Commit Graph

117 Commits

Author SHA1 Message Date
Uwe Kleine-König c73a310762 pwm: Handle .get_state() failures
This suppresses diagnosis for PWM_DEBUG routines and makes sure that
pwm->state isn't modified in pwm_device_request() if .get_state() fails.

Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20221130152148.2769768-12-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2022-12-06 12:46:29 +01:00
Uwe Kleine-König 3dae106f4c pwm/tracing: Also record trace events for failed API calls
Record and report an error code for the events. This allows to report
about failed calls without ambiguity and so gives a more complete
picture.

Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20221130152148.2769768-3-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2022-12-06 12:46:23 +01:00
Andy Shevchenko 55f363e19c pwm: core: Remove S_IFREG from debugfs_create_file()
The debugfs_create_file() already has a check and adds S_IFREG
automatically. Remove unneeded flag.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20221117165812.27757-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2022-12-06 12:46:07 +01:00
Uwe Kleine-König fa1b9aa449 pwm: Don't initialize list head before calling list_add()
list_add() just overwrites the members of the element to add (here:
chip->list) without any checks, even in the DEBUG_LIST case. So save the
effort to initialize the list.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20221117211143.3817381-5-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2022-12-06 12:46:07 +01:00
Uwe Kleine-König 4034e59448 pwm: Mark free pwm IDs as used in alloc_pwms()
alloc_pwms() only identified a free range of IDs and this range was marked
as used only later by pwmchip_add(). Instead let alloc_pwms() already do
the marking (which makes the function actually allocating the range and so
justifies the function name). This way access to the allocated_pwms
bitfield is limited to two functions only.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20221117211143.3817381-4-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2022-12-06 12:46:06 +01:00
Uwe Kleine-König c8135b5174 pwm: Reduce time the pwm_lock mutex is held in pwmchip_add()
This simplifies error handling as the need for goto error handling goes
away and at the end of the function the code can be simplified as this
code isn't used in the error case any more.

Now memory allocation and the call to of_pwmchip_add() are done without
holding the lock. Both don't access the data structures protected by
&pwm_lock.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20221117211143.3817381-3-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2022-12-06 12:46:06 +01:00
Uwe Kleine-König e51b156b18 pwm: Document variables protected by pwm_lock
To simplify validation of the used locking, document for the global pwm
mutex what it actually protects against concurrent access. Also note for
two functions modifying these that pwm_lock is held by the caller.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20221117211143.3817381-2-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2022-12-06 12:46:05 +01:00
Linus Torvalds 3fb55dd140 pwm: Changes for v6.1-rc1
The Rockchip and Mediatek drivers gain support for more chips and the
 LPSS driver undergoes some refactoring and receives some improvements.
 Other than that there are various cleanups of the core.
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Merge tag 'pwm/for-6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm

Pull pwm updates from Thierry Reding:
 "The Rockchip and Mediatek drivers gain support for more chips and the
  LPSS driver undergoes some refactoring and receives some improvements.

  Other than that there are various cleanups of the core"

* tag 'pwm/for-6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm:
  pwm: sysfs: Replace sprintf() with sysfs_emit()
  pwm: core: Replace custom implementation of device_match_fwnode()
  pwm: lpss: Add a comment to the bypass field
  pwm: lpss: Make use of bits.h macros for all masks
  pwm: lpss: Use DEFINE_RUNTIME_DEV_PM_OPS() and pm_ptr() macros
  pwm: lpss: Use device_get_match_data() to get device data
  pwm: lpss: Move resource mapping to the glue drivers
  pwm: lpss: Move exported symbols to PWM_LPSS namespace
  pwm: lpss: Deduplicate board info data structures
  dt-bindings: pwm: Add compatible for Mediatek MT8188
  dt-bindings: pwm: rockchip: Add rockchip,rk3128-pwm
  dt-bindings: pwm: rockchip: Add description for rk3588
  pwm: sysfs: Switch to DEFINE_SIMPLE_DEV_PM_OPS() and pm_sleep_ptr()
  pwm: rockchip: Convert to use dev_err_probe()
2022-10-07 11:32:10 -07:00
Andy Shevchenko b431980286 pwm: core: Replace custom implementation of device_match_fwnode()
Replace custom implementation of the device_match_fwnode(). This hides
the implementation details and makes future changes easier.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2022-09-28 16:54:25 +02:00
Andy Shevchenko b5ae0ad564 pwm: core: Make of_pwm_get() static
There are no users outside of PWM core of the of_pwm_get().
Make it static.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20220826172642.16404-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2022-09-19 06:17:05 -07:00
Andy Shevchenko b88c48bfdd pwm: core: Get rid of unused devm_of_pwm_get()
The devm_of_pwm_get() has recently lost its single user, drop
the dead API as well.

