[v5 2/5] drm/panel-simple: Support DP AUX backlight

From: Rajeev Nandan
Date: Sun May 30 2021 - 11:57:33 EST


If there is no backlight specified in the device tree and the panel
has access to the DP AUX channel then create a DP AUX backlight if
supported by the panel.

Signed-off-by: Rajeev Nandan <rajeevny@xxxxxxxxxxxxxx>
---

This patch depends on [1] (drm/panel: panel-simple: Stash DP AUX bus;
allow using it for DDC) and the previous patch (2/5) of this series.

Changes in v4:
- New

Changes in v5:
- Address review comments and move backlight functions to drm_panel.c (Douglas)
- Create and register DP AUX backlight if there is no backlight specified in the
device tree and panel has the DP AUX channel. (Douglas)
- The new drm_panel_dp_aux_backlight() will do the drm_edp_backlight_supported() check.

[1] https://lore.kernel.org/dri-devel/20210524165920.v8.7.I18e60221f6d048d14d6c50a770b15f356fa75092@changeid/

drivers/gpu/drm/panel/panel-simple.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.c
index b09be6e..047fad5 100644
--- a/drivers/gpu/drm/panel/panel-simple.c
+++ b/drivers/gpu/drm/panel/panel-simple.c
@@ -800,6 +800,12 @@ static int panel_simple_probe(struct device *dev, const struct panel_desc *desc,
if (err)
goto disable_pm_runtime;

+ if (!panel->base.backlight && panel->aux) {
+ err = drm_panel_dp_aux_backlight(&panel->base, panel->aux);
+ if (err)
+ goto disable_pm_runtime;
+ }
+
drm_panel_add(&panel->base);

return 0;
--
2.7.4