drm/panel: samsung-s6e88a0-ams427ap24: Add brightness control

The tables for brightness to candela, aid and elvss were taken from downstream
kernel file "dsi_panel_S6E88A0_AMS427AP24_qhd_octa_video.dtsi" [1][2][3].

The gamma table gets generated in "ss_dsi_smart_dimming_S6E88A0_AMS427AP24.c" [4]
with hard-coded starting values. The function smart_dimming_init() [5] goes
through the v{*}_adjustments, generate_gray_scale and gamma_init procedure.
Instead of calculating it manually, it's easier to compile a custom downstream
kernel with SMART_DIMMING_DEBUG enabled and read out dmesg early at boot.

Selection of the values for aid and elvss are again according to downstream
file "dsi_panel_S6E88A0_AMS427AP24_qhd_octa_video.dtsi" [6][7].

The set of write commands is guided by downstream file "ss_dsi_panel_common.c" [8]
followed by "ss_dsi_panel_S6E88A0_AMS427AP24.c" [9].

The dsi mode flag MIPI_DSI_MODE_VIDEO_NO_HFP prevents screen flickering while
changing the brightness.

[1] https://github.com/msm8916-mainline/linux-downstream/blob/GT-I9195I/drivers/video/msm/mdss/samsung/S6E88A0_AMS427AP24/dsi_panel_S6E88A0_AMS427AP24_qhd_octa_video.dtsi#L341-L397
[2] https://github.com/msm8916-mainline/linux-downstream/blob/GT-I9195I/drivers/video/msm/mdss/samsung/S6E88A0_AMS427AP24/dsi_panel_S6E88A0_AMS427AP24_qhd_octa_video.dtsi#L214-L254
[3] https://github.com/msm8916-mainline/linux-downstream/blob/GT-I9195I/drivers/video/msm/mdss/samsung/S6E88A0_AMS427AP24/dsi_panel_S6E88A0_AMS427AP24_qhd_octa_video.dtsi#L301-L320
[4] https://github.com/msm8916-mainline/linux-downstream/blob/GT-I9195I/drivers/video/msm/mdss/samsung/S6E88A0_AMS427AP24/ss_dsi_smart_dimming_S6E88A0_AMS427AP24.c
[5] https://github.com/msm8916-mainline/linux-downstream/blob/GT-I9195I/drivers/video/msm/mdss/samsung/S6E88A0_AMS427AP24/ss_dsi_smart_dimming_S6E88A0_AMS427AP24.c#L1816-L1900
[6] https://github.com/msm8916-mainline/linux-downstream/blob/GT-I9195I/drivers/video/msm/mdss/samsung/S6E88A0_AMS427AP24/dsi_panel_S6E88A0_AMS427AP24_qhd_octa_video.dtsi#L256-L268
[7] https://github.com/msm8916-mainline/linux-downstream/blob/GT-I9195I/drivers/video/msm/mdss/samsung/S6E88A0_AMS427AP24/dsi_panel_S6E88A0_AMS427AP24_qhd_octa_video.dtsi#L322-L334
[8] https://github.com/msm8916-mainline/linux-downstream/blob/GT-I9195I/drivers/video/msm/mdss/samsung/ss_dsi_panel_common.c#L1389-L1517
[9] https://github.com/msm8916-mainline/linux-downstream/blob/GT-I9195I/drivers/video/msm/mdss/samsung/S6E88A0_AMS427AP24/ss_dsi_panel_S6E88A0_AMS427AP24.c#L666-L678

Signed-off-by: Jakob Hauser <jahau@rocketmail.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/30c154954a4e0f75d90f6ef6f393a5ba8b3ffea9.1730070570.git.jahau@rocketmail.com
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/30c154954a4e0f75d90f6ef6f393a5ba8b3ffea9.1730070570.git.jahau@rocketmail.com

2 files changed, 521 insertions, 12 deletions

diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
index f8adc38447fb..d7469c565d1d 100644
--- a/drivers/gpu/drm/panel/Kconfig
+++ b/drivers/gpu/drm/panel/Kconfig
@@ -636,6 +636,7 @@ config DRM_PANEL_SAMSUNG_S6E88A0_AMS427AP24
 	tristate "Samsung AMS427AP24 panel with S6E88A0 controller"
 	depends on GPIOLIB && OF && REGULATOR
 	depends on DRM_MIPI_DSI
+	depends on BACKLIGHT_CLASS_DEVICE
 	help
 	  Say Y here if you want to enable support for Samsung AMS427AP24 panel
 	  with S6E88A0 controller (found in Samsung Galaxy S4 Mini Value Edition
diff --git a/drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams427ap24.c b/drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams427ap24.c
index 8e4d012667d7..4b8aa088f445 100644
--- a/drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams427ap24.c
+++ b/drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams427ap24.c
@@ -4,6 +4,7 @@
  * Copyright (c) 2024 Jakob Hauser <jahau@rocketmail.com>
  */
 
+#include <linux/backlight.h>
 #include <linux/delay.h>
 #include <linux/gpio/consumer.h>
 #include <linux/module.h>
@@ -16,8 +17,24 @@
 #include <drm/drm_panel.h>
 #include <drm/drm_probe_helper.h>
 
+#define NUM_STEPS_CANDELA	54
+#define NUM_STEPS_AID		39
+#define NUM_STEPS_ELVSS		17
+
+/* length of the payload data, thereof fixed and variable */
+#define FIX_LEN_AID		4
+#define FIX_LEN_ELVSS		2
+#define FIX_LEN_GAMMA		1
+#define VAR_LEN_AID		2
+#define VAR_LEN_ELVSS		1
+#define VAR_LEN_GAMMA		33
+#define LEN_AID			(FIX_LEN_AID + VAR_LEN_AID)
+#define LEN_ELVSS		(FIX_LEN_ELVSS + VAR_LEN_ELVSS)
+#define LEN_GAMMA		(FIX_LEN_GAMMA + VAR_LEN_GAMMA)
+
 struct s6e88a0_ams427ap24 {
 	struct drm_panel panel;
+	struct backlight_device *bl_dev;
 	struct mipi_dsi_device *dsi;
 	struct regulator_bulk_data *supplies;
 	struct gpio_desc *reset_gpio;
@@ -34,6 +51,470 @@ struct s6e88a0_ams427ap24 *to_s6e88a0_ams427ap24(struct drm_panel *panel)
 	return container_of(panel, struct s6e88a0_ams427ap24, panel);
 }
 
