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authorTomi Valkeinen <tomi.valkeinen@ti.com>2019-10-03 10:28:09 +0200
committerPavel <pavel@ucw.cz>2020-01-06 00:20:06 +0100
commit699a8c7c4bd376aee4808e6272188319e900c8af (patch)
treeb35f95250a065850ed2a35cf22ceb0209fc4c164 /drivers
parentleds: lm3532: add pointer to documentation and fix typo (diff)
downloadlinux-dev-699a8c7c4bd376aee4808e6272188319e900c8af.tar.xz
linux-dev-699a8c7c4bd376aee4808e6272188319e900c8af.zip
leds: Add of_led_get() and led_put()
This patch adds basic support for a kernel driver to get a LED device. This will be used by the led-backlight driver. Only OF version is implemented for now, and the behavior is similar to PWM's of_pwm_get() and pwm_put(). Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com> Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Pavel Machek <pavel@ucw.cz>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/leds/led-class.c44
1 files changed, 44 insertions, 0 deletions
diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
index 438774315e6c..03ce74a2e6a9 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -19,6 +19,7 @@
#include <linux/spinlock.h>
#include <linux/timer.h>
#include <uapi/linux/uleds.h>
+#include <linux/of.h>
#include "leds.h"
static struct class *leds_class;
@@ -214,6 +215,49 @@ static int led_resume(struct device *dev)
static SIMPLE_DEV_PM_OPS(leds_class_dev_pm_ops, led_suspend, led_resume);
+/**
+ * of_led_get() - request a LED device via the LED framework
+ * @np: device node to get the LED device from
+ * @index: the index of the LED
+ *
+ * Returns the LED device parsed from the phandle specified in the "leds"
+ * property of a device tree node or a negative error-code on failure.
+ */
+struct led_classdev *of_led_get(struct device_node *np, int index)
+{
+ struct device *led_dev;
+ struct led_classdev *led_cdev;
+ struct device_node *led_node;
+
+ led_node = of_parse_phandle(np, "leds", index);
+ if (!led_node)
+ return ERR_PTR(-ENOENT);
+
+ led_dev = class_find_device_by_of_node(leds_class, led_node);
+ of_node_put(led_node);
+
+ if (!led_dev)
+ return ERR_PTR(-EPROBE_DEFER);
+
+ led_cdev = dev_get_drvdata(led_dev);
+
+ if (!try_module_get(led_cdev->dev->parent->driver->owner))
+ return ERR_PTR(-ENODEV);
+
+ return led_cdev;
+}
+EXPORT_SYMBOL_GPL(of_led_get);
+
+/**
+ * led_put() - release a LED device
+ * @led_cdev: LED device
+ */
+void led_put(struct led_classdev *led_cdev)
+{
+ module_put(led_cdev->dev->parent->driver->owner);
+}
+EXPORT_SYMBOL_GPL(led_put);
+
static int led_classdev_next_name(const char *init_name, char *name,
size_t len)
{