The of_property_for_each_u32() macro needs five parameters, two of which
are primarily meant as internal variables for the macro itself (in the
for() clause). Yet these two parameters are used by a few drivers, and this
can be considered misuse or at least bad practice.
Now that the kernel uses C11 to build, these two parameters can be avoided
by declaring them internally, thus changing this pattern:
struct property *prop;
const __be32 *p;
u32 val;
of_property_for_each_u32(np, "xyz", prop, p, val) { ... }
to this:
u32 val;
of_property_for_each_u32(np, "xyz", val) { ... }
However two variables cannot be declared in the for clause even with C11,
so declare one struct that contain the two variables we actually need. As
the variables inside this struct are not meant to be used by users of this
macro, give the struct instance the noticeable name "_it" so it is visible
during code reviews, helping to avoid new code to use it directly.
Most usages are trivially converted as they do not use those two
parameters, as expected. The non-trivial cases are:
- drivers/clk/clk.c, of_clk_get_parent_name(): easily doable anyway
- drivers/clk/clk-si5351.c, si5351_dt_parse(): this is more complex as the
checks had to be replicated in a different way, making code more verbose
and somewhat uglier, but I refrained from a full rework to keep as much
of the original code untouched having no hardware to test my changes
All the changes have been build tested. The few for which I have the
hardware have been runtime-tested too.
Reviewed-by: Andre Przywara <andre.przywara@arm.com> # drivers/clk/sunxi/clk-simple-gates.c, drivers/clk/sunxi/clk-sun8i-bus-gates.c
Acked-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org> # drivers/gpio/gpio-brcmstb.c
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com> # drivers/irqchip/irq-atmel-aic-common.c
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> # drivers/iio/adc/ti_am335x_adc.c
Acked-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com> # drivers/pwm/pwm-samsung.c
Acked-by: Richard Leitner <richard.leitner@linux.dev> # drivers/usb/misc/usb251xb.c
Acked-by: Mark Brown <broonie@kernel.org> # sound/soc/codecs/arizona.c
Reviewed-by: Richard Fitzgerald <rf@opensource.cirrus.com> # sound/soc/codecs/arizona.c
Acked-by: Michael Ellerman <mpe@ellerman.id.au> # arch/powerpc/sysdev/xive/spapr.c
Acked-by: Stephen Boyd <sboyd@kernel.org> # clk
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Acked-by: Lee Jones <lee@kernel.org>
Link: https://lore.kernel.org/r/20240724-of_property_for_each_u32-v3-1-bea82ce429e2@bootlin.com
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
This was missed in the basic driver and is useful for debug, so add it.
Example regmap output before the patch:
|root@zed-tg:~# cat /sys/kernel/debug/regmap/44a60000.pwm/registers
|0: 00020100
And with it:
|root@zed-tg:~# cat /sys/kernel/debug/regmap/44a60000.pwm/registers
|00: 00020100
|04: 00000000
|08: 00000000
|0c: 601a3471
|10: 00000000
|14: 00000002
|18: 00000001
|1c: 00000000
|...
Signed-off-by: Trevor Gamblin <tgamblin@baylibre.com>
Link: https://lore.kernel.org/r/20240711125743.3956935-1-tgamblin@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
Currently the variables of type struct atmel_tcb_pwm_device
are named "tcbpwm", and variables of type atmel_tcb_pwm_chip are either
named "tcbpwm" (too!) or "tcbpwmc". Rename the chips with device name to
"tcbpwmc" to get a consistent naming.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Link: https://lore.kernel.org/r/20240709092221.47025-2-u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
The two outputs provided by the supported hardware share some settings,
so access to the other PWM is required when one of them is configured.
Instead of an explicit if to deterimine the other PWM just use
hwpwm ^ 1. Further atcbpwm is never NULL, so drop the corresponding
check.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Link: https://lore.kernel.org/r/20240709101806.52394-4-u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
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>
There are devm variants for clk_prepare_enable() and pwmchip_add(); and
clk_prepare_enable() can be done together with devm_clk_get(). This
allows to simplify the error paths in .probe() and drop .remove()
completely.
With the remove callback gone, the last user of platform_get_drvdata()
is gone and so the call to platform_set_drvdata() can be dropped, too.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Reviewed-by: Sean Anderson <sean.anderson@seco.com>
Link: https://lore.kernel.org/r/20240628063524.92907-2-u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
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>
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>
Apply the pinctrl setting of sleep state when system enters
suspend state.
Restore to the default pinctrl setting when system resumes.
