[v6,1/4] leds: Add of_led_get() and led_put()

Submitted by Jean-Jacques Hiblot on Sept. 10, 2019, 1:27 p.m.

Details

Message ID 20190910132734.9544-2-jjhiblot@ti.com
State New
Headers show
Series "Add a generic driver for LED-based backlight" ( rev: 5 ) in DRI devel

Not browsing as part of any series.

Commit Message

Jean-Jacques Hiblot Sept. 10, 2019, 1:27 p.m.
From: Tomi Valkeinen <tomi.valkeinen@ti.com>

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>
---
 drivers/leds/led-class.c | 50 ++++++++++++++++++++++++++++++++++++++++
 include/linux/leds.h     |  4 ++++
 2 files changed, 54 insertions(+)

Patch hide | download patch | download mbox

diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
index 159c6caa374b..d4d22f4b5052 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -18,6 +18,7 @@ 
 #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;
@@ -213,6 +214,55 @@  static int led_resume(struct device *dev)
 
 static SIMPLE_DEV_PM_OPS(leds_class_dev_pm_ops, led_suspend, led_resume);
 
+static int led_match_led_node(struct device *led_dev, const void *data)
+{
+	return led_dev->of_node == data;
+}
+
+/**
+ * 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(leds_class, NULL, led_node,
+		led_match_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 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 bee8e3f8dddd..0a71c7cdd191 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -19,6 +19,7 @@ 
 
 struct device;
 struct led_pattern;
+struct device_node;
 /*
  * LED Core
  */
@@ -145,6 +146,9 @@  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, int index);
+extern void led_put(struct led_classdev *led_cdev);
+
 /**
  * led_blink_set - set blinking with software fallback
  * @led_cdev: the LED to start blinking

Comments

Hi Jean,

Please rebase your patch set onto linux-leds.git [0] -
we've had some updates in the meantime and now your
set doesn't apply.

Best regards,
Jacek Anaszewski

On 9/10/19 3:27 PM, Jean-Jacques Hiblot wrote:
> From: Tomi Valkeinen <tomi.valkeinen@ti.com>
> 
> 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>
> ---
>  drivers/leds/led-class.c | 50 ++++++++++++++++++++++++++++++++++++++++
>  include/linux/leds.h     |  4 ++++
>  2 files changed, 54 insertions(+)
> 
> diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
> index 159c6caa374b..d4d22f4b5052 100644
> --- a/drivers/leds/led-class.c
> +++ b/drivers/leds/led-class.c
> @@ -18,6 +18,7 @@
>  #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;
> @@ -213,6 +214,55 @@ static int led_resume(struct device *dev)
>  
>  static SIMPLE_DEV_PM_OPS(leds_class_dev_pm_ops, led_suspend, led_resume);
>  
> +static int led_match_led_node(struct device *led_dev, const void *data)
> +{
> +	return led_dev->of_node == data;
> +}
> +
> +/**
> + * 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(leds_class, NULL, led_node,
> +		led_match_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 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 bee8e3f8dddd..0a71c7cdd191 100644
> --- a/include/linux/leds.h
> +++ b/include/linux/leds.h
> @@ -19,6 +19,7 @@
>  
>  struct device;
>  struct led_pattern;
> +struct device_node;
>  /*
>   * LED Core
>   */
> @@ -145,6 +146,9 @@ 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, int index);
> +extern void led_put(struct led_classdev *led_cdev);
> +
>  /**
>   * led_blink_set - set blinking with software fallback
>   * @led_cdev: the LED to start blinking
> 

[0]
https://git.kernel.org/pub/scm/linux/kernel/git/j.anaszewski/linux-leds.git/log/?h=for-next