Commit Graph

165 Commits

Author SHA1 Message Date
Masahiro Yamada ceb8bf2cea module: Convert default symbol namespace to string literal
Commit cdd30ebb1b ("module: Convert symbol namespace to string
literal") only converted MODULE_IMPORT_NS() and EXPORT_SYMBOL_NS(),
leaving DEFAULT_SYMBOL_NAMESPACE as a macro expansion.

This commit converts DEFAULT_SYMBOL_NAMESPACE in the same way to avoid
annoyance for the default namespace as well.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2024-12-03 08:22:25 -08:00
Uwe Kleine-König b2eaa1170e pwm: Assume a disabled PWM to emit a constant inactive output
Some PWM hardwares (e.g. MC33XS2410) cannot implement a zero duty cycle
but can instead disable the hardware which also results in a constant
inactive output.

There are some checks (enabled with CONFIG_PWM_DEBUG) to help
implementing a driver without violating the normal rounding rules. Make
them less strict to let above described hardware pass without warning.

Reported-by: Dimitri Fedrau <dima.fedrau@gmail.com>
Link: https://lore.kernel.org/r/20241103205215.GA509903@debian
Fixes: 3ad1f3a332 ("pwm: Implement some checks for lowlevel drivers")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Reviewed-by: Dimitri Fedrau <dima.fedrau@gmail.com>
Tested-by: Dimitri Fedrau <dima.fedrau@gmail.com>
Link: https://lore.kernel.org/r/20241105153521.1001864-2-u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
2024-11-07 12:03:39 +01:00
David Lechner 2ea25aab93 pwm: core: export pwm_get_state_hw()
Export the pwm_get_state_hw() function. This is useful in cases where
we want to know what the hardware is actually doing, rather than what
what we requested it should do.

Locking had to be rearranged to ensure that the chip is still
operational before trying to access ops now that this can be called
from outside the pwm core.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/20241029-pwm-export-pwm_get_state_hw-v2-1-03ba063a3230@baylibre.com
[ukleinek: Add dummy for !CONFIG_PWM]
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
2024-11-03 21:13:21 +01:00
Andy Shevchenko fdb62922ae pwm: core: use device_match_name() instead of strcmp(dev_name(...
Use the dedicated helper for comparing device names against strings.

Note, the current code has a check for the dev_name() against NULL.
With the current implementations of the device_add() and dev_set_name()
it most likely a theoretical assumption that that might happen, while
I don't see how. Hence, that check has simply been removed.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20241025142704.405340-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
2024-10-25 22:52:45 +02:00
Uwe Kleine-König 65406de2b0 pwm: Reorder symbols in core.c
This moves pwm_get() and friends above the functions handling
registration of pwmchips. The motivation is that character device
support needs pwm_get() and pwm_put() and so ideally is defined below
these and when a pwmchip is registered this registers the character
device. So the natural order is

	pwm_get() and friend
	pwm character device symbols
	pwm_chip functions

. The advantage of having these in their natural order is that static
functions don't need to be forward declared.

Note that the diff that git produces for this change some functions are
moved down instead. This is technically equivalent, but not how this
change was created.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/193b3d933294da34e020650bff93b778de46b1c5.1726819463.git.u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
2024-09-28 15:13:56 +02:00
Uwe Kleine-König 1afd01db1a pwm: Add tracing for waveform callbacks
This adds trace events for the recently introduced waveform callbacks.
With the introduction of some helper macros consistency among the
different events is ensured.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/1d71879b0de3bf01459c7a9d0f040d43eb5ace56.1726819463.git.u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
2024-09-28 15:13:56 +02:00
Uwe Kleine-König 6c5126c640 pwm: Provide new consumer API functions for waveforms
Provide API functions for consumers to work with waveforms.