+enum candela {
+	CANDELA_10CD, /* 0 */
+	CANDELA_11CD,
+	CANDELA_12CD,
+	CANDELA_13CD,
+	CANDELA_14CD,
+	CANDELA_15CD,
+	CANDELA_16CD,
+	CANDELA_17CD,
+	CANDELA_19CD,
+	CANDELA_20CD,
+	CANDELA_21CD,
+	CANDELA_22CD,
+	CANDELA_24CD,
+	CANDELA_25CD,
+	CANDELA_27CD,
+	CANDELA_29CD,
+	CANDELA_30CD,
+	CANDELA_32CD,
+	CANDELA_34CD,
+	CANDELA_37CD,
+	CANDELA_39CD,
+	CANDELA_41CD,
+	CANDELA_44CD,
+	CANDELA_47CD,
+	CANDELA_50CD,
+	CANDELA_53CD,
+	CANDELA_56CD,
+	CANDELA_60CD,
+	CANDELA_64CD,
+	CANDELA_68CD,
+	CANDELA_72CD,
+	CANDELA_77CD,
+	CANDELA_82CD,
+	CANDELA_87CD,
+	CANDELA_93CD,
+	CANDELA_98CD,
+	CANDELA_105CD,
+	CANDELA_111CD,
+	CANDELA_119CD,
+	CANDELA_126CD,
+	CANDELA_134CD,
+	CANDELA_143CD,
+	CANDELA_152CD,
+	CANDELA_162CD,
+	CANDELA_172CD,
+	CANDELA_183CD,
+	CANDELA_195CD,
+	CANDELA_207CD,
+	CANDELA_220CD,
+	CANDELA_234CD,
+	CANDELA_249CD,
+	CANDELA_265CD,
+	CANDELA_282CD,
+	CANDELA_300CD, /* 53 */
+};
+
+static const int s6e88a0_ams427ap24_br_to_cd[NUM_STEPS_CANDELA] = {
+	/* columns: brightness from, brightness till, candela */
+	/* 0 */    10,  /* 10CD */
+	/* 11 */   11,  /* 11CD */
+	/* 12 */   12,  /* 12CD */
+	/* 13 */   13,  /* 13CD */
+	/* 14 */   14,  /* 14CD */
+	/* 15 */   15,  /* 15CD */
+	/* 16 */   16,  /* 16CD */
+	/* 17 */   17,  /* 17CD */
+	/* 18 */   18,  /* 19CD */
+	/* 19 */   19,  /* 20CD */
+	/* 20 */   20,  /* 21CD */
+	/* 21 */   21,  /* 22CD */
+	/* 22 */   22,  /* 24CD */
+	/* 23 */   23,  /* 25CD */
+	/* 24 */   24,  /* 27CD */
+	/* 25 */   25,  /* 29CD */
+	/* 26 */   26,  /* 30CD */
+	/* 27 */   27,  /* 32CD */
+	/* 28 */   28,  /* 34CD */
+	/* 29 */   29,  /* 37CD */
+	/* 30 */   30,  /* 39CD */
+	/* 31 */   32,  /* 41CD */
+	/* 33 */   34,  /* 44CD */
+	/* 35 */   36,  /* 47CD */
+	/* 37 */   38,  /* 50CD */
+	/* 39 */   40,  /* 53CD */
+	/* 41 */   43,  /* 56CD */
+	/* 44 */   46,  /* 60CD */
+	/* 47 */   49,  /* 64CD */
+	/* 50 */   52,  /* 68CD */
+	/* 53 */   56,  /* 72CD */
+	/* 57 */   59,  /* 77CD */
+	/* 60 */   63,  /* 82CD */
+	/* 64 */   67,  /* 87CD */
+	/* 68 */   71,  /* 93CD */
+	/* 72 */   76,  /* 98CD */
+	/* 77 */   80,  /* 105CD */
+	/* 81 */   86,  /* 111CD */
+	/* 87 */   91,  /* 119CD */
+	/* 92 */   97,  /* 126CD */
+	/* 98 */   104, /* 134CD */
+	/* 105 */  110, /* 143CD */
+	/* 111 */  118, /* 152CD */
+	/* 119 */  125, /* 162CD */
+	/* 126 */  133, /* 172CD */
+	/* 134 */  142, /* 183CD */
+	/* 143 */  150, /* 195CD */
+	/* 151 */  160, /* 207CD */
+	/* 161 */  170, /* 220CD */
+	/* 171 */  181, /* 234CD */
+	/* 182 */  205, /* 249CD */
+	/* 206 */  234, /* 265CD */
+	/* 235 */  254, /* 282CD */
+	/* 255 */  255, /* 300CD */
+};
+
+static const u8 s6e88a0_ams427ap24_aid[NUM_STEPS_AID][VAR_LEN_AID] = {
+	{ 0x03, 0x77 }, /* AOR 90.9%, 10CD */
+	{ 0x03, 0x73 }, /* AOR 90.5%, 11CD */
+	{ 0x03, 0x69 }, /* AOR 89.4%, 12CD */
+	{ 0x03, 0x65 }, /* AOR 89.0%, 13CD */
+	{ 0x03, 0x61 }, /* AOR 88.6%, 14CD */
+	{ 0x03, 0x55 }, /* AOR 87.4%, 15CD */
+	{ 0x03, 0x50 }, /* AOR 86.9%, 16CD */
+	{ 0x03, 0x45 }, /* AOR 85.8%, 17CD */
+	{ 0x03, 0x35 }, /* AOR 84.1%, 19CD */
+	{ 0x03, 0x27 }, /* AOR 82.7%, 20CD */
+	{ 0x03, 0x23 }, /* AOR 82.3%, 21CD */
+	{ 0x03, 0x17 }, /* AOR 81.0%, 22CD */
+	{ 0x03, 0x11 }, /* AOR 80.4%, 24CD */
+	{ 0x03, 0x04 }, /* AOR 79.1%, 25CD */
+	{ 0x02, 0xf4 }, /* AOR 77.5%, 27CD */
+	{ 0x02, 0xe3 }, /* AOR 75.7%, 29CD */
+	{ 0x02, 0xd7 }, /* AOR 74.5%, 30CD */
+	{ 0x02, 0xc6 }, /* AOR 72.7%, 32CD */
+	{ 0x02, 0xb7 }, /* AOR 71.2%, 34CD */
+	{ 0x02, 0xa1 }, /* AOR 69.0%, 37CD */
+	{ 0x02, 0x91 }, /* AOR 67.3%, 39CD */
+	{ 0x02, 0x78 }, /* AOR 64.8%, 41CD */
+	{ 0x02, 0x62 }, /* AOR 62.5%, 44CD */
+	{ 0x02, 0x45 }, /* AOR 59.5%, 47CD */
+	{ 0x02, 0x30 }, /* AOR 57.4%, 50CD */
+	{ 0x02, 0x13 }, /* AOR 54.4%, 53CD */
+	{ 0x01, 0xf5 }, /* AOR 51.3%, 56CD */
+	{ 0x01, 0xd3 }, /* AOR 47.8%, 60CD */
+	{ 0x01, 0xb1 }, /* AOR 44.4%, 64CD */
+	{ 0x01, 0x87 }, /* AOR 40.1%, 68CD */
+	{ 0x01, 0x63 }, /* AOR 36.6%, 72CD */
