Commit Graph

19 Commits

Author SHA1 Message Date
Uwe Kleine-König
6c452cff79 pwm: Make .get_state() callback return an error code
.get_state() might fail in some cases. To make it possible that a driver
signals such a failure change the prototype of .get_state() to return an
error code.

This patch was created using coccinelle and the following semantic patch:

@p1@
identifier getstatefunc;
identifier driver;
@@
 struct pwm_ops driver = {
        ...,
        .get_state = getstatefunc
        ,...
 };

@p2@
identifier p1.getstatefunc;
identifier chip, pwm, state;
@@
-void
+int
 getstatefunc(struct pwm_chip *chip, struct pwm_device *pwm, struct pwm_state *state)
 {
   ...
-  return;
+  return 0;
   ...
 }

plus the actual change of the prototype in include/linux/pwm.h (plus some
manual fixing of indentions and empty lines).

So for now all drivers return success unconditionally. They are adapted
in the following patches to make the changes easier reviewable.

Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Tzung-Bi Shih <tzungbi@kernel.org>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Acked-by: Douglas Anderson <dianders@chromium.org>
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20221130152148.2769768-2-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 12:46:22 +01:00
Uwe Kleine-König
45558b3abb pwm: sifive: Call pwm_sifive_update_clock() while mutex is held
As was documented in commit 0f02f491b7 ("pwm: sifive: Reduce time the
controller lock is held") a caller of pwm_sifive_update_clock() must
hold the mutex. So fix pwm_sifive_clock_notifier() to grab the lock.

While this necessity was only documented later, the race exists since
the driver was introduced.

Fixes: 9e37a53eb0 ("pwm: sifive: Add a driver for SiFive SoC PWM")
Reported-by: Emil Renner Berthing <emil.renner.berthing@canonical.com>
Reviewed-by: Emil Renner Berthing <emil.renner.berthing@canonical.com>
Link: https://lore.kernel.org/r/20221018061656.1428111-1-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>
2022-12-06 12:46:03 +01:00
Uwe Kleine-König
2375e964d5 pwm: sifive: Shut down hardware only after pwmchip_remove() completed
The PWMs are expected to be functional until pwmchip_remove() is called.
So disable the clks only afterwards.

Fixes: 9e37a53eb0 ("pwm: sifive: Add a driver for SiFive SoC PWM")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Tested-by: Emil Renner Berthing <emil.renner.berthing@canonical.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2022-07-29 13:41:13 +02:00
Uwe Kleine-König
ace41d7564 pwm: sifive: Ensure the clk is enabled exactly once per running PWM
.apply() assumes the clk to be for a given PWM iff the PWM is enabled.
So make sure this is the case when .probe() completes. And in .remove()
disable the according number of times.

This fixes a clk enable/disable imbalance, if some PWMs are already running
at probe time.

Fixes: 9e37a53eb0 (pwm: sifive: Add a driver for SiFive SoC PWM)
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Tested-by: Emil Renner Berthing <emil.renner.berthing@canonical.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2022-07-29 13:41:05 +02:00
Uwe Kleine-König
1695b421e1 pwm: sifive: Simplify clk handling
The clk is necessary for both register access and (enabled) operation of
the PWM. Instead of

	clk_enable()
	update_hw()
	if pwm_got_enabled():
		clk_enable()
	elif pwm_got_disabled():
		clk_disable()
	clk_disable()

which is some cases only calls clk_enable() to immediately afterwards
call clk_disable again, do:

	if (!prev_state.enabled)
		clk_enable()

	# clk enabled exactly once

	update_hw()

	if (!next_state.enabled)
		clk_disable()

which is much easier.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Tested-by: Emil Renner Berthing <emil.renner.berthing@canonical.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2022-07-29 13:40:58 +02:00
Uwe Kleine-König
3586b02663 pwm: sifive: Enable clk only after period check in .apply()
For the period check and the initial calculations of register values there
is no hardware access needed. So delay enabling the clk a bit to simplify
the code flow a bit.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Tested-by: Emil Renner Berthing <emil.renner.berthing@canonical.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2022-07-29 13:40:54 +02:00
Uwe Kleine-König
0f02f491b7 pwm: sifive: Reduce time the controller lock is held
The lock is only to serialize access and update to user_count and
approx_period between different PWMs served by the same pwm_chip.
So the lock needs only to be taken during the check if the (chip global)
period can and/or needs to be changed.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Tested-by: Emil Renner Berthing <emil.renner.berthing@canonical.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2022-07-29 13:40:50 +02:00
Uwe Kleine-König
61180f68ad pwm: sifive: Fold pwm_sifive_enable() into its only caller
There is only a single caller of pwm_sifive_enable() which only enables
or disables the clk. Put this implementation directly into
pwm_sifive_apply() which allows further simplification in the next
change.

