[PATCH 3/4] drm/mediatek: fine tune the dsi panel's power sequence

[Jitao Shi]

Add the drm_panel_prepare_power and drm_panel_unprepare_power control.
Turn on panel power(drm_panel_prepare_power) and control before dsi
enable. And then dsi enable, send dcs cmd in drm_panel_prepare, last
turn on backlight.

Signed-off-by: Jitao Shi <jitao....@mediatek.com>
---
 drivers/gpu/drm/mediatek/mtk_dsi.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c 
b/drivers/gpu/drm/mediatek/mtk_dsi.c
index a1ff152ef468..455fe582c6b5 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -615,10 +615,13 @@ static int mtk_dsi_poweron(struct mtk_dsi *dsi)
        dsi->data_rate = DIV_ROUND_UP_ULL(dsi->vm.pixelclock * bit_per_pixel,
                                          dsi->lanes);
 
+       if (panel_bridge_prepare_power(dsi->next_bridge))
+               DRM_INFO("can't prepare power the panel\n");
+
        ret = clk_set_rate(dsi->hs_clk, dsi->data_rate);
        if (ret < 0) {
                dev_err(dev, "Failed to set data rate: %d\n", ret);
-               goto err_refcount;
+               goto err_prepare_power;
        }
 
        phy_power_on(dsi->phy);
@@ -661,7 +664,9 @@ static int mtk_dsi_poweron(struct mtk_dsi *dsi)
        clk_disable_unprepare(dsi->engine_clk);
 err_phy_power_off:
        phy_power_off(dsi->phy);
-err_refcount:
+err_prepare_power:
+       if (panel_bridge_unprepare_power(dsi->next_bridge))
+               DRM_INFO("Can't unprepare power the panel\n");
        dsi->refcount--;
        return ret;
 }
@@ -694,6 +699,9 @@ static void mtk_dsi_poweroff(struct mtk_dsi *dsi)
        clk_disable_unprepare(dsi->digital_clk);
 
        phy_power_off(dsi->phy);
+
+       if (panel_bridge_unprepare_power(dsi->next_bridge))
+               DRM_INFO("Can't unprepare power the panel\n");
 }
 
 static void mtk_output_dsi_enable(struct mtk_dsi *dsi)
-- 
2.25.1