drm/panel: s6e63m0: Implement 28 backlight levels

A later version of the s6e63m0 driver in the Samsung
GT-I9070 vendor tree provides 28 different backlight
levels making use of elaborate control of the ACL
and ELVSS regulator. Implement this more fine-grained
backlight control.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Guido Günther <agx@sigxcpu.org>
Cc: Stephan Gerhold <stephan@gerhold.net>
Cc: Paweł Chmiel <pawel.mikolaj.chmiel@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201117175621.870085-2-linus.walleij@linaro.org

1 files changed, 257 insertions, 53 deletions

diff --git a/drivers/gpu/drm/panel/panel-samsung-s6e63m0.c b/drivers/gpu/drm/panel/panel-samsung-s6e63m0.c
index 8fce399fb97d..0418d6f1530b 100644
--- a/drivers/gpu/drm/panel/panel-samsung-s6e63m0.c
+++ b/drivers/gpu/drm/panel/panel-samsung-s6e63m0.c
@@ -43,57 +43,234 @@
 #define S6E63M0_LCD_ID_VALUE_SM2	0xB4
 #define S6E63M0_LCD_ID_VALUE_SM2_1	0xB6
 
-#define NUM_GAMMA_LEVELS             11
-#define GAMMA_TABLE_COUNT           23
+#define NUM_GAMMA_LEVELS	28
+#define GAMMA_TABLE_COUNT	23
 
-#define MAX_BRIGHTNESS              (NUM_GAMMA_LEVELS - 1)
+#define MAX_BRIGHTNESS		(NUM_GAMMA_LEVELS - 1)
 