Note, the new code should use either plain pwm_get() or managed
devm_pwm_get() or devm_fwnode_pwm_get() APIs.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20220826172642.16404-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2022-09-19 06:17:05 -07:00
Uwe Kleine-König 0829c35dc5 pwm: Drop support for legacy drivers
There are no drivers left providing the legacy callbacks. So drop
support for these.

If this commit breaks your out-of-tree pwm driver, look at e.g. commit
ec00cd5e63 ("pwm: renesas-tpu: Implement .apply() callback") for an
example of the needed conversion for your driver.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2022-06-22 15:31:13 +02:00
Linus Torvalds 41652aae67 pwm: Changes for v5.17-rc1
This contains a number of nice cleanups and improvements for the core
 and various drivers as well as a minor tweak to the json-schema device
 tree bindings.
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Merge tag 'pwm/for-5.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm

Pull pwm updates from Thierry Reding:
 "This contains a number of nice cleanups and improvements for the core
  and various drivers, as well as a minor tweak to the json-schema
  device tree bindings"

* tag 'pwm/for-5.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm:
  dt-bindings: pwm: Avoid selecting schema on node name match
  pwm: img: Use only a single idiom to get a runtime PM reference
  pwm: vt8500: Implement .apply() callback
  pwm: img: Implement .apply() callback
  pwm: twl: Implement .apply() callback
  pwm: Restore initial state if a legacy callback fails
  pwm: Prevent a glitch for legacy drivers
  pwm: Move legacy driver handling into a dedicated function
2022-01-20 13:25:01 +02:00
Thomas Zimmermann a713ca234e Merge drm/drm-next into drm-misc-next
Backmerging from drm/drm-next for v5.16-rc1.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
2021-11-18 09:36:39 +01:00
Uwe Kleine-König e45a178e9e pwm: Restore initial state if a legacy callback fails
It is not entirely accurate to go back to the initial state after e.g.
.enable() failed, as .config() still modified the hardware, but this same
inconsistency exists for drivers that implement .apply().

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2021-11-17 17:10:42 +01:00
Uwe Kleine-König 92f69e582e pwm: Prevent a glitch for legacy drivers
If a running PWM is reconfigured to disabled calling the ->config()
callback before disabling the hardware might result in a glitch where
the (maybe) new period and duty_cycle are visible on the output before
disabling the hardware.

So handle disabling before calling ->config(). Also exit early in this case
which is possible because period and duty_cycle don't matter for disabled PWMs.
In return however ->config has to be called even if state->period ==
pwm->state.period && state->duty_cycle != pwm->state.duty_cycle because setting
these might have been skipped in the previous call.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2021-11-17 17:09:22 +01:00
Uwe Kleine-König 77965c98cf pwm: Move legacy driver handling into a dedicated function
There is no change in behaviour, only some code is moved from
pwm_apply_state to a separate function.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2021-11-17 17:09:08 +01:00
Uwe Kleine-König 4ad91a2278 pwm: Make it explicit that pwm_apply_state() might sleep
At least some implementations sleep. So mark pwm_apply_state() with a
might_sleep() to make callers aware. In the worst case this uncovers a
valid atomic user, then we revert this patch and at least gained some more
knowledge and then can work on a concept similar to
gpio_get_value/gpio_get_value_cansleep.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2021-11-05 11:51:41 +01:00
Bjorn Andersson 3ab7b6ac5d
pwm: Introduce single-PWM of_xlate function
The existing pxa driver and the upcoming addition of PWM support in the
TI sn565dsi86 DSI/eDP bridge driver both has a single PWM channel and
thereby a need for a of_xlate function with the period as its single
argument.

