Commit f2db78e3 authored by Suraj Kandpal's avatar Suraj Kandpal
Browse files

drm/dp: Modify drm_edp_backlight_set_level 



Modify drm_edp_backlight_set_level to be able to set the value
for register in DP_EDP_PANEL_TARGET_LUMINANCE_VALUE. We multiply
the level with 1000 since we get the value in Nits and the
register accepts it in milliNits.

--v2
-Add comment regarding the unit [Arun]

Signed-off-by: default avatarSuraj Kandpal <suraj.kandpal@intel.com>
Reviewed-by: default avatarArun R Murthy <arun.r.murthy@intel.com>
Link: https://lore.kernel.org/r/20250620063445.3603086-9-suraj.kandpal@intel.com
parent 2ff7f0c3

drivers/gpu/drm/display/drm_dp_helper.c

+12 −4
Original line number Diff line number Diff line
@@ -3944,20 +3944,28 @@ int drm_edp_backlight_set_level(struct drm_dp_aux *aux, const struct drm_edp_bac 
				u32 level)

{

	int ret;

	u8 buf[2] = { 0 };

	unsigned int offset = DP_EDP_BACKLIGHT_BRIGHTNESS_MSB;

	u8 buf[3] = { 0 };



	/* The panel uses the PWM for controlling brightness levels */

	if (!bl->aux_set)

	if (!(bl->aux_set || bl->luminance_set))

		return 0;



	if (bl->lsb_reg_used) {

	if (bl->luminance_set) {

		level = level * 1000;

		level &= 0xffffff;

		buf[0] = (level & 0x0000ff);

		buf[1] = (level & 0x00ff00) >> 8;

		buf[2] = (level & 0xff0000) >> 16;

		offset = DP_EDP_PANEL_TARGET_LUMINANCE_VALUE;

	} else if (bl->lsb_reg_used) {

		buf[0] = (level & 0xff00) >> 8;

		buf[1] = (level & 0x00ff);

	} else {

		buf[0] = level;

	}



	ret = drm_dp_dpcd_write_data(aux, DP_EDP_BACKLIGHT_BRIGHTNESS_MSB, buf, sizeof(buf));

	ret = drm_dp_dpcd_write_data(aux, offset, buf, sizeof(buf));

	if (ret < 0) {

		drm_err(aux->drm_dev,

			"%s: Failed to write aux backlight level: %d\n",