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, 5 insertions, 3 deletions

diff --git a/drivers/pwm/pwm-xilinx.c b/drivers/pwm/pwm-xilinx.c
index 4dab2b86c427..f7a50fdcd9a5 100644
--- a/drivers/pwm/pwm-xilinx.c
+++ b/drivers/pwm/pwm-xilinx.c
@@ -169,9 +169,9 @@ static int xilinx_pwm_apply(struct pwm_chip *chip, struct pwm_device *unused,
 	return 0;
 }
 
-static void xilinx_pwm_get_state(struct pwm_chip *chip,
-				 struct pwm_device *unused,
-				 struct pwm_state *state)
+static int xilinx_pwm_get_state(struct pwm_chip *chip,
+				struct pwm_device *unused,
+				struct pwm_state *state)
 {
 	struct xilinx_timer_priv *priv = xilinx_pwm_chip_to_priv(chip);
 	u32 tlr0, tlr1, tcsr0, tcsr1;
@@ -191,6 +191,8 @@ static void xilinx_pwm_get_state(struct pwm_chip *chip,
 	 */
 	if (state->period == state->duty_cycle)
 		state->duty_cycle = 0;
+
+	return 0;
 }
 
 static const struct pwm_ops xilinx_pwm_ops = {