[PATCH v2 0/5] Add new panel driver Samsung S6E88A0-AMS427AP24

[PATCH v2 0/5] Add new panel driver Samsung S6E88A0-AMS427AP24

[Jakob Hauser]

The patchset adds a new driver for Samsung AMS427AP24 panel with S6E88A0
controller. Patches are based on current branch drm-misc-next.

Changes in v2:
 - Patch 1: New patch to move the bt-bindings properties "flip-horizontal"
   and "flip-vertical" to "panel-common.yaml". File "samsung,s6e8aa0.yaml"
   needs to be changed accordingly.
 - Patch 2: Adapted property "flip-horizontal" to being moved to
   "panel-common.yaml".
 - Patch 3: Removed bool "prepared" from struct s6e88a0_ams427ap24 and instead
   used framework-provided "panel->prepared" in functions
   s6e88a0_ams427ap24_prepare() and s6e88a0_ams427ap24_unprepare(). Mentioned
   this in the commit message.
 - Patch 3: In commit message removed comment "Coulnd't read out RAW EDID..."
   and put it below the '---' line.
 - Patch 4: 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.

v1: https://lore.kernel.org/dri-devel/cover.1728582727.git.jahau@rocketmail.com/T/#t

Jakob Hauser (5):
  dt-bindings: display: panel: Move flip properties to panel-common
  dt-bindings: display: panel: Add Samsung S6E88A0-AMS427AP24 bindings
  drm/panel: samsung-s6e88a0-ams427ap24: Add initial driver
  drm/panel: samsung-s6e88a0-ams427ap24: Add brightness control
  drm/panel: samsung-s6e88a0-ams427ap24: Add flip option

 .../bindings/display/panel/panel-common.yaml  |   8 +
 .../panel/samsung,s6e88a0-ams427ap24.yaml     |  65 ++
 .../display/panel/samsung,s6e8aa0.yaml        |  10 +-
 drivers/gpu/drm/panel/Kconfig                 |  10 +
 drivers/gpu/drm/panel/Makefile                |   1 +
 .../panel/panel-samsung-s6e88a0-ams427ap24.c  | 771 ++++++++++++++++++
 6 files changed, 857 insertions(+), 8 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/display/panel/samsung,s6e88a0-ams427ap24.yaml
 create mode 100644 drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams427ap24.c

-- 
2.39.5

[PATCH v2 1/5] dt-bindings: display: panel: Move flip properties to panel-common

[Jakob Hauser]

The flip properties were used by "samsung,s6e8aa0.yaml" only so far. By
introducing "samsung,s6e88a0-ams427ap24.yaml" they become more common.

Signed-off-by: Jakob Hauser <jahau@rocketmail.com>
---
Patch is based on current branch drm-misc-next.
---
 .../bindings/display/panel/panel-common.yaml           |  8 ++++++++
 .../bindings/display/panel/samsung,s6e8aa0.yaml        | 10 ++--------
 2 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/Documentation/devicetree/bindings/display/panel/panel-common.yaml b/Documentation/devicetree/bindings/display/panel/panel-common.yaml
index 0a57a31f4f3d..087415753d60 100644
--- a/Documentation/devicetree/bindings/display/panel/panel-common.yaml
+++ b/Documentation/devicetree/bindings/display/panel/panel-common.yaml
@@ -51,6 +51,14 @@ properties:
     $ref: /schemas/types.yaml#/definitions/uint32
     enum: [0, 90, 180, 270]
 
+  flip-horizontal:
+    description: boolean to flip image horizontally
+    type: boolean
+
+  flip-vertical:
+    description: boolean to flip image vertically
+    type: boolean
+
   # Display Timings
   panel-timing:
     description:
diff --git a/Documentation/devicetree/bindings/display/panel/samsung,s6e8aa0.yaml b/Documentation/devicetree/bindings/display/panel/samsung,s6e8aa0.yaml
index 4601fa460680..19c8cc83db97 100644
--- a/Documentation/devicetree/bindings/display/panel/samsung,s6e8aa0.yaml
+++ b/Documentation/devicetree/bindings/display/panel/samsung,s6e8aa0.yaml
@@ -21,6 +21,8 @@ properties:
 
   reset-gpios: true
   display-timings: true
+  flip-horizontal: true
+  flip-vertical: true
 
   vdd3-supply:
     description: core voltage supply
@@ -46,14 +48,6 @@ properties:
   panel-height-mm:
     description: physical panel height [mm]
 
