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Subject[PATCH] Input: cap11xx - switch to using set_brightness_blocking()
Updating LED state requires access to regmap and therefore we may sleep, so
we could not do that directly form set_brightness() method. Historically
we used private work to adjust the brightness, but with the introduction of
set_brightness_blocking() we no longer need it.

As a bonus, not having our own work item means we do not have
use-after-free issue as we neglected to cancel outstanding work on driver
unbind.

Reported-by: Sven Van Asbroeck <thesven73@gmail.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
drivers/input/keyboard/cap11xx.c | 47 ++++++++++++++------------------
1 file changed, 21 insertions(+), 26 deletions(-)

diff --git a/drivers/input/keyboard/cap11xx.c b/drivers/input/keyboard/cap11xx.c
index 312916f99597..c0baf323ddda 100644
--- a/drivers/input/keyboard/cap11xx.c
+++ b/drivers/input/keyboard/cap11xx.c
@@ -75,9 +75,8 @@
struct cap11xx_led {
struct cap11xx_priv *priv;
struct led_classdev cdev;
- struct work_struct work;
u32 reg;
- enum led_brightness new_brightness;
+ enum led_brightness brightness;
};
#endif

@@ -233,30 +232,28 @@ static void cap11xx_input_close(struct input_dev *idev)
}

#ifdef CONFIG_LEDS_CLASS
-static void cap11xx_led_work(struct work_struct *work)
-{
- struct cap11xx_led *led = container_of(work, struct cap11xx_led, work);
- struct cap11xx_priv *priv = led->priv;
- int value = led->new_brightness;
-
- /*
- * All LEDs share the same duty cycle as this is a HW limitation.
- * Brightness levels per LED are either 0 (OFF) and 1 (ON).
- */
- regmap_update_bits(priv->regmap, CAP11XX_REG_LED_OUTPUT_CONTROL,
- BIT(led->reg), value ? BIT(led->reg) : 0);
-}
-
-static void cap11xx_led_set(struct led_classdev *cdev,
- enum led_brightness value)
+static int cap11xx_led_set(struct led_classdev *cdev,
+ enum led_brightness value)
{
struct cap11xx_led *led = container_of(cdev, struct cap11xx_led, cdev);
+ struct cap11xx_priv *priv = led->priv;
+ int error = 0;
+
+ if (led->brightness != value) {
+ /*
+ * All LEDs share the same duty cycle as this is a HW
+ * limitation. Brightness levels per LED are either
+ * 0 (OFF) and 1 (ON).
+ */
+ error = regmap_update_bits(priv->regmap,
+ CAP11XX_REG_LED_OUTPUT_CONTROL,
+ BIT(led->reg),
+ value ? BIT(led->reg) : 0);
+ if (!error)
+ led->brightness = value;
+ }

- if (led->new_brightness == value)
- return;
-
- led->new_brightness = value;
- schedule_work(&led->work);
+ return error;
}

static int cap11xx_init_leds(struct device *dev,
@@ -299,7 +296,7 @@ static int cap11xx_init_leds(struct device *dev,
led->cdev.default_trigger =
of_get_property(child, "linux,default-trigger", NULL);
led->cdev.flags = 0;
- led->cdev.brightness_set = cap11xx_led_set;
+ led->cdev.brightness_set_blocking = cap11xx_led_set;
led->cdev.max_brightness = 1;
led->cdev.brightness = LED_OFF;

@@ -312,8 +309,6 @@ static int cap11xx_init_leds(struct device *dev,
led->reg = reg;
led->priv = priv;

- INIT_WORK(&led->work, cap11xx_led_work);
-
error = devm_led_classdev_register(dev, &led->cdev);
if (error) {
of_node_put(child);
--
2.20.1.611.gfbb209baf1-goog

--
Dmitry

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