> Create a function that fills in the value for PANEL_TARGET_LUMINANCE_VALUE
> which helps in changing the luminance in nits using VESA interface.
>
> --v2
> -Prefer using luminance over nits [Jani]
>
> Signed-off-by: Suraj Kandpal <suraj.kandpal@xxxxxxxxx>
> Tested-by: Ben Kao <ben.kao@xxxxxxxxx>
> ---
Reviewed-by: Arun R Murthy <arun.r.murthy@xxxxxxxxx>
Thanks and Regards,
Arun R Murthy
--------------------
> .../drm/i915/display/intel_dp_aux_backlight.c | 30 +++++++++++++++++++
> 1 file changed, 30 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
> b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
> index a733b5623563..a9facfacac95 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
> @@ -474,6 +474,31 @@ static u32 intel_dp_aux_vesa_get_backlight(struct
> intel_connector *connector, en
> return connector->panel.backlight.level; }
>
> +static int
> +intel_dp_aux_vesa_set_luminance(struct intel_connector *connector, u32
> +level) {
> + struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder);
> + u8 buf[3];
> + int ret;
> +
> + level = level * 1000;
> + level &= 0xffffff;
> + buf[0] = (level & 0x0000ff);
> + buf[1] = (level & 0x00ff00) >> 8;
> + buf[2] = (level & 0xff0000) >> 16;
> +
> + ret = drm_dp_dpcd_write(&intel_dp->aux,
> DP_EDP_PANEL_TARGET_LUMINANCE_VALUE,
> + buf, sizeof(buf));
> + if (ret != sizeof(buf)) {
> + drm_err(intel_dp->aux.drm_dev,
> + "%s: Failed to set VESA Aux Luminance: %d\n",
> + intel_dp->aux.name, ret);
> + return -EINVAL;
> + } else {
> + return 0;
> + }
> +}
> +
> static void
> intel_dp_aux_vesa_set_backlight(const struct drm_connector_state
> *conn_state, u32 level) { @@ -481,6 +506,11 @@
> intel_dp_aux_vesa_set_backlight(const struct drm_connector_state
> *conn_state, u3
> struct intel_panel *panel = &connector->panel;
> struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder);
>
> + if (panel->backlight.edp.vesa.luminance_control_support) {
> + if (!intel_dp_aux_vesa_set_luminance(connector, level))
> + return;
> + }
> +
> if (!panel->backlight.edp.vesa.info.aux_set) {
> const u32 pwm_level =
> intel_backlight_level_to_pwm(connector, level);
>
> --
> 2.34.1