 /* array of gamma tables for gamma value 2.2 */
 static u8 const s6e63m0_gamma_22[NUM_GAMMA_LEVELS][GAMMA_TABLE_COUNT] = {
-	{ MCS_PGAMMACTL, 0x00,
-	  0x18, 0x08, 0x24, 0x78, 0xEC, 0x3D, 0xC8,
-	  0xC2, 0xB6, 0xC4, 0xC7, 0xB6, 0xD5, 0xD7,
-	  0xCC, 0x00, 0x39, 0x00, 0x36, 0x00, 0x51 },
-	{ MCS_PGAMMACTL, 0x00,
-	  0x18, 0x08, 0x24, 0x73, 0x4A, 0x3D, 0xC0,
-	  0xC2, 0xB1, 0xBB, 0xBE, 0xAC, 0xCE, 0xCF,
-	  0xC5, 0x00, 0x5D, 0x00, 0x5E, 0x00, 0x82 },
-	{ MCS_PGAMMACTL, 0x00,
-	  0x18, 0x08, 0x24, 0x70, 0x51, 0x3E, 0xBF,
-	  0xC1, 0xAF, 0xB9, 0xBC, 0xAB, 0xCC, 0xCC,
-	  0xC2, 0x00, 0x65, 0x00, 0x67, 0x00, 0x8D },
-	{ MCS_PGAMMACTL, 0x00,
-	  0x18, 0x08, 0x24, 0x6C, 0x54, 0x3A, 0xBC,
-	  0xBF, 0xAC, 0xB7, 0xBB, 0xA9, 0xC9, 0xC9,
-	  0xBE, 0x00, 0x71, 0x00, 0x73, 0x00, 0x9E },
-	{ MCS_PGAMMACTL, 0x00,
-	  0x18, 0x08, 0x24, 0x69, 0x54, 0x37, 0xBB,
-	  0xBE, 0xAC, 0xB4, 0xB7, 0xA6, 0xC7, 0xC8,
-	  0xBC, 0x00, 0x7B, 0x00, 0x7E, 0x00, 0xAB },
-	{ MCS_PGAMMACTL, 0x00,
-	  0x18, 0x08, 0x24, 0x66, 0x55, 0x34, 0xBA,
-	  0xBD, 0xAB, 0xB1, 0xB5, 0xA3, 0xC5, 0xC6,
-	  0xB9, 0x00, 0x85, 0x00, 0x88, 0x00, 0xBA },
-	{ MCS_PGAMMACTL, 0x00,
-	  0x18, 0x08, 0x24, 0x63, 0x53, 0x31, 0xB8,
-	  0xBC, 0xA9, 0xB0, 0xB5, 0xA2, 0xC4, 0xC4,
-	  0xB8, 0x00, 0x8B, 0x00, 0x8E, 0x00, 0xC2 },
-	{ MCS_PGAMMACTL, 0x00,
-	  0x18, 0x08, 0x24, 0x62, 0x54, 0x30, 0xB9,
-	  0xBB, 0xA9, 0xB0, 0xB3, 0xA1, 0xC1, 0xC3,
-	  0xB7, 0x00, 0x91, 0x00, 0x95, 0x00, 0xDA },
-	{ MCS_PGAMMACTL, 0x00,
-	  0x18, 0x08, 0x24, 0x66, 0x58, 0x34, 0xB6,
-	  0xBA, 0xA7, 0xAF, 0xB3, 0xA0, 0xC1, 0xC2,
-	  0xB7, 0x00, 0x97, 0x00, 0x9A, 0x00, 0xD1 },
-	{ MCS_PGAMMACTL, 0x00,
-	  0x18, 0x08, 0x24, 0x64, 0x56, 0x33, 0xB6,
-	  0xBA, 0xA8, 0xAC, 0xB1, 0x9D, 0xC1, 0xC1,
-	  0xB7, 0x00, 0x9C, 0x00, 0x9F, 0x00, 0xD6 },
-	{ MCS_PGAMMACTL, 0x00,
-	  0x18, 0x08, 0x24, 0x5f, 0x50, 0x2d, 0xB6,
-	  0xB9, 0xA7, 0xAd, 0xB1, 0x9f, 0xbe, 0xC0,
-	  0xB5, 0x00, 0xa0, 0x00, 0xa4, 0x00, 0xdb },
+	/* 30 cd */
+	{ MCS_PGAMMACTL, 0x02,
+	  0x18, 0x08, 0x24, 0xA1, 0x51, 0x7B, 0xCE,
+	  0xCB, 0xC2, 0xC7, 0xCB, 0xBC, 0xDA, 0xDD,
+	  0xD3, 0x00, 0x53, 0x00, 0x52, 0x00, 0x6F, },
+	/* 40 cd */
+	{ MCS_PGAMMACTL, 0x02,
+	  0x18, 0x08, 0x24, 0x97, 0x58, 0x71, 0xCC,
+	  0xCB, 0xC0, 0xC5, 0xC9, 0xBA, 0xD9, 0xDC,
+	  0xD1, 0x00, 0x5B, 0x00, 0x5A, 0x00, 0x7A, },
+	/* 50 cd */
+	{ MCS_PGAMMACTL, 0x02,
+	  0x18, 0x08, 0x24, 0x96, 0x58, 0x72, 0xCB,