Signed-off-by: Shenwei Wang <shenwei.wang@nxp.com>
Link: https://lore.kernel.org/r/20240702164514.11007-1-shenwei.wang@nxp.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
We no longer need empty runtime PM handles for PCI devices after
commits [1] and [2]. Drop them and let PCI core take care of power
state transitions.
[1] c5eb119007 ("PCI / PM: Allow runtime PM without callback functions")
[2] fa885b06ec ("PCI/PM: Allow runtime PM with no PM callbacks at all")
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Raag Jadav <raag.jadav@intel.com>
Link: https://lore.kernel.org/r/20240605131533.20037-3-raag.jadav@intel.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
There is no semantic change, but it is a nicer on the eyes of a reader,
because
TIM_CCR1 + 4 * ch
encodes internal register knowledge, while
TIM_CCRx(ch + 1)
keeps that information completely in the header defining the registers.
While I expected this to not result in any changes in the binary, gcc 13
(as provided by Debian in the gcc-13-arm-linux-gnueabihf 13.2.0-12cross1
package) compiles the new version with an allmodconfig to more compact
code:
$ source/scripts/bloat-o-meter drivers/pwm/pwm-stm32.o-pre drivers/pwm/pwm-stm32.o
add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-488 (-488)
Function old new delta
stm32_pwm_get_state 968 936 -32
stm32_pwm_apply_locked 1920 1464 -456
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/d7ef7a6158df4ba6687233b0e00d37796b069fb3.1718791090.git.u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
Add a software PWM which toggles a GPIO from a high-resolution timer.
This will naturally not be as accurate or as efficient as a hardware
PWM, but it is useful in some cases. I have for example used it for
evaluating LED brightness handling (via leds-pwm) on a board where the
LED was just hooked up to a GPIO, and for a simple verification of the
timer frequency on another platform.
Since high-resolution timers are used, sleeping GPIO chips are not
supported and are rejected in the probe function.
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Co-developed-by: Stefan Wahren <wahrenst@gmx.net>
Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
Co-developed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Andy Shevchenko <andy@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Dhruva Gole <d-gole@ti.com>
Link: https://lore.kernel.org/r/20240604-pwm-gpio-v7-2-6b67cf60db92@linaro.org
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
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>
The cros-ec device tree binding only uses #pwm-cells = <1>, and so there
is no period provided in the device tree. Up to now this was handled by
hardcoding the period to the only supported value in the custom xlate
callback. Apart from that, the default xlate callback (i.e.
of_pwm_xlate_with_flags()) handles this just fine (and better, e.g. by
checking args->args_count >= 1 before accessing args->args[0]).
To simplify make use of of_pwm_xlate_with_flags(), drop the custom
callback and provide the default period in .probe() already.
Apart from simplifying the driver this also drops the last non-core user
of pwm_request_from_chip() and so makes further simplifications
possible.
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/20240607084416.897777-7-u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
The get_state() callback is never called (in a visible way) after there
is a consumer for a pwm device. The core handles loosing the information
about duty_cycle just fine.
Simplify the driver accordingly.
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/20240607084416.897777-6-u.kleine-koenig@baylibre.com
[Drop kdoc comment for channel to make W=1 builds happy]
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
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>
make allmodconfig && make W=1 C=1 reports:
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/pwm/pwm-imx1.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/pwm/pwm-imx27.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/pwm/pwm-intel-lgm.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/pwm/pwm-mediatek.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/pwm/pwm-pxa.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/pwm/pwm-samsung.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/pwm/pwm-spear.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/pwm/pwm-visconti.o
Add the missing invocations of the MODULE_DESCRIPTION() macro.
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Link: https://lore.kernel.org/r/20240610-md-drivers-pwm-v2-1-b337cfaa70ea@quicinc.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
Similar to commit 7d91999954 ("pwm: jz4740: Use
regmap_{set,clear}_bits") convert two more regmap_update_bits() calls to
regmap_{set,clear}_bits() which were missed back then.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Reviewed-by: Paul Cercueil <paul@crapouillou.net>
Link: https://lore.kernel.org/r/20240606164047.534741-5-u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
Add support for the Analog Devices AXI PWM Generator. This device is an
FPGA-implemented peripheral used as PWM signal generator and can be
interfaced with AXI4. The register map of this peripheral makes it
possible to configure the period and duty cycle of the output signal.
Link: https://analogdevicesinc.github.io/hdl/library/axi_pwm_gen/index.html
Co-developed-by: Sergiu Cuciurean <sergiu.cuciurean@analog.com>
Signed-off-by: Sergiu Cuciurean <sergiu.cuciurean@analog.com>
Co-developed-by: David Lechner <dlechner@baylibre.com>
Signed-off-by: David Lechner <dlechner@baylibre.com>
Signed-off-by: Drew Fustini <dfustini@baylibre.com>
Acked-by: Nuno Sa <nuno.sa@analog.com>
Co-developed-by: Trevor Gamblin <tgamblin@baylibre.com>
Signed-off-by: Trevor Gamblin <tgamblin@baylibre.com>
Link: https://lore.kernel.org/r/20240605203507.1934434-3-tgamblin@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
The hardware only supports a single period length for both PWM outputs. So
atmel_tcb_pwm_config() checks the configuration of the other output if it's
compatible with the currently requested setting. The register values are
then actually updated in atmel_tcb_pwm_enable(). To make this race free
the lock must be held during the whole process, so grab the lock in
.apply() instead of individually in atmel_tcb_pwm_disable() and
atmel_tcb_pwm_enable() which then also covers atmel_tcb_pwm_config().
To simplify handling, use the guard helper to let the compiler care for
unlocking. Otherwise unlocking would be more difficult as there is more
than one exit path in atmel_tcb_pwm_apply().
Fixes: 9421bade07 ("pwm: atmel: add Timer Counter Block PWM driver")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Link: https://lore.kernel.org/r/20240709101806.52394-3-u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
When the state changes from enabled to disabled, polarity, duty_cycle
and period are not configured in hardware and TIM_CCER_CCxE is just
cleared. However if the state changes from one disabled state to
another, all parameters are written to hardware because the early exit
from stm32_pwm_apply() is only taken if the pwm is currently enabled.
This yields surprises like: Applying
{ .period = 1, .duty_cycle = 0, .enabled = false }
succeeds if the pwm is initially on, but fails if it's already off
because 1 is a too small period.
Update the check for lazy disable to always exit early if the target
state is disabled, no matter what is currently configured.
Fixes: 7edf736920 ("pwm: Add driver for STM32 plaftorm")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/20240703110010.672654-2-u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
"Failed to lock the clock" is an appropriate error message for
clk_rate_exclusive_get() failing, but not for the clock running too
fast for the driver's calculations.
Adapt the error message accordingly.
Fixes: d44d635635 ("pwm: stm32: Fix for settings using period > UINT32_MAX")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/285182163211203fc823a65b180761f46e828dcb.1718979150.git.u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
A small prescaler is beneficial, as this improves the resolution of the
duty_cycle configuration. However if the prescaler is too small, the
maximal possible period becomes considerably smaller than the requested
value.
One situation where this goes wrong is the following: With a parent
clock rate of 208877930 Hz and max_arr = 0xffff = 65535, a request for
period = 941243 ns currently results in PSC = 1. The value for ARR is
then calculated to
ARR = 941243 * 208877930 / (1000000000 * 2) - 1 = 98301
This value is bigger than 65535 however and so doesn't fit into the
respective register field. In this particular case the PWM was
configured for a period of 313733.4806027616 ns (with ARR = 98301 &
0xffff). Even if ARR was configured to its maximal value, only period =
627495.6861167669 ns would be achievable.
Fix the calculation accordingly and adapt the comment to match the new
algorithm.
With the calculation fixed the above case results in PSC = 2 and so an
actual period of 941229.1667195285 ns.
Fixes: 8002fbeef1 ("pwm: stm32: Calculate prescaler with a division instead of a loop")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/b4d96b79917617434a540df45f20cb5de4142f88.1718979150.git.u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
The driver doesn't use the driver_data member of struct i2c_device_id,
so don't explicitly initialize this member.
This prepares putting driver_data in an anonymous union which requires
either no initialization or named designators. But it's also a nice
cleanup on its own.
While add it, also remove the trailing commas after the sentinel entry.
Link: https://lore.kernel.org/r/20240508130618.2148631-2-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
While calculating frequency for the given period u64 numbers are
multiplied before division what can lead to overflow in theory so use
secure mul_u64_u64_div_u64() which handles overflow correctly.
Fixes: 329db102a2 ("pwm: meson: make full use of common clock framework")
Suggested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: George Stark <gnstark@salutedevices.com>
Link: https://lore.kernel.org/r/20240425171253.2752877-4-gnstark@salutedevices.com
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
clk_round_rate() can return not only zero if requested frequency can not
be provided but also negative error code so add check for it too.
Also change type of variable holding clk_round_rate() result from
unsigned long to long. It's safe due to clk_round_rate() returns long.