-  flip-horizontal:
-    description: boolean to flip image horizontally
-    type: boolean
-
-  flip-vertical:
-    description: boolean to flip image vertically
-    type: boolean
-
 required:
   - compatible
   - reg
-- 
2.39.5

Re: [PATCH v2 1/5] dt-bindings: display: panel: Move flip properties to panel-common

[Krzysztof Kozlowski]

On Tue, Oct 22, 2024 at 11:33:35PM +0200, Jakob Hauser wrote:
> The flip properties were used by "samsung,s6e8aa0.yaml" only so far. By
> introducing "samsung,s6e88a0-ams427ap24.yaml" they become more common.
> 
> Signed-off-by: Jakob Hauser <jahau@rocketmail.com>
> ---
> Patch is based on current branch drm-misc-next.
> ---
>  .../bindings/display/panel/panel-common.yaml           |  8 ++++++++
>  .../bindings/display/panel/samsung,s6e8aa0.yaml        | 10 ++--------
>  2 files changed, 10 insertions(+), 8 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/display/panel/panel-common.yaml b/Documentation/devicetree/bindings/display/panel/panel-common.yaml
> index 0a57a31f4f3d..087415753d60 100644
> --- a/Documentation/devicetree/bindings/display/panel/panel-common.yaml
> +++ b/Documentation/devicetree/bindings/display/panel/panel-common.yaml
> @@ -51,6 +51,14 @@ properties:
>      $ref: /schemas/types.yaml#/definitions/uint32
>      enum: [0, 90, 180, 270]
>  
> +  flip-horizontal:
> +    description: boolean to flip image horizontally
> +    type: boolean
> +
> +  flip-vertical:
> +    description: boolean to flip image vertically
> +    type: boolean
> +

I actually wonder how or why would you need to flip the images. I
understand rotation, but this is mirror flip, right? Is it for some
transparent displays?

The change is fine, I just really wonder about hardware.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Best regards,
Krzysztof

Re: [PATCH v2 1/5] dt-bindings: display: panel: Move flip properties to panel-common

[Jakob Hauser]

Hi Krzysztof,

On 23.10.24 09:15, Krzysztof Kozlowski wrote:
> On Tue, Oct 22, 2024 at 11:33:35PM +0200, Jakob Hauser wrote:
>> The flip properties were used by "samsung,s6e8aa0.yaml" only so far. By
>> introducing "samsung,s6e88a0-ams427ap24.yaml" they become more common.
>>
>> Signed-off-by: Jakob Hauser <jahau@rocketmail.com>
>> ---
>> Patch is based on current branch drm-misc-next.
>> ---
>>   .../bindings/display/panel/panel-common.yaml           |  8 ++++++++
>>   .../bindings/display/panel/samsung,s6e8aa0.yaml        | 10 ++--------
>>   2 files changed, 10 insertions(+), 8 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/display/panel/panel-common.yaml b/Documentation/devicetree/bindings/display/panel/panel-common.yaml
>> index 0a57a31f4f3d..087415753d60 100644
>> --- a/Documentation/devicetree/bindings/display/panel/panel-common.yaml
>> +++ b/Documentation/devicetree/bindings/display/panel/panel-common.yaml
>> @@ -51,6 +51,14 @@ properties:
>>       $ref: /schemas/types.yaml#/definitions/uint32
>>       enum: [0, 90, 180, 270]
>>   
>> +  flip-horizontal:
>> +    description: boolean to flip image horizontally
>> +    type: boolean
>> +
>> +  flip-vertical:
>> +    description: boolean to flip image vertically
>> +    type: boolean
>> +
> 
> I actually wonder how or why would you need to flip the images. I
> understand rotation, but this is mirror flip, right? Is it for some
> transparent displays?