+	{ 0x01, 0x35 }, /* AOR 31.7%, 77CD */
+	{ 0x01, 0x05 }, /* AOR 26.9%, 82CD */
+	{ 0x00, 0xd5 }, /* AOR 21.8%, 87CD */
+	{ 0x00, 0xa1 }, /* AOR 16.5%, 93CD */
+	{ 0x00, 0x6f }, /* AOR 11.4%, 98CD */
+	{ 0x00, 0x31 }, /* AOR 5.0%, 105CD */
+	{ 0x01, 0x86 }, /* AOR 40.0%, 111CD ~ 172CD */
+	{ 0x00, 0x08 }, /* AOR 0.6%, 183CD ~ 300CD */
+};
+
+static const u8 s6e88a0_ams427ap24_elvss[NUM_STEPS_ELVSS][VAR_LEN_ELVSS] = {
+	{ 0x14 }, /* 10CD ~ 111CD */
+	{ 0x13 }, /* 119CD */
+	{ 0x12 }, /* 126CD */
+	{ 0x12 }, /* 134CD */
+	{ 0x11 }, /* 143CD */
+	{ 0x10 }, /* 152CD */
+	{ 0x0f }, /* 162CD */
+	{ 0x0e }, /* 172CD */
+	{ 0x11 }, /* 183CD */
+	{ 0x11 }, /* 195CD */
+	{ 0x10 }, /* 207CD */
+	{ 0x0f }, /* 220CD */
+	{ 0x0f }, /* 234CD */
+	{ 0x0e }, /* 249CD */
+	{ 0x0d }, /* 265CD */
+	{ 0x0c }, /* 282CD */
+	{ 0x0b }, /* 300CD */
+};
+
+static const u8 s6e88a0_ams427ap24_gamma[NUM_STEPS_CANDELA][VAR_LEN_GAMMA] = {
+	/* 10CD */
+	{ 0x00, 0xc8, 0x00, 0xc4, 0x00, 0xc5, 0x8c, 0x8a, 0x8a, 0x8c, 0x8b,
+	  0x8c, 0x87, 0x89, 0x89, 0x88, 0x87, 0x8c, 0x80, 0x82, 0x88, 0x7b,
+	  0x72, 0x8c, 0x60, 0x68, 0x8c, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
+	/* 11CD */
+	{ 0x00, 0xc8, 0x00, 0xc4, 0x00, 0xc5, 0x8c, 0x8a, 0x8a, 0x8c, 0x8b,
+	  0x8c, 0x87, 0x89, 0x89, 0x88, 0x87, 0x8c, 0x80, 0x82, 0x88, 0x7b,
+	  0x72, 0x8c, 0x60, 0x68, 0x8c, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
+	/* 12CD */
+	{ 0x00, 0xc8, 0x00, 0xc4, 0x00, 0xc5, 0x8c, 0x8a, 0x8a, 0x8b, 0x8b,
+	  0x8c, 0x88, 0x89, 0x8a, 0x88, 0x87, 0x8c, 0x81, 0x82, 0x87, 0x7a,
+	  0x72, 0x8b, 0x60, 0x68, 0x8c, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
+	/* 13CD */
+	{ 0x00, 0xc8, 0x00, 0xc4, 0x00, 0xc5, 0x8c, 0x8a, 0x8a, 0x8b, 0x8b,
+	  0x8c, 0x88, 0x89, 0x8a, 0x88, 0x87, 0x8c, 0x81, 0x82, 0x87, 0x7a,
+	  0x72, 0x8b, 0x61, 0x69, 0x8c, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
+	/* 14CD */
+	{ 0x00, 0xc8, 0x00, 0xc4, 0x00, 0xc5, 0x8c, 0x8a, 0x89, 0x8c, 0x8b,
+	  0x8c, 0x88, 0x89, 0x8a, 0x87, 0x86, 0x8a, 0x82, 0x82, 0x87, 0x79,
+	  0x71, 0x89, 0x63, 0x6c, 0x8e, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
+	/* 15CD */
+	{ 0x00, 0xc8, 0x00, 0xc4, 0x00, 0xc5, 0x8c, 0x8a, 0x8a, 0x8c, 0x8c,
+	  0x8c, 0x86, 0x87, 0x88, 0x85, 0x85, 0x8a, 0x83, 0x83, 0x88, 0x78,
+	  0x72, 0x89, 0x64, 0x6c, 0x8e, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
+	/* 16CD */
+	{ 0x00, 0xc8, 0x00, 0xc4, 0x00, 0xc5, 0x8c, 0x8a, 0x89, 0x8c, 0x8b,
+	  0x8c, 0x86, 0x88, 0x88, 0x86, 0x86, 0x8a, 0x84, 0x84, 0x88, 0x78,
+	  0x72, 0x89, 0x5d, 0x67, 0x8b, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
+	/* 17CD */
+	{ 0x00, 0xc8, 0x00, 0xc4, 0x00, 0xc5, 0x8c, 0x8a, 0x89, 0x8b, 0x8b,
+	  0x8b, 0x87, 0x89, 0x89, 0x86, 0x86, 0x8a, 0x84, 0x83, 0x87, 0x78,
+	  0x73, 0x89, 0x64, 0x6e, 0x8e, 0x38, 0x32, 0x24, 0x00, 0x00, 0x00 },
+	/* 19CD */
+	{ 0x00, 0xc8, 0x00, 0xc4, 0x00, 0xc5, 0x8c, 0x8a, 0x89, 0x8b, 0x8b,
+	  0x8b, 0x87, 0x89, 0x89, 0x86, 0x86, 0x89, 0x84, 0x84, 0x87, 0x77,
+	  0x72, 0x88, 0x65, 0x6f, 0x8e, 0x38, 0x32, 0x24, 0x00, 0x00, 0x00 },
+	/* 20CD */
+	{ 0x00, 0xc8, 0x00, 0xc4, 0x00, 0xc5, 0x8c, 0x8a, 0x89, 0x8b, 0x8b,
+	  0x8b, 0x88, 0x89, 0x89, 0x85, 0x85, 0x88, 0x82, 0x83, 0x85, 0x79,
+	  0x73, 0x88, 0x65, 0x6f, 0x8e, 0x38, 0x32, 0x24, 0x00, 0x00, 0x00 },
+	/* 21CD */
+	{ 0x00, 0xc8, 0x00, 0xc4, 0x00, 0xc5, 0x8c, 0x8a, 0x89, 0x8b, 0x8b,
+	  0x8b, 0x88, 0x89, 0x89, 0x85, 0x85, 0x88, 0x82, 0x83, 0x85, 0x79,
+	  0x74, 0x88, 0x65, 0x6f, 0x8e, 0x38, 0x32, 0x24, 0x00, 0x00, 0x00 },
+	/* 22CD */
+	{ 0x00, 0xc8, 0x00, 0xc4, 0x00, 0xc5, 0x8c, 0x8a, 0x89, 0x8c, 0x8b,
+	  0x8c, 0x86, 0x88, 0x87, 0x86, 0x86, 0x89, 0x82, 0x83, 0x85, 0x7c,
+	  0x75, 0x87, 0x65, 0x6f, 0x8e, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
+	/* 24CD */
+	{ 0x00, 0xc8, 0x00, 0xc4, 0x00, 0xc5, 0x8c, 0x8a, 0x89, 0x8c, 0x8b,
+	  0x8c, 0x86, 0x88, 0x87, 0x86, 0x86, 0x89, 0x82, 0x83, 0x85, 0x7c,
+	  0x76, 0x86, 0x66, 0x6f, 0x8e, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
