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 <ja...@rocketmail.com>
---
Changes in v2:
 - In the table "s6e88a0_ams427ap24_aid" in comment of the second-last line
   changed the format of "40,00 %" to "40.0%" like all others.
---
 drivers/gpu/drm/panel/Kconfig                 |   1 +
 .../panel/panel-samsung-s6e88a0-ams427ap24.c  | 519 +++++++++++++++++-
 2 files changed, 508 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 0ab2768e0e2b..6e02b881434d 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 <ja...@rocketmail.com>
  */
 
+#include <linux/backlight.h>
 #include <linux/delay.h>
 #include <linux/gpio/consumer.h>
 #include <linux/module.h>
@@ -17,8 +18,17 @@
 #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
+
+#define SEQ_LENGTH_AID         5
+#define SEQ_LENGTH_ELVSS       2
+#define SEQ_LENGTH_GAMMA       33
+
 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;
@@ -35,6 +45,464 @@ 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] = {
+       /* brightness till, candela */
+       10, /* 10CD */
+       11, /* 11CD */
+       12, /* 12CD */
+       13, /* 13CD */
+       14, /* 14CD */
+       15, /* 15CD */
+       16, /* 16CD */
+       17, /* 17CD */
+       18, /* 19CD */
+       19, /* 20CD */
+       20, /* 21CD */
+       21, /* 22CD */
+       22, /* 24CD */
+       23, /* 25CD */
+       24, /* 27CD */
+       25, /* 29CD */
+       26, /* 30CD */
+       27, /* 32CD */
+       28, /* 34CD */
+       29, /* 37CD */
+       30, /* 39CD */
+       32, /* 41CD */
+       34, /* 44CD */
+       36, /* 47CD */
+       38, /* 50CD */
+       40, /* 53CD */
+       43, /* 56CD */
+       46, /* 60CD */
+       49, /* 64CD */
+       52, /* 68CD */
+       56, /* 72CD */
+       59, /* 77CD */
+       63, /* 82CD */
+       67, /* 87CD */
+       71, /* 93CD */
+       76, /* 98CD */
+       80, /* 105CD */
+       86, /* 111CD */
+       91, /* 119CD */
+       97, /* 126CD */
+       104, /* 134CD */
+       110, /* 143CD */
+       118, /* 152CD */
+       125, /* 162CD */
+       133, /* 172CD */
+       142, /* 183CD */
+       150, /* 195CD */
+       160, /* 207CD */
+       170, /* 220CD */
+       181, /* 234CD */
+       205, /* 249CD */
+       234, /* 265CD */
+       254, /* 282CD */
+       255, /* 300CD */
+};
+
+static const u8 s6e88a0_ams427ap24_aid[NUM_STEPS_AID][SEQ_LENGTH_AID] = {
+       { 0x40, 0x08, 0x20, 0x03, 0x77 }, /* AOR 90.9%, 10CD */
+       { 0x40, 0x08, 0x20, 0x03, 0x73 }, /* AOR 90.5%, 11CD */
+       { 0x40, 0x08, 0x20, 0x03, 0x69 }, /* AOR 89.4%, 12CD */
+       { 0x40, 0x08, 0x20, 0x03, 0x65 }, /* AOR 89.0%, 13CD */
+       { 0x40, 0x08, 0x20, 0x03, 0x61 }, /* AOR 88.6%, 14CD */
+       { 0x40, 0x08, 0x20, 0x03, 0x55 }, /* AOR 87.4%, 15CD */
+       { 0x40, 0x08, 0x20, 0x03, 0x50 }, /* AOR 86.9%, 16CD */
+       { 0x40, 0x08, 0x20, 0x03, 0x45 }, /* AOR 85.8%, 17CD */
+       { 0x40, 0x08, 0x20, 0x03, 0x35 }, /* AOR 84.1%, 19CD */
+       { 0x40, 0x08, 0x20, 0x03, 0x27 }, /* AOR 82.7%, 20CD */
