| Message ID | 20190804201637.1240-16-sam@ravnborg.org (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | drm: panel related updates | expand |
Hi Sam, Thank you for the patch. On Sun, Aug 04, 2019 at 10:16:36PM +0200, Sam Ravnborg wrote: > Panels often supports backlight as specified in a device tree. > Update the drm_panel infrastructure to support this to > simplify the drivers. > > With this the panel driver just needs to add the following to the > probe() function: > > err = drm_panel_of_backlight(panel); > if (err) > return err; > > Then drm_panel will handle all the rest. Do you have an example on how this will simplify drivers ? How many existing panel drivers would benefit from this, and do you plan to convert them ? > > Signed-off-by: Sam Ravnborg <sam@ravnborg.org> > Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> > Cc: Maxime Ripard <maxime.ripard@bootlin.com> > Cc: Sean Paul <sean@poorly.run> > Cc: Thierry Reding <thierry.reding@gmail.com> > Cc: Sam Ravnborg <sam@ravnborg.org> > Cc: David Airlie <airlied@linux.ie> > Cc: Daniel Vetter <daniel@ffwll.ch> > --- > drivers/gpu/drm/drm_panel.c | 41 +++++++++++++++++++++++++++++++++++++ > include/drm/drm_panel.h | 23 +++++++++++++++++++++ > 2 files changed, 64 insertions(+) > > diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c > index 0853764040de..d8139674b883 100644 > --- a/drivers/gpu/drm/drm_panel.c > +++ b/drivers/gpu/drm/drm_panel.c > @@ -21,6 +21,7 @@ > * DEALINGS IN THE SOFTWARE. > */ > > +#include <linux/backlight.h> > #include <linux/err.h> > #include <linux/module.h> > > @@ -110,6 +111,7 @@ int drm_panel_enable(struct drm_panel *panel) > if (ret >= 0) > panel->enabled = true; > > + backlight_enable(panel->backlight); > return ret; > } > EXPORT_SYMBOL(drm_panel_enable); > @@ -134,6 +136,8 @@ int drm_panel_disable(struct drm_panel *panel) > if (!panel->enabled) > return 0; > > + backlight_disable(panel->backlight); > + > if (panel->funcs && panel->funcs->disable) > ret = panel->funcs->disable(panel); > > @@ -308,6 +312,43 @@ struct drm_panel *of_drm_find_panel(const struct device_node *np) > EXPORT_SYMBOL(of_drm_find_panel); > #endif > > +#ifdef CONFIG_BACKLIGHT_CLASS_DEVICE > +/** > + * drm_panel_of_backlight - use backlight device node for backlight > + * @panel: DRM panel > + * > + * Use this function to enable backlight handling if your panel > + * uses device tree and has a backlight handle. > + * > + * When panel is enabled backlight will be enabled after a > + * successfull call to &drm_panel_funcs.enable() > + * > + * When panel is disabled backlight will be disabled before the > + * call to &drm_panel_funcs.disable(). > + * > + * A typical implementation for a panel driver supporting device tree > + * will call this function and then backlight just works. > + * > + * Return: 0 on success or a negative error code on failure. > + */ > +int drm_panel_of_backlight(struct drm_panel *panel) > +{ > + struct backlight_device *backlight; > + > + if (!panel || !panel->dev) > + return -EINVAL; > + > + backlight = devm_of_find_backlight(panel->dev); > + > + if (IS_ERR(backlight)) > + return PTR_ERR(backlight); > + > + panel->backlight = backlight; > + return 0; > +} > +EXPORT_SYMBOL(drm_panel_of_backlight); > +#endif > + > MODULE_AUTHOR("Thierry Reding <treding@nvidia.com>"); > MODULE_DESCRIPTION("DRM panel infrastructure"); > MODULE_LICENSE("GPL and additional rights"); > diff --git a/include/drm/drm_panel.h b/include/drm/drm_panel.h > index 7493500fc9bd..31349c2393b7 100644 > --- a/include/drm/drm_panel.h > +++ b/include/drm/drm_panel.h > @@ -28,6 +28,7 @@ > #include <linux/errno.h> > #include <linux/list.h> > > +struct backlight_device; > struct device_node; > struct drm_connector; > struct drm_device; > @@ -59,6 +60,10 @@ struct display_timing; > * > * To save power when no video data is transmitted, a driver can power down > * the panel. This is the job of the .unprepare() function. > + * > + * Backlight can be handled automatically if configured using > + * drm_panel_of_backlight(). Then the driver do not need to implement the > + * functionality to enable/disable backlight. > */ > struct drm_panel_funcs { > /** > @@ -139,6 +144,15 @@ struct drm_panel { > */ > struct device *dev; > > + /** > + * @backlight: > + * > + * Backlight device, used to turn on backlight after > + * the call to enable(), and to turn off > + * backlight before call to disable(). > + */ > + struct backlight_device *backlight; > + > /** > * @funcs: > * > @@ -193,4 +207,13 @@ static inline struct drm_panel *of_drm_find_panel(const struct device_node *np) > } > #endif > > +#if defined(CONFIG_BACKLIGHT_CLASS_DEVICE) && defined(CONFIG_DRM_PANEL) > +int drm_panel_of_backlight(struct drm_panel *panel); I would expect callers of this function to depend on (or select) CONFIG_DRM_PANEL, so I would drop it from here. > +#else > +static inline int drm_panel_of_backlight(struct drm_panel *panel) > +{ > + return -EINVAL; Maybe -ENOSYS ? > +} > +#endif > + > #endif
diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c index 0853764040de..d8139674b883 100644 --- a/drivers/gpu/drm/drm_panel.c +++ b/drivers/gpu/drm/drm_panel.c @@ -21,6 +21,7 @@ * DEALINGS IN THE SOFTWARE. */ +#include <linux/backlight.h> #include <linux/err.h> #include <linux/module.h> @@ -110,6 +111,7 @@ int drm_panel_enable(struct drm_panel *panel) if (ret >= 0) panel->enabled = true; + backlight_enable(panel->backlight); return ret; } EXPORT_SYMBOL(drm_panel_enable); @@ -134,6 +136,8 @@ int drm_panel_disable(struct drm_panel *panel) if (!panel->enabled) return 0; + backlight_disable(panel->backlight); + if (panel->funcs && panel->funcs->disable) ret = panel->funcs->disable(panel); @@ -308,6 +312,43 @@ struct drm_panel *of_drm_find_panel(const struct device_node *np) EXPORT_SYMBOL(of_drm_find_panel); #endif +#ifdef CONFIG_BACKLIGHT_CLASS_DEVICE +/** + * drm_panel_of_backlight - use backlight device node for backlight + * @panel: DRM panel + * + * Use this function to enable backlight handling if your panel + * uses device tree and has a backlight handle. + * + * When panel is enabled backlight will be enabled after a + * successfull call to &drm_panel_funcs.enable() + * + * When panel is disabled backlight will be disabled before the + * call to &drm_panel_funcs.disable(). + * + * A typical implementation for a panel driver supporting device tree + * will call this function and then backlight just works. + * + * Return: 0 on success or a negative error code on failure. + */ +int drm_panel_of_backlight(struct drm_panel *panel) +{ + struct backlight_device *backlight; + + if (!panel || !panel->dev) + return -EINVAL; + + backlight = devm_of_find_backlight(panel->dev); + + if (IS_ERR(backlight)) + return PTR_ERR(backlight); + + panel->backlight = backlight; + return 0; +} +EXPORT_SYMBOL(drm_panel_of_backlight); +#endif + MODULE_AUTHOR("Thierry Reding <treding@nvidia.com>"); MODULE_DESCRIPTION("DRM panel infrastructure"); MODULE_LICENSE("GPL and additional rights"); diff --git a/include/drm/drm_panel.h b/include/drm/drm_panel.h index 7493500fc9bd..31349c2393b7 100644 --- a/include/drm/drm_panel.h +++ b/include/drm/drm_panel.h @@ -28,6 +28,7 @@ #include <linux/errno.h> #include <linux/list.h> +struct backlight_device; struct device_node; struct drm_connector; struct drm_device; @@ -59,6 +60,10 @@ struct display_timing; * * To save power when no video data is transmitted, a driver can power down * the panel. This is the job of the .unprepare() function. + * + * Backlight can be handled automatically if configured using + * drm_panel_of_backlight(). Then the driver do not need to implement the + * functionality to enable/disable backlight. */ struct drm_panel_funcs { /** @@ -139,6 +144,15 @@ struct drm_panel { */ struct device *dev; + /** + * @backlight: + * + * Backlight device, used to turn on backlight after + * the call to enable(), and to turn off + * backlight before call to disable(). + */ + struct backlight_device *backlight; + /** * @funcs: * @@ -193,4 +207,13 @@ static inline struct drm_panel *of_drm_find_panel(const struct device_node *np) } #endif +#if defined(CONFIG_BACKLIGHT_CLASS_DEVICE) && defined(CONFIG_DRM_PANEL) +int drm_panel_of_backlight(struct drm_panel *panel); +#else +static inline int drm_panel_of_backlight(struct drm_panel *panel) +{ + return -EINVAL; +} +#endif + #endif
Panels often supports backlight as specified in a device tree. Update the drm_panel infrastructure to support this to simplify the drivers. With this the panel driver just needs to add the following to the probe() function: err = drm_panel_of_backlight(panel); if (err) return err; Then drm_panel will handle all the rest. Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Maxime Ripard <maxime.ripard@bootlin.com> Cc: Sean Paul <sean@poorly.run> Cc: Thierry Reding <thierry.reding@gmail.com> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: David Airlie <airlied@linux.ie> Cc: Daniel Vetter <daniel@ffwll.ch> --- drivers/gpu/drm/drm_panel.c | 41 +++++++++++++++++++++++++++++++++++++ include/drm/drm_panel.h | 23 +++++++++++++++++++++ 2 files changed, 64 insertions(+)