Introduce a common helper function in the core that can be used as
of_xlate by such drivers and migrate the pxa driver to use this.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Tested-by: Steev Klimaszewski <steev@kali.org>
Tested-By: Steev Klimaszewski <steev@kali.org>
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20211025170925.3096444-1-bjorn.andersson@linaro.org
2021-10-27 17:02:33 +02:00
Uwe Kleine-König 8083f58d08 pwm: Make pwmchip_remove() return void
Since some time pwmchip_remove() always returns 0 so the return value
isn't usefull. Now that all callers are converted to ignore its value
the function can be changed to return void.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2021-09-02 21:38:56 +02:00
Colin Ian King bebedf2bb4 pwm: Remove redundant assignment to pointer pwm
The pointer pwm is being initialized with a value that is never read and
it is being updated later with a new value. The initialization is
redundant and can be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2021-07-07 21:43:32 +02:00
Andy Shevchenko 9ae241d06e pwm: core: Simplify some devm_*pwm*() functions
Use devm_add_action_or_reset() instead of devres_alloc() and
devres_add(), which works the same. This will simplify the
code. There is no functional changes.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2021-06-30 19:12:19 +02:00
Andy Shevchenko c333b936c1 pwm: core: Remove unused devm_pwm_put()
There are no users and seems no will come of the devm_pwm_put().
Remove the function.

While at it, slightly update documentation.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2021-06-30 19:12:19 +02:00
Andy Shevchenko e625fb70a6 pwm: core: Unify fwnode checks in the module
Historically we have two different approaches on how to check type of fwnode.
Unify them using the latest and greatest fwnode related APIs.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2021-06-30 19:12:19 +02:00
Andy Shevchenko e5c38ba9f2 pwm: core: Reuse fwnode_to_pwmchip() in ACPI case
In ACPI case we may use matching by fwnode as provided via
fwnode_to_pwmchip(). This makes device_to_pwmchip() not needed
anymore.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2021-06-30 19:12:19 +02:00
Andy Shevchenko ca06616b1e pwm: core: Convert to use fwnode for matching
When we traverse the list of the registered PWM controllers,
use fwnode to match. This will help for further cleanup.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2021-06-30 19:12:19 +02:00
Uwe Kleine-König ad5e085c63 pwm: Drop irrelevant error path from pwmchip_remove()
Since the PWM core uses device links (commit b2c200e3f2 ("pwm: Add
consumer device link")) each consumer driver that requested the PWMs is
already gone. If they called pwm_put() (as they should) the
PWMF_REQUESTED bit is not set. If they failed (which is a bug) the
PWMF_REQUESTED bit might still be set, but the driver that cared is
gone, so nothing bad happens if the PWM chip goes away even if the
PWMF_REQUESTED is still present.

So the check can be dropped.

With this change pwmchip_remove() returns always 0, so lowlevel drivers
don't need to check the return code any more. Once all drivers dropped
this check this function can be changed to return void.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2021-06-28 13:27:01 +02:00
Uwe Kleine-König bcda91bf86 pwm: Add a device-managed function to add PWM chips
This potentially simplifies low-level PWM drivers.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2021-06-28 13:17:48 +02:00
Clemens Gruber 9e40ee18a1 pwm: core: Support new usage_power setting in PWM state
If usage_power is set, the PWM driver is only required to maintain
the power output but has more freedom regarding signal form.

If supported, the signal can be optimized, for example to
improve EMI by phase shifting individual channels.

