The driver consists of core, PCI, and platform parts. It would be better
to split them into separate files.
The platform driver is now called pwm-lpss-platform. Thus, previously
set CONFIG_PWM_LPSS=m is not enough to build it. But we are on the safe
side since it seems no one from outside Intel is using it for now.
While here, move to use macros module_pci_driver() and
module_platform_driver().
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Alan Cox <alan@linux.intel.com>
[thierry.reding: change select to depends on PWM_LPSS, cleanup]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This driver supports all current STi platforms' PWM IPs.
Signed-off-by: Ajit Pal Singh <ajitpal.singh@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
[thierry.reding: rename module to pwm-sti, fix build breakage]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This commit adds a driver for the PWM controller found on Rockchip
RK29, RK30 and RK31 SoCs.
Signed-off-by: Beniamino Galvani <b.galvani@gmail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Add support for the six-channel Kona PWM controller found on Broadcom
mobile SoCs like bcm281xx.
Signed-off-by: Tim Kryger <tim.kryger@linaro.org>
Reviewed-by: Alex Elder <elder@linaro.org>
Reviewed-by: Markus Mayer <markus.mayer@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Add support for Intel Low Power I/O subsystem PWM controllers found on
Intel BayTrail SoC.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Chew, Kean Ho <kean.ho.chew@intel.com>
Signed-off-by: Chang, Rebecca Swee Fun <rebecca.swee.fun.chang@intel.com>
Signed-off-by: Chew, Chiau Ee <chiau.ee.chew@intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Add a new driver for the ARM CLPS711X Pulse Width Modulator (PWM) interface.
This CPU contain two 4-bit PWM outputs with constant period, based on CPU
PLL frequency. PWM polarity is determined by hardware by power on reset.
Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The FTM PWM device can be found on Vybrid VF610 Tower and
Layerscape LS-1 SoCs.
Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com>
Signed-off-by: Alison Wang <b18965@freescale.com>
Signed-off-by: Jingchang Lu <b35083@freescale.com>
Reviewed-by: Sascha Hauer <s.hauer@pengutronix.de>
Reviewed-by: Yuan Yao <yao.yuan@freescale.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The patches for this release cycle include various enhancements (device
tree support, better compile coverage, ...) for existing drivers. There
is a new driver for Atmel SoCs.
Various drivers as well as the sysfs support received minor fixes and
cleanups.
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.0.22 (GNU/Linux)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=Rq3R
-----END PGP SIGNATURE-----
Merge tag 'pwm/for-3.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm
Pull pwm changes from Thierry Reding:
"The patches for this release cycle include various enhancements
(device tree support, better compile coverage, ...) for existing
drivers. There is a new driver for Atmel SoCs.
Various drivers as well as the sysfs support received minor fixes and
cleanups"
* tag 'pwm/for-3.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm:
pwm: tiecap: Remove duplicate put_sync call
pwm: tiehrpwm: use dev_err() instead of pr_err()
pwm: pxa: remove unnecessary space before tabs
pwm: ep93xx: split module author names
pwm: use seq_puts() instead of seq_printf()
pwm: atmel-pwm: Do not unprepare clock after successful registration
of: Add Atmel PWM controller device tree binding
pwm: atmel-pwm: Add Atmel PWM controller driver
backlight: pwm_bl: Remove error message upon devm_kzalloc() failure
pwm: pca9685: depends on I2C rather than REGMAP_I2C
pwm: renesas-tpu: Enable driver compilation with COMPILE_TEST
pwm: jz4740: Use devm_clk_get()
pwm: jz4740: Pass device to clk_get()
pwm: sysfs: Convert to use ATTRIBUTE_GROUPS macro
pwm: pxa: Add device tree support
This is the other of the LP3943 MFD driver.
LP3943 can be used as a PWM generator, up to 2 channels.
* Two PWM generators supported
* Supported PWM operations
request, free, config, enable and disable
* Pin assignment
A driver data, 'pin_used' is checked when a PWM is requested.
If the output pin is already assigned, then returns as failure.
If the pin is available, 'pin_used' is set.
When the PWM is not used anymore, then it is cleared.
