| Message ID | 20190918145730.22805-3-jjhiblot@ti.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add a generic driver for LED-based backlight | expand |
Hi Jean, Thank you for the patch. I have one nit below. On 9/18/19 4:57 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 c2167b66b61f..2b8f20f94128 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 +215,55 @@ 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_of_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_of_node); Now we have class_find_device_by_of_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) > { > diff --git a/include/linux/leds.h b/include/linux/leds.h > index b8df71193329..6f7371bc7757 100644 > --- a/include/linux/leds.h > +++ b/include/linux/leds.h > @@ -20,6 +20,7 @@ > > struct device; > struct led_pattern; > +struct device_node; > /* > * LED Core > */ > @@ -196,6 +197,9 @@ 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 >
diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c index c2167b66b61f..2b8f20f94128 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 +215,55 @@ 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_of_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_of_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) { diff --git a/include/linux/leds.h b/include/linux/leds.h index b8df71193329..6f7371bc7757 100644 --- a/include/linux/leds.h +++ b/include/linux/leds.h @@ -20,6 +20,7 @@ struct device; struct led_pattern; +struct device_node; /* * LED Core */ @@ -196,6 +197,9 @@ 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