Signed-off-by: Clemens Gruber <clemens.gruber@pqgruber.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2021-06-04 11:43:52 +02:00
Uwe Kleine-König 69230cfac3 pwm: Autodetect default value for of_pwm_n_cells from device tree
This allows to simplify all drivers that use three pwm-cells.
The only ugly side effect is that if a driver specified of_pwm_n_cells = 2
it suddenly supports device trees that use #pwm-cells = <3>. This however
isn't a bad thing because the driver doesn't need explicit support for
three cells as the core handles all the details. Also there is no such
in-tree driver.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2021-05-25 18:18:25 +02:00
Uwe Kleine-König 5447e78336 pwm: Drop of_pwm_simple_xlate() in favour of of_pwm_xlate_with_flags()
Since the previous commit the latter function can do everything that the
former does. So simplify accordingly.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2021-05-25 18:18:07 +02:00
Uwe Kleine-König cf38c978cf pwm: Make of_pwm_xlate_with_flags() work with #pwm-cells = <2>
The two functions of_pwm_simple_xlate() and of_pwm_xlate_with_flags()
are quite similar. of_pwm_simple_xlate() only supports two-cell PWM
specifiers while of_pwm_xlate_with_flags() only supports PWM specifiers
with 3 or more cells. The latter can easily be modified to behave
identically to of_pwm_simple_xlate() for two-cell PWM specifiers. This
is implemented here and allows to drop of_pwm_simple_xlate() in the next
commit.

There is a small detail that is different now in the two-cell specifier
case in of_pwm_xlate_with_flags(): pwm->args.polarity is unconditionally
initialized to PWM_POLARITY_NORMAL in the latter. I didn't find a case
where this matters and doing that explicitly is the more robust
approach.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
[thierry.reding@gmail.com: fix up checkpatch warnings]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2021-05-25 18:13:51 +02:00
Uwe Kleine-König 9666cec380 pwm: Drop function pwmchip_add_with_polarity()
pwmchip_add() only calls pwmchip_add_with_polarity() and nothing else. All
other users of pwmchip_add_with_polarity() are gone. So drop
pwmchip_add_with_polarity() and move the code instead to pwmchip_add().

The initial assignment to pwm->state.polarity is dropped. In every correct
usage of the PWM API this value is overwritten later anyhow.

Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2021-03-22 12:31:32 +01:00
Uwe Kleine-König d58cb0ee51 pwm: Return -EINVAL for old-style drivers without .set_polarity callback
Since commit 2b1c1a5d51 ("pwm: Use -EINVAL for unsupported polarity")
all drivers implementing the apply callback are unified to return
-EINVAL if an unsupported polarity is requested. Do the same in the
compat code for old-style drivers.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2021-03-22 11:55:20 +01:00
Uwe Kleine-König f9a8ee8c8b pwm: Always allocate PWM chip base ID dynamically
Since commit 5e5da1e9fb ("pwm: ab8500: Explicitly allocate pwm chip
base dynamically") all drivers use dynamic ID allocation explicitly. New
drivers are supposed to do the same, so remove support for driver
specified base IDs and drop all assignments in the low-level drivers.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2021-03-22 11:53:00 +01:00
Soham Biswas 765edf0bf0 pwm: core: Use octal permission
Permission bits are easier readable in octal than with using the
symbolic names.

Fixes the following warning generated by checkpatch:

    WARNING: Symbolic permissions 'S_IRUGO' are not preferred. Consider using octal permissions '0444'.
    #1341: FILE: drivers/pwm/core.c:1341:
    +       debugfs_create_file("pwm", S_IFREG | S_IRUGO, NULL, NULL,

Signed-off-by: Soham Biswas <sohambiswas41@gmail.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2020-12-17 14:19:00 +01:00
Liu Shixin f339e79bae pwm: Convert to use DEFINE_SEQ_ATTRIBUTE macro
Use DEFINE_SEQ_ATTRIBUTE macro to simplify the code.

Signed-off-by: Liu Shixin <liushixin2@huawei.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2020-09-24 09:18:09 +02:00
Guru Das Srinagesh a9d887dc1c pwm: Convert period and duty cycle to u64
Because period and duty cycle are defined as ints with units of
nanoseconds, the maximum time duration that can be set is limited to
~2.147 seconds. Change their definitions to u64 in the structs of the
PWM framework so that higher durations may be set.

