes broke it
This patch changes the compatibility string to match with the smallest
supported chip (EP7209). Since the DT-support for this CPU is not yet
announced, this change is safe.
Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
OMAP GP timers can have different input clocks that allow different PWM
frequencies. However, there is no other way of setting the clock source but
through clocks or clock-names properties of the timer itself. This limits
PWM functionality to only the frequencies allowed by the particular clock
source. Allowing setting the clock source by PWM rather than by timer
allows different PWMs to have different ranges by not hard-wiring the clock
source to the timer.
Signed-off-by: Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Thierry Reding <treding@nvidia.com>
Acked-by: Pali Rohár <pali.rohar@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
The PWM device exposed by the HLCDC IP is configured with an inverted
polarity by default. Registering the PWM chip with the normal polarity
was not a problem before commit 42e8992c58d4 ("pwm: Add core
infrastructure to allow atomic updates") because the ->set_polarity()
hook was called no matter the current polarity state, but this is no longer
the case.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Allow a user to read PWM capture results from sysfs. To start a capture
and read the result, simply read the file:
$ cat $PWMCHIP/capture
The output format is "<period> <duty cycle>".
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Supply a PWM capture callback op in order to pass back information
obtained by running analysis on a PWM signal. This would normally (at
least during testing) be called from the sysfs routines with a view to
printing out PWM capture data which has been encoded into a string.
Signed-off-by: Lee Jones <lee.jones@linaro.org>
[thierry.reding@gmail.com: make capture data unsigned int for symmetry]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This patch adds to check the return value from pwm_apply_state()
used in enable_store(). The error of enable_store() doesn't work
if the return value doesn't received.
Signed-off-by: Ryo Kodama <ryo.kodama.vz@renesas.com>
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Fixes: 39100ceea7 ("pwm: Switch to the atomic API")
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
It seems like in the process of refactoring pwm_config() to utilize the
newly-introduced pwm_apply_state() API, some args/bounds checking was
dropped.
In particular, I noted that we are now allowing invalid period
selections, e.g.:
# echo 1 > /sys/class/pwm/pwmchip0/export
# cat /sys/class/pwm/pwmchip0/pwm1/period
100
# echo 101 > /sys/class/pwm/pwmchip0/pwm1/duty_cycle
[... driver may or may not reject the value, or trigger some logic bug ...]
It's better to see:
# echo 1 > /sys/class/pwm/pwmchip0/export
# cat /sys/class/pwm/pwmchip0/pwm1/period
100
# echo 101 > /sys/class/pwm/pwmchip0/pwm1/duty_cycle
-bash: echo: write error: Invalid argument
This patch reintroduces some bounds checks in both pwm_config() (for its
signed parameters; we don't want to convert negative values into large
unsigned values) and in pwm_apply_state() (which fix the above described
behavior, as well as other potential API misuses).
Fixes: 5ec803edcb ("pwm: Add core infrastructure to allow atomic updates")
Signed-off-by: Brian Norris <briannorris@chromium.org>
Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This set of changes introduces an atomic API to the PWM subsystem. This
is influenced by the DRM atomic API that was introduced a while back,
though it is obviously a lot simpler. The fundamental idea remains the
same, though: drivers provide a single callback to implement the atomic
configuration of a PWM channel.
As a side-effect the PWM subsystem gains the ability for initial state
retrieval, so that the logical state mirrors that of the hardware. Many
use-cases don't care about this, but for others it is essential.
These new features require changes in all users, which these patches
take care of. The core is transitioned to use the atomic callback if
available and provides a fallback mechanism for other drivers.
Changes to transition users and drivers to the atomic API are postponed
to v4.8.
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Merge tag 'pwm/for-4.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm
Pull pwm updates from Thierry Reding:
"This set of changes introduces an atomic API to the PWM subsystem.
This is influenced by the DRM atomic API that was introduced a while
back, though it is obviously a lot simpler. The fundamental idea
remains the same, though: drivers provide a single callback to
implement the atomic configuration of a PWM channel.
As a side-effect the PWM subsystem gains the ability for initial state
retrieval, so that the logical state mirrors that of the hardware.
Many use-cases don't care about this, but for others it is essential.
These new features require changes in all users, which these patches
take care of. The core is transitioned to use the atomic callback if
available and provides a fallback mechanism for other drivers.
Changes to transition users and drivers to the atomic API are
postponed to v4.8"
* tag 'pwm/for-4.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm: (30 commits)
pwm: Add information about polarity, duty cycle and period to debugfs
pwm: Switch to the atomic API
pwm: Update documentation
pwm: Add core infrastructure to allow atomic updates
pwm: Add hardware readout infrastructure
pwm: Move the enabled/disabled info into pwm_state
pwm: Introduce the pwm_state concept
pwm: Keep PWM state in sync with hardware state
ARM: Explicitly apply PWM config extracted from pwm_args
drm: i915: Explicitly apply PWM config extracted from pwm_args
input: misc: pwm-beeper: Explicitly apply PWM config extracted from pwm_args
input: misc: max8997: Explicitly apply PWM config extracted from pwm_args
backlight: lm3630a: explicitly apply PWM config extracted from pwm_args
backlight: lp855x: Explicitly apply PWM config extracted from pwm_args
backlight: lp8788: Explicitly apply PWM config extracted from pwm_args
backlight: pwm_bl: Use pwm_get_args() where appropriate
fbdev: ssd1307fb: Use pwm_get_args() where appropriate
regulator: pwm: Use pwm_get_args() where appropriate
leds: pwm: Use pwm_get_args() where appropriate
input: misc: max77693: Use pwm_get_args() where appropriate
...
