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