Note that one relevant difference between pwm_get_state() and
pwm_get_waveform*() is that the latter yields the actually configured
hardware state, while the former yields the last state passed to
pwm_apply*() and so doesn't account for hardware specific rounding.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Tested-by: Trevor Gamblin <tgamblin@baylibre.com>
Link: https://lore.kernel.org/r/6c97d27682853f603e18e9196043886dd671845d.1726819463.git.u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
2024-09-28 15:13:56 +02:00
Uwe Kleine-König 17e40c2515 pwm: New abstraction for PWM waveforms
Up to now the configuration of a PWM setting is described exclusively by
a struct pwm_state which contains information about period, duty_cycle,
polarity and if the PWM is enabled. (There is another member usage_power
which doesn't completely fit into pwm_state, I ignore it here for
simplicity.)

Instead of a polarity the new abstraction has a member duty_offset_ns
that defines when the rising edge happens after the period start. This
is more general, as with a pwm_state the rising edge can only happen at
the period's start or such that the falling edge is at the end of the
period (i.e. duty_offset_ns == 0 or duty_offset_ns == period_length_ns -
duty_length_ns).

A disabled PWM is modeled by .period_length_ns = 0. In my eyes this is a
nice usage of that otherwise unusable setting, as it doesn't define
anything about the future which matches the fact that consumers should
consider the state of the output as undefined and it's just there to say
"No further requirements about the output, you can save some power.".

Further I renamed period and duty_cycle to period_length_ns and
duty_length_ns. In the past there was confusion from time to time about
duty_cycle being measured in nanoseconds because people expected a
percentage of period instead. With "length_ns" as suffix the semantic
should be more obvious to people unfamiliar with the pwm subsystem.
period is renamed to period_length_ns for consistency.

The API for consumers doesn't change yet, but lowlevel drivers can
implement callbacks that work with pwm_waveforms instead of pwm_states.
A new thing about these callbacks is that the calculation of hardware
settings needed to implement a certain waveform is separated from
actually writing these settings. The motivation for that is that this
allows a consumer to query the hardware capabilities without actually
modifying the hardware state.

The rounding rules that are expected to be implemented in the
round_waveform_tohw() are: First pick the biggest possible period not
bigger than wf->period_length_ns. For that period pick the biggest
possible duty setting not bigger than wf->duty_length_ns. Third pick the
biggest possible offset not bigger than wf->duty_offset_ns. If the
requested period is too small for the hardware, it's expected that a
setting with the minimal period and duty_length_ns = duty_offset_ns = 0
is returned and this fact is signaled by a return value of 1.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Tested-by: Trevor Gamblin <tgamblin@baylibre.com>
Link: https://lore.kernel.org/r/df0faa33bf9e7c9e2e5eab8d31bbf61e861bd401.1726819463.git.u.kleine-koenig@baylibre.com
[ukleinek: Update pwm_check_rounding() to return bool instead of int.]
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
2024-09-28 15:12:44 +02:00
Uwe Kleine-König 1cc2e1faaf pwm: Add more locking
This ensures that a pwm_chip that has no corresponding driver isn't used
and that a driver doesn't go away while a callback is still running.

In the presence of device links this isn't necessary yet (so this is no
fix) but for pwm character device support this is needed.

To not serialize all pwm_apply_state() calls, this introduces a per chip
lock. An additional complication is that for atomic chips a mutex cannot
be used (as pwm_apply_atomic() must not sleep) and a spinlock cannot be
held while calling an operation for a sleeping chip. So depending on the
chip being atomic or not a spinlock or a mutex is used.

An additional change implemented here is that on driver remove the
.free() callback is called for each requested pwm_device. This is the
right time because later (e.g. when the consumer calls pwm_put()) the
free function is (maybe) not available any more.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/026aa891c8270a11723a1ba7e4256f456f7e1e86.1726819463.git.u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
2024-09-27 17:03:15 +02:00
Uwe Kleine-König d6a800796e pwm: Simplify pwm_capture()
When pwm_capture() is called, pwm is valid, so the checks for pwm and
pwm->chip->ops being NULL can be dropped.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/ee7b3322c7b3e28defdfb886a70b8ba40d298416.1722261050.git.u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
2024-09-05 11:14:14 +02:00
Uwe Kleine-König f9ecc2febf pwm: Don't export pwm_capture()
There is only a single caller of this function, and that's in
drivers/pwm/core.c itself. So don't export the function.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/20240712171821.1470833-2-u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
2024-09-05 11:14:14 +02:00
Uwe Kleine-König 9dd42d019e pwm: Allow pwm state transitions from an invalid state
While driving a PWM via the sysfs API it's hard to determine the right
order of writes to the pseudo files "period" and "duty_cycle":