There is no change in behaviour.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Tested-by: Emil Renner Berthing <emil.renner.berthing@canonical.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2022-07-29 13:40:45 +02:00
Uwe Kleine-König
20550a6188 pwm: sifive: Simplify offset calculation for PWMCMP registers
Instead of explicitly using PWM_SIFIVE_PWMCMP0 + pwm->hwpwm *
PWM_SIFIVE_SIZE_PWMCMP for each access to one of the PWMCMP registers,
introduce a macro that takes the hwpwm id as parameter.

For the register definition using a plain 4 instead of the cpp constant
PWM_SIFIVE_SIZE_PWMCMP is easier to read, so define the offset macro
without the constant. The latter can then be dropped as there are no
users left.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Tested-by: Emil Renner Berthing <emil.renner.berthing@canonical.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2022-07-29 13:40:40 +02:00
Wan Jiabing
762c4e7fce pwm: sifive: Simplify if-if to if-else
Use if and else instead of if(A) and if (!A).

Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2022-05-20 15:57:43 +02:00
Uwe Kleine-König
ceb2c2842f pwm: sifive: Don't check the return code of pwmchip_remove()
pwmchip_remove() returns always 0. Don't use the value to make it
possible to eventually change the function to return void. Also the
driver core ignores the return value of pwm_sifive_remove().

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2021-09-02 21:38:55 +02:00
Uwe Kleine-König
e9fdf122cf pwm: Simplify all drivers with explicit of_pwm_n_cells = 3
With the previous commit there is no need for the lowlevel driver any
more to specify it it uses two or three cells. So simplify accordingly.

The only non-trival change affects the pwm-rockchip driver: It used to only
support three cells if the hardware supports polarity. Now the default
number depends on the device tree which has to match hardware anyhow
(and if it doesn't the error is just a bit delayed as a PWM handle with
an inverted setting is catched when pwm_apply_state() is called).

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2021-05-25 18:19:15 +02:00
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
Yangtao Li
96cfceba39 pwm: sifive: Convert to devm_platform_ioremap_resource()
Use devm_platform_ioremap_resource() to simplify code.

Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2020-12-17 14:18:46 +01:00
Krzysztof Kozlowski
5530fcaf9c pwm: sifive: Simplify with dev_err_probe()
Common pattern of handling deferred probe can be simplified with
dev_err_probe().  Less code and also it prints the error value.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Palmer Dabbelt <palmerdabbelt@google.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2020-09-24 09:18:11 +02:00
Guru Das Srinagesh
4cc23430a5 pwm: sifive: Use 64-bit division macro
Since the PWM framework is switching struct pwm_args.period's datatype
to u64, prepare for this transition by using DIV64_U64_ROUND_CLOSEST to
handle a 64-bit divisor.

Signed-off-by: Guru Das Srinagesh <gurus@codeaurora.org>
Acked-by: Palmer Dabbelt <palmerdabbelt@google.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2020-06-17 20:42:09 +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
Ding Xiang
f6abac0379 pwm: sifive: Remove redundant error message
devm_ioremap_resource() already outputs an error message, so remove the
extra error message on failure.

Signed-off-by: Ding Xiang <dingxiang@cmss.chinamobile.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-09-21 00:26:16 +02:00
Yash Shah
9e37a53eb0 pwm: sifive: Add a driver for SiFive SoC PWM
Adds a PWM driver for PWM chip present in SiFive's HiFive Unleashed SoC.

Signed-off-by: Wesley W. Terpstra <wesley@sifive.com>
[Atish: Various fixes and code cleanup]
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Yash Shah <yash.shah@sifive.com>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2019-06-25 14:48:12 +02:00