+       { 0x40, 0x08, 0x20, 0x03, 0x23 }, /* AOR 82.3%, 21CD */
+       { 0x40, 0x08, 0x20, 0x03, 0x17 }, /* AOR 81.0%, 22CD */
+       { 0x40, 0x08, 0x20, 0x03, 0x11 }, /* AOR 80.4%, 24CD */
+       { 0x40, 0x08, 0x20, 0x03, 0x04 }, /* AOR 79.1%, 25CD */
+       { 0x40, 0x08, 0x20, 0x02, 0xf4 }, /* AOR 77.5%, 27CD */
+       { 0x40, 0x08, 0x20, 0x02, 0xe3 }, /* AOR 75.7%, 29CD */
+       { 0x40, 0x08, 0x20, 0x02, 0xd7 }, /* AOR 74.5%, 30CD */
+       { 0x40, 0x08, 0x20, 0x02, 0xc6 }, /* AOR 72.7%, 32CD */
+       { 0x40, 0x08, 0x20, 0x02, 0xb7 }, /* AOR 71.2%, 34CD */
+       { 0x40, 0x08, 0x20, 0x02, 0xa1 }, /* AOR 69.0%, 37CD */
+       { 0x40, 0x08, 0x20, 0x02, 0x91 }, /* AOR 67.3%, 39CD */
+       { 0x40, 0x08, 0x20, 0x02, 0x78 }, /* AOR 64.8%, 41CD */
+       { 0x40, 0x08, 0x20, 0x02, 0x62 }, /* AOR 62.5%, 44CD */
+       { 0x40, 0x08, 0x20, 0x02, 0x45 }, /* AOR 59.5%, 47CD */
+       { 0x40, 0x08, 0x20, 0x02, 0x30 }, /* AOR 57.4%, 50CD */
+       { 0x40, 0x08, 0x20, 0x02, 0x13 }, /* AOR 54.4%, 53CD */
+       { 0x40, 0x08, 0x20, 0x01, 0xf5 }, /* AOR 51.3%, 56CD */
+       { 0x40, 0x08, 0x20, 0x01, 0xd3 }, /* AOR 47.8%, 60CD */
+       { 0x40, 0x08, 0x20, 0x01, 0xb1 }, /* AOR 44.4%, 64CD */
+       { 0x40, 0x08, 0x20, 0x01, 0x87 }, /* AOR 40.1%, 68CD */
+       { 0x40, 0x08, 0x20, 0x01, 0x63 }, /* AOR 36.6%, 72CD */
+       { 0x40, 0x08, 0x20, 0x01, 0x35 }, /* AOR 31.7%, 77CD */
+       { 0x40, 0x08, 0x20, 0x01, 0x05 }, /* AOR 26.9%, 82CD */
+       { 0x40, 0x08, 0x20, 0x00, 0xd5 }, /* AOR 21.8%, 87CD */
+       { 0x40, 0x08, 0x20, 0x00, 0xa1 }, /* AOR 16.5%, 93CD */
+       { 0x40, 0x08, 0x20, 0x00, 0x6f }, /* AOR 11.4%, 98CD */
+       { 0x40, 0x08, 0x20, 0x00, 0x31 }, /* AOR 5.0%, 105CD */
+       { 0x40, 0x08, 0x20, 0x01, 0x86 }, /* AOR 40.0%, 111CD ~ 172CD */
+       { 0x40, 0x08, 0x20, 0x00, 0x08 }, /* AOR 0.6%, 183CD ~ 300CD */
+};
+
+static const u8 s6e88a0_ams427ap24_elvss[NUM_STEPS_ELVSS][SEQ_LENGTH_ELVSS] = {
+       { 0x28, 0x14 }, /* 10CD ~ 111CD */
+       { 0x28, 0x13 }, /* 119CD */
+       { 0x28, 0x12 }, /* 126CD */
+       { 0x28, 0x12 }, /* 134CD */
+       { 0x28, 0x11 }, /* 143CD */
+       { 0x28, 0x10 }, /* 152CD */
+       { 0x28, 0x0f }, /* 162CD */
+       { 0x28, 0x0e }, /* 172CD */
+       { 0x28, 0x11 }, /* 183CD */
+       { 0x28, 0x11 }, /* 195CD */
+       { 0x28, 0x10 }, /* 207CD */
+       { 0x28, 0x0f }, /* 220CD */
+       { 0x28, 0x0f }, /* 234CD */
+       { 0x28, 0x0e }, /* 249CD */
+       { 0x28, 0x0d }, /* 265CD */
+       { 0x28, 0x0c }, /* 282CD */
+       { 0x28, 0x0b }, /* 300CD */
+};
+
+static const u8 s6e88a0_ams427ap24_gamma[NUM_STEPS_CANDELA][SEQ_LENGTH_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[SEQ_LENGTH_AID + 1];
+       u8 b6[SEQ_LENGTH_ELVSS + 1];
+       u8 ca[SEQ_LENGTH_GAMMA + 1];
+
+       /* 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 */
+       b2[0] = 0xb2;
+       switch (candela_enum) {
+       case CANDELA_10CD ... CANDELA_105CD:
+               memcpy(&b2[1], s6e88a0_ams427ap24_aid[candela_enum],