If you want to go from duty_cycle/period = 50/100 to 150/300 you have to
write period first (because 150/100 is invalid). If however you start at
400/500 the duty_cycle must be configured first. The rule that works is:
If you increase period write period first, otherwise write duty_cycle
first. A complication however is that it's usually sensible to configure
the polarity before both period and duty_cycle. This can only be done if
the current state's duty_cycle and period configuration isn't bogus
though. It is still worse (but I think only theoretic) if you have a PWM
that only supports inverted polarity and you start with period = 0 and
polarity = normal. Then you can change neither period (because polarity
= normal is refused) nor polarity (because there is still period = 0).

To simplify the corner cases for userspace, let invalid target states
pass if the current state is invalid already.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/20240628103519.105020-2-u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
2024-07-10 17:53:52 +02:00
Uwe Kleine-König 0007fa1292 pwm: Use guards for pwm_lookup_lock instead of explicity mutex_lock + mutex_unlock
With the compiler caring for unlocking the mutex several functions can
be simplified. Benefit from that.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/28807cb5d9dbce66860f74829c0f57cd9c01373e.1719520143.git.u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
2024-07-10 17:53:52 +02:00
Uwe Kleine-König 4c50c71c69 pwm: Use guards for export->lock instead of explicity mutex_lock + mutex_unlock
With the compiler caring for unlocking the mutex several functions can
be simplified. Benefit from that.

There is just one caller left for mutex_lock(&export->lock). The code
flow is too complicated there to convert it to the compiler assisted
variant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/210010f2e579a92476462726e18e0135f6854909.1719520143.git.u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
2024-07-10 17:53:52 +02:00
Uwe Kleine-König 650af6c083 pwm: Use guards for pwm_lock instead of explicity mutex_lock + mutex_unlock
With the compiler caring for unlocking the mutex several functions can
be simplified. Benefit from that.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/2102fe8189bdf1f02ff3785b551a69be27a65af4.1719520143.git.u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
2024-07-10 17:53:51 +02:00
Uwe Kleine-König 44ee95184e pwm: Register debugfs operations after the pwm class
While the debugfs operations don't technically depend on an initialized
class, they loop over the idr that only can get entries when the class
is properly initialized.

This also fixes the ugly (but harmless) corner case that the debugfs
file stays around after the pwm class failed to initialize.

While at it, add an appropriate error message when class initialization
fails.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/20240626222529.2901200-2-u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
2024-07-10 17:53:51 +02:00
Uwe Kleine-König d6f66e2926 pwm: Make pwm_request_from_chip() private to the core
The last user of this function outside of core.c is gone, so it can be
made static.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Reviewed-by: Tzung-Bi Shih <tzungbi@kernel.org>
Link: https://lore.kernel.org/r/20240607084416.897777-8-u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
2024-07-10 17:52:47 +02:00
Uwe Kleine-König 33c651a3fb pwm: Make use of a symbol namespace for the core
Define all pwm core's symbols in the namespace "PWM". The necessary
module import statement is just added to the main header, this way every
file that knows about the public functions automatically has this
namespace available.

Thanks to Biju Das for pointing out a cut'n'paste failure in my initial
patch.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/20240607160012.1206874-2-u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
2024-07-10 17:52:47 +02:00
Uwe Kleine-König c6837aa180 pwm: Don't check pointer for being non-NULL after use
After assigning chip = pwm->chip; the compiler is free to assume that
pwm is non-NULL and so can optimize out the check for pwm against NULL.

While it's probably a programming error to pass a NULL pointer to
pwm_put() this shouldn't be dropped without careful consideration and
wasn't intended.

So assign chip only after the NULL check.