The PWM states make it possible to also output the polarity, duty cycle
and period information in the debugfs summary output. This simplifies
gathering information about PWMs without needing to walk through the
sysfs attributes of every PWM.
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
[thierry.reding@gmail.com: use more spaces in debugfs output]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Add an ->apply() method to the pwm_ops struct to allow PWM drivers to
implement atomic updates. This method is preferred over the ->enable(),
->disable() and ->config() methods if available.
Add the pwm_apply_state() function to the PWM user API.
Note that the pwm_apply_state() does not guarantee the atomicity of the
update operation, it all depends on the availability and implementation
of the ->apply() method.
pwm_enable/disable/set_polarity/config() are now implemented as wrappers
around the pwm_apply_state() function.
pwm_adjust_config() is allowing smooth handover between the bootloader
and the kernel. This function tries to adapt the current PWM state to
the PWM arguments coming from a PWM lookup table or a DT definition
without changing the duty_cycle/period proportion.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
[thierry.reding@gmail.com: fix a couple of typos]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Add a ->get_state() function to the pwm_ops struct to let PWM drivers
initialize the PWM state attached to a PWM device.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Prepare the transition to PWM atomic update by moving the enabled and
disabled state into the pwm_state struct. This way we can easily update
the whole PWM state by copying the new state in the ->state field.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The PWM state, represented by its period, duty_cycle and polarity is
currently directly stored in the PWM device. Declare a pwm_state
structure embedding those field so that we can later use this struct
to atomically update all the PWM parameters at once.
All pwm_get_xxx() helpers are now implemented as wrappers around
pwm_get_state().
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Before the introduction of pwm_args, the core was resetting the PWM
period and polarity states to the reference values (those provided
through the DT, a PWM lookup table or hardcoded in the driver).
Now that all PWM users are correctly using pwm_args to configure their
PWM device, we can safely remove the pwm_apply_args() call in pwm_get()
and of_pwm_get().
We can also get rid of the pwm_set_period() call in pwm_apply_args(),
because PWM users are now directly using pargs->period instead of
pwm_get_period(). By doing that we avoid messing with the current PWM
period.
The only remaining bit in pwm_apply_args() is the initial polarity
setting, and it should go away when all PWM users have been patched to
use the atomic API (with this API the polarity will be set along with
other PWM arguments when configuring the PWM).
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Use pwm_get/set_xxx() helpers instead of directly accessing the pwm->xxx
field. Doing that will ease adaptation of the PWM framework to support
atomic update.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
PWM devices are not protected against concurrent accesses. The lock in
struct pwm_device might let PWM users think it is, but it's actually
only protecting the enabled state.
Removing this lock should be fine as long as all PWM users are aware
that accesses to the PWM device have to be serialized, which seems to be
the case for all of them except the sysfs interface. Patch the sysfs
code by adding a lock to the pwm_export struct and making sure it's
taken for all relevant accesses to the exported PWM device.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Commit 5c31252c4a ("pwm: Add the pwm_is_enabled() helper") introduced
a new function to test whether a PWM device is enabled or not without
manipulating PWM internal fields.
Hiding this is necessary if we want to smoothly move to the atomic PWM
config approach without impacting PWM drivers. Fix this driver to use
pwm_is_enabled() instead of directly accessing the ->flags field.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
pwm_apply_args() is supposed to initialize a PWM device according to the
arguments provided by the DT or the PWM lookup, but this function was
called inside pwm_device_request(), which in turn was called before the
core had a chance to initialize the pwm->args fields.
Fix that by calling pwm_apply_args directly in pwm_get() and of_pwm_get()
after initializing pwm->args field.
This commit also fixes an invalid pointer dereference introduced by
commit e39c0df1be ("pwm: Introduce the pwm_args concept").
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Fixes: e39c0df1be ("pwm: Introduce the pwm_args concept")
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
checkpatch requires that declarations be separated from code by a blank
line. Add one for readability and to silence the warning.
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Currently the PWM core mixes the current PWM state with the per-platform
reference config (specified through the PWM lookup table, DT definition
or directly hardcoded in PWM drivers).
Create a struct pwm_args to store this reference configuration, so that
PWM users can differentiate between the current and reference
configurations.
Patch all places where pwm->args should be initialized. We keep the
pwm_set_polarity/period() calls until all PWM users are patched to use
pwm_args instead of pwm_get_period/polarity().
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
[thierry.reding@gmail.com: reword kerneldoc comments]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Use flat regmap cache to avoid lockdep warning at probe:
[ 0.697285] WARNING: CPU: 0 PID: 1 at kernel/locking/lockdep.c:2755 lockdep_trace_alloc+0x15c/0x160()
[ 0.697449] DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags))
The RB-tree regmap cache needs to allocate new space on first writes.
However, allocations in an atomic context (e.g. when a spinlock is held)
are not allowed. The function regmap_write calls map->lock, which
acquires a spinlock in the fast_io case. Since the pwm-fsl-ftm driver
uses MMIO, the regmap bus of type regmap_mmio is being used which has
fast_io set to true.
The MMIO space of the pwm-fsl-ftm driver is reasonable condense, hence
using the much faster flat regmap cache is anyway the better choice.
Signed-off-by: Stefan Agner <stefan@agner.ch>
Cc: Mark Brown <broonie@kernel.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
After going through the math and constraints checking to compute load
and match values, it is helpful to know what the resultant period and
duty cycle are.
Signed-off-by: David Rivshin <drivshin@allworx.com>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
When converting period and duty_cycle from nanoseconds to fclk cycles,
the error introduced by the integer division can be appreciable, especially
in the case of slow fclk or short period. Use DIV_ROUND_CLOSEST_ULL() so
that the error is kept to +/- 0.5 clock cycles.