Yes, it's mirror flip. The two cases we have here so far are displays 
for smartphones.

The panel "samsung-s6e88a0-ams427ap24", which this patchset is for, is 
used in device "samsung-serranove" (Samsung Galaxy S4 Mini "Value 
Edition"). By default this panel shows a mirrored picture, it needs flip 
to fix that. I can't think of any good reason and it seems rather 
unique. Maybe there was some mistake during fast-paced development and 
easier to fix that way instead of changing suppliers specification, or 
some purchase related topic, but that's just wild guessing. I 
implemented the flip as an option because I don't know if this driver 
could be extended for similar panels that might not need the flip, e.g. 
older device "samsung-serranolte" (Samsung Galaxy S4 Mini LTE).

For panel "samsung-s6e8aa0" I can't say much because I'm not familiar 
with that. Within the kernel it is used by devices 
"exynos4412-galaxy-s3" (Samsung Galaxy S III) and "exynos4210-trats" 
(don't know what this is). Looking into their devicetree files they 
apply horizontal and vertical flip at once, actually that's a rotation 
by 180 degrees. Looking into the panel driver it seems that this is what 
the hardware interface offers.

> The change is fine, I just really wonder about hardware.
> 
> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

...

Kind regards,
Jakob

[PATCH v2 2/5] dt-bindings: display: panel: Add Samsung S6E88A0-AMS427AP24 bindings

[Jakob Hauser]

Add bindings for Samsung AMS427AP24 panel with S6E88A0 controller.

Signed-off-by: Jakob Hauser <jahau@rocketmail.com>
---
Patch is based on current branch drm-misc-next.

Changes in v2:
 - Adapted property "flip-horizontal" to being moved to "panel-common.yaml".
---
 .../panel/samsung,s6e88a0-ams427ap24.yaml     | 65 +++++++++++++++++++
 1 file changed, 65 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/panel/samsung,s6e88a0-ams427ap24.yaml

diff --git a/Documentation/devicetree/bindings/display/panel/samsung,s6e88a0-ams427ap24.yaml b/Documentation/devicetree/bindings/display/panel/samsung,s6e88a0-ams427ap24.yaml
new file mode 100644
index 000000000000..2677bc578dde
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/panel/samsung,s6e88a0-ams427ap24.yaml
@@ -0,0 +1,65 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/panel/samsung,s6e88a0-ams427ap24.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Samsung AMS427AP24 panel with S6E88A0 controller
+
+maintainers:
+  - Jakob Hauser <jahau@rocketmail.com>
+
+allOf:
+  - $ref: panel-common.yaml#
+
+properties:
+  compatible:
+    const: samsung,s6e88a0-ams427ap24
+
+  reg:
+    maxItems: 1
+
+  port: true
+  reset-gpios: true
+  flip-horizontal: true
+
+  vdd3-supply:
+    description: core voltage supply
+
+  vci-supply:
+    description: voltage supply for analog circuits
+
+required:
+  - compatible
+  - reg
+  - port
+  - reset-gpios
+  - vdd3-supply
+  - vci-supply
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+
+    dsi {
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            panel@0 {
+                    compatible = "samsung,s6e88a0-ams427ap24";
+                    reg = <0>;
+
+                    vdd3-supply = <&pm8916_l17>;
+                    vci-supply = <&pm8916_l6>;
+                    reset-gpios = <&tlmm 25 GPIO_ACTIVE_LOW>;
+                    flip-horizontal;
+
+                    port {
+                            panel_in: endpoint {
+                                    remote-endpoint = <&mdss_dsi0_out>;
+                            };
+                    };
+            };
+    };
-- 
2.39.5

Re: [PATCH v2 2/5] dt-bindings: display: panel: Add Samsung S6E88A0-AMS427AP24 bindings