+	  0xCA, 0xBF, 0xC6, 0xC9, 0xBA, 0xD6, 0xD9,
+	  0xCD, 0x00, 0x61, 0x00, 0x61, 0x00, 0x83, },
+	/* 60 cd */
+	{ MCS_PGAMMACTL, 0x02,
+	  0x18, 0x08, 0x24, 0x91, 0x5E, 0x6E, 0xC9,
+	  0xC9, 0xBD, 0xC4, 0xC9, 0xB8, 0xD3, 0xD7,
+	  0xCA, 0x00, 0x69, 0x00, 0x67, 0x00, 0x8D, },
+	/* 70 cd */
+	{ MCS_PGAMMACTL, 0x02,
+	  0x18, 0x08, 0x24, 0x8E, 0x62, 0x6B, 0xC7,
+	  0xC9, 0xBB, 0xC3, 0xC7, 0xB7, 0xD3, 0xD7,
+	  0xCA, 0x00, 0x6E, 0x00, 0x6C, 0x00, 0x94, },
+	/* 80 cd */
+	{ MCS_PGAMMACTL, 0x02,
+	  0x18, 0x08, 0x24, 0x89, 0x68, 0x65, 0xC9,
+	  0xC9, 0xBC, 0xC1, 0xC5, 0xB6, 0xD2, 0xD5,
+	  0xC9, 0x00, 0x73, 0x00, 0x72, 0x00, 0x9A, },
+	/* 90 cd */
+	{ MCS_PGAMMACTL, 0x02,
+	  0x18, 0x08, 0x24, 0x89, 0x69, 0x64, 0xC7,
+	  0xC8, 0xBB, 0xC0, 0xC5, 0xB4, 0xD2, 0xD5,
+	  0xC9, 0x00, 0x77, 0x00, 0x76, 0x00, 0xA0, },
+	/* 100 cd */
+	{ MCS_PGAMMACTL, 0x02,
+	  0x18, 0x08, 0x24, 0x86, 0x69, 0x60, 0xC6,
+	  0xC8, 0xBA, 0xBF, 0xC4, 0xB4, 0xD0, 0xD4,
+	  0xC6, 0x00, 0x7C, 0x00, 0x7A, 0x00, 0xA7, },
+	/* 110 cd */
+	{ MCS_PGAMMACTL, 0x02,
+	  0x18, 0x08, 0x24, 0x86, 0x6A, 0x60, 0xC5,
+	  0xC7, 0xBA, 0xBD, 0xC3, 0xB2, 0xD0, 0xD4,
+	  0xC5, 0x00, 0x80, 0x00, 0x7E, 0x00, 0xAD, },
+	/* 120 cd */
+	{ MCS_PGAMMACTL, 0x02,
+	  0x18, 0x08, 0x24, 0x82, 0x6B, 0x5E, 0xC4,
+	  0xC8, 0xB9, 0xBD, 0xC2, 0xB1, 0xCE, 0xD2,
+	  0xC4, 0x00, 0x85, 0x00, 0x82, 0x00, 0xB3, },
+	/* 130 cd */
+	{ MCS_PGAMMACTL, 0x02,
+	  0x18, 0x08, 0x24, 0x8C, 0x6C, 0x60, 0xC3,
+	  0xC7, 0xB9, 0xBC, 0xC1, 0xAF, 0xCE, 0xD2,
+	  0xC3, 0x00, 0x88, 0x00, 0x86, 0x00, 0xB8, },
+	/* 140 cd */
+	{ MCS_PGAMMACTL, 0x02,
+	  0x18, 0x08, 0x24, 0x80, 0x6C, 0x5F, 0xC1,
+	  0xC6, 0xB7, 0xBC, 0xC1, 0xAE, 0xCD, 0xD0,
+	  0xC2, 0x00, 0x8C, 0x00, 0x8A, 0x00, 0xBE, },
+	/* 150 cd */
+	{ MCS_PGAMMACTL, 0x02,
+	  0x18, 0x08, 0x24, 0x80, 0x6E, 0x5F, 0xC1,
+	  0xC6, 0xB6, 0xBC, 0xC0, 0xAE, 0xCC, 0xD0,
+	  0xC2, 0x00, 0x8F, 0x00, 0x8D, 0x00, 0xC2, },
+	/* 160 cd */
+	{ MCS_PGAMMACTL, 0x02,
+	  0x18, 0x08, 0x24, 0x7F, 0x6E, 0x5F, 0xC0,
+	  0xC6, 0xB5, 0xBA, 0xBF, 0xAD, 0xCB, 0xCF,
+	  0xC0, 0x00, 0x94, 0x00, 0x91, 0x00, 0xC8, },
+	/* 170 cd */
+	{ MCS_PGAMMACTL, 0x02,
+	  0x18, 0x08, 0x24, 0x7C, 0x6D, 0x5C, 0xC0,
+	  0xC6, 0xB4, 0xBB, 0xBE, 0xAD, 0xCA, 0xCF,
+	  0xC0, 0x00, 0x96, 0x00, 0x94, 0x00, 0xCC, },
+	/* 180 cd */
+	{ MCS_PGAMMACTL, 0x02,
+	  0x18, 0x08, 0x24, 0x7B, 0x6D, 0x5B, 0xC0,
