On Wed, Jan 17, 2018 at 05:09:57PM +0000, Daniel Thompson wrote:
> On 16/01/18 10:34, Meghana Madhyastha wrote:
> >Add devm_of_find_backlight and the corresponding release
> >function because some drivers use devres versions of functions
> >for acquiring device resources.
> >
> >Signed-off-by: Meghana Madhyastha <meghana.madhyastha@xxxxxxxxx>
> >---
> > drivers/video/backlight/backlight.c | 29 +++++++++++++++++++++++++++++
> > include/linux/backlight.h | 7 +++++++
> > 2 files changed, 36 insertions(+)
> >
> >diff --git a/drivers/video/backlight/backlight.c b/drivers/video/backlight/backlight.c
> >index 7e4a5d77d..b3f76945f 100644
> >--- a/drivers/video/backlight/backlight.c
> >+++ b/drivers/video/backlight/backlight.c
> >@@ -620,6 +620,35 @@ struct backlight_device *of_find_backlight(struct device *dev)
> > }
> > EXPORT_SYMBOL(of_find_backlight);
> >+static void devm_backlight_put(void *data)
> >+{
> >+ backlight_put(data);
>
> Shouldn't this be using devres_release()?
backlight_put calls put_device which essentially does a release right?
And looking at the code in other driver, looks like most of them use
put_device (to the best of my knowledge, correct me if I'm mistaken).
Thanks and regards,
Meghana
>
> >+}
> >+
> >+/**
> >+ * devm_of_find_backlight - Resource-managed of_find_backlight()
> >+ * @dev: Device
> >+ *
> >+ * Device managed version of of_find_backlight(). The reference on the backlight
> >+ * device is automatically dropped on driver detach.
> >+ */
> >+struct backlight_device *devm_of_find_backlight(struct device *dev)
> >+{
> >+ struct backlight_device *bd;
> >+ int ret;
> >+
> >+ bd = of_find_backlight(dev);
> >+ if (IS_ERR_OR_NULL(bd))
> >+ return bd;
> >+ ret = devm_add_action(dev, devm_backlight_put, bd);
> >+ if (ret) {
> >+ backlight_put(bd);
> >+ return ERR_PTR(ret);
> >+ }
> >+ return bd;
> >+}
> >+EXPORT_SYMBOL(devm_of_find_backlight);
> >+
> > static void __exit backlight_class_exit(void)
> > {
> > class_destroy(backlight_class);
> >diff --git a/include/linux/backlight.h b/include/linux/backlight.h
> >index 32ea510da..1d373f5a6 100644
> >--- a/include/linux/backlight.h
> >+++ b/include/linux/backlight.h
> >@@ -215,11 +215,18 @@ of_find_backlight_by_node(struct device_node *node)
> > #if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
> > struct backlight_device *of_find_backlight(struct device *dev);
> >+struct backlight_device *devm_of_find_backlight(struct device *dev);
> > #else
> > static inline struct backlight_device *of_find_backlight(struct device *dev)
> > {
> > return NULL;
> > }
> >+
> >+static inline struct backlight_device *
> >+devm_of_find_backlight(struct device *dev)
> >+{
> >+ return NULL;
> >+}
> > #endif
> > #endif
> >
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