Also use the right format specifiers in debug prints in both core.c,
pwm-stm32-lp.c as well as video/fbdev/ssd1307fb.c.

Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Guru Das Srinagesh <gurus@codeaurora.org>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2020-06-17 20:42:11 +02:00
Kees Cook f5641d053d pwm: Add missing "CONFIG_" prefix
The IS_ENABLED() use was missing the CONFIG_ prefix which would have
lead to skipping this code.

Fixes: 3ad1f3a332 ("pwm: Implement some checks for lowlevel drivers")
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2020-06-04 19:09:28 +02:00
Christophe JAILLET db539cb928 pwm: Add missing '\n' in log messages
Message logged by 'dev_xxx()' or 'pr_xxx()' should end with a '\n'.

Fixes: 3ad1f3a332 ("pwm: Implement some checks for lowlevel drivers")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2020-04-14 15:57:51 +02:00
Jason Yan 374c1104eb pwm: Make pwm_apply_state_debug() static
Fix the following gcc warning:

    drivers/pwm/core.c:467:6: warning: symbol 'pwm_apply_state_debug' was
        not declared. Should it be static?

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Jason Yan <yanaijie@huawei.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2020-04-03 21:41:09 +02:00
Uwe Kleine-König 3ad1f3a332 pwm: Implement some checks for lowlevel drivers
There are some expectations which the callbacks provided by lowlevel
drivers should fulfill. Implement checks that help driver authors to get
these semantics right. As these have some overhead the checks can be
disabled using a Kconfig setting.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2020-03-30 16:55:26 +02:00
Uwe Kleine-König 1188829abc pwm: Implement tracing for .get_state() and .apply_state()
This allows to log all calls to the driver's lowlevel functions which
simplifies debugging in some cases.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2020-01-20 12:28:37 +01:00
Thierry Reding cfc4c189bc pwm: Read initial hardware state at request time
Drivers that support reading the hardware state (using ->get_state())
may want to rely on per-PWM data to do so. Defer reading the hardware
state for the first time until the PWM has been requested and after
drivers have had a chance to allocate per-PWM data.

Conceptually this is also a more natural place to read the hardware
state because the PWM core doesn't need to know the hardware state of a
PWM unless there is a user for it. This also ensures that the state is
read everytime a user requests a PWM. If the PWM changes between users
for some reason, the PWM core will reload the state from hardware and
keep its copy of the state up-to-date.

Tested-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Tested-by: Michal Vokáč <michal.vokac@ysoft.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-12-09 10:05:41 +01:00
Thierry Reding 40a6b9a009 Revert "pwm: Let pwm_get_state() return the last implemented state"
It turns out that commit 01ccf903ed ("pwm: Let pwm_get_state() return
the last implemented state") causes backlight failures on a number of
boards. The reason is that some of the drivers do not write the full
state through to the hardware registers, which means that ->get_state()
subsequently does not return the correct state. Consumers which rely on
pwm_get_state() returning the current state will therefore get confused
and subsequently try to program a bad state.

Before this change can be made, existing drivers need to be more
carefully audited and fixed to behave as the framework expects. Until
then, keep the original behaviour of returning the software state that
was applied rather than reading the state back from hardware.

Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Tested-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Tested-by: Michal Vokáč <michal.vokac@ysoft.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-10-21 16:48:52 +02:00
Uwe Kleine-König 71523d1812 pwm: Ensure pwm_apply_state() doesn't modify the state argument
It is surprising for a PWM consumer when the variable holding the
requested state is modified by pwm_apply_state(). Consider for example a
driver doing:

        #define PERIOD 5000000
        #define DUTY_LITTLE 10
        ...
        struct pwm_state state = {
                .period = PERIOD,
                .duty_cycle = DUTY_LITTLE,
                .polarity = PWM_POLARITY_NORMAL,
                .enabled = true,
        };

        pwm_apply_state(mypwm, &state);
        ...
        state.duty_cycle = PERIOD / 2;
        pwm_apply_state(mypwm, &state);

For sure the second call to pwm_apply_state() should still have
state.period = PERIOD and not something the hardware driver chose for a
reason that doesn't necessarily apply to the second call.