+	  0xC5, 0xB3, 0xBA, 0xBE, 0xAD, 0xCA, 0xCE,
+	  0xBF,	0x00, 0x99, 0x00, 0x97, 0x00, 0xD0, },
+	/* 190 cd */
+	{ MCS_PGAMMACTL, 0x02,
+	  0x18, 0x08, 0x24, 0x7A, 0x6D, 0x59, 0xC1,
+	  0xC5, 0xB4, 0xB8, 0xBD, 0xAC, 0xC9, 0xCE,
+	  0xBE, 0x00, 0x9D, 0x00, 0x9A, 0x00, 0xD5, },
+	/* 200 cd */
+	{ MCS_PGAMMACTL, 0x02,
+	  0x18, 0x08, 0x24, 0x79, 0x6D, 0x58, 0xC1,
+	  0xC4, 0xB4, 0xB6, 0xBD, 0xAA, 0xCA, 0xCD,
+	  0xBE, 0x00, 0x9F, 0x00, 0x9D, 0x00, 0xD9, },
+	/* 210 cd */
+	{ MCS_PGAMMACTL, 0x02,
+	  0x18, 0x08, 0x24, 0x79, 0x6D, 0x57, 0xC0,
+	  0xC4, 0xB4, 0xB7, 0xBD, 0xAA, 0xC8, 0xCC,
+	  0xBD, 0x00, 0xA2, 0x00, 0xA0, 0x00, 0xDD, },
+	/* 220 cd */
+	{ MCS_PGAMMACTL, 0x02,
+	  0x18, 0x08, 0x24, 0x78, 0x6F, 0x58, 0xBF,
+	  0xC4, 0xB3, 0xB5, 0xBB, 0xA9, 0xC8, 0xCC,
+	  0xBC, 0x00, 0xA6, 0x00, 0xA3, 0x00, 0xE2, },
+	/* 230 cd */
+	{ MCS_PGAMMACTL, 0x02,
+	  0x18, 0x08, 0x24, 0x75, 0x6F, 0x56, 0xBF,
+	  0xC3, 0xB2, 0xB6, 0xBB, 0xA8, 0xC7, 0xCB,
+	  0xBC, 0x00, 0xA8, 0x00, 0xA6, 0x00, 0xE6, },
+	/* 240 cd */
+	{ MCS_PGAMMACTL, 0x02,
+	  0x18, 0x08, 0x24, 0x76, 0x6F, 0x56, 0xC0,
+	  0xC3, 0xB2, 0xB5, 0xBA, 0xA8, 0xC6, 0xCB,
+	  0xBB, 0x00, 0xAA, 0x00, 0xA8, 0x00, 0xE9, },
+	/* 250 cd */
+	{ MCS_PGAMMACTL, 0x02,
+	  0x18, 0x08, 0x24, 0x74, 0x6D, 0x54, 0xBF,
+	  0xC3, 0xB2, 0xB4, 0xBA, 0xA7, 0xC6, 0xCA,
+	  0xBA, 0x00, 0xAD, 0x00, 0xAB, 0x00, 0xED, },
+	/* 260 cd */
+	{ MCS_PGAMMACTL, 0x02,
+	  0x18, 0x08, 0x24, 0x74, 0x6E, 0x54, 0xBD,
+	  0xC2, 0xB0, 0xB5, 0xBA, 0xA7, 0xC5, 0xC9,
+	  0xBA, 0x00, 0xB0, 0x00, 0xAE, 0x00, 0xF1, },
+	/* 270 cd */
+	{ MCS_PGAMMACTL, 0x02,
+	  0x18, 0x08, 0x24, 0x71, 0x6C, 0x50, 0xBD,
+	  0xC3, 0xB0, 0xB4, 0xB8, 0xA6, 0xC6, 0xC9,
+	  0xBB, 0x00, 0xB2, 0x00, 0xB1, 0x00, 0xF4, },
+	/* 280 cd */
+	{ MCS_PGAMMACTL, 0x02,
+	  0x18, 0x08, 0x24, 0x6E, 0x6C, 0x4D, 0xBE,
+	  0xC3, 0xB1, 0xB3, 0xB8, 0xA5, 0xC6, 0xC8,
+	  0xBB, 0x00, 0xB4, 0x00, 0xB3, 0x00, 0xF7, },
+	/* 290 cd */
+	{ MCS_PGAMMACTL, 0x02,
+	  0x18, 0x08, 0x24, 0x71, 0x70, 0x50, 0xBD,
+	  0xC1, 0xB0, 0xB2, 0xB8, 0xA4, 0xC6, 0xC7,
+	  0xBB, 0x00, 0xB6, 0x00, 0xB6, 0x00, 0xFA, },
+	/* 300 cd */
+	{ MCS_PGAMMACTL, 0x02,
+	  0x18, 0x08, 0x24, 0x70, 0x6E, 0x4E, 0xBC,
+	  0xC0, 0xAF, 0xB3, 0xB8, 0xA5, 0xC5, 0xC7,
+	  0xBB, 0x00, 0xB9, 0x00, 0xB8, 0x00, 0xFC, },
+};
+
+#define NUM_ACL_LEVELS 7
+#define ACL_TABLE_COUNT 28
+
