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, 6 insertions, 4 deletions

diff --git a/drivers/pwm/pwm-crc.c b/drivers/pwm/pwm-crc.c
index 7b357d1cf642..4099850117ba 100644
--- a/drivers/pwm/pwm-crc.c
+++ b/drivers/pwm/pwm-crc.c
@@ -121,8 +121,8 @@ static int crc_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 	return 0;
 }
 
-static void crc_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
-			      struct pwm_state *state)
+static int crc_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
+			     struct pwm_state *state)
 {
 	struct crystalcove_pwm *crc_pwm = to_crc_pwm(chip);
 	struct device *dev = crc_pwm->chip.dev;
@@ -132,13 +132,13 @@ static void crc_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
 	error = regmap_read(crc_pwm->regmap, PWM0_CLK_DIV, &clk_div_reg);
 	if (error) {
 		dev_err(dev, "Error reading PWM0_CLK_DIV %d\n", error);
-		return;
+		return 0;
 	}
 
 	error = regmap_read(crc_pwm->regmap, PWM0_DUTY_CYCLE, &duty_cycle_reg);
 	if (error) {
 		dev_err(dev, "Error reading PWM0_DUTY_CYCLE %d\n", error);
-		return;
+		return 0;
 	}
 
 	clk_div = (clk_div_reg & ~PWM_OUTPUT_ENABLE) + 1;
@@ -149,6 +149,8 @@ static void crc_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
 		DIV_ROUND_UP_ULL(duty_cycle_reg * state->period, PWM_MAX_LEVEL);
 	state->polarity = PWM_POLARITY_NORMAL;
 	state->enabled = !!(clk_div_reg & PWM_OUTPUT_ENABLE);
+
+	return 0;
 }
 
 static const struct pwm_ops crc_pwm_ops = {