2019-07-17 14:16:10

by Jean-Jacques Hiblot

Subject: [PATCH v4 2/4] leds: Add managed API to get a LED from a device driver

If the LED is acquired by a consumer device with devm_led_get(), it is
automatically released when the device is detached.

Signed-off-by: Jean-Jacques Hiblot <[email protected]>
Acked-by: Pavel Machek <[email protected]>
---
drivers/leds/led-class.c | 42 ++++++++++++++++++++++++++++++++++++++++
include/linux/leds.h | 2 ++
2 files changed, 44 insertions(+)

diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
index 9f48798a713d..714b55f1da0f 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -263,6 +263,48 @@ void led_put(struct led_classdev *led_cdev)
}
EXPORT_SYMBOL_GPL(led_put);

+static void devm_led_release(struct device *dev, void *res)
+{
+ struct led_classdev **p = res;
+
+ led_put(*p);
+}
+
+/**
+ * devm_led_get - Resource-managed request of a LED device
+ * @dev: LED consumer
+ * @idx: index of the LED to obtain in the consumer
+ *
+ * The device node of the device is parse to find the request LED device.
+ * The LED device returned from this function is automatically released
+ * on driver detach.
+ *
+ * @return a pointer to a LED device or ERR_PTR(errno) on failure.
+ */
+struct led_classdev *__must_check devm_led_get(struct device *dev,
+ int index)
+{
+ struct led_classdev *led;
+ struct led_classdev **dr;
+
+ led = of_led_get(dev->of_node, index);
+ if (IS_ERR(led))
+ return led;
+
+ dr = devres_alloc(devm_led_release, sizeof(struct led_classdev *),
+ GFP_KERNEL);
+ if (!dr) {
+ led_put(led);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ *dr = led;
+ devres_add(dev, dr);
+
+ return led;
+}
+EXPORT_SYMBOL_GPL(devm_led_get);
+
static int match_name(struct device *dev, const void *data)
{
if (!dev_name(dev))
diff --git a/include/linux/leds.h b/include/linux/leds.h
index 0a71c7cdd191..7fcec566d774 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -148,6 +148,8 @@ extern void led_classdev_resume(struct led_classdev *led_cdev);

extern struct led_classdev *of_led_get(struct device_node *np, int index);
extern void led_put(struct led_classdev *led_cdev);
+struct led_classdev *__must_check devm_led_get(struct device *dev,
+ int index);

/**
* led_blink_set - set blinking with software fallback
--
2.17.1

2019-07-31 13:24:53

by Tomi Valkeinen

Subject: Re: [PATCH v4 2/4] leds: Add managed API to get a LED from a device driver

On 17/07/2019 17:15, Jean-Jacques Hiblot wrote:

> +struct led_classdev *__must_check devm_led_get(struct device *dev,
> + int index)
> +{
> + struct led_classdev *led;
> + struct led_classdev **dr;
> +

Should you check here if dev->of_node == NULL? Or should of_led_get()
check it.

> + led = of_led_get(dev->of_node, index);
> + if (IS_ERR(led))
> + return led;
> +
> + dr = devres_alloc(devm_led_release, sizeof(struct led_classdev *),
> + GFP_KERNEL);
> + if (!dr) {
> + led_put(led);
> + return ERR_PTR(-ENOMEM);
> + }
> +
> + *dr = led;
> + devres_add(dev, dr);
> +
> + return led;
> +}

Tomi

--
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki