[PATCH v4 03/13] drm: bridge: icn6211: Fix HFP_HSW_HBP_HI and HFP_MIN handling

[Marek Vasut]

The HFP_HSW_HBP_HI register must be programmed with 2 LSbits of each
Horizontal Front Porch/Sync/Back Porch. Currently the driver programs
this register to 0, which breaks displays with either value above 255.

The HFP_MIN register must be set to the same value as HFP_LI, otherwise
there is visible image distortion, usually in the form of missing lines
at the bottom of the panel.

Fix this by correctly programming the HFP_HSW_HBP_HI and HFP_MIN registers.

Acked-by: Maxime Ripard <max...@cerno.tech>
Fixes: ce517f18944e3 ("drm: bridge: Add Chipone ICN6211 MIPI-DSI to RGB bridge")
Signed-off-by: Marek Vasut <ma...@denx.de>
Cc: Jagan Teki <ja...@amarulasolutions.com>
Cc: Maxime Ripard <max...@cerno.tech>
Cc: Robert Foss <robert.f...@linaro.org>
Cc: Sam Ravnborg <s...@ravnborg.org>
Cc: Thomas Zimmermann <tzimmerm...@suse.de>
To: dri-devel@lists.freedesktop.org
---
V2: Rebase on next-20220214
V3: Add AB from Maxime
V4: No change
---
 drivers/gpu/drm/bridge/chipone-icn6211.c | 23 ++++++++++++++++-------
 1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/bridge/chipone-icn6211.c 
b/drivers/gpu/drm/bridge/chipone-icn6211.c
index 376e0f80da5ca..c871a90c0b8f4 100644
--- a/drivers/gpu/drm/bridge/chipone-icn6211.c
+++ b/drivers/gpu/drm/bridge/chipone-icn6211.c
@@ -35,6 +35,9 @@
 #define HSYNC_LI               0x24
 #define HBP_LI                 0x25
 #define HFP_HSW_HBP_HI         0x26
+#define HFP_HSW_HBP_HI_HFP(n)          (((n) & 0x300) >> 4)
+#define HFP_HSW_HBP_HI_HS(n)           (((n) & 0x300) >> 6)
+#define HFP_HSW_HBP_HI_HBP(n)          (((n) & 0x300) >> 8)
 #define VFP                    0x27
 #define VSYNC                  0x28
 #define VBP                    0x29
@@ -163,6 +166,7 @@ static void chipone_atomic_enable(struct drm_bridge *bridge,
 {
        struct chipone *icn = bridge_to_chipone(bridge);
        struct drm_display_mode *mode = &icn->mode;
+       u16 hfp, hbp, hsync;
 
        ICN6211_DSI(icn, MIPI_CFG_PW, MIPI_CFG_PW_CONFIG_DSI);
 
@@ -178,13 +182,18 @@ static void chipone_atomic_enable(struct drm_bridge 
*bridge,
                    ((mode->hdisplay >> 8) & 0xf) |
                    (((mode->vdisplay >> 8) & 0xf) << 4));
 
-       ICN6211_DSI(icn, HFP_LI, mode->hsync_start - mode->hdisplay);
+       hfp = mode->hsync_start - mode->hdisplay;
+       hsync = mode->hsync_end - mode->hsync_start;
+       hbp = mode->htotal - mode->hsync_end;
 
-       ICN6211_DSI(icn, HSYNC_LI, mode->hsync_end - mode->hsync_start);
-
-       ICN6211_DSI(icn, HBP_LI, mode->htotal - mode->hsync_end);
-
-       ICN6211_DSI(icn, HFP_HSW_HBP_HI, 0x00);
+       ICN6211_DSI(icn, HFP_LI, hfp & 0xff);
+       ICN6211_DSI(icn, HSYNC_LI, hsync & 0xff);
+       ICN6211_DSI(icn, HBP_LI, hbp & 0xff);
+       /* Top two bits of Horizontal Front porch/Sync/Back porch */
+       ICN6211_DSI(icn, HFP_HSW_HBP_HI,
+                   HFP_HSW_HBP_HI_HFP(hfp) |
+                   HFP_HSW_HBP_HI_HS(hsync) |
+                   HFP_HSW_HBP_HI_HBP(hbp));
 
        ICN6211_DSI(icn, VFP, mode->vsync_start - mode->vdisplay);
 
@@ -194,7 +203,7 @@ static void chipone_atomic_enable(struct drm_bridge *bridge,
 
        /* dsi specific sequence */
        ICN6211_DSI(icn, SYNC_EVENT_DLY, 0x80);
-       ICN6211_DSI(icn, HFP_MIN, 0x28);
+       ICN6211_DSI(icn, HFP_MIN, hfp & 0xff);
        ICN6211_DSI(icn, MIPI_PD_CK_LANE, 0xa0);
        ICN6211_DSI(icn, PLL_CTRL(12), 0xff);
        ICN6211_DSI(icn, BIST_POL, BIST_POL_DE_POL);
-- 
2.34.1