Reported-by: David Lechner <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/66a6f562-1fdd-4e45-995a-e7995432aa0c@baylibre.com
Fixes: 4c56b1434b ("pwm: Add a struct device to struct pwm_chip")
Link: https://lore.kernel.org/r/20240329101648.544155-2-u.kleine-koenig@pengutronix.de
Reviewed-by: David Lechner <dlechner@baylibre.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-04-30 18:56:55 +02:00
Uwe Kleine-König 4c56b1434b pwm: Add a struct device to struct pwm_chip
This replaces the formerly dynamically allocated struct device. This
allows to additionally use it to track the lifetime of the struct
pwm_chip. Otherwise the new struct device provides the same sysfs API as
was provided by the dynamic device before.

Link: https://lore.kernel.org/r/35c65ea7f6de789a568ff39d7b6b4ce80de4b7dc.1710670958.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-04-26 21:29:17 +02:00
Uwe Kleine-König ee37bf5074 pwm: Ensure a struct pwm has the same lifetime as its pwm_chip
It's required to not free the memory underlying a requested PWM
while a consumer still has a reference to it. While currently a pwm_chip
doesn't live long enough in all cases, linking the struct pwm to the
pwm_chip results in the right lifetime as soon as the pwmchip is living
long enough. This happens with the following commits.

Note this is a breaking change for all pwm drivers that don't use
pwmchip_alloc().

Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org> # for struct_size() and __counted_by()
Link: https://lore.kernel.org/r/7e9e958841f049026c0023b309cc9deecf0ab61d.1710670958.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-04-26 21:29:17 +02:00
Uwe Kleine-König e9cc807f87 pwm: Move contents of sysfs.c into core.c
With the upcoming restructuring having all in a single file simplifies
things a bit. The relevant and somewhat visible changes are:

 - Some dropped prototypes from include/linux/pwm.h that were only
   necessary that core.c has a declaration of the symbols defined in
   sysfs.c. The respective functions are static now.

 - The pwm class now also exists if CONFIG_SYSFS isn't enabled. Having
   CONFIG_SYSFS is not very relevant today, but even without it the
   class and device stuff still provides lifetime tracking.

 - Both files had an initcall, these are merged into a single one now.
   Instead of a big #ifdef block for CONFIG_DEBUG_FS, a single
   if (IS_ENABLED(CONFIG_DEBUG_FS)) is used now. This increases compile
   coverage a bit and is a tad nicer on the eyes.

Link: https://lore.kernel.org/r/9e2d39a5280d7dda5bfc6682a8aef510148635b2.1710670958.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-04-26 21:29:17 +02:00
Uwe Kleine-König 05947224ff pwm: Ensure that pwm_chips are allocated using pwmchip_alloc()
Memory holding a struct device must not be freed before the reference
count drops to zero. So a struct pwm_chip must not live in memory
freed by a driver on unbind. All in-tree drivers were fixed accordingly,
but as out-of-tree drivers, that were not adapted, still compile fine,
catch these in pwmchip_add().

Link: https://lore.kernel.org/r/35f5b229c98f78b2f6ce2397259a4a936be477c0.1707900770.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-04-26 21:29:16 +02:00
Uwe Kleine-König 73dfe970c0 pwm: Fix setting period with #pwm-cells = <1> and of_pwm_single_xlate()
For drivers making use of of_pwm_single_xlate() (i.e. those that don't
pass a hwpwm index) and also don't pass flags, setting period was
wrongly skipped. This affects the pwm-pxa and ti-sn65dsi86 drivers.

Reported-by: Karel Balej <balejk@matfyz.cz>
Link: https://lore.kernel.org/r/D05IVTPYH35N.2CLDG6LSILRSN@matfyz.cz
Fixes: 40ade0c2e7 ("pwm: Let the of_xlate callbacks accept references without period")
Tested-by: Karel Balej <balejk@matfyz.cz>
Link: https://lore.kernel.org/r/20240329103544.545290-2-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-03-29 13:50:10 +01:00
Uwe Kleine-König 024913dbf9 pwm: Provide pwmchip_alloc() function and a devm variant of it
This function allocates a struct pwm_chip and driver data. Compared to
the status quo the split into pwm_chip and driver data is new, otherwise
it doesn't change anything relevant (yet).