+static u8 const s6e63m0_acl[NUM_ACL_LEVELS][ACL_TABLE_COUNT] = {
+	/* NULL ACL */
+	{ MCS_BCMODE,
+	  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	  0x00, 0x00, 0x00 },
+	/* 40P ACL */
+	{ MCS_BCMODE,
+	  0x4D, 0x96, 0x1D, 0x00, 0x00, 0x01, 0xDF, 0x00,
+	  0x00, 0x03, 0x1F, 0x00, 0x00, 0x00, 0x00, 0x00,
+	  0x01, 0x06, 0x0C, 0x11, 0x16, 0x1C, 0x21, 0x26,
+	  0x2B, 0x31, 0x36 },
+	/* 43P ACL */
+	{ MCS_BCMODE,
+	  0x4D, 0x96, 0x1D, 0x00, 0x00, 0x01, 0xDF, 0x00,
+	  0x00, 0x03, 0x1F, 0x00, 0x00, 0x00, 0x00, 0x00,
+	  0x01, 0x07, 0x0C, 0x12, 0x18, 0x1E, 0x23, 0x29,
+	  0x2F, 0x34, 0x3A },
+	/* 45P ACL */
+	{ MCS_BCMODE,
+	  0x4D, 0x96, 0x1D, 0x00, 0x00, 0x01, 0xDF, 0x00,
+	  0x00, 0x03, 0x1F, 0x00, 0x00, 0x00, 0x00, 0x00,
+	  0x01, 0x07, 0x0D, 0x13, 0x19, 0x1F, 0x25, 0x2B,
+	  0x31, 0x37, 0x3D },
+	/* 47P ACL */
+	{ MCS_BCMODE,
+	  0x4D, 0x96, 0x1D, 0x00, 0x00, 0x01, 0xDF, 0x00,
+	  0x00, 0x03, 0x1F, 0x00, 0x00, 0x00, 0x00, 0x00,
+	  0x01, 0x07, 0x0E, 0x14, 0x1B, 0x21, 0x27, 0x2E,
+	  0x34, 0x3B, 0x41 },
+	/* 48P ACL */
+	{ MCS_BCMODE,
+	  0x4D, 0x96, 0x1D, 0x00, 0x00, 0x01, 0xDF, 0x00,
+	  0x00, 0x03, 0x1F, 0x00, 0x00, 0x00, 0x00, 0x00,
+	  0x01, 0x08, 0x0E, 0x15, 0x1B, 0x22, 0x29, 0x2F,
+	  0x36, 0x3C, 0x43 },
+	/* 50P ACL */
+	{ MCS_BCMODE,
+	  0x4D, 0x96, 0x1D, 0x00, 0x00, 0x01, 0xDF, 0x00,
+	  0x00, 0x03, 0x1F, 0x00, 0x00, 0x00, 0x00, 0x00,
+	  0x01, 0x08, 0x0F, 0x16, 0x1D, 0x24, 0x2A, 0x31,
+	  0x38, 0x3F, 0x46 },
+};
+
+/* This tells us which ACL level goes with which gamma */
+static u8 const s6e63m0_acl_per_gamma[NUM_GAMMA_LEVELS] = {
+	/* 30 - 60 cd: ACL off/NULL */
+	0, 0, 0, 0,
+	/* 70 - 250 cd: 40P ACL */
+	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+	/* 260 - 300 cd: 50P ACL */
+	6, 6, 6, 6, 6,
+};
+
+/* The ELVSS backlight regulator has 5 levels */
+#define S6E63M0_ELVSS_LEVELS 5
+
+static u8 const s6e63m0_elvss_offsets[S6E63M0_ELVSS_LEVELS] = {
+	0x00,   /* not set */
+	0x0D,   /* 30 cd - 100 cd */
+	0x09,   /* 110 cd - 160 cd */
+	0x07,   /* 170 cd - 200 cd */
+	0x00,   /* 210 cd - 300 cd */
+};
+
+/* This tells us which ELVSS level goes with which gamma */
+static u8 const s6e63m0_elvss_per_gamma[NUM_GAMMA_LEVELS] = {
+	/* 30 - 100 cd */
+	1, 1, 1, 1, 1, 1, 1, 1,
+	/* 110 - 160 cd */
+	2, 2, 2, 2, 2, 2,
+	/* 170 - 200 cd */
+	3, 3, 3, 3,
+	/* 210 - 300 cd */
+	4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
 };
 