+                      SEQ_LENGTH_AID);
+               break;
+       case CANDELA_111CD ... CANDELA_172CD:
+               memcpy(&b2[1], s6e88a0_ams427ap24_aid[CANDELA_111CD],
+                      SEQ_LENGTH_AID);
+               break;
+       case CANDELA_183CD ... CANDELA_300CD:
+               memcpy(&b2[1], s6e88a0_ams427ap24_aid[CANDELA_111CD + 1],
+                      SEQ_LENGTH_AID);
+               break;
+       default:
+               dev_err(dev, "Failed to get aid data\n");
+               return -EINVAL;
+       }
+
+       /* get elvss */
+       b6[0] = 0xb6;
+       if (candela_enum <= CANDELA_111CD) {
+               memcpy(&b6[1], s6e88a0_ams427ap24_elvss[0], SEQ_LENGTH_ELVSS);
+       } else {
+               memcpy(&b6[1], s6e88a0_ams427ap24_elvss[candela_enum - 
CANDELA_111CD],
+                      SEQ_LENGTH_ELVSS);
+       }
+
+       /* get gamma */
+       ca[0] = 0xca;
+       memcpy(&ca[1], s6e88a0_ams427ap24_gamma[candela_enum], 
SEQ_LENGTH_GAMMA);
+
+       /* write: key on, aid, acl off, elvss, gamma, gamma update, key off */
+       mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf0, 0x5a, 0x5a);
+       mipi_dsi_dcs_write_buffer_multi(&dsi_ctx, b2, ARRAY_SIZE(b2));
+       mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x55, 0x00);
+       mipi_dsi_dcs_write_buffer_multi(&dsi_ctx, b6, ARRAY_SIZE(b6));
+       mipi_dsi_dcs_write_buffer_multi(&dsi_ctx, ca, ARRAY_SIZE(ca));
+       mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf7, 0x03);
+       mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf0, 0xa5, 0xa5);
+
+       return dsi_ctx.accum_err;
+}
+
 static void s6e88a0_ams427ap24_reset(struct s6e88a0_ams427ap24 *ctx)
 {
        gpiod_set_value_cansleep(ctx->reset_gpio, 0);
@@ -49,6 +517,8 @@ 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;
 
@@ -68,20 +538,15 @@ static int s6e88a0_ams427ap24_on(struct s6e88a0_ams427ap24 
*ctx)
        mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xcc, 0x4c);
        mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf2, 0x03, 0x0d);
        mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf1, 0xa5, 0xa5);
-       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);
-       mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xb2,
-                                    0x40, 0x08, 0x20, 0x00, 0x08);
-       mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xb6, 0x28, 0x0b);
-       mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf7, 0x03);
-       mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0x55, 0x00);
        mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf0, 0xa5, 0xa5);
        mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xfc, 0xa5, 0xa5);
 
+       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;
@@ -181,6 +646,32 @@ 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;
@@ -209,12 +700,16 @@ 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);
-- 
2.39.5

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