The intention is that after all drivers are switched to use this
allocation function, its possible to add a struct device to struct
pwm_chip to properly track the latter's lifetime without touching all
drivers again. Proper lifetime tracking is a necessary precondition to
introduce character device support for PWMs (that implements atomic
setting and doesn't suffer from the sysfs overhead of the /sys/class/pwm
userspace support).

The new function pwmchip_priv() (obviously?) only works for chips
allocated with pwmchip_alloc().

Link: https://lore.kernel.org/r/9577d6053a5a52536057dc8654ff567181c2da82.1707900770.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-02-15 12:59:15 +01:00
Uwe Kleine-König 4e59267c7a pwm: Provide an inline function to get the parent device of a given chip
Currently a pwm_chip stores in its struct device *dev member a pointer
to the parent device. Preparing a change that embeds a full struct
device in struct pwm_chip, this accessor function should be used in all
drivers directly accessing chip->dev now. This way struct pwm_chip and
this new function can be changed without having to touch all drivers in
the same change set.

Make use of this function in the framework's core sources.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/cc30090d2f9762bed9854a55612144bccc910781.1707900770.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-02-15 12:37:29 +01:00
Uwe Kleine-König 62928315ad pwm: Reorder symbols in core.c
This moves the functions called by pwm consumers above the functions
called by pwm providers. When character device support is added later
this is hooked into the chip registration functions. As the needed
callbacks are a kind of consumer and make use of the consumer functions,
having this order is more natural and prevents having to add
declarations for static functions.

Also move the global variables for pwm tables to the respective
functions to have them properly grouped.

Link: https://lore.kernel.org/r/eed83de07bdfb69b5ceba0b9aed757ee612dea8f.1706182805.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-02-15 12:28:02 +01:00
Uwe Kleine-König 91bb23493f pwm: Drop duplicate check against chip->npwm in of_pwm_xlate_with_flags()
args->args[0] is passed as parameter "index" to pwm_request_from_chip().
The latter function also checks for index >= npwm, so
of_pwm_xlate_with_flags() doesn't need to do that.

Link: https://lore.kernel.org/r/b06e445a6ed62a339add727eccb969a33d678386.1704835845.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-02-15 12:28:02 +01:00
Uwe Kleine-König 40ade0c2e7 pwm: Let the of_xlate callbacks accept references without period
With this extension of_pwm_xlate_with_flags() is suitable to replace the
custom xlate function of the pwm-clps711x driver.

While touching these very similar functions align their implementations.

Link: https://lore.kernel.org/r/127622315d07d9d419ae8e6373c7e5be7fab7a62.1704835845.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-02-15 12:28:02 +01:00
Uwe Kleine-König 4e77431cda pwm: Drop useless member .of_pwm_n_cells of struct pwm_chip
Apart from the two of_xlate implementations this member is write-only.
In the of_xlate functions of_pwm_xlate_with_flags() and
of_pwm_single_xlate() it's more sensible to check for args->args_count
because this is what is actually used in the device tree.

Acked-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/53d8c545aa8f79a920358be9e72e382b3981bdc4.1704835845.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-02-15 12:28:01 +01:00
Uwe Kleine-König a297d07b9a pwm: Fix out-of-bounds access in of_pwm_single_xlate()
With args->args_count == 2 args->args[2] is not defined. Actually the
flags are contained in args->args[1].

Fixes: 3ab7b6ac5d ("pwm: Introduce single-PWM of_xlate function")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/243908750d306e018a3d4bf2eb745d53ab50f663.1704835845.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-01-12 18:24:55 +01:00
Uwe Kleine-König efb704abed pwm: Reduce number of pointer dereferences in pwm_device_request()
pwm->chip and pwm->chip->ops are used several times in this function.
Introduce local variables for these.