So declare the state argument as a pointer to a const type and adapt all
drivers' .apply callbacks.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-09-21 03:25:10 +02:00
Uwe Kleine-König 01ccf903ed pwm: Let pwm_get_state() return the last implemented state
When pwm_apply_state() is called the lowlevel driver usually has to
apply some rounding because the hardware doesn't support nanosecond
resolution. So let pwm_get_state() return the actually implemented state
instead of the last applied one if possible.

Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-09-21 01:48:54 +02:00
Uwe Kleine-König fc3c5512e3 pwm: Introduce local struct pwm_chip in pwm_apply_state()
pwm->chip is dereferenced several times in the pwm_apply_state()
function. Introducing a local variable for it helps keeping some lines a
bit shorter.

Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-09-21 01:48:54 +02:00
Hans de Goede 6cf9481b44 pwm: Fallback to the static lookup-list when acpi_pwm_get fails
Commit 4a6ef8e37c ("pwm: Add support referencing PWMs from ACPI")
made pwm_get unconditionally return the acpi_pwm_get return value if
the device passed to pwm_get has an ACPI fwnode.

But even if the passed in device has an ACPI fwnode, it does not
necessarily have the necessary ACPI package defining its pwm bindings,
especially since the binding / API of this ACPI package has only been
introduced very recently.

Up until now X86/ACPI devices which use a separate pwm controller for
controlling their LCD screen's backlight brightness have been relying
on the static lookup-list to get their pwm.

pwm_get unconditionally returning the acpi_pwm_get return value breaks
this, breaking backlight control on these devices.

This commit fixes this by making pwm_get fall back to the static
lookup-list if acpi_pwm_get returns -ENOENT.

BugLink: https://bugs.freedesktop.org/show_bug.cgi?id=96571
Reported-by: youling257@gmail.com
Fixes: 4a6ef8e37c ("pwm: Add support referencing PWMs from ACPI")
Cc: Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-08-08 13:17:38 +02:00
Linus Torvalds 6e2bbb688a pwm: Changes for v5.3-rc1
This set of changes contains a new driver for SiFive SoCs as well as
 enhancements to the core (device links are used to track dependencies
 between PWM providers and consumers, support for PWM controllers via
 ACPI, sysfs will now suspend/resume PWMs that it has claimed) and
 various existing drivers.
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Merge tag 'pwm/for-5.3-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 contains a new driver for SiFive SoCs as well as
  enhancements to the core (device links are used to track dependencies
  between PWM providers and consumers, support for PWM controllers via
  ACPI, sysfs will now suspend/resume PWMs that it has claimed) and
  various existing drivers"

* tag 'pwm/for-5.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm: (37 commits)
  pwm: fsl-ftm: Make sure to unlock mutex on failure
  pwm: fsl-ftm: Use write protection for prescaler & polarity
  pwm: fsl-ftm: More relaxed permissions for updating period
  pwm: atmel-hlcdc: Add compatible for SAM9X60 HLCDC's PWM
  pwm: bcm2835: Improve precision of PWM
  leds: pwm: Support ACPI via firmware-node framework
  pwm: Add support referencing PWMs from ACPI
  pwm: rcar: Remove suspend/resume support
  pwm: sysfs: Add suspend/resume support
  pwm: Add power management descriptions
  pwm: meson: Add documentation to the driver
  pwm: meson: Add support PWM_POLARITY_INVERSED when disabling
  pwm: meson: Don't cache struct pwm_state internally
  pwm: meson: Read the full hardware state in meson_pwm_get_state()
  pwm: meson: Simplify the calculation of the pre-divider and count
  pwm: meson: Move pwm_set_chip_data() to meson_pwm_request()
  pwm: meson: Add the per-channel register offsets and bits in a struct
  pwm: meson: Add the meson_pwm_channel data to struct meson_pwm
  pwm: meson: Pass struct pwm_device to meson_pwm_calc()
  pwm: meson: Don't duplicate the polarity internally
  ...
2019-07-09 08:57:45 -07:00