+	/* 25CD */
+	{ 0x00, 0xc8, 0x00, 0xc4, 0x00, 0xc5, 0x8c, 0x8a, 0x89, 0x8b, 0x8b,
+	  0x8b, 0x86, 0x89, 0x88, 0x87, 0x87, 0x89, 0x82, 0x82, 0x84, 0x7f,
+	  0x7a, 0x89, 0x6b, 0x73, 0x8f, 0x33, 0x2f, 0x22, 0x00, 0x00, 0x00 },
+	/* 27CD */
+	{ 0x00, 0xc8, 0x00, 0xc4, 0x00, 0xc5, 0x8c, 0x8a, 0x89, 0x8b, 0x8b,
+	  0x8b, 0x86, 0x89, 0x88, 0x87, 0x87, 0x89, 0x82, 0x82, 0x84, 0x7f,
+	  0x7a, 0x89, 0x6b, 0x73, 0x8f, 0x33, 0x2f, 0x22, 0x00, 0x00, 0x00 },
+	/* 29CD */
+	{ 0x00, 0xc8, 0x00, 0xc4, 0x00, 0xc5, 0x8c, 0x8a, 0x89, 0x8b, 0x8b,
+	  0x8b, 0x86, 0x89, 0x88, 0x85, 0x84, 0x87, 0x84, 0x85, 0x86, 0x80,
+	  0x7b, 0x88, 0x6a, 0x73, 0x8f, 0x33, 0x2f, 0x22, 0x00, 0x00, 0x00 },
+	/* 30CD */
+	{ 0x00, 0xc8, 0x00, 0xc4, 0x00, 0xc5, 0x8c, 0x8a, 0x89, 0x8b, 0x8b,
+	  0x8b, 0x86, 0x89, 0x88, 0x85, 0x84, 0x87, 0x84, 0x85, 0x86, 0x80,
+	  0x7b, 0x88, 0x6a, 0x73, 0x8f, 0x33, 0x2f, 0x22, 0x00, 0x00, 0x00 },
+	/* 32CD */
+	{ 0x00, 0xc8, 0x00, 0xc4, 0x00, 0xc5, 0x8c, 0x8a, 0x89, 0x8b, 0x8b,
+	  0x8b, 0x86, 0x89, 0x88, 0x85, 0x84, 0x87, 0x84, 0x85, 0x86, 0x80,
+	  0x7b, 0x88, 0x6a, 0x73, 0x8f, 0x33, 0x2f, 0x22, 0x00, 0x00, 0x00 },
+	/* 34CD */
+	{ 0x00, 0xc8, 0x00, 0xc4, 0x00, 0xc5, 0x8c, 0x8a, 0x89, 0x8b, 0x8b,
+	  0x8b, 0x86, 0x89, 0x88, 0x85, 0x84, 0x87, 0x83, 0x84, 0x84, 0x7f,
+	  0x79, 0x86, 0x6c, 0x76, 0x91, 0x33, 0x2f, 0x22, 0x00, 0x00, 0x00 },
+	/* 37CD */
+	{ 0x00, 0xc8, 0x00, 0xc4, 0x00, 0xc5, 0x8b, 0x89, 0x89, 0x8b, 0x8b,
+	  0x8b, 0x86, 0x88, 0x88, 0x87, 0x86, 0x87, 0x83, 0x84, 0x84, 0x7f,
+	  0x79, 0x86, 0x6c, 0x76, 0x90, 0x33, 0x2f, 0x22, 0x00, 0x00, 0x00 },
+	/* 39CD */
+	{ 0x00, 0xc8, 0x00, 0xc4, 0x00, 0xc5, 0x8b, 0x89, 0x89, 0x8b, 0x8b,
+	  0x8b, 0x86, 0x88, 0x87, 0x84, 0x84, 0x86, 0x83, 0x85, 0x85, 0x80,
+	  0x79, 0x85, 0x6c, 0x76, 0x90, 0x33, 0x2f, 0x22, 0x00, 0x00, 0x00 },
+	/* 41CD */
+	{ 0x00, 0xc8, 0x00, 0xc4, 0x00, 0xc5, 0x8b, 0x89, 0x89, 0x8b, 0x8b,
+	  0x8b, 0x86, 0x88, 0x87, 0x84, 0x84, 0x86, 0x81, 0x84, 0x83, 0x7f,
+	  0x79, 0x84, 0x6e, 0x79, 0x93, 0x33, 0x2f, 0x22, 0x00, 0x00, 0x00 },
+	/* 44CD */
+	{ 0x00, 0xc8, 0x00, 0xc4, 0x00, 0xc5, 0x8b, 0x89, 0x89, 0x8b, 0x8b,
+	  0x8b, 0x86, 0x88, 0x87, 0x84, 0x84, 0x86, 0x81, 0x84, 0x83, 0x7f,
+	  0x79, 0x84, 0x6e, 0x79, 0x92, 0x33, 0x2f, 0x22, 0x00, 0x00, 0x00 },
+	/* 47CD */
+	{ 0x00, 0xc8, 0x00, 0xc4, 0x00, 0xc5, 0x8b, 0x89, 0x89, 0x8b, 0x8b,
+	  0x8b, 0x86, 0x88, 0x87, 0x84, 0x85, 0x86, 0x81, 0x84, 0x83, 0x7f,
+	  0x79, 0x83, 0x6f, 0x79, 0x91, 0x33, 0x2f, 0x22, 0x00, 0x00, 0x00 },
+	/* 50CD */
+	{ 0x00, 0xc8, 0x00, 0xc4, 0x00, 0xc5, 0x8b, 0x89, 0x89, 0x8b, 0x8b,
+	  0x8b, 0x86, 0x88, 0x87, 0x84, 0x85, 0x86, 0x82, 0x84, 0x83, 0x7f,
+	  0x79, 0x83, 0x6f, 0x79, 0x90, 0x33, 0x2f, 0x22, 0x00, 0x00, 0x00 },
+	/* 53CD */
+	{ 0x00, 0xc8, 0x00, 0xc4, 0x00, 0xc5, 0x8b, 0x89, 0x89, 0x8b, 0x8b,
+	  0x8b, 0x86, 0x88, 0x87, 0x83, 0x83, 0x85, 0x84, 0x85, 0x85, 0x7f,
+	  0x79, 0x83, 0x70, 0x79, 0x8f, 0x33, 0x2f, 0x22, 0x00, 0x00, 0x00 },
+	/* 56CD */
+	{ 0x00, 0xc8, 0x00, 0xc4, 0x00, 0xc5, 0x8b, 0x89, 0x89, 0x8b, 0x8a,
+	  0x8a, 0x87, 0x89, 0x87, 0x83, 0x83, 0x85, 0x84, 0x85, 0x84, 0x7f,
+	  0x79, 0x82, 0x70, 0x7a, 0x8e, 0x33, 0x2f, 0x22, 0x00, 0x00, 0x00 },
+	/* 60CD */
+	{ 0x00, 0xc8, 0x00, 0xc4, 0x00, 0xc5, 0x8b, 0x89, 0x89, 0x8b, 0x8a,
+	  0x8a, 0x87, 0x89, 0x87, 0x83, 0x83, 0x85, 0x84, 0x85, 0x84, 0x7e,
+	  0x79, 0x82, 0x71, 0x7a, 0x8d, 0x33, 0x2f, 0x22, 0x00, 0x00, 0x00 },
+	/* 64CD */
+	{ 0x00, 0xc8, 0x00, 0xc4, 0x00, 0xc5, 0x8b, 0x89, 0x89, 0x8b, 0x8a,
+	  0x8a, 0x86, 0x88, 0x86, 0x84, 0x84, 0x86, 0x82, 0x83, 0x82, 0x80,
+	  0x7a, 0x84, 0x71, 0x7a, 0x8c, 0x33, 0x2f, 0x22, 0x00, 0x00, 0x00 },
+	/* 68CD */
+	{ 0x00, 0xc8, 0x00, 0xc4, 0x00, 0xc5, 0x8a, 0x89, 0x89, 0x8c, 0x8a,
+	  0x8a, 0x86, 0x88, 0x86, 0x84, 0x84, 0x86, 0x82, 0x84, 0x82, 0x81,
+	  0x7b, 0x83, 0x72, 0x7b, 0x8b, 0x33, 0x2f, 0x22, 0x00, 0x00, 0x00 },
+	/* 72CD */
+	{ 0x00, 0xc8, 0x00, 0xc4, 0x00, 0xc5, 0x8a, 0x89, 0x89, 0x8c, 0x8a,
+	  0x8a, 0x86, 0x88, 0x86, 0x85, 0x85, 0x86, 0x82, 0x84, 0x82, 0x81,
