On Fri, 24 Jan 2025, Suraj Kandpal <suraj.kandpal@xxxxxxxxx> wrote:
> Create a function that fills in the value for
> PANEL_TARGET_LUMINANCE_VALUE which helps in changing the brightness in
> NITS using VESA interface.
>
> Signed-off-by: Suraj Kandpal <suraj.kandpal@xxxxxxxxx>
> ---
> .../drm/i915/display/intel_dp_aux_backlight.c | 29 +++++++++++++++++++
> 1 file changed, 29 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 ac9a69fe3f10..d794397656dd 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 +474,30 @@ 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_nits_brightness(struct intel_connector *connector, u32 level)
_set_luminance()?
Troughout the series, I'd prefer "luminance" over "nits", i.e. measure
over unit.
> +{
> + 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 VESA AUX Nits backlight level: %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 +505,11 @@ 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.nits_support) {
> + if (!intel_dp_aux_vesa_set_nits_brightness(connector, level))
> + return;
> + }
> +
> if (!panel->backlight.edp.vesa.info.aux_set) {
> const u32 pwm_level = intel_backlight_level_to_pwm(connector, level);
--
Jani Nikula, Intel