It is defined as unsigned long type for atomic bit operation APIs,
but only LSB 16bits are used because LP3943 has 16 outputs.
Signed-off-by: Milo Kim <milo.kim@ti.com>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Add a PWM framework driver for the PWM controller found on Atmel SoCs.
Signed-off-by: Bo Shen <voice.shen@atmel.com>
Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
[thierry.reding: coding style and other minor cleanups]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Remove the non-standard EP93xx PWM driver in drivers/misc and add
a new driver for the PWM controllers on the EP93xx platform based
on the PWM framework.
These PWM controllers each support 1 PWM channel with programmable
duty cycle, frequency, and polarity inversion.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ryan Mallon <rmallon@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
The Timer Pulse Unit (TPU) is a 4-channels 16-bit timer used to generate
waveforms. This driver exposes PWM functions through the PWM API for
other drivers to use.
The code is loosely based on the leds-renesas-tpu driver by Magnus Damm
and the TPU PWM driver shipped in the Armadillo EVA 800 kernel sources.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Tested-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Add a simple sysfs interface to the generic PWM framework.
/sys/class/pwm/
`-- pwmchipN/ for each PWM chip
|-- export (w/o) ask the kernel to export a PWM channel
|-- npwm (r/o) number of PWM channels in this PWM chip
|-- pwmX/ for each exported PWM channel
| |-- duty_cycle (r/w) duty cycle (in nanoseconds)
| |-- enable (r/w) enable/disable PWM
| |-- period (r/w) period (in nanoseconds)
| `-- polarity (r/w) polarity of PWM (normal/inversed)
`-- unexport (w/o) return a PWM channel to the kernel
Based on work by Lars Poeschel.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Lars Poeschel <poeschel@lemonage.de>
Cc: Ryan Mallon <rmallon@gmail.com>
Cc: Rob Landley <rob@landley.net>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Add pwm driver for the NXP pca9685 16 channel pwm-led controller.
The driver is really barebones at this stage. E.g. the OE' pin and
therefore the corresponding registers are not supported.
The driver was tested on a HW where this pin is tied to GND.
Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
[thierry.reding@gmail.com: style and whitespace cleanups]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This patch adds a PWM driver based on Atmel Timer Counter Block. The
Timer Counter Block is used in Waveform generator mode.
A Timer Counter Block provides up to 6 PWM devices grouped by 2:
* group 0 = PWM 0 and 1
* group 1 = PWM 2 and 3
* group 2 = PMW 4 and 5
PWM devices in a given group must be configured with the same period
value. If a PWM device in a group tries to change the period value and
the other device is already configured with a different value an error
will be returned.
This driver requires device tree support. The Timer Counter Block number
used to create a PWM chip is given by the tc-block field in an
"atmel,tcb-pwm" compatible node.
This patch was tested on kizbox board (at91sam9g20 SoC) with pwm-leds.
Signed-off-by: Boris BREZILLON <linux-arm@overkiz.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
This driver only supported the Charging indicator LED.
New set of drivers going to provide support for both PWMs and LEDs for twl4030
and twl6030 series of PMICs.
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
The driver supports the following LED outputs as generic PWM driver:
TWL4030 LEDA and LEDB (PWMA and PWMB)
TWL6030 Charging indicator LED (PWM LED)
On TWL6030 when the PWM requested LED is configured to be controlled by SW.
In this case the user can enable/disable and set the duty period freely.
When the PWM has been freed, the LED driver is put back to HW control.
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
The driver supports the following PWM outputs:
TWL4030 PWM0 and PWM1
TWL6030 PWM1 and PWM2
On TWL4030 the PWM signals are muxed. Upon requesting the PWM the driver
will select the correct mux so the PWM can be used. When the PWM has been
freed the original configuration is going to be restored.
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
In some platforms (like am33xx), PWM sub modules (ECAP, EHRPWM, EQEP)
are integrated to PWM subsystem. These PWM submodules has resources
shared and only one register bit-field is provided to control
module/clock enable/disable, makes it difficult to handle common
resources from independent PWMSS submodule drivers.