+	  0x7b, 0x83, 0x72, 0x7c, 0x8a, 0x33, 0x2f, 0x22, 0x00, 0x00, 0x00 },
+	/* 77CD */
+	{ 0x00, 0xc8, 0x00, 0xc4, 0x00, 0xc5, 0x8a, 0x89, 0x89, 0x8c, 0x8a,
+	  0x8a, 0x85, 0x87, 0x85, 0x85, 0x87, 0x87, 0x82, 0x84, 0x82, 0x81,
+	  0x7c, 0x82, 0x72, 0x7c, 0x89, 0x33, 0x2f, 0x22, 0x00, 0x00, 0x00 },
+	/* 82CD */
+	{ 0x00, 0xc8, 0x00, 0xc4, 0x00, 0xc5, 0x8a, 0x89, 0x89, 0x8c, 0x8a,
+	  0x8a, 0x85, 0x87, 0x85, 0x85, 0x87, 0x87, 0x82, 0x84, 0x82, 0x81,
+	  0x7c, 0x82, 0x73, 0x7c, 0x88, 0x33, 0x2f, 0x22, 0x00, 0x00, 0x00 },
+	/* 87CD */
+	{ 0x00, 0xc8, 0x00, 0xc4, 0x00, 0xc5, 0x8a, 0x89, 0x89, 0x8c, 0x8a,
+	  0x8a, 0x85, 0x87, 0x85, 0x84, 0x84, 0x86, 0x80, 0x84, 0x81, 0x80,
+	  0x7a, 0x82, 0x76, 0x7f, 0x89, 0x33, 0x2f, 0x22, 0x00, 0x00, 0x00 },
+	/* 93CD */
+	{ 0x00, 0xc8, 0x00, 0xc4, 0x00, 0xc5, 0x8a, 0x89, 0x89, 0x8b, 0x8a,
+	  0x8a, 0x86, 0x87, 0x85, 0x84, 0x85, 0x86, 0x80, 0x84, 0x80, 0x80,
+	  0x7a, 0x82, 0x76, 0x80, 0x88, 0x33, 0x2f, 0x22, 0x00, 0x00, 0x00 },
+	/* 98CD */
+	{ 0x00, 0xc8, 0x00, 0xc4, 0x00, 0xc5, 0x8a, 0x89, 0x89, 0x8b, 0x8a,
+	  0x8a, 0x86, 0x87, 0x85, 0x85, 0x85, 0x86, 0x80, 0x84, 0x80, 0x80,
+	  0x7a, 0x82, 0x76, 0x80, 0x88, 0x33, 0x2f, 0x22, 0x00, 0x00, 0x00 },
+	/* 105CD */
+	{ 0x00, 0xc8, 0x00, 0xc4, 0x00, 0xc5, 0x89, 0x88, 0x88, 0x8b, 0x8a,
+	  0x8a, 0x84, 0x87, 0x85, 0x85, 0x85, 0x85, 0x80, 0x84, 0x80, 0x7f,
+	  0x79, 0x81, 0x71, 0x7d, 0x87, 0x38, 0x32, 0x24, 0x00, 0x00, 0x00 },
+	/* 111CD */
+	{ 0x00, 0xdf, 0x00, 0xde, 0x00, 0xde, 0x85, 0x85, 0x84, 0x87, 0x86,
+	  0x87, 0x85, 0x86, 0x85, 0x83, 0x83, 0x83, 0x81, 0x82, 0x82, 0x80,
+	  0x7d, 0x82, 0x75, 0x7f, 0x86, 0x85, 0x85, 0x82, 0x00, 0x00, 0x00 },
+	/* 119CD */
+	{ 0x00, 0xe3, 0x00, 0xe1, 0x00, 0xe2, 0x85, 0x85, 0x84, 0x86, 0x85,
+	  0x85, 0x84, 0x85, 0x84, 0x83, 0x83, 0x83, 0x82, 0x82, 0x82, 0x7e,
+	  0x7b, 0x81, 0x75, 0x7f, 0x86, 0x85, 0x85, 0x82, 0x00, 0x00, 0x00 },
+	/* 126CD */
+	{ 0x00, 0xe6, 0x00, 0xe5, 0x00, 0xe5, 0x85, 0x84, 0x84, 0x85, 0x85,
+	  0x85, 0x84, 0x84, 0x84, 0x82, 0x83, 0x83, 0x80, 0x81, 0x81, 0x80,
+	  0x7f, 0x83, 0x73, 0x7c, 0x84, 0x85, 0x85, 0x82, 0x00, 0x00, 0x00 },
+	/* 134CD */
+	{ 0x00, 0xe9, 0x00, 0xe8, 0x00, 0xe8, 0x84, 0x84, 0x83, 0x85, 0x85,
+	  0x85, 0x84, 0x84, 0x83, 0x81, 0x82, 0x82, 0x81, 0x81, 0x81, 0x7f,
+	  0x7d, 0x81, 0x73, 0x7c, 0x83, 0x85, 0x85, 0x82, 0x00, 0x00, 0x00 },
+	/* 143CD */
+	{ 0x00, 0xed, 0x00, 0xec, 0x00, 0xec, 0x84, 0x83, 0x83, 0x84, 0x84,
+	  0x84, 0x84, 0x84, 0x83, 0x82, 0x83, 0x83, 0x81, 0x80, 0x81, 0x7f,
+	  0x7e, 0x81, 0x70, 0x79, 0x81, 0x85, 0x85, 0x82, 0x00, 0x00, 0x00 },
+	/* 152CD */
+	{ 0x00, 0xf0, 0x00, 0xf0, 0x00, 0xf0, 0x83, 0x83, 0x83, 0x83, 0x83,
+	  0x83, 0x84, 0x84, 0x83, 0x81, 0x81, 0x81, 0x80, 0x80, 0x81, 0x80,
+	  0x80, 0x82, 0x6f, 0x78, 0x7f, 0x85, 0x85, 0x82, 0x00, 0x00, 0x00 },
+	/* 162CD */
+	{ 0x00, 0xf4, 0x00, 0xf3, 0x00, 0xf4, 0x83, 0x83, 0x83, 0x83, 0x83,
+	  0x83, 0x82, 0x81, 0x81, 0x81, 0x81, 0x81, 0x80, 0x80, 0x81, 0x80,
+	  0x7f, 0x82, 0x6f, 0x78, 0x7f, 0x85, 0x85, 0x82, 0x00, 0x00, 0x00 },
+	/* 172CD */
+	{ 0x00, 0xf8, 0x00, 0xf8, 0x00, 0xf8, 0x82, 0x82, 0x82, 0x82, 0x82,
+	  0x82, 0x82, 0x81, 0x81, 0x80, 0x81, 0x80, 0x80, 0x80, 0x81, 0x81,
+	  0x80, 0x83, 0x6d, 0x76, 0x7d, 0x85, 0x85, 0x82, 0x00, 0x00, 0x00 },
+	/* 183CD */
+	{ 0x00, 0xe0, 0x00, 0xdf, 0x00, 0xdf, 0x84, 0x84, 0x83, 0x86, 0x86,
+	  0x86, 0x83, 0x84, 0x83, 0x82, 0x82, 0x82, 0x81, 0x83, 0x81, 0x81,
+	  0x7e, 0x81, 0x80, 0x82, 0x84, 0x85, 0x85, 0x82, 0x00, 0x00, 0x00 },
+	/* 195CD */
+	{ 0x00, 0xe4, 0x00, 0xe3, 0x00, 0xe3, 0x84, 0x83, 0x83, 0x85, 0x85,
+	  0x85, 0x83, 0x84, 0x83, 0x81, 0x82, 0x82, 0x82, 0x83, 0x81, 0x81,
+	  0x80, 0x82, 0x7d, 0x7f, 0x81, 0x85, 0x85, 0x82, 0x00, 0x00, 0x00 },
+	/* 207CD */
+	{ 0x00, 0xe7, 0x00, 0xe6, 0x00, 0xe6, 0x83, 0x82, 0x82, 0x85, 0x85,
+	  0x85, 0x82, 0x83, 0x83, 0x82, 0x82, 0x82, 0x80, 0x81, 0x80, 0x81,
+	  0x80, 0x82, 0x7d, 0x7f, 0x81, 0x85, 0x85, 0x82, 0x00, 0x00, 0x00 },
+	/* 220CD */
+	{ 0x00, 0xeb, 0x00, 0xea, 0x00, 0xea, 0x83, 0x83, 0x82, 0x84, 0x84,
+	  0x84, 0x82, 0x83, 0x82, 0x81, 0x81, 0x82, 0x81, 0x82, 0x81, 0x80,
+	  0x7e, 0x80, 0x7d, 0x7f, 0x81, 0x85, 0x85, 0x82, 0x00, 0x00, 0x00 },
+	/* 234CD */
+	{ 0x00, 0xef, 0x00, 0xee, 0x00, 0xee, 0x83, 0x82, 0x82, 0x83, 0x83,
+	  0x83, 0x82, 0x82, 0x82, 0x81, 0x81, 0x81, 0x80, 0x80, 0x80, 0x80,
+	  0x80, 0x81, 0x7b, 0x7c, 0x7f, 0x85, 0x85, 0x82, 0x00, 0x00, 0x00 },
+	/* 249CD */
+	{ 0x00, 0xf3, 0x00, 0xf2, 0x00, 0xf2, 0x82, 0x81, 0x81, 0x83, 0x83,
+	  0x83, 0x82, 0x82, 0x82, 0x81, 0x81, 0x81, 0x80, 0x81, 0x80, 0x7f,
+	  0x7e, 0x7f, 0x7b, 0x7c, 0x7f, 0x85, 0x85, 0x82, 0x00, 0x00, 0x00 },
+	/* 265CD */
+	{ 0x00, 0xf7, 0x00, 0xf7, 0x00, 0xf7, 0x81, 0x81, 0x80, 0x82, 0x82,
+	  0x82, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x81, 0x80, 0x7f,
+	  0x7e, 0x7f, 0x7b, 0x7c, 0x7f, 0x85, 0x85, 0x82, 0x00, 0x00, 0x00 },
+	/* 282CD */
+	{ 0x00, 0xfb, 0x00, 0xfb, 0x00, 0xfb, 0x80, 0x80, 0x80, 0x81, 0x81,
+	  0x81, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x7f, 0x7f, 0x7f, 0x7f,
+	  0x7f, 0x7f, 0x78, 0x79, 0x7d, 0x85, 0x85, 0x82, 0x00, 0x00, 0x00 },
+	/* 300CD */
+	{ 0x01, 0x00, 0x01, 0x00, 0x01, 0x00, 0x80, 0x80, 0x80, 0x80, 0x80,
+	  0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
+	  0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x00, 0x00, 0x00 },
+};
+
+static int s6e88a0_ams427ap24_set_brightness(struct backlight_device *bd)
+{
+	struct s6e88a0_ams427ap24 *ctx = bl_get_data(bd);
+	struct mipi_dsi_device *dsi = ctx->dsi;
+	struct mipi_dsi_multi_context dsi_ctx = { .dsi = dsi };
+	struct device *dev = &dsi->dev;
+	int brightness = bd->props.brightness;
+	int candela_enum;
+	u8 b2[LEN_AID] = { 0xb2, 0x40, 0x08, 0x20, 0x00, 0x00 };
+	u8 b6[LEN_ELVSS] = { 0xb6, 0x28, 0x00 };
+	u8 ca[LEN_GAMMA];
+
+	/* get candela enum from brightness */
+	for (candela_enum = 0; candela_enum < NUM_STEPS_CANDELA; candela_enum++)
+		if (brightness <= s6e88a0_ams427ap24_br_to_cd[candela_enum])
+			break;
+
+	/* get aid */
+	switch (candela_enum) {
+	case CANDELA_10CD ... CANDELA_105CD:
+		memcpy(&b2[FIX_LEN_AID],
+		       s6e88a0_ams427ap24_aid[candela_enum],
+		       VAR_LEN_AID);
+		break;
+	case CANDELA_111CD ... CANDELA_172CD:
+		memcpy(&b2[FIX_LEN_AID],
+		       s6e88a0_ams427ap24_aid[CANDELA_111CD],
+		       VAR_LEN_AID);
+		break;
+	case CANDELA_183CD ... CANDELA_300CD:
+		memcpy(&b2[FIX_LEN_AID],
+		       s6e88a0_ams427ap24_aid[CANDELA_111CD + 1],
+		       VAR_LEN_AID);
+		break;
+	default:
+		dev_err(dev, "Failed to get aid data\n");
+		return -EINVAL;
+	}
+
+	/* get elvss */
+	if (candela_enum <= CANDELA_111CD) {
+		memcpy(&b6[FIX_LEN_ELVSS],
+		       s6e88a0_ams427ap24_elvss[0],
+		       VAR_LEN_ELVSS);
+	} else {
+		memcpy(&b6[FIX_LEN_ELVSS],
+		       s6e88a0_ams427ap24_elvss[candela_enum - CANDELA_111CD],
+		       VAR_LEN_ELVSS);
+	}
+
+	/* get gamma */
+	ca[0] = 0xca;
+	memcpy(&ca[FIX_LEN_GAMMA],
+	       s6e88a0_ams427ap24_gamma[candela_enum],
+	       VAR_LEN_GAMMA);
+
+	/* write data */
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf0, 0x5a, 0x5a); // level 1 key on
+	mipi_dsi_dcs_write_buffer_multi(&dsi_ctx, b2, ARRAY_SIZE(b2)); // set aid
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x55, 0x00); // acl off
+	mipi_dsi_dcs_write_buffer_multi(&dsi_ctx, b6, ARRAY_SIZE(b6)); // set elvss
+	mipi_dsi_dcs_write_buffer_multi(&dsi_ctx, ca, ARRAY_SIZE(ca)); // set gamma
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf7, 0x03); // gamma update
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf0, 0xa5, 0xa5); // level 1 key off
+
+	return dsi_ctx.accum_err;
+}
+
 static void s6e88a0_ams427ap24_reset(struct s6e88a0_ams427ap24 *ctx)
 {
 	gpiod_set_value_cansleep(ctx->reset_gpio, 0);
@@ -48,6 +529,8 @@ static int s6e88a0_ams427ap24_on(struct s6e88a0_ams427ap24 *ctx)
 {
 	struct mipi_dsi_device *dsi = ctx->dsi;
 	struct mipi_dsi_multi_context dsi_ctx = { .dsi = dsi };
+	struct device *dev = &dsi->dev;
+	int ret;
 
