Re: [PATCH v8 2/5] leds: Add of_led_get() and led_put()

[Jean-Jacques Hiblot]

Hi Sebastian,

On 03/10/2019 12:42, Sebastian Reichel wrote:
> Hi,
>
> On Thu, Oct 03, 2019 at 10:28:09AM +0200, Jean-Jacques Hiblot wrote:
> > From: Tomi Valkeinen <tomi.valkeinen@xxxxxx>
> >
> > 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>
> > Signed-off-by: Jean-Jacques Hiblot <jjhiblot@xxxxxx>
> > Acked-by: Pavel Machek <pavel@xxxxxx>
> > ---
> >   drivers/leds/led-class.c | 44 ++++++++++++++++++++++++++++++++++++++++
> >   include/linux/leds.h     |  4 ++++
> >   2 files changed, 48 insertions(+)
> >
> > diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
> > index c2167b66b61f..455545f5d663 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);
> If you convert led_node into a fwnode, you can use
> class_find_device_by_fwnode() instead. That way the
> first patch can just be dropped.

Thanks for the reviews.

The first patch could be dropped  indeed, but it would break something 
else I'm working on: getting regulator support in the LED core.

This has been discussed during the v7 iteration of this series.

JJ


> -- Sebastian
>
> > +	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
> > --
> > 2.17.1
> >
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