So the solution here implemented in this patch is, to create driver for
PWMSS and take the role of parent driver for PWM submodules. PWMSS
parent driver enumerates all the child nodes under PWMSS module. Also
symbol "pwmss_submodule_state_change" exported to enable clock gating
for individual PWMSS submodules, and submodule drivers has to enable
clock gating from their drivers.
As this is only supported during DT boot, the parent/child relationship
is created and populated in DT execution flow. The only required change
is inside DTS file, making EHRPWM & ECAP as a child to PWMSS node.
Signed-off-by: Philip, Avinash <avinashphilip@ti.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Add support for PWM chips present on SPEAr platforms. These PWM
chips support 4 channel output with programmable duty cycle and
frequency.
More details on these PWM chips can be obtained from relevant
chapter of reference manual, present at following[1] location.
1. http://www.st.com/internet/mcu/product/251211.jsp
Cc: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: Shiraz Hashim <shiraz.hashim@st.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Vipin Kumar <vipin.kumar@st.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
All legacy PWM providers have now been moved to the PWM subsystem. The
plan for 3.8 is to adapt all board files to provide a lookup table for
PWM devices in order to get rid of the global namespace. Subsequently,
users of the legacy pwm_request() and pwm_free() functions can be
migrated to the new pwm_get() and pwm_put() functions. Once this has
been completed, the legacy API and the compatibility code in the core
can be removed.
In addition to the above, these changes also add support for configuring
the polarity of a PWM signal (currently only supported on ECAP and
EHRPWM) and include a much needed rework of the i.MX driver. Managed
functions to obtain and release a PWM device (devm_pwm_get() and
devm_pwm_put()) have been added and the pwm-backlight driver has been
updated to use them. If the PWM subsystem hasn't been enabled, dummy
functions are provided that allow the subsystem to safely compile out.
Some common checks on input parameters have been moved to the core and
removed from the drivers. Finally, a small fix corrects the description
of the PWM specifier's second cell in the device tree representation.
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.0.19 (GNU/Linux)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=MQ5V
-----END PGP SIGNATURE-----
Merge tag 'for-3.7-rc1' of git://gitorious.org/linux-pwm/linux-pwm
Pull pwm changes from Thierry Reding:
"All legacy PWM providers have now been moved to the PWM subsystem.
The plan for 3.8 is to adapt all board files to provide a lookup table
for PWM devices in order to get rid of the global namespace.
Subsequently, users of the legacy pwm_request() and pwm_free()
functions can be migrated to the new pwm_get() and pwm_put()
functions. Once this has been completed, the legacy API and the
compatibility code in the core can be removed.
In addition to the above, these changes also add support for
configuring the polarity of a PWM signal (currently only supported on
ECAP and EHRPWM) and include a much needed rework of the i.MX driver.
Managed functions to obtain and release a PWM device (devm_pwm_get()
and devm_pwm_put()) have been added and the pwm-backlight driver has
been updated to use them. If the PWM subsystem hasn't been enabled,
dummy functions are provided that allow the subsystem to safely
compile out.
Some common checks on input parameters have been moved to the core and
removed from the drivers. Finally, a small fix corrects the
description of the PWM specifier's second cell in the device tree
representation."
* tag 'for-3.7-rc1' of git://gitorious.org/linux-pwm/linux-pwm: (23 commits)
pwm: dt: Fix description of second PWM cell
pwm: Check for negative duty-cycle and period
pwm: Add Ingenic JZ4740 support
MIPS: JZ4740: Export timer API
pwm: Move PUV3 PWM driver to PWM framework
unicore32: pwm: Use managed resource allocations
unicore32: pwm: Remove unnecessary indirection
unicore32: pwm: Use module_platform_driver()
unicore32: pwm: Properly remap memory-mapped registers
pwm-backlight: Use devm_pwm_get() instead of pwm_get()
pwm: Move AB8500 PWM driver to PWM framework
pwm: Fix compilation error when CONFIG_PWM is not defined
pwm: i.MX: fix clock lookup
pwm: i.MX: use per clock unconditionally
pwm: i.MX: add devicetree support
pwm: i.MX: Use module_platform_driver
pwm: i.MX: add functions to enable/disable pwm.
pwm: i.MX: remove unnecessary if in pwm_[en|dis]able
pwm: i.MX: factor out SoC specific functions
pwm: pwm-tiehrpwm: Add support for configuring polarity of PWM
...