[Krzysztof Kozlowski]

On Tue, Oct 22, 2024 at 11:33:36PM +0200, Jakob Hauser wrote:
> Add bindings for Samsung AMS427AP24 panel with S6E88A0 controller.
> 
> Signed-off-by: Jakob Hauser <jahau@rocketmail.com>
> ---
> Patch is based on current branch drm-misc-next.
> 
> Changes in v2:
>  - Adapted property "flip-horizontal" to being moved to "panel-common.yaml".
> ---
>  .../panel/samsung,s6e88a0-ams427ap24.yaml     | 65 +++++++++++++++++++
>  1 file changed, 65 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/display/panel/samsung,s6e88a0-ams427ap24.yaml
> 


A nit, subject: drop second/last, redundant "bindings". The
"dt-bindings" prefix is already stating that these are bindings.
See also:
https://elixir.bootlin.com/linux/v6.7-rc8/source/Documentation/devicetree/bindings/submitting-patches.rst#L18

> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/gpio/gpio.h>
> +
> +    dsi {
> +            #address-cells = <1>;
> +            #size-cells = <0>;

Use 4 spaces for example indentation.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Best regards,
Krzysztof

[PATCH v2 3/5] drm/panel: samsung-s6e88a0-ams427ap24: Add initial driver

[Jakob Hauser]

This initial part of the panel driver was mostly generated by the
"linux-mdss-dsi-panel-driver-generator" tool [1], reading downstream
Android kernel file "dsi_panel_S6E88A0_AMS427AP24_qhd_octa_video.dtsi" [2].

On top of the generic output of the tool, there were a couple of changes
applied:
- Added mipi_dsi_dcs_set_display_on() to function s6e88a0_ams427ap24_on(),
  otherwise the display does not show up.
- In functions s6e88a0_ams427ap24_on() and s6e88a0_ams427ap24_off()
  changed DSI commands to multi context and used "accum_err" returns.
- In functions s6e88a0_ams427ap24_on() and s6e88a0_ams427ap24_off() replaced
  msleep() by mipi_dsi_msleep().
- The function s6e88a0_ams427ap24_get_modes() was changed to make use of
  drm_connector_helper_get_modes_fixed(). This also required to include
  drm/drm_probe_helper.h.
- In function s6e88a0_ams427ap24_probe() registring the regulators was changed
  to devm_regulator_bulk_get_const(). This required to change supplies in struct
  s6e88a0_ams427ap24 to a pointer.
- Removed bool "prepared" from struct s6e88a0_ams427ap24 and instead used
  framework-provided "panel->prepared" in functions s6e88a0_ams427ap24_prepare()
  and s6e88a0_ams427ap24_unprepare().

[1] https://github.com/msm8916-mainline/linux-mdss-dsi-panel-driver-generator
[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

Signed-off-by: Jakob Hauser <jahau@rocketmail.com>
---
Coulnd't read out RAW EDID, /sys/class/drm/card0-DSI-1/edid is empty.

Changes in v2:
 - Removed bool "prepared" from struct s6e88a0_ams427ap24 and instead used
   framework-provided "panel->prepared" in functions s6e88a0_ams427ap24_prepare()
   and s6e88a0_ams427ap24_unprepare(). Mentioned this in the commit message.
---
 drivers/gpu/drm/panel/Kconfig                 |   9 +
 drivers/gpu/drm/panel/Makefile                |   1 +
 .../panel/panel-samsung-s6e88a0-ams427ap24.c  | 260 ++++++++++++++++++
 3 files changed, 270 insertions(+)
 create mode 100644 drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams427ap24.c

diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
index bce4cb64184a..f8adc38447fb 100644
--- a/drivers/gpu/drm/panel/Kconfig
+++ b/drivers/gpu/drm/panel/Kconfig
@@ -632,6 +632,15 @@ config DRM_PANEL_SAMSUNG_AMS639RQ08
 	  Say Y or M here if you want to enable support for the
 	  Samsung AMS639RQ08 FHD Plus (2340x1080@60Hz) CMD mode panel.
 