Fixes: 6604c6556d ("pwm: Add PWM driver for OMAP using dual-mode timers")
Signed-off-by: David Rivshin <drivshin@allworx.com>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Add sanity checking to ensure that we do not program load or match values
that are out of range if a user requests period or duty_cycle values which
are not achievable. The match value cannot be less than the load value (but
can be equal), and neither can be 0xffffffff. This means that there must be
at least one fclk cycle between load and match, and another between match
and overflow.
Fixes: 6604c6556d ("pwm: Add PWM driver for OMAP using dual-mode timers")
Signed-off-by: David Rivshin <drivshin@allworx.com>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
[thierry.reding@gmail.com: minor coding style cleanups]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Fix the calculation of load_value and match_value. Currently they
are slightly too low, which produces a noticeably wrong PWM rate with
sufficiently short periods (i.e. when 1/period approaches clk_rate/2).
Example:
clk_rate=32768Hz, period=122070ns, duty_cycle=61035ns (8192Hz/50% PWM)
Correct values: load = 0xfffffffc, match = 0xfffffffd
Current values: load = 0xfffffffa, match = 0xfffffffc
effective PWM: period=183105ns, duty_cycle=91553ns (5461Hz/50% PWM)
Fixes: 6604c6556d ("pwm: Add PWM driver for OMAP using dual-mode timers")
Signed-off-by: David Rivshin <drivshin@allworx.com>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Tested-by: Adam Ford <aford173@gmail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The change fixes potential oops while accessing iomem on invalid address
if devm_ioremap_resource() fails due to some reason.
The devm_ioremap_resource() function returns ERR_PTR() and never returns
NULL, which makes useless a following check for NULL.
Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
Fixes: 3a9f595702 ("pwm: Add Broadcom BCM7038 PWM controller support")
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This is part of an ongoing process to migrate from ARCH_SHMOBILE to
ARCH_RENESAS the motivation for which being that RENESAS seems to be a
more appropriate name than SHMOBILE for the majority of Renesas ARM
based SoCs.
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The clk API may return 0 on clk_get_rate(), so we should check the
result before using it as a divisor.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Joachim Eastwood <manabian@gmail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The clk API may return 0 on clk_get_rate(), so we should check the
result before using it as a divisor.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Commit d1cd214277 ("pwm: Set enable state properly on failed call to
enable") introduced a mutex that is needed to protect internal state of
PWM devices. Since that mutex is acquired in pwm_set_polarity() and in
pwm_enable() and might potentially block, all PWM devices effectively
become "might sleep".
It's rather pointless to keep the .can_sleep field around, but given
that there are external users let's postpone the removal for the next
release cycle.
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
"omap" is NULL so we can't dereference it.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Ran into this on UML:
drivers/built-in.o: In function `fsl_pwm_probe':
linux/drivers/pwm/pwm-fsl-ftm.c:436: undefined reference to `devm_ioremap_resource'
collect2: error: ld returned 1 exit status
devm_ioremap_resource() is defined only when HAS_IOMEM is selected.
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Xiubo Li <Li.Xiubo@freescale.com>
Cc: Alison Wang <b18965@freescale.com>
Cc: Jingchang Lu <b35083@freescale.com>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Yuan Yao <yao.yuan@freescale.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Adds support for using a OMAP dual-mode timer with PWM capability
as a Linux PWM device. The driver controls the timer by using the
dmtimer API.
Add a platform_data structure for each pwm-omap-dmtimer nodes containing
the dmtimers functions in order to get driver not rely on platform
specific functions.
Cc: Grant Erickson <marathon96@gmail.com>
Cc: NeilBrown <neilb@suse.de>
Cc: Joachim Eastwood <manabian@gmail.com>
Suggested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Tony Lindgren <tony@atomide.com>
[thierry.reding@gmail.com: coding style bikeshed, fix timer leak]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
From: Ryo Kodama <ryo.kodama.vz@renesas.com>
When period_ns is set to the same value of RCAR_PWM_MAX_CYCLE in
rcar_pwm_get_clock_division(), this function should allow such value
for improving accuracy of frequency division setting.
Signed-off-by: Ryo Kodama <ryo.kodama.vz@renesas.com>
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Instead of silent acceptance of unsupported requested configuration
for PWM period and setting the boundary supported value, return
-ERANGE to a caller.
Duty period value equal to 0 or period is still accepted to allow
configuration by PWM sysfs interface, when it is set to 0 by default.
For reference this is a list of restrictions on period_ns == 1/freq:
| PWM parent clock | parent clock divisor | max freq | min freq |
+------------------+----------------------+----------+----------+
| HCLK == 13 MHz | 1 (min) | 50.7 KHz | 198.3 Hz |
| HCLK == 13 MHz | 15 (max) | 3.38 KHz | 13.22 Hz |
| RTC == 32.7 KHz | 1 (min) | 128 Hz | 0.5 Hz |
| RTC == 32.7 KHz | 15 (max) | 8.533 Hz | 0.033 Hz |
Note that PWM sysfs interface does not support setting of period more
than NSEC_PER_SEC / MAX_INT32 ~ 2 seconds, however this PWM controller
supports a period up to 30 seconds.
Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The change fixes a problem, if duty_ns is too small in comparison
to period_ns (as a valid corner case duty_ns is 0 ns), then due to
PWM_DUTY() macro applied on a value the result is overflowed over 8
bits, and instead of the highest bitfield duty cycle value 0xff the
invalid duty cycle bitfield value 0x00 is written.
For reference the LPC32xx spec defines PWMx_DUTY bitfield description
is this way and it seems to be correct:
[Low]/[High] = [PWM_DUTY]/[256-PWM_DUTY], where 0 < PWM_DUTY <= 255.