There is no semantical change, but with ARCH=arm, allmodconfig and
gcc-13 bloat-o-meter reports a slight improvement:

	add/remove: 1/1 grow/shrink: 1/1 up/down: 8/-36 (-28)
	Function                                     old     new   delta
	pwm_apply_state                              476     480      +4
	__initcall__kmod_core__307_1092_pwm_debugfs_init4       -       4      +4
	__initcall__kmod_core__307_1090_pwm_debugfs_init4       4       -      -4
	pwm_request_from_chip                        628     596     -32
	Total: Before=15091, After=15063, chg -0.19%

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2023-12-20 16:24:44 +01:00
Sean Young 7170d3beaf pwm: Make it possible to apply PWM changes in atomic context
Some PWM devices require sleeping, for example if the pwm device is
connected over I2C. However, many PWM devices could be used from atomic
context, e.g. memory mapped PWM. This is useful for, for example, the
pwm-ir-tx driver which requires precise timing. Sleeping causes havoc
with the generated IR signal.

Since not all PWM devices can support atomic context, we also add a
pwm_might_sleep() function to check if is not supported.

Signed-off-by: Sean Young <sean@mess.org>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2023-12-20 16:07:06 +01:00
Sean Young c748a6d77c pwm: Rename pwm_apply_state() to pwm_apply_might_sleep()
In order to introduce a pwm api which can be used from atomic context,
we will need two functions for applying pwm changes:

	int pwm_apply_might_sleep(struct pwm *, struct pwm_state *);
	int pwm_apply_atomic(struct pwm *, struct pwm_state *);

This commit just deals with renaming pwm_apply_state(), a following
commit will introduce the pwm_apply_atomic() function.

Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> # for input
Acked-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Acked-by: Lee Jones <lee@kernel.org>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2023-12-20 16:07:04 +01:00
Uwe Kleine-König b0445a18d3 pwm: Narrow scope of struct pwm_device pointer
In the expression determining the size of the allocation for chip->pwms
it's more natural to use sizeof(*chip->pwms) than sizeof(*pwm). With
that changed, the variable pwm is only used in a for loop and its scope
can be reduced accordingly.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2023-12-20 16:04:13 +01:00
Uwe Kleine-König 0360a48733 pwm: Mention PWM chip ID in /sys/kernel/debug/pwm
While it's not hard to match the entries from /sys/kernel/debug/pwm to
the corresponding pwmchip in /sys/class/pwm, it's a bit simpler to have
the number mentioned in /sys/kernel/debug/pwm.

Link: https://lore.kernel.org/r/20230808165250.942396-3-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>
2023-12-20 16:04:13 +01:00
Uwe Kleine-König 54c86dd20b pwm: Replace PWM chip unique base by unique ID
Traditionally each PWM device had a unique ID stored in the "pwm" member
of struct pwm_device. However this number was hardly used and dropped
in the previous commit. To identify a certain PWM you're supposed to use
the chip's ID and the hwpwm of the PWM device now.

With the PWM chip base gone PWM chips can get their IDs better and
simpler using an idr.

This is expected to change the numbering of PWM chips, but nothing
should rely on the numbering anyhow.

Other than that the side effects are:

 - The PWM chip IDs are smaller and in most cases consecutive.
 - The ordering in /sys/kernel/debug/pwm is ordered by ascending PWM
   chip ID.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2023-12-20 16:04:12 +01:00
Uwe Kleine-König f3e25e68ce pwm: Drop unused member "pwm" from struct pwm_device
This member is only assigned to and never read. So drop it.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2023-12-20 16:04:12 +01:00
Uwe Kleine-König a6e5654e0b pwm: Drop pwm_[sg]et_chip_data()
The semantic of chip_data is a bit surprising as it's cleared when
pwm_put() is called. Also there is a big overlap with the standard driver
data.

All drivers were adapted to not make use of chip_data any more, so it can
go away.

Link: https://lore.kernel.org/r/20230705080650.2353391-9-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>
2023-10-13 10:07:17 +02:00
Uwe Kleine-König 384461abca pwm: Manage owner assignment implicitly for drivers
Instead of requiring each driver to care for assigning the owner member
of struct pwm_ops, handle that implicitly using a macro. Note that the
owner member has to be moved to struct pwm_chip, as the ops structure
usually lives in read-only memory and so cannot be modified.

