drm/bridge: tc358775: fix support for jeida-18 and jeida-24

[ Upstream commit 30ea09a182cb37c4921b9d477ed18107befe6d78 ]

The bridge always uses 24bpp internally. Therefore, for jeida-18
mapping we need to discard the lowest two bits for each channel and thus
starting with LV_[RGB]2. jeida-24 has the same mapping but uses four
lanes instead of three, with the forth pair transmitting the lowest two
bits of each channel. Thus, the mapping between jeida-18 and jeida-24
is actually the same, except that one channel is turned off (by
selecting the RGB666 format in VPCTRL).

While at it, remove the bogus comment about the hardware default because
the default is overwritten in any case.

Tested with a jeida-18 display (Evervision VGG644804).

Fixes: b26975593b17 ("display/drm/bridge: TC358775 DSI/LVDS driver")
Signed-off-by: Michael Walle <mwalle@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Robert Foss <rfoss@kernel.org>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240225062008.33191-5-tony@atomide.com
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/gpu/drm/bridge/tc358775.c b/drivers/gpu/drm/bridge/tc358775.c
index 55697fa4d7c8bbee602038bf56bca68ac80a5565..2e299cfe4e487d571bc2d1e09ef7487b393b8298 100644 (file)
--- a/drivers/gpu/drm/bridge/tc358775.c
+++ b/drivers/gpu/drm/bridge/tc358775.c
@@ -453,10 +453,6 @@ static void tc_bridge_enable(struct drm_bridge *bridge)
        dev_dbg(tc->dev, "bus_formats %04x bpc %d\n",
                connector->display_info.bus_formats[0],
                tc->bpc);
-       /*
-        * Default hardware register settings of tc358775 configured
-        * with MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA jeida-24 format
-        */
        if (connector->display_info.bus_formats[0] ==
                MEDIA_BUS_FMT_RGB888_1X7X4_SPWG) {
                /* VESA-24 */
@@ -467,14 +463,15 @@ static void tc_bridge_enable(struct drm_bridge *bridge)
                d2l_write(tc->i2c, LV_MX1619, LV_MX(LVI_B6, LVI_B7, LVI_B1, LVI_B2));
                d2l_write(tc->i2c, LV_MX2023, LV_MX(LVI_B3, LVI_B4, LVI_B5, LVI_L0));
                d2l_write(tc->i2c, LV_MX2427, LV_MX(LVI_HS, LVI_VS, LVI_DE, LVI_R6));
-       } else { /*  MEDIA_BUS_FMT_RGB666_1X7X3_SPWG - JEIDA-18 */
-               d2l_write(tc->i2c, LV_MX0003, LV_MX(LVI_R0, LVI_R1, LVI_R2, LVI_R3));
-               d2l_write(tc->i2c, LV_MX0407, LV_MX(LVI_R4, LVI_L0, LVI_R5, LVI_G0));
-               d2l_write(tc->i2c, LV_MX0811, LV_MX(LVI_G1, LVI_G2, LVI_L0, LVI_L0));
-               d2l_write(tc->i2c, LV_MX1215, LV_MX(LVI_G3, LVI_G4, LVI_G5, LVI_B0));
-               d2l_write(tc->i2c, LV_MX1619, LV_MX(LVI_L0, LVI_L0, LVI_B1, LVI_B2));
-               d2l_write(tc->i2c, LV_MX2023, LV_MX(LVI_B3, LVI_B4, LVI_B5, LVI_L0));
-               d2l_write(tc->i2c, LV_MX2427, LV_MX(LVI_HS, LVI_VS, LVI_DE, LVI_L0));
+       } else {
+               /* JEIDA-18 and JEIDA-24 */
+               d2l_write(tc->i2c, LV_MX0003, LV_MX(LVI_R2, LVI_R3, LVI_R4, LVI_R5));
+               d2l_write(tc->i2c, LV_MX0407, LV_MX(LVI_R6, LVI_R1, LVI_R7, LVI_G2));
+               d2l_write(tc->i2c, LV_MX0811, LV_MX(LVI_G3, LVI_G4, LVI_G0, LVI_G1));
+               d2l_write(tc->i2c, LV_MX1215, LV_MX(LVI_G5, LVI_G6, LVI_G7, LVI_B2));
+               d2l_write(tc->i2c, LV_MX1619, LV_MX(LVI_B0, LVI_B1, LVI_B3, LVI_B4));
+               d2l_write(tc->i2c, LV_MX2023, LV_MX(LVI_B5, LVI_B6, LVI_B7, LVI_L0));
+               d2l_write(tc->i2c, LV_MX2427, LV_MX(LVI_HS, LVI_VS, LVI_DE, LVI_R0));
        }
 
        d2l_write(tc->i2c, VFUEN, VFUEN_EN);