In addition according to my oscilloscope measurements LPC32xx PWM is
"tristate" in sense that it produces a wave with floating min/max
voltage levels for different duty cycle values, for corner cases:
PWM_DUTY == 0x01 => signal is in range from -1.05v to 0v
....
PWM_DUTY == 0x80 => signal is in range from -0.75v to +0.75v
....
PWM_DUTY == 0xff => signal is in range from 0v to +1.05v
PWM_DUTY == 0x00 => signal is around 0v, PWM is off
Due to this peculiarity on very long period ranges (less than 1KHz)
and odd pre-divider values PWM generated wave does not remind a
clock shape signal, but rather a heartbit shape signal with positive
and negative peaks, so I would recommend to use high-speed HCLK clock
as a PWM parent clock and avoid using RTC clock as a parent.
The change corrects PWM output in corner cases and prevents any
possible overflows in calculation of values for PWM_DUTY and
PWM_RELOADV bitfields, thus helper macro definitions may be removed.
Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
As a preparatory change for switching LPC32xx mach support to common
clock framework fix clk_enable/clk_disable calls without matching
clk_prepare/clk_unprepare.
The driver can not be used on a platform with common clock framework
until clk_prepare/clk_unprepare calls are added, otherwise clk_enable
calls will fail and a WARN is generated:
# echo 1 > /sys/bus/platform/drivers/lpc32xx-pwm/4005c000.pwm/pwm/pwmchip0/pwm0/enable
------------[ cut here ]------------
WARNING: CPU: 0 PID: 701 at drivers/clk/clk.c:727 clk_core_enable+0x2c/0xa4()
Modules linked in: sc16is7xx
CPU: 0 PID: 701 Comm: sh Tainted: G W 4.3.0-rc2+ #171
Hardware name: LPC32XX SoC (Flattened Device Tree)
Backtrace:
[<>] (dump_backtrace) from [<>] (show_stack+0x18/0x1c)
[<>] (show_stack) from [<>] (dump_stack+0x20/0x28)
[<>] (dump_stack) from [<>] (warn_slowpath_common+0x90/0xb8)
[<>] (warn_slowpath_common) from [<>] (warn_slowpath_null+0x24/0x2c)
[<>] (warn_slowpath_null) from [<>] (clk_core_enable+0x2c/0xa4)
[<>] (clk_core_enable) from [<>] (clk_enable+0x24/0x38)
[<>] (clk_enable) from [<>] (lpc32xx_pwm_enable+0x1c/0x40)
[<>] (lpc32xx_pwm_enable) from [<>] (pwm_enable+0x48/0x5c)
[<>] (pwm_enable) from [<>] (pwm_enable_store+0x5c/0x78)
[<>] (pwm_enable_store) from [<>] (dev_attr_store+0x20/0x2c)
[<>] (dev_attr_store) from [<>] (sysfs_kf_write+0x44/0x50)
[<>] (sysfs_kf_write) from [<>] (kernfs_fop_write+0x134/0x194)
[<>] (kernfs_fop_write) from [<>] (__vfs_write+0x34/0xdc)
[<>] (__vfs_write) from [<>] (vfs_write+0xb8/0x140)
[<>] (vfs_write) from [<>] (SyS_write+0x50/0x90)
[<>] (SyS_write) from [<>] (ret_fast_syscall+0x0/0x38)
Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
LPC32xx SoC has two independent PWM controllers, they have different
clock parents, clock gates and even slightly different controls, and
each of these two PWM controllers has one output channel. Due to
almost similar controls arranged in a row it is incorrectly set that
there is one PWM controller with two channels, fix this problem, which
at the moment prevents separate configuration of different clock
parents and gates for both PWM controllers.
The change makes previous PWM device node description incompatible
with this update.
Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
A FTM PWM instance enables/disables three clocks: The bus clock, the
counter clock and the PWM clock. The bus clock gets enabled on
pwm_request, whereas the counter and PWM clocks will be enabled upon
pwm_enable.
The driver has three closesly related issues when enabling/disabling
clocks during suspend/resume:
- The three clocks are not treated differently in regards to the
individual PWM state enabled/requested. This can lead to clocks
getting disabled which have not been enabled in the first place
(a PWM channel which only has been requested going through
suspend/resume).
- When entering suspend, the current behavior relies on the
FTM_OUTMASK register: If a PWM output is unmasked, the driver
assumes the clocks are enabled. However, some PWM instances
have only 2 channels connected (e.g. Vybrid's FTM1). In that case,
the FTM_OUTMASK reads 0x3 if all channels are disabled, even if
the code wrote 0xff to it before. For those PWM instances, the
current approach to detect enabled PWM signals does not work.
- A third issue applies to the bus clock only, which can get enabled
multiple times (once for each PWM channel of a PWM chip). This is
fine, however when entering suspend mode, the clock only gets
disabled once.
This change introduces a different approach by relying on the enable
and prepared counters of the clock framework and using the frameworks
PWM signal states to address all three issues.
Clocks get disabled during suspend and back enabled on resume
regarding to the PWM channels individual state (requested/enabled).
Since we do not count the clock enables in the driver, this change no
longer clears the Status and Control registers Clock Source Selection
(FTM_SC[CLKS]). However, since we disable the selected clock anyway,
and we explicitly select the clock source on reenabling a PWM channel
this approach should not make a difference in practice.
Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Setting of PWM_SW_UPDATE is bit different in Intel Broxton compared to the
previous generation SoCs. Previously it was OK to set the bit many times
(from userspace via sysfs for example) before the PWM is actually enabled.
