drm/panel: s6e63m0: Fix init sequence again

The DSI version of the panel behaved instable and close
scrutiny of the vendor driver from the Samsung
GT-S8190 shows a different initialization sequence for
the DSI mode panel than the DPI mode panel.

Make the initialization depend on whether we are in
DSI or DPI mode and handle the differences.

After this the panel on the GT-I8190 becomes much more
stable.

Also spell out some more custom DCS commands found in
the vendor source code to cut down a bit on magic
where we can.

Fixes: f0aee45f ("drm/panel: s6e63m0: Fix init sequence")
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Stephan Gerhold <stephan@gerhold.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20201205122229.1952980-1-linus.walleij@linaro.org

drivers/gpu/drm/panel/panel-samsung-s6e63m0.c

@@ -25,6 +25,14 @@
 /* Manufacturer Command Set */
 #define MCS_ELVSS_ON		0xb1
 #define MCS_TEMP_SWIRE		0xb2
+#define MCS_PENTILE_1		0xb3
+#define MCS_PENTILE_2		0xb4
+#define MCS_GAMMA_DELTA_Y_RED	0xb5
+#define MCS_GAMMA_DELTA_X_RED	0xb6
+#define MCS_GAMMA_DELTA_Y_GREEN	0xb7
+#define MCS_GAMMA_DELTA_X_GREEN	0xb8
+#define MCS_GAMMA_DELTA_Y_BLUE	0xb9
+#define MCS_GAMMA_DELTA_X_BLUE	0xba
 #define MCS_MIECTL1		0xc0
 #define MCS_BCMODE		0xc1
 #define MCS_ERROR_CHECK		0xd5
@@ -281,6 +289,7 @@ struct s6e63m0 {
 	struct backlight_device *bl_dev;
 	u8 lcd_type;
 	u8 elvss_pulse;
+	bool dsi_mode;
 
 	struct regulator_bulk_data supplies[2];
 	struct gpio_desc *reset_gpio;
@@ -395,6 +404,18 @@ static int s6e63m0_check_lcd_type(struct s6e63m0 *ctx)
 
 static void s6e63m0_init(struct s6e63m0 *ctx)
 {
+	/*
+	 * We do not know why there is a difference in the DSI mode.
+	 * (No datasheet.)
+	 *
+	 * In the vendor driver this sequence is called
+	 * "SEQ_PANEL_CONDITION_SET" or "DCS_CMD_SEQ_PANEL_COND_SET".
+	 */
+	if (ctx->dsi_mode)
+		s6e63m0_dcs_write_seq_static(ctx, MCS_PANELCTL,
+					     0x01, 0x2c, 0x2c, 0x07, 0x07, 0x5f, 0xb3,
+					     0x6d, 0x97, 0x1d, 0x3a, 0x0f, 0x00, 0x00);
+	else
 		s6e63m0_dcs_write_seq_static(ctx, MCS_PANELCTL,
 					     0x01, 0x27, 0x27, 0x07, 0x07, 0x54, 0x9f,
 					     0x63, 0x8f, 0x1a, 0x33, 0x0d, 0x00, 0x00);
@@ -414,40 +435,40 @@ static void s6e63m0_init(struct s6e63m0 *ctx)
 
 	s6e63m0_dcs_write_seq_static(ctx, MCS_SRCCTL,
 				     0x00, 0x8e, 0x07);
-	s6e63m0_dcs_write_seq_static(ctx, 0xb3, 0x6c);
+	s6e63m0_dcs_write_seq_static(ctx, MCS_PENTILE_1, 0x6c);
 
-	s6e63m0_dcs_write_seq_static(ctx, 0xb5,
+	s6e63m0_dcs_write_seq_static(ctx, MCS_GAMMA_DELTA_Y_RED,
 				     0x2c, 0x12, 0x0c, 0x0a, 0x10, 0x0e, 0x17,
 				     0x13, 0x1f, 0x1a, 0x2a, 0x24, 0x1f, 0x1b,
 				     0x1a, 0x17, 0x2b, 0x26, 0x22, 0x20, 0x3a,
 				     0x34, 0x30, 0x2c, 0x29, 0x26, 0x25, 0x23,
 				     0x21, 0x20, 0x1e, 0x1e);
 
-	s6e63m0_dcs_write_seq_static(ctx, 0xb6,
+	s6e63m0_dcs_write_seq_static(ctx, MCS_GAMMA_DELTA_X_RED,
 				     0x00, 0x00, 0x11, 0x22, 0x33, 0x44, 0x44,
 				     0x44, 0x55, 0x55, 0x66, 0x66, 0x66, 0x66,
 				     0x66, 0x66);
 
-	s6e63m0_dcs_write_seq_static(ctx, 0xb7,
+	s6e63m0_dcs_write_seq_static(ctx, MCS_GAMMA_DELTA_Y_GREEN,
 				     0x2c, 0x12, 0x0c, 0x0a, 0x10, 0x0e, 0x17,
 				     0x13, 0x1f, 0x1a, 0x2a, 0x24, 0x1f, 0x1b,
 				     0x1a, 0x17, 0x2b, 0x26, 0x22, 0x20, 0x3a,
 				     0x34, 0x30, 0x2c, 0x29, 0x26, 0x25, 0x23,
 				     0x21, 0x20, 0x1e, 0x1e);
 
-	s6e63m0_dcs_write_seq_static(ctx, 0xb8,
+	s6e63m0_dcs_write_seq_static(ctx, MCS_GAMMA_DELTA_X_GREEN,
 				     0x00, 0x00, 0x11, 0x22, 0x33, 0x44, 0x44,
 				     0x44, 0x55, 0x55, 0x66, 0x66, 0x66, 0x66,
 				     0x66, 0x66);
 
-	s6e63m0_dcs_write_seq_static(ctx, 0xb9,
+	s6e63m0_dcs_write_seq_static(ctx, MCS_GAMMA_DELTA_Y_BLUE,
 				     0x2c, 0x12, 0x0c, 0x0a, 0x10, 0x0e, 0x17,
 				     0x13, 0x1f, 0x1a, 0x2a, 0x24, 0x1f, 0x1b,
 				     0x1a, 0x17, 0x2b, 0x26, 0x22, 0x20, 0x3a,
 				     0x34, 0x30, 0x2c, 0x29, 0x26, 0x25, 0x23,
 				     0x21, 0x20, 0x1e, 0x1e);
 
-	s6e63m0_dcs_write_seq_static(ctx, 0xba,
+	s6e63m0_dcs_write_seq_static(ctx, MCS_GAMMA_DELTA_X_BLUE,
 				     0x00, 0x00, 0x11, 0x22, 0x33, 0x44, 0x44,
 				     0x44, 0x55, 0x55, 0x66, 0x66, 0x66, 0x66,
 				     0x66, 0x66);
@@ -704,6 +725,7 @@ int s6e63m0_probe(struct device *dev,
 	if (!ctx)
 		return -ENOMEM;
 
+	ctx->dsi_mode = dsi_mode;
 	ctx->dcs_read = dcs_read;
 	ctx->dcs_write = dcs_write;
 	dev_set_drvdata(dev, ctx);