leds: sgm3140: Add missing timer cleanup and flash gpio control

[ Upstream commit 205c29887a333ee4b37596e6533373e38cb23947 ]

Enabling strobe and then setting brightness to 0 causes the driver to enter
invalid state after strobe end timer fires. We should cancel strobe mode
resources when changing brightness (aka torch mode).

Fixes: cef8ec8 ("leds: add sgm3140 driver")
Signed-off-by: Ondrej Jirman <megi@xff.cz>
Link: https://lore.kernel.org/r/20240217191133.1757553-1-megi@xff.cz
Signed-off-by: Lee Jones <lee@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/leds/flash/leds-sgm3140.c

@@ -114,8 +114,11 @@ static int sgm3140_brightness_set(struct led_classdev *led_cdev,
 				"failed to enable regulator: %d\n", ret);
 			return ret;
 		}
+		gpiod_set_value_cansleep(priv->flash_gpio, 0);
 		gpiod_set_value_cansleep(priv->enable_gpio, 1);
 	} else {
+		del_timer_sync(&priv->powerdown_timer);
+		gpiod_set_value_cansleep(priv->flash_gpio, 0);
 		gpiod_set_value_cansleep(priv->enable_gpio, 0);
 		ret = regulator_disable(priv->vin_regulator);
 		if (ret) {