Starting from Intel Broxton it seems that we must set PWM_SW_UPDATE only
once before the PWM is enabled. Otherwise it is possible that the PWM does
not start properly.
Change the sequence of how PWM_SW_UPDATE is programmed so that we only set
it in pwm_lpss_config() when the PWM is already enabled. The initial
setting of PWM_SW_UPDATE will be done when PWM gets enabled. This should
make the driver work with the previous generation Intel SoCs and Broxton.
Add also small delay after the bit is set to let the hardware propagate it
properly.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
We have two users of core part right now. Let them to select core part
automatically.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
For Broxton PWM controller, base unit is defined as 8-bit integer
and 14-bit fraction, so need to update base unit setting to output
wave with right frequency.
Signed-off-by: Qipeng Zha <qipeng.zha@intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
It's possible that the PWM clock becomes an orphan. So better check the
result of clk_get_rate() in order to prevent a division by zero.
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Currently pwm-bcm2835 assumes a fixed clock rate and stores the
resulting scaler in the driver structure. But with the upcoming
PWM clock support for clk-bcm2835 the rate could change, so
calculate the scaler in the ->config() callback.
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The LPSS PWM driver calls pwm_lpss_disable() when the PWM device is
released (for example unexported from sysfs). This in turn calls
pm_runtime_put() which makes runtime PM count to be unbalanced if the
device has not been enabled at this point.
This is easy to reproduce:
# cd /sys/class/pwm/pwmchip0
# echo 0 > export
# echo 0 > unexport
The count is unbalanced and prevents the PWM device from being powered on
next time.
Fix this by removing ->free() callback. There are no resources to be
released anyway.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This round contains a couple of new drivers for the Marvell Berlin
family of SoCs, various SoCs from Renesas and Broadcom as well as the
backlight PWM present on MediaTek SoCs.
Further existing drivers are extended to support a wider range of
hardware.
The remaining patches are minor fixes and cleanups across the board.
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Merge tag 'pwm/for-4.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm
Pull pwm updates from Thierry Reding:
"This round contains a couple of new drivers for the Marvell Berlin
family of SoCs, various SoCs from Renesas and Broadcom as well as the
backlight PWM present on MediaTek SoCs.
Further existing drivers are extended to support a wider range of
hardware.
The remaining patches are minor fixes and cleanups across the board.
Note that one of the patches included in this pull request is against
arch/unicore32. I've included it here because I couldn't get a
response from Guan Xuetao and I consider the change low-risk.
Equivalent patches have been merged and tested in Samsung and PXA
trees. The goal is to finally get rid of legacy code paths that have
repeatedly been causing headaches"
* tag 'pwm/for-4.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm: (24 commits)
pwm: sunxi: Fix whitespace issue
pwm: sysfs: Make use of the DEVICE_ATTR_[RW][WO] macro's
pwm: sysfs: Remove unnecessary temporary variable
unicore32: nb0916: Use PWM lookup table
pwm: pwm-rcar: Revise the device tree binding document about compatible
pwm: Return -ENODEV if no PWM lookup match is found
pwm: sun4i: Add support for PWM controller on sun5i SoCs
pwm: Set enable state properly on failed call to enable
pwm: lpss: Add support for runtime PM
pwm: lpss: Add more Intel Broxton IDs
pwm: lpss: Support all four PWMs on Intel Broxton
pwm: lpss: Add support for multiple PWMs
pwm-pca9685: enable ACPI device found on Galileo Gen2
pwm: Add MediaTek display PWM driver support
dt-bindings: pwm: Add MediaTek display PWM bindings
pwm: tipwmss: Enable on TI DRA7x and AM437x
pwm: atmel-hlcdc: add sama5d2 SoC support.
pwm: Add Broadcom BCM7038 PWM controller support
Documentation: dt: add Broadcom BCM7038 PWM controller binding
pwm: Add support for R-Car PWM Timer
...
This patch changes no code, it just fixes the whitespacing. Operators
should be separated from operands by a single space.
Signed-off-by: Olliver Schinagl <oliver@schinagl.nl>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
For the npwm property the PWM sysfs interface already made use of the
DEVICE_ATTR_RO macro. This patch expands this to the other sysfs
properties so that the code base is concise and makes use of this
helpful macro.
This has the advantage of slightly reducing the code size, improving
readability and no longer using magic values for permissions.
Signed-off-by: Olliver Schinagl <oliver@schinagl.nl>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Use the result of pwm_is_enabled() directly instead of storing it in a
temporary variable.
Signed-off-by: Olliver Schinagl <oliver@schinagl.nl>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
When looking up a PWM using the lookup table, assume that all entries
will have been added already, so failure to find a match means that no
corresponding entry has been registered.
This fixes an issue where -EPROBE_DEFER would be returned if the PWM
lookup table is empty. After this fix, -EPROBE_DEFER is reserved for
situations where no provider has yet registered for a matching entry.
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The PWM controller on sun5i SoCs is identical to the one found on sun7i
SoCs. On the A13 package only one of the 2 pins is routed to the outside,
so only advertise one PWM channel there.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The pwm_enable() function didn't clear the enabled bit if a call to the
driver's ->enable() callback returned an error. The result was that the
state of the PWM core was wrong. Clearing the bit when enable returns
an error ensures the state is properly set.
Tested-by: Jonathan Richardson <jonathar@broadcom.com>
Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Jonathan Richardson <jonathar@broadcom.com>
[thierry.reding@gmail.com: add missing kerneldoc for the lock]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
To be able to save some power when PWM is not in use, add support for
runtime PM for this driver. This also allows the platform to transition to
low power S0ix states when the system is idle.
