On Thu, Jan 18, 2018 at 04:32:26PM +0530, Meghana Madhyastha wrote:
> 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.madhyas...@gmail.com>
> > >---
> > > 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).
Sorry, the name confused me. I mistakenly though this was API code like
devm_gpiod_put and devm_clk_put, rather than a static method.
Whilst its my fault for overlooking the "static" please could rename this to
devm_backlight_release(). I don't want to keep being confused every time
I re-read it!
Daniel.
>
> 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
> > >
