[PATCH 7/9] drm/panel/panel-sitronix-st7701: Infer horizontal pixel count from TFT mode

[Marek Vasut]

The horizontal pixel count is a property of the TFT matrix. Currently the
driver hard-codes content of this register to specific value which is
only compatible with one TFT matrix, likely the TS8550B one.

Calculate the horizontal pixel count from the mode instead.

Signed-off-by: Marek Vasut <ma...@denx.de>
Cc: Guido Günther <a...@sigxcpu.org>
Cc: Jagan Teki <ja...@amarulasolutions.com>
Cc: Laurent Pinchart <laurent.pinch...@ideasonboard.com>
Cc: Linus Walleij <linus.wall...@linaro.org>
Cc: Sam Ravnborg <s...@ravnborg.org>
Cc: Thierry Reding <thierry.red...@gmail.com>
---
 drivers/gpu/drm/panel/panel-sitronix-st7701.c | 21 +++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/panel/panel-sitronix-st7701.c 
b/drivers/gpu/drm/panel/panel-sitronix-st7701.c
index 42e46e804146..177180f1c2c8 100644
--- a/drivers/gpu/drm/panel/panel-sitronix-st7701.c
+++ b/drivers/gpu/drm/panel/panel-sitronix-st7701.c
@@ -74,11 +74,9 @@
 #define DSI_CMD2_BK0_LNESET_LINEDELTA  GENMASK(1, 0)
 #define DSI_CMD2_BK0_PORCTRL_VBP_MASK  GENMASK(7, 0)
 #define DSI_CMD2_BK0_PORCTRL_VFP_MASK  GENMASK(7, 0)
-#define DSI_INVSEL_DEFAULT             GENMASK(5, 4)
-#define DSI_INVSEL_NLINV               GENMASK(2, 0)
-#define DSI_INVSEL_RTNI                        GENMASK(2, 1)
-#define DSI_CMD2_BK0_INVSEL_B1         DSI_INVSEL_RTNI
-#define DSI_CMD2_BK0_INVSEL_B0         (DSI_INVSEL_DEFAULT | DSI_INVSEL_NLINV)
+#define DSI_CMD2_BK0_INVSEL_ONES_MASK  GENMASK(5, 4)
+#define DSI_CMD2_BK0_INVSEL_NLINV_MASK GENMASK(2, 0)
+#define DSI_CMD2_BK0_INVSEL_RTNI_MASK  GENMASK(4, 0)
 
 /* Command2, BK1 bytes */
 #define DSI_CMD2_BK1_VRHA_SET          0x45
@@ -114,6 +112,7 @@ struct st7701_panel_desc {
        /* TFT matrix driver configuration, panel specific. */
        const u8        pv_gamma[16];   /* Positive voltage gamma control */
        const u8        nv_gamma[16];   /* Negative voltage gamma control */
+       const u8        nlinv;          /* Inversion selection */
 };
 
 struct st7701 {
@@ -186,8 +185,17 @@ static void st7701_init_sequence(struct st7701 *st7701)
                              mode->vtotal - mode->vsync_end),
                   FIELD_PREP(DSI_CMD2_BK0_PORCTRL_VFP_MASK,
                              mode->vsync_start - mode->vdisplay));
+       /*
+        * Horizontal pixel count configuration:
+        * PCLK = 512 + (RTNI[4:0] * 16)
+        * The PCLK is number of pixel clock per line, which matches
+        * mode htotal. The minimum is 512 PCLK.
+        */
        ST7701_DSI(st7701, DSI_CMD2_BK0_INVSEL,
-                  DSI_CMD2_BK0_INVSEL_B0, DSI_CMD2_BK0_INVSEL_B1);
+                  DSI_CMD2_BK0_INVSEL_ONES_MASK |
+                  FIELD_PREP(DSI_CMD2_BK0_INVSEL_NLINV_MASK, desc->nlinv),
+                  FIELD_PREP(DSI_CMD2_BK0_INVSEL_RTNI_MASK,
+                             DIV_ROUND_UP(mode->htotal, 16)));
 
        /* Command2, BK1 */
        ST7701_DSI(st7701, DSI_CMD2BKX_SEL,
@@ -410,6 +418,7 @@ static const struct st7701_panel_desc ts8550b_desc = {
                CFIELD_PREP(DSI_CMD2_BK0_GAMCTRL_AJ_MASK, 0) |
                CFIELD_PREP(DSI_CMD2_BK0_GAMCTRL_VC255_MASK, 0x1f)
        },
+       .nlinv = 7,
 };
 
 static int st7701_dsi_probe(struct mipi_dsi_device *dsi)
-- 
2.35.1