Signed-off-by: Huiquan Zhong <huiquan.zhong@intel.com>
Signed-off-by: Qipeng Zha <qipeng.zha@intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Add more Intel Broxton ACPI and PCI IDs to the driver supported devices
list.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Intel Broxton has similar PWM than Intel Braswell but instead of one it has
four PWMs included in one PCI/ACPI device. This patch adds support for all
the four PWMs and changes the PCI part of the driver to use
'pwm_lpss_bxt_info' instead.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
New Intel SoCs such as Broxton will have four PWMs per PCI (or ACPI)
device. Each PWM has 1k of register space allocated from the parent device.
Add support for this.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
There is a chip connected to i2c bus on Intel Galileo Gen2 board. Enable it via
ACPI ID INT3492.
Cc: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Add display PWM driver support to modify backlight for MT8173 and
MT6595. The PWM has one channel to control the brightness of the
display. When the (high_width / period) is closer to 1, the screen
is brighter; otherwise, it is darker.
Signed-off-by: YH Huang <yh.huang@mediatek.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
TIPWMSS is present on TI's DRA7x and AM437x SoCs. Enable its usage.
Instead of adding each SoC individually, use the more generic symbol
ARCH_OMAP2PLUS instead.
Signed-off-by: Vignesh R <vigneshr@ti.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Add sama5d2 hlcdc backlight PWM support. This chip doesn't have to deal with an
errata, so it's a simple addition of the mfd compatible string.
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Add support for the BCM7038-style PWM controller found in all BCM7xxx STB SoCs.
This controller has a hardcoded 2 channels per controller, and cascades a
variable frequency generator on top of a fixed frequency generator which offers
a range of a 148ns period all the way to ~622ms periods.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Commit dca1a4b5ff ("clk: at91: keep slow clk enabled to prevent system
hang") added a workaround for the slow clock as it is not properly handled
by its users.
Get and use the slow clock as it is necessary for the timer counters.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
This patch adds support for R-Car SoCs PWM Timer. The PWM timer of
R-Car H2 has 7 channels. So, we can use the channels if we describe
device tree nodes.
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Add a PWM controller driver for the Marvell Berlin SoCs. This PWM
controller has 4 channels.
Signed-off-by: Antoine Tenart <antoine.tenart@free-electrons.com>
Acked-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This platform driver has a OF device ID table but the OF module alias
information is not created so module autoloading won't work.
This patch adds the missing MODULE_DEVICE_TABLE() for OF to export that
information so modules have the correct aliases built-in and autoloading
works correctly.
A longer explanation by Javier Canillas can be found here:
https://lkml.org/lkml/2015/7/30/519
Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This set of changes introduces the beginnings of a new API that's based
around the concept of states that can be atomically applied. Drivers go
to various lengths to implement something similar, which indicates that
the core should really be providing the necessary framework.
On top of that, there is a bit of cleanup as well as improved kerneldoc
and integration into the device-drivers DocBook.
Regarding drivers there is a new one for the NXP LPC18xx family of SoCs
and a couple of fixes for existing drivers (pca9685, Broadcom Kona and
Atmel HLCDC).
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Merge tag 'pwm/for-4.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm
Pull pwm updates from Thierry Reding:
"This set of changes introduces the beginnings of a new API that's
based around the concept of states that can be atomically applied.
Drivers go to various lengths to implement something similar, which
indicates that the core should really be providing the necessary
framework.
On top of that, there is a bit of cleanup as well as improved
kerneldoc and integration into the device-drivers DocBook.
Regarding drivers there is a new one for the NXP LPC18xx family of
SoCs and a couple of fixes for existing drivers (pca9685, Broadcom
Kona and Atmel HLCDC)"
* tag 'pwm/for-4.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm:
ARM: at91: pwm: atmel-hlcdc: Add at91sam9n12 errata
pwm: Add NXP LPC18xx PWM/SCT DT binding documentation
pwm: NXP LPC18xx PWM/SCT driver
pwm-pca9685: Support changing the output frequency
pwm-pca9685: Fix several driver bugs
pwm: kona: Modify settings application sequence
pwm: pca9685: Drop owner assignment
pwm: Add to device-drivers documentation
pwm: Clean up kerneldoc
pwm: Remove useless whitespace
pwm: sysfs: Remove unnecessary padding
pwm: sysfs: Properly convert from enum to string
pwm: Make use of pwm_get_xxx() helpers where appropriate
pwm: Add pwm_get_polarity() helper function
pwm: Constify PWM device where possible
pwm: Add the pwm_is_enabled() helper
The errata for HLCDC PWM of at91sam9n12 are the same as for at91sam9x5.
Signed-off-by: Josh Wu <josh.wu@atmel.com>
Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This commit adds support for NXP LPC18xx PWM/SCT.
NXP LPC SoCs family, which includes LPC18xx/LPC43xx, provides a State
Configurable Timer (SCT) which can be configured as a Pulse Width
Modulator. Other SoCs in that family may share the same hardware.
The PWM supports a total of 16 channels, but only 15 can be simultaneously
requested. There's only one period, global to all the channels, thus PWM
driver will refuse setting different values to it, unless there's only one
channel requested.
Signed-off-by: Ariel D'Alessandro <ariel@vanguardiasur.com.ar>
[thierry.reding@gmail.com: remove excessive padding of fields]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Previously, period_ns and duty_ns were only used to determine the
ratio of ON and OFF time, the default frequency of 200 Hz was never
changed.
The PCA9685 however is capable of changing the PWM output frequency,
which is expected when changing the period.
This patch configures the prescaler accordingly, using the formula
and notes provided in the PCA9685 datasheet.
Bounds checking for the minimum and maximum frequencies, last updated
in revision v.4 of said datasheet, is also added.
The prescaler is only touched if the period changed, because we have to
put the chip into sleep mode to unlock the prescale register.