 struct s6e63m0 {
@@ -103,6 +280,7 @@ struct s6e63m0 {
 	struct drm_panel panel;
 	struct backlight_device *bl_dev;
 	u8 lcd_type;
+	u8 elvss_pulse;
 
 	struct regulator_bulk_data supplies[2];
 	struct gpio_desc *reset_gpio;
@@ -188,17 +366,25 @@ static int s6e63m0_check_lcd_type(struct s6e63m0 *ctx)
 
 	dev_info(ctx->dev, "MTP ID: %02x %02x %02x\n", id1, id2, id3);
 
-	/* We attempt to detect what panel is mounted on the controller */
+	/*
+	 * We attempt to detect what panel is mounted on the controller.
+	 * The third ID byte represents the desired ELVSS pulse for
+	 * some displays.
+	 */
 	switch (id2) {
 	case S6E63M0_LCD_ID_VALUE_M2:
 		dev_info(ctx->dev, "detected LCD panel AMS397GE MIPI M2\n");
+		ctx->elvss_pulse = id3;
 		break;
 	case S6E63M0_LCD_ID_VALUE_SM2:
 	case S6E63M0_LCD_ID_VALUE_SM2_1:
 		dev_info(ctx->dev, "detected LCD panel AMS397GE MIPI SM2\n");
+		ctx->elvss_pulse = id3;
 		break;
 	default:
 		dev_info(ctx->dev, "unknown LCD panel type %02x\n", id2);
+		/* Default ELVSS pulse level */
+		ctx->elvss_pulse = 0x16;
 		break;
 	}
 
@@ -448,15 +634,33 @@ static const struct drm_panel_funcs s6e63m0_drm_funcs = {
 static int s6e63m0_set_brightness(struct backlight_device *bd)
 {
 	struct s6e63m0 *ctx = bl_get_data(bd);
-
 	int brightness = bd->props.brightness;
-
-	/* disable and set new gamma */
+	u8 elvss_val;
+	u8 elvss_cmd_set[5];
+	int i;
+
+	/* Adjust ELVSS to candela level */
+	i = s6e63m0_elvss_per_gamma[brightness];
+	elvss_val = ctx->elvss_pulse + s6e63m0_elvss_offsets[i];
+	if (elvss_val > 0x1f)
+		elvss_val = 0x1f;
+	elvss_cmd_set[0] = MCS_TEMP_SWIRE;
+	elvss_cmd_set[1] = elvss_val;
+	elvss_cmd_set[2] = elvss_val;
+	elvss_cmd_set[3] = elvss_val;
+	elvss_cmd_set[4] = elvss_val;
+	s6e63m0_dcs_write(ctx, elvss_cmd_set, 5);
+
+	/* Update the ACL per gamma value */
+	i = s6e63m0_acl_per_gamma[brightness];
+	s6e63m0_dcs_write(ctx, s6e63m0_acl[i],
+			  ARRAY_SIZE(s6e63m0_acl[i]));
+
+	/* Update gamma table */
 	s6e63m0_dcs_write(ctx, s6e63m0_gamma_22[brightness],
 			  ARRAY_SIZE(s6e63m0_gamma_22[brightness]));
+	s6e63m0_dcs_write_seq_static(ctx, MCS_PGAMMACTL, 0x03);
 
-	/* update gamma table. */
-	s6e63m0_dcs_write_seq_static(ctx, MCS_PGAMMACTL, 0x01);
 
 	return s6e63m0_clear_error(ctx);
 }