dsi_display: (doze) interpolated brightness: back to lp2

If set to lp1 screen will dim then go brighter when screen turn on during
screen off fod

It's still like that on lp2 but a lot less often

Signed-off-by: onettboots <blackcocopet@gmail.com>

Author: pwnrazr

drivers/gpu/drm/msm/dsi-staging/dsi_display.c

@@ -1057,6 +1057,45 @@ static bool dsi_display_get_cont_splash_status(struct dsi_display *display)
 	return true;
 }
 
+static u32 interpolate(uint32_t x, uint32_t xa, uint32_t xb,                                                    uint32_t ya, uint32_t yb)
+{
+        return ya + (yb - ya) * (x - xa) / (xb - xa);
+}
+
+struct blbl {
+        u32 bl;
+        u32 aod_bl;
+};
+
+struct blbl aod_bl_lut[] = {
+        {0, 1},
+        {10, 1},
+        {40, 9},
+        {90, 30},
+        {120, 40},
+};
+
+u32 dsi_panel_get_aod_bl(struct dsi_display *display) {
+        int i;
+        //cached value is better than reading display->panel->bl_config.bl_level
+        u32 cur_bl = dsi_panel_backlight_get();
+
+        for (i = 0; i < 5; i++)
+                if (aod_bl_lut[i].bl >= cur_bl)
+                        break;
+        if (i == 0)
+                return aod_bl_lut[i].aod_bl;
+
+        if (i == 4)
+                return aod_bl_lut[i - 1].aod_bl;
+
+        return interpolate(cur_bl,
+                           aod_bl_lut[i - 1].bl,
+                           aod_bl_lut[i].bl,
+                           aod_bl_lut[i - 1].aod_bl,
+                           aod_bl_lut[i].aod_bl);
+}
+
 int dsi_display_set_power(struct drm_connector *connector,
 		int power_mode, void *disp)
 {
@@ -1086,6 +1125,8 @@ int dsi_display_set_power(struct drm_connector *connector,
 		rc = dsi_panel_set_lp1(display->panel);
 		break;
 	case SDE_MODE_DPMS_LP2:
+		dsi_panel_set_backlight(display->panel, dsi_panel_get_aod_bl(display));
+		usleep_range(20000, 30000);
 		rc = dsi_panel_set_lp2(display->panel);
 		break;
 	case SDE_MODE_DPMS_ON:

drivers/gpu/drm/msm/dsi-staging/dsi_panel.c

@@ -608,6 +608,13 @@ static int dsi_panel_wled_register(struct dsi_panel *panel,
 	return 0;
 }
 
+static int saved_backlight = -1;
+
+int dsi_panel_backlight_get(void)
+{
+                return saved_backlight;
+}
+
 static int dsi_panel_update_backlight(struct dsi_panel *panel,
 	u32 bl_lvl)
 {

include/linux/msm_drm_notify.h

@@ -45,4 +45,6 @@ struct msm_drm_notifier {
 
 int msm_drm_register_client(struct notifier_block *nb);
 int msm_drm_unregister_client(struct notifier_block *nb);
+
+int dsi_panel_backlight_get(void);
 #endif