This commit moves the driver to drivers/pwm and converts it to the new
PWM framework.
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Tested-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
This commit moves the driver to drivers/pwm and converts it to the new
PWM framework.
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Tested-by: Qin Rui <qinrui@mprc.pku.edu.cn>
Acked-by: Guan Xuetao <gxt@mprc.pku.edu.cn>
This commit moves the driver to drivers/pwm and converts it to the new
PWM framework.
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Arun Murthy <arun.murthy@stericsson.com>
This commit moves the driver to drivers/pwm and converts it to the new
PWM framework. In order for this to work properly, register the PWM as
child of the multi-function TWL6030 device.
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Enhanced high resolution PWM module (EHRPWM) hardware can be used to
generate PWM output over 2 channels. This commit adds PWM driver support
for EHRPWM device present on AM33XX SOC. Current implementation supports
simple PWM functionality.
Reviewed-by: Vaibhav Bedia <vaibhav.bedia@ti.com>
Signed-off-by: Philip, Avinash <avinashphilip@ti.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
ECAP hardware on AM33XX SOC supports auxiliary PWM (APWM) feature. This
commit adds PWM driver support for ECAP hardware on AM33XX SOC.
In the ECAP hardware, each PWM pin can also be configured to be in
capture mode. Current implementation only supports PWM mode of
operation. Also, hardware supports sync between multiple PWM pins but
the driver supports simple independent PWM functionality.
Reviewed-by: Vaibhav Bedia <vaibhav.bedia@ti.com>
Signed-off-by: Philip, Avinash <avinashphilip@ti.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Move the driver to drivers/pwm/ and convert it to use the framework.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Alexey Charkov <alchark@gmail.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Move the driver to drivers/pwm/ and convert it to use the framework.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Kukjin Kim <kgene.kim@samsung.com>
[eric@eukrea.com: fix pwmchip_add return code test]
Signed-off-by: Eric Bénard <eric@eukrea.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Move the driver to drivers/pwm/ and convert it to use the framework.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
[eric@eukrea.com: set chip.dev to prevent probe failure]
[eric@eukrea.com: fix pwmchip_add return code test]
Signed-off-by: Eric Bénard <eric@eukrea.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
This commit moves the PXA PWM driver to the drivers/pwm subdirectory and
converts it to use the new PWM framework.
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
This commit moves the Blackfin PWM driver to the drivers/pwm sub-
directory and converts it to register with the new PWM framework.
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
This commit adds a generic PWM framework driver for the PWFM controller
found on NVIDIA Tegra SoCs. The driver is based on code from the
Chromium kernel tree and was originally written by Gary King (NVIDIA)
and later modified by Simon Que (Chromium).
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
This patch adds framework support for PWM (pulse width modulation) devices.
The is a barebone PWM API already in the kernel under include/linux/pwm.h,
but it does not allow for multiple drivers as each of them implements the
pwm_*() functions.
There are other PWM framework patches around from Bill Gatliff. Unlike
his framework this one does not change the existing API for PWMs so that
this framework can act as a drop in replacement for the existing API.
Why another framework?
Several people argue that there should not be another framework for PWMs
but they should be integrated into one of the existing frameworks like led
or hwmon. Unlike these frameworks the PWM framework is agnostic to the
purpose of the PWM. In fact, a PWM can drive a LED, but this makes the
LED framework a user of a PWM, like already done in leds-pwm.c. The gpio
framework also is not suitable for PWMs. Every gpio could be turned into
a PWM using timer based toggling, but on the other hand not every PWM hardware
device can be turned into a gpio due to the lack of hardware capabilities.
This patch does not try to improve the PWM API yet, this could be done in
subsequent patches.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net>
Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Reviewed-by: Shawn Guo <shawn.guo@linaro.org>
[thierry.reding@avionic-design.de: fixup typos, kerneldoc comments]
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Andy Shevchenko