+config DRM_PANEL_SAMSUNG_S6E88A0_AMS427AP24
+	tristate "Samsung AMS427AP24 panel with S6E88A0 controller"
+	depends on GPIOLIB && OF && REGULATOR
+	depends on DRM_MIPI_DSI
+	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
+	  GT-I9195I). To compile this driver as a module, choose M here.
+
 config DRM_PANEL_SAMSUNG_S6E88A0_AMS452EF01
 	tristate "Samsung AMS452EF01 panel with S6E88A0 DSI video mode controller"
 	depends on OF
diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
index 4db02c2411ae..7dcf72646cac 100644
--- a/drivers/gpu/drm/panel/Makefile
+++ b/drivers/gpu/drm/panel/Makefile
@@ -77,6 +77,7 @@ obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E63J0X03) += panel-samsung-s6e63j0x03.o
 obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E63M0) += panel-samsung-s6e63m0.o
 obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E63M0_SPI) += panel-samsung-s6e63m0-spi.o
 obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E63M0_DSI) += panel-samsung-s6e63m0-dsi.o
+obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E88A0_AMS427AP24) += panel-samsung-s6e88a0-ams427ap24.o
 obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E88A0_AMS452EF01) += panel-samsung-s6e88a0-ams452ef01.o
 obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E8AA0) += panel-samsung-s6e8aa0.o
 obj-$(CONFIG_DRM_PANEL_SAMSUNG_SOFEF00) += panel-samsung-sofef00.o
diff --git a/drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams427ap24.c b/drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams427ap24.c
new file mode 100644
index 000000000000..0ab2768e0e2b
--- /dev/null
+++ b/drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams427ap24.c
@@ -0,0 +1,260 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Samsung AMS427AP24 panel with S6E88A0 controller
+ * Copyright (c) 2024 Jakob Hauser <jahau@rocketmail.com>
+ */
+
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/regulator/consumer.h>
+
+#include <video/mipi_display.h>
+
+#include <drm/drm_mipi_dsi.h>
+#include <drm/drm_modes.h>
+#include <drm/drm_panel.h>
+#include <drm/drm_probe_helper.h>
+
+struct s6e88a0_ams427ap24 {
+	struct drm_panel panel;
+	struct mipi_dsi_device *dsi;
+	struct regulator_bulk_data *supplies;
+	struct gpio_desc *reset_gpio;
+};
+
+const struct regulator_bulk_data s6e88a0_ams427ap24_supplies[] = {
+	{ .supply = "vdd3" },
+	{ .supply = "vci" },
+};
+
+static inline
+struct s6e88a0_ams427ap24 *to_s6e88a0_ams427ap24(struct drm_panel *panel)
+{
+	return container_of(panel, struct s6e88a0_ams427ap24, panel);
+}
+
+static void s6e88a0_ams427ap24_reset(struct s6e88a0_ams427ap24 *ctx)
+{
+	gpiod_set_value_cansleep(ctx->reset_gpio, 0);
+	usleep_range(5000, 6000);
+	gpiod_set_value_cansleep(ctx->reset_gpio, 1);
+	usleep_range(1000, 2000);
+	gpiod_set_value_cansleep(ctx->reset_gpio, 0);
+	usleep_range(18000, 19000);
+}
+
+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 };
+
+	dsi->mode_flags |= MIPI_DSI_MODE_LPM;
+
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf0, 0x5a, 0x5a);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xfc, 0x5a, 0x5a);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xb0, 0x11);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xfd, 0x11);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xb0, 0x13);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xfd, 0x18);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xb0, 0x02);