Fixes: 329db102a2 ("pwm: meson: make full use of common clock framework")
Signed-off-by: Dmitry Rokosov <ddrokosov@salutedevices.com>
Signed-off-by: George Stark <gnstark@salutedevices.com>
Link: https://lore.kernel.org/r/20240425171253.2752877-3-gnstark@salutedevices.com
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Drop checking state argument for NULL pointer in meson_pwm_get_state()
due to it is called only from pwm core with always valid arguments.
Signed-off-by: Dmitry Rokosov <ddrokosov@salutedevices.com>
Signed-off-by: George Stark <gnstark@salutedevices.com>
Link: https://lore.kernel.org/r/20240425171253.2752877-2-gnstark@salutedevices.com
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Introduce a new compatible support in the Amlogic PWM driver.
The PWM HW is actually the same for all SoCs supported so far. A specific
compatible is needed only because the clock sources of the PWMs are
hard-coded in the driver.
It is better to have the clock source described in DT but this changes the
bindings so a new compatible must be introduced.
When all supported platform have migrated to the new compatible, support
for the legacy ones may be removed from the driver.
The addition of this new compatible makes the old ones obsolete, as
described in the DT documentation.
Adding a callback to setup the clock will also make it easier to add
support for the new PWM HW found in a1, s4, c3 and t7 SoC families.
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Link: https://lore.kernel.org/r/20240221151154.26452-6-jbrunet@baylibre.com
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
stm32_pwm_config() took the duty_cycle and period values with the type
int, however stm32_pwm_apply() passed u64 values there. Expand the
function parameters to u64 to not discard relevant bits and adapt the
calculations to the wider type.
To ensure the calculations won't overflow, check in .probe() the input
clk doesn't run faster than 1 GHz.
Link: https://lore.kernel.org/r/06b4a650a608d0887d934c1b2b8919e0f78e4db2.1710711976.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
While mathematically it's ok to calculate the number of cyles for the
duty cycle as:
duty_cycles = period_cycles * duty_ns / period_ns
this doesn't always give the right result when doing integer math. This
is best demonstrated using an example: With the input clock running at
208877930 Hz a request for duty_cycle = 383 ns and period = 49996 ns
results in
period_cycles = clkrate * period_ns / NSEC_PER_SEC = 10443.06098828
Now calculating duty_cycles with the above formula gives:
duty_cycles = 10443.06098828 * 383 / 49996 = 80.00024719
However with period_cycle truncated to an integer results in:
duty_cycles = 10443 * 383 / 49996 = 79.99977998239859
So while a value of (a little more than) 80 would be the right result,
only 79 is used here. The problem here is that 14443 is a rounded result
that should better not be used to do further math. So to fix that use
the exact formular similar to how period_cycles is calculated.
Link: https://lore.kernel.org/r/7628ecd8a7538aa5a7397f0fc4199a077168e8a6.1710711976.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Giving an indication about the problem if probing a device fails is a
nice move. Do that for the stm32 pwm driver.
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Link: https://lore.kernel.org/r/20240315145443.982807-2-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
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>
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>
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>
The code handling the sysfs API uses "child" and "parent" to refer to
the devices corresponding to a struct pwm or a struct pwm_chip
respectively.
Other parts of the pwm core use "parent" to refer to the parent device of
a struct pwm_chip.
So rename "child" to "pwm_dev" and "parent" to "pwmchip_dev" which
better explains the semantic. Also two functions are changed to match
the new names:
child_to_pwm_export() -> pwmexport_from_dev()
child_to_pwm_device() -> pwm_from_dev()
(which have the additional advantage to start with "pwm" which gives the
right scope). Additionally introduce a wrapper for dev_get_drvdata() to
convert a pwmchip_dev to the respective pwm_chip.
Link: https://lore.kernel.org/r/9cc05aceeae2f06ecb850bccb15ba821e768c183.1710670958.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
While the compiler probably optimizes out the pointer dereference, using
the local variable holding the same value also benefits the human
reader. So simplify accordingly. Also move a loop over all capture lines
into the capture if block to group the operations related to capturing
in .probe().
Link: https://lore.kernel.org/r/a7a81f3838f7ed7f4d6dbee3d646989cc265f676.1710068192.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
This has the advantage of handling EPROBE_DEFER correctly and being more
compact.
This change also introduces an error message for a few error paths that
lacked an error indicator before. Also sti_pwm_probe_dt() is renamed to
sti_pwm_probe_regmap() to better fit what it actually does.
Link: https://lore.kernel.org/r/8e540733ab882f2b8873712faf85c4f0cb48133a.1710068192.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