The upside is that new low level drivers cannot forget the assignment and
save one line each. The pwm-crc driver didn't assign .owner, that's not
a problem in practice though as the driver cannot be compiled as a
module.

Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com> # Intel LPSS
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com> # pwm-{bcm,brcm}*.c
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com> # sun4i
Acked-by: Andi Shyti <andi.shyti@kernel.org>
Acked-by: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp> # pwm-visconti
Acked-by: Heiko Stuebner <heiko@sntech.de> # pwm-rockchip
Acked-by: Michael Walle <michael@walle.cc> # pwm-sl28cpld
Acked-by: Neil Armstrong <neil.armstrong@linaro.org> # pwm-meson
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20230804142707.412137-2-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>
2023-10-13 10:07:17 +02:00
Uwe Kleine-König 86eed2a103 pwm: Fix order of freeing resources in pwmchip_remove()
pwmchip_add() calls of_pwmchip_add() only after adding the chip to
pwm_chips and releasing pwm_lock. So the proper order in
pwmchip_remove() is to call of_pwmchip_remove() before taking the mutex
and removing the chip from pwm_chips. This way pwmchip_remove() releases
the resources in reverse order compared to pwmchip_add() requesting
them.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2023-07-28 09:42:37 +02:00
Uwe Kleine-König 84c33f4278 pwm: Drop unused #include <linux/radix-tree.h>
core.c doens't use any of the symbols provided by linux/radix-tree.h
and compiles just fine without this include. So drop the #include.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2023-07-28 09:30:47 +02:00
Uwe Kleine-König 018121e655 pwm: Remove outdated documentation for pwmchip_remove()
pwmchip_remove() returns void since some time but the documentation still
mentions the situations where it used to return an error code. Just remove
this old and now wrong text.

Fixes: 8083f58d08 ("pwm: Make pwmchip_remove() return void")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2023-07-28 09:24:29 +02:00
Rob Herring 0a41b0c5d9 pwm: Explicitly include correct DT includes
The DT of_device.h and of_platform.h date back to the separate
of_platform_bus_type before it as merged into the regular platform bus.
As part of that merge prepping Arm DT support 13 years ago, they
"temporarily" include each other. They also include platform_device.h
and of.h. As a result, there's a pretty much random mix of those include
files used throughout the tree. In order to detangle these headers and
replace the implicit includes with struct declarations, users need to
explicitly include the correct includes.

Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-by: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Tzung-Bi Shih <tzungbi@kernel.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2023-07-24 13:28:05 +02:00
Uwe Kleine-König b4f78ff746 pwm: Use a consistent name for pwm_chip pointers in the core
Most variables of type struct pwm_chip * are named "chip", there are
only three outliers called "pc". Change these three to "chip", too, for
consistency.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2023-07-20 08:50:55 +02:00
Thierry Reding 247ee6c780 pwm: Remove unused radix tree
The radix tree's only use was to map PWM channels to the global number
space. With that number space gone, the radix tree is now unused, so it
can simply be removed.

Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2023-04-14 11:35:52 +02:00
Uwe Kleine-König 0af4d704ba pwm: Delete deprecated functions pwm_request() and pwm_free()
Since commit 5a7fbe452a ("backlight: pwm_bl: Drop support for legacy PWM
probing") the last user of pwm_request() and pwm_free() is gone. So remove
these functions that were deprecated over 10 years ago in commit
8138d2ddbc ("pwm: Add table-based lookup for static mappings").

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
[thierry.reding@gmail.com: clean up a bit after removal]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2023-04-13 14:27:53 +02:00
Uwe Kleine-König 1271a7b98e pwm: Zero-initialize the pwm_state passed to driver's .get_state()
This is just to ensure that .usage_power is properly initialized and
doesn't contain random stack data. The other members of struct pwm_state
should get a value assigned in a successful call to .get_state(). So in
the absence of bugs in driver implementations, this is only a safe-guard
and no fix.

Reported-by: Munehisa Kamata <kamatam@amazon.com>
Link: https://lore.kernel.org/r/20230310214004.2619480-1-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>
2023-03-23 14:44:43 +01:00
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