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>

1 files changed, 5 insertions, 3 deletions

diff --git a/drivers/pwm/pwm-imx27.c b/drivers/pwm/pwm-imx27.c
index ea91a2f81a9f..3a22c2fddc45 100644
--- a/drivers/pwm/pwm-imx27.c
+++ b/drivers/pwm/pwm-imx27.c
@@ -118,8 +118,8 @@ static void pwm_imx27_clk_disable_unprepare(struct pwm_imx27_chip *imx)
 	clk_disable_unprepare(imx->clk_ipg);
 }
 
-static void pwm_imx27_get_state(struct pwm_chip *chip,
-				struct pwm_device *pwm, struct pwm_state *state)
+static int pwm_imx27_get_state(struct pwm_chip *chip,
+			       struct pwm_device *pwm, struct pwm_state *state)
 {
 	struct pwm_imx27_chip *imx = to_pwm_imx27_chip(chip);
 	u32 period, prescaler, pwm_clk, val;
@@ -128,7 +128,7 @@ static void pwm_imx27_get_state(struct pwm_chip *chip,
 
 	ret = pwm_imx27_clk_prepare_enable(imx);
 	if (ret < 0)
-		return;
+		return 0;
 
 	val = readl(imx->mmio_base + MX3_PWMCR);
 
@@ -170,6 +170,8 @@ static void pwm_imx27_get_state(struct pwm_chip *chip,
 	state->duty_cycle = DIV_ROUND_UP_ULL(tmp, pwm_clk);
 
 	pwm_imx27_clk_disable_unprepare(imx);
+
+	return 0;
 }
 
 static void pwm_imx27_sw_reset(struct pwm_chip *chip)