Hi Tomi,
Thanks for the patch. Generally, I'd prefer to add files
drivers/leds/of.c and include/linux/of_leds.h and put related functions
there. Those functions' names should begin with "of_". Please provide
also no-op versions of the functions to address configurations when
CONFIG_OF isn't enabled. I have also few comments below.
On 08/25/2015 01:34 PM, Tomi Valkeinen wrote:
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@xxxxxx>
---
drivers/leds/led-class.c | 75 ++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/leds.h | 4 +++
2 files changed, 79 insertions(+)
diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
index beabfbc6f7cd..0cb4fd7d71d6 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -20,6 +20,7 @@
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/timer.h>
+#include <linux/of.h>
#include "leds.h"
static struct class *leds_class;
@@ -216,6 +217,80 @@ static int led_resume(struct device *dev)
static SIMPLE_DEV_PM_OPS(leds_class_dev_pm_ops, led_suspend, led_resume);
+/* find OF node for the given led_cdev */
+static struct device_node *find_led_of_node(struct led_classdev *led_cdev)
+{
+ struct device *led_dev = led_cdev->dev;
+ struct device_node *child;
+
+ for_each_child_of_node(led_dev->parent->of_node, child) {
+ if (of_property_match_string(child, "label", led_cdev->name) == 0)
+ return child;
+ }
+
+ return NULL;
+}
+
+static int led_match_led_node(struct device *led_dev, const void *data)
+{
+ struct led_classdev *led_cdev = dev_get_drvdata(led_dev);
+ const struct device_node *target_node = data;
+ struct device_node *led_node;
+
+ led_node = find_led_of_node(led_cdev);
+ if (!led_node)
+ return 0;
+
+ of_node_put(led_node);
+
+ return led_node == target_node ? 1 : 0;
+}
+
+/**
+ * of_led_get() - request a LED device via the LED framework
+ * @np: device node to get the LED device from
+ *
+ * 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)
+{
+ struct device *led_dev;
+ struct led_classdev *led_cdev;
+ struct device_node *led_node;
+
+ led_node = of_parse_phandle(np, "leds", 0);
+ if (!led_node)
+ return ERR_PTR(-ENODEV);
+
+ led_dev = class_find_device(leds_class, NULL, led_node,
+ led_match_led_node);
Single of_node_put(led_node) here will do.
+ if (!led_dev) {
+ of_node_put(led_node);
+ return ERR_PTR(-EPROBE_DEFER);
+ }
+
+ of_node_put(led_node);
+ 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);
Please move it to include/linux/leds.h, make static inline and provide
also no-op version for the case when CONFIG_LEDS_CLASS isn't enabled.
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 b122eeafb5dc..efc9b28af564 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -21,6 +21,7 @@
#include <linux/workqueue.h>
struct device;
+struct device_node;
/*
* LED Core
*/
@@ -113,6 +114,9 @@ extern void devm_led_classdev_unregister(struct device *parent,
extern void led_classdev_suspend(struct led_classdev *led_cdev);
extern void led_classdev_resume(struct led_classdev *led_cdev);
+extern struct led_classdev *of_led_get(struct device_node *np);
We need also no-op version for (!CONFIG_OF || !CONFIG_LEDS_CLASS).
+extern void led_put(struct led_classdev *led_cdev);
+
/**
* led_blink_set - set blinking with software fallback
* @led_cdev: the LED to start blinking
--
Best Regards,
Jacek Anaszewski
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