If it is changed, the PWM output frequency changes for all outputs,
because there is one prescaler per chip. This is documented in the
PCA9685 datasheet and in the comments.
If the duty cycle is not changed at the same time as the period, then
we restart the PWM output using the duty cycle to period ratio from
before the period change.
When using LEDs for example, previously set brightness levels stay the
same when the frequency changes.
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Signed-off-by: Clemens Gruber <clemens.gruber@pqgruber.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Problems:
- When duty_ns == period_ns, the full OFF bit was not cleared and the
PWM output of the PCA9685 stayed off.
- When duty_ns == period_ns and the catch-all channel was used, the
ALL_LED_OFF_L register was not cleared.
- The full ON bit was not cleared when setting the OFF time, therefore
the exact OFF time was ignored when setting a duty_ns < period_ns
Solution: Clear both OFF registers when setting full ON and clear the
full ON bit when changing the OFF registers.
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Signed-off-by: Clemens Gruber <clemens.gruber@pqgruber.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Update the driver so that settings are applied in accordance with the
most recent version of the hardware spec. The revised sequence clears
the trigger bit, waits 400ns, writes settings, sets the trigger bit,
and waits another 400ns. This corrects an issue where occasionally a
requested change was not properly reflected in the PWM output.
Reviewed-by: Arun Ramamurthy <arunrama@broadcom.com>
Reviewed-by: Scott Branden <sbranden@broadcom.com>
Tested-by: Scott Branden <sbranden@broadcom.com>
Reviewed-by: Tim Kryger <tim.kryger@gmail.com>
Signed-off-by: Jonathan Richardson <jonathar@broadcom.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
i2c_driver does not need to set an owner because i2c_register_driver()
will set it.
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Padding initializers so that assignment operators align is bound to lead
to inconsistencies or churn. Single spaces around the assignment is just
fine.
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The current code will check for polarity in a boolean way. While it is
correct that polarity is either normal or inversed, make it more obvious
that it's an enumeration by using a switch statement and explicit
matches on the enumeration values.
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The Crystalcove PMIC provides three PWM signals and this driver exports
one of them on the BYT platform which is used to control backlight for
DSI panel. This is platform device implementation of the drivers/mfd
cell device for CRC PMIC.
CC: Samuel Ortiz <sameo@linux.intel.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Alexandre Courbot <gnurou@gmail.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Paul Bolle <pebolle@tiscali.nl>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Tested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Shobhit Kumar <shobhit.kumar@intel.com>
Reviewed-by: Varka Bhadram <varkabhadram@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Use the pwm_get_xxx() helpers instead of directly accessing the fields
in struct pwm_device. This will allow us to smoothly move to the atomic
update approach.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Some PWM drivers are testing the PWMF_ENABLED flag. Create a helper
function to hide the logic behind enabled test. This will allow us to
smoothly move from the current approach to an atomic PWM update
approach.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This has a couple of fixes for Atmel, Samsung and Broadcom drivers. Some
preparatory patches for more upcoming Intel work is included as well.
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Merge tag 'pwm/for-4.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm
Pull pwm updates from Thierry Reding:
"This has a couple of fixes for Atmel, Samsung and Broadcom drivers.
Some preparatory patches for more upcoming Intel work is included as
well"
* tag 'pwm/for-4.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm:
pwm: lpss: pci: Add support for Broxton platform
pwm: bcm-kona: Don't set polarity in probe
pwm: Add pwmchip_add_with_polarity() API
pwm: atmel: Fix incorrect CDTY value after disabling
pwm: atmel: Fix incorrect CDTY value after enabling
pwm: samsung: Use MODULE_DEVICE_TABLE() to include OF modalias
pwm: Add support to remove registered consumer lookup tables
Omit setting the polarity to normal during probe and instead use the new
pwmchip_add_with_polarity() function to register a PWM chip with inverse
polarity by default for all channels to reflect the hardware default.
Signed-off-by: Arun Ramamurthy <arunrama@broadcom.com>
Reviewed-by: Ray Jui <rjui@broadcom.com>
Signed-off-by: Scott Branden <sbranden@broadcom.com>
Signed-off-by: Tim Kryger <tim.kryger@gmail.com>
Signed-off-by: Jonathan Richardson <jonathar@broadcom.com>
[thierry.reding@gmail.com: use pwmchip_add_with_polarity()]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Add a new function to register a PWM chip with channels that have their
initial polarity as specified by an additional parameter. This benefits
drivers of controllers that by default operate with inversed polarity
by removing the need to modify the polarity during initialization.
Signed-off-by: Tim Kryger <tim.kryger@gmail.com>
Signed-off-by: Jonathan Richardson <jonathar@broadcom.com>
[thierry.reding@gmail.com: export pwmchip_add_with_polarity()]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
pwm-leds calls .config() and .disable() in a row. This exhibits that it
may happen that the channel gets disabled before CDTY has been updated
with CUPD. The issue gets quite worse with long periods. So, ensure that
at least one period has past before disabling the channel by polling
ISR.
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Tested-by: Gaël PORTAY <gael.portay@gmail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
CUPD is not flushed before enabling the channel so it will update
CDTY/CPRD just after one period. So we always set CUPD, even when the
channel is not enabled.
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
If the pwm-samsung driver is built as a module, modalias information is
not filled so the module is not autoloaded. Use the MODULE_DEVICE_TABLE()
macro to export the OF device ID so the module contains that information.
Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The PWM hardware on Pistachio platform has a maximum timebase steps
value to 255. To fix it, let's introduce a compatible-specific
data structure to contain the SoC-specific details and use it to
specify a maximum timebase.
Also, let's limit the minimum timebase to 16 steps, to allow a sane
range of duty cycle steps.
Fixes: 277bb6a29e ("pwm: Imagination Technologies PWM DAC driver")
Signed-off-by: Naidu Tellapati <naidu.tellapati@imgtec.com>
Signed-off-by: Ezequiel Garcia <ezequiel.garcia@imgtec.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
In case some drivers are unloading, they can remove lookup tables which
they had registered during their load time to avoid redundant entries if
loaded again.
CC: Samuel Ortiz <sameo@linux.intel.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Alexandre Courbot <gnurou@gmail.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Shobhit Kumar <shobhit.kumar@intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
For platforms that don't support DT, some early MFD modules can register
lookup tables. Remove the __init annotation so that this works. This is
similar to gpio_add_lookup_table() which allows late additions.
CC: Samuel Ortiz <sameo@linux.intel.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Alexandre Courbot <gnurou@gmail.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Shobhit Kumar <shobhit.kumar@intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
When disabling the Samsung PWM the output state remains at the level it
was at the end of a PWM cycle. In other words, calling pwm_disable()
when at 100% duty cycle will keep the output active, while at all other
settings the output will go/stay inactive. On top of that the Samsung
PWM settings are double-buffered, which means the new settings only get
applied at the start of a new PWM cycle.
This results in a race if the PWM is at 100% duty cycle and a driver
calls:
pwm_config(pwm, 0, period);
pwm_disable(pwm);
In this case the PWMs output will unexpectedly stay active, unless a new
PWM cycle happened to start between the register writes in pwm_config()
and pwm_disable(). As far as I can tell this is a regression introduced
by 3bdf878, before that a call to pwm_config() would call
pwm_samsung_enable() which, while heavy-handed, made sure the expected
settings were live.
To resolve this, while not re-introducing the issues 3bdf878 (flickering
as the PWM got reset while in a PWM cycle) fixed, only force an update
of the settings when at 100% duty cycle, which shouldn't have any
noticeable effect on the output but is enough to ensure the behaviour is
as expected on disable.
Signed-off-by: Sjoerd Simons <sjoerd.simons@collabora.co.uk>
Reviewed-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Acked-by: Lukasz Majewski <l.majewski@samsung.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The driver computes which clock divider it sould be using from the
requested period. This computation assumes that the link between the
register value and the actual divider value is raising 2 to the power of
the registry value.
div = 1 << regvalue
This is true only for the first 5 values out of 8. Next values are 64,
256 and, 1024 - instead of 32, 64, 128.
This affects only the users requesting a period > 0.04369s.
Replace the computation with a look-up table.
Signed-off-by: Gaetan Hug <ghug@induct.be>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
sama5d4 SoC also has an errata on the HLCDC PWM. It is the same as the
sama5d3 that is forbidding the use of div1 prescaler.
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The regmap_config struct may be const because it is not modified by the
driver and regmap_init() accepts pointer to const.
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Instead of using the literal value for the number of nanoseconds per
second, use the macro instead to increase readability.
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The of_node_put() function tests whether its argument is NULL and then
returns immediately. Thus the test around the call is not needed.
This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The Pistachio SOC from Imagination Technologies includes a Pulse Width
Modulation DAC which produces 1 to 4 digital bit-outputs which represent
digital waveforms. These PWM outputs are primarily in charge of controlling
backlight LED devices.
Reviewed-by: Andrew Bresticker <abrestic@chromium.org>
Signed-off-by: Naidu Tellapati <Naidu.Tellapati@imgtec.com>
Signed-off-by: Sai Masarapu <Sai.Masarapu@imgtec.com>
Signed-off-by: Ezequiel Garcia <ezequiel.garcia@imgtec.com>
Reviewed-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
[thierry.reding: fixup license header as discussed on list]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This patch introduces a bitmap which is used to keep track of the
pwm channels which have been configured in a pwm chip.
The method used earlier to find the number of configured channels,
was to count the pwmdevices with PWMF_REQUESTED field set
and period value configured. This was not correct and failed
when of_pwm_get()/pwm_get() and then pwm_config() was used.
Signed-off-by: Ajit Pal Singh <ajitpal.singh@st.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This adds a generic PWM framework driver for the PWM controller
found on Allwinner SoCs.
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The slow and system clock should never return a rate of zero, but this
might happen if the clocks property defined in the DT is referencing the
wrong clocks.
Prevent any division by zero from happening by testing the clk_freq
value before calling do_div().
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The include/linux/clk.h header defines dummy implementations for the
various clk_*() functions if HAVE_CLK is not selected to improve build
coverage in randconfig builds.
The dummy implementation of clk_get_rate() returns 0, which causes the
Atmel HLCDC PWM driver's atmel_hlcdc_pwm_config() implementation to end
up calling:
do_div(clk_period_ns, 0)
On x86, do_div(n, base) will end up evaluating to this:
n >>= ilog2(base)
with base = 0, the implementation of ilog2() will call ____ilog2_NaN(),
which is purposely undefined and results in a linker failure:
ERROR: "____ilog2_NaN" [drivers/pwm/pwm-atmel-hlcdc.ko] undefined!
The implementation of do_div() checks that base is a power of 2 before
calling ilog2(). The compiler doesn't optimize this away, presumably
because is_power_of_2() is an inline function and the compiler doesn't
or can't inspect it closely enough. ilog2() being a macro it still ends
up generating the ____ilog2_NaN() because of the constant 0.
The root of the problem is that the driver really should be checking
before possibly dividing by zero. That should eventually be fixed, but
for now just assume that the clock runs at a sensible frequency when
available.
Reported-by: Jim Davis <jim.epost@gmail.com>
Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Lee Jones