 	dsi->mode_flags |= MIPI_DSI_MODE_LPM;
 
@@ -67,20 +550,15 @@ static int s6e88a0_ams427ap24_on(struct s6e88a0_ams427ap24 *ctx)
 	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xcc, 0x4c); // pixel clock divider pol.
 	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf2, 0x03, 0x0d); // unknown
 	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf1, 0xa5, 0xa5); // level 3 key off
-	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xca,
-				     0x01, 0x00, 0x01, 0x00, 0x01, 0x00, 0x80,
-				     0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
-				     0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
-				     0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
-				     0x80, 0x80, 0x00, 0x00, 0x00); // set gamma
-	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xb2,
-				     0x40, 0x08, 0x20, 0x00, 0x08); // set aid
-	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xb6, 0x28, 0x0b); // set elvss
-	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf7, 0x03); // gamma update
-	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x55, 0x00); // acl off
 	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf0, 0xa5, 0xa5); // level 1 key off
 	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xfc, 0xa5, 0xa5); // level 2 key off
 
+	ret = s6e88a0_ams427ap24_set_brightness(ctx->bl_dev);
+	if (ret < 0) {
+		dev_err(dev, "Failed to set brightness: %d\n", ret);
+		return ret;
+	}
+
 	mipi_dsi_dcs_set_display_on_multi(&dsi_ctx);
 
