disp: msm: sde: add support for digital dimming

Add a new connector property to allow DC dimming feature to set
dimming backlight LUT. This change also adds a connector event
for client to register for backlight info needed for digital dimming
feature, including OS brightness, OS brightness_max, panel_backlight,
panel_backlight_max, and scale factors from ABA and LTM features.

Change-Id: I78f713fb2b965ca24effd973b4dfa9ff07a852f8
Signed-off-by: Ping Li <pingli@codeaurora.org>

msm/dsi/dsi_display.c

@@ -243,6 +243,14 @@ int dsi_display_set_backlight(struct drm_connector *connector,
 	if (bl_temp > panel->bl_config.bl_max_level)
 		bl_temp = panel->bl_config.bl_max_level;
 
+	/* use bl_temp as index of dimming bl lut to find the dimming panel backlight */
+	if (bl_temp != 0 && panel->bl_config.dimming_bl_lut &&
+	    bl_temp < panel->bl_config.dimming_bl_lut->length) {
+		DSI_DEBUG("before dimming bl_temp = %u, after dimming bl_temp = %lu\n",
+			bl_temp, panel->bl_config.dimming_bl_lut->mapped_bl[bl_temp]);
+		bl_temp = panel->bl_config.dimming_bl_lut->mapped_bl[bl_temp];
+	}
+
 	DSI_DEBUG("bl_scale = %u, bl_scale_sv = %u, bl_lvl = %u\n",
 		bl_scale, bl_scale_sv, (u32)bl_temp);
 	rc = dsi_display_clk_ctrl(dsi_display->dsi_clk_handle,