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 <[email protected]>
Reviewed-by: Baolin Wang <[email protected]>
Reviewed-by: Tzung-Bi Shih <[email protected]>
Reviewed-by: Neil Armstrong <[email protected]>
Reviewed-by: Nobuhiro Iwamatsu <[email protected]>
Reviewed-by: Andre Przywara <[email protected]>
Reviewed-by: Dave Stevenson <[email protected]>
Acked-by: Douglas Anderson <[email protected]>
Acked-by: Jernej Skrabec <[email protected]>
Acked-by: Pavel Machek <[email protected]>
Acked-by: Conor Dooley <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Uwe Kleine-König <[email protected]>
Signed-off-by: Thierry Reding <[email protected]>

1 files changed, 4 insertions, 2 deletions

diff --git a/drivers/pwm/pwm-sifive.c b/drivers/pwm/pwm-sifive.c
index bb7239313401..62b6acc6373d 100644
--- a/drivers/pwm/pwm-sifive.c
+++ b/drivers/pwm/pwm-sifive.c
@@ -105,8 +105,8 @@ static void pwm_sifive_update_clock(struct pwm_sifive_ddata *ddata,
 		"New real_period = %u ns\n", ddata->real_period);
 }
 
-static void pwm_sifive_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
-				 struct pwm_state *state)
+static int pwm_sifive_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
+				struct pwm_state *state)
 {
 	struct pwm_sifive_ddata *ddata = pwm_sifive_chip_to_ddata(chip);
 	u32 duty, val;
@@ -123,6 +123,8 @@ static void pwm_sifive_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
 	state->duty_cycle =
 		(u64)duty * ddata->real_period >> PWM_SIFIVE_CMPWIDTH;
 	state->polarity = PWM_POLARITY_INVERSED;
+
+	return 0;
 }
 
 static int pwm_sifive_apply(struct pwm_chip *chip, struct pwm_device *pwm,