 	return dsi_ctx.accum_err;
@@ -172,6 +650,32 @@ static const struct drm_panel_funcs s6e88a0_ams427ap24_panel_funcs = {
 	.get_modes = s6e88a0_ams427ap24_get_modes,
 };
 
+static const struct backlight_ops s6e88a0_ams427ap24_bl_ops = {
+	.update_status	= s6e88a0_ams427ap24_set_brightness,
+};
+
+static int s6e88a0_ams427ap24_register_backlight(struct s6e88a0_ams427ap24 *ctx)
+{
+	struct backlight_properties props = {
+		.type		= BACKLIGHT_RAW,
+		.brightness	= 180,
+		.max_brightness = 255,
+	};
+	struct mipi_dsi_device *dsi = ctx->dsi;
+	struct device *dev = &dsi->dev;
+	int ret = 0;
+
+	ctx->bl_dev = devm_backlight_device_register(dev, dev_name(dev), dev, ctx,
+						     &s6e88a0_ams427ap24_bl_ops,
+						     &props);
+	if (IS_ERR(ctx->bl_dev)) {
+		ret = PTR_ERR(ctx->bl_dev);
+		dev_err(dev, "error registering backlight device (%d)\n", ret);
+	}
+
+	return ret;
+}
+
 static int s6e88a0_ams427ap24_probe(struct mipi_dsi_device *dsi)
 {
 	struct device *dev = &dsi->dev;
@@ -200,12 +704,16 @@ static int s6e88a0_ams427ap24_probe(struct mipi_dsi_device *dsi)
 	dsi->lanes = 2;
 	dsi->format = MIPI_DSI_FMT_RGB888;
 	dsi->mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_BURST |
-			  MIPI_DSI_MODE_NO_EOT_PACKET;
+			  MIPI_DSI_MODE_NO_EOT_PACKET | MIPI_DSI_MODE_VIDEO_NO_HFP;
 
 	drm_panel_init(&ctx->panel, dev, &s6e88a0_ams427ap24_panel_funcs,
 		       DRM_MODE_CONNECTOR_DSI);
 	ctx->panel.prepare_prev_first = true;
 
+	ret = s6e88a0_ams427ap24_register_backlight(ctx);
+	if (ret < 0)
+		return ret;
+
 	drm_panel_add(&ctx->panel);
 
 	ret = mipi_dsi_attach(dsi);