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xb8, 0x30);
+
+	mipi_dsi_dcs_exit_sleep_mode_multi(&dsi_ctx);
+	mipi_dsi_msleep(&dsi_ctx, 20);
+
+	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf1, 0x5a, 0x5a);
+	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);
+
+	mipi_dsi_dcs_set_display_on_multi(&dsi_ctx);
+
+	return dsi_ctx.accum_err;
+}
+
+static int s6e88a0_ams427ap24_off(struct s6e88a0_ams427ap24 *ctx)
+{
+	struct mipi_dsi_device *dsi = ctx->dsi;
+	struct mipi_dsi_multi_context dsi_ctx = { .dsi = dsi };
+
+	dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;
+
+	mipi_dsi_dcs_set_display_off_multi(&dsi_ctx);
+	mipi_dsi_dcs_enter_sleep_mode_multi(&dsi_ctx);
+	mipi_dsi_msleep(&dsi_ctx, 120);
+
+	return dsi_ctx.accum_err;
+}
+
+static int s6e88a0_ams427ap24_prepare(struct drm_panel *panel)
+{
+	struct s6e88a0_ams427ap24 *ctx = to_s6e88a0_ams427ap24(panel);
+	struct device *dev = &ctx->dsi->dev;
+	int ret;
+
+	if (panel->prepared)
+		return 0;
+
+	ret = regulator_bulk_enable(ARRAY_SIZE(s6e88a0_ams427ap24_supplies),
+				    ctx->supplies);
+	if (ret < 0) {
+		dev_err(dev, "Failed to enable regulators: %d\n", ret);
+		return ret;
+	}
+
+	s6e88a0_ams427ap24_reset(ctx);
+
+	ret = s6e88a0_ams427ap24_on(ctx);
+	if (ret < 0) {
+		dev_err(dev, "Failed to initialize panel: %d\n", ret);
+		gpiod_set_value_cansleep(ctx->reset_gpio, 1);
+		regulator_bulk_disable(ARRAY_SIZE(s6e88a0_ams427ap24_supplies),
+				       ctx->supplies);
+		return ret;
+	}
+
+	panel->prepared = true;
+	return 0;
+}
+
+static int s6e88a0_ams427ap24_unprepare(struct drm_panel *panel)
+{
+	struct s6e88a0_ams427ap24 *ctx = to_s6e88a0_ams427ap24(panel);
+	struct device *dev = &ctx->dsi->dev;
+	int ret;
+
+	if (!panel->prepared)
+		return 0;
+
+	ret = s6e88a0_ams427ap24_off(ctx);
+	if (ret < 0)
+		dev_err(dev, "Failed to un-initialize panel: %d\n", ret);
+
+	gpiod_set_value_cansleep(ctx->reset_gpio, 1);
+	regulator_bulk_disable(ARRAY_SIZE(s6e88a0_ams427ap24_supplies),
+			       ctx->supplies);
+
+	panel->prepared = false;
+	return 0;
+}
+
+static const struct drm_display_mode s6e88a0_ams427ap24_mode = {
+	.clock = (540 + 94 + 4 + 18) * (960 + 12 + 1 + 3) * 60 / 1000,
+	.hdisplay = 540,
+	.hsync_start = 540 + 94,
+	.hsync_end = 540 + 94 + 4,
+	.htotal = 540 + 94 + 4 + 18,
+	.vdisplay = 960,
+	.vsync_start = 960 + 12,
+	.vsync_end = 960 + 12 + 1,
+	.vtotal = 960 + 12 + 1 + 3,
+	.width_mm = 55,
+	.height_mm = 95,
+	.type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED,
+};
+
+static int s6e88a0_ams427ap24_get_modes(struct drm_panel *panel,
+					struct drm_connector *connector)
+{
+	return drm_connector_helper_get_modes_fixed(connector,
+						    &s6e88a0_ams427ap24_mode);
+}
+
+static const struct drm_panel_funcs s6e88a0_ams427ap24_panel_funcs = {
+	.prepare = s6e88a0_ams427ap24_prepare,
+	.unprepare = s6e88a0_ams427ap24_unprepare,
+	.get_modes = s6e88a0_ams427ap24_get_modes,
+};
+
+static int s6e88a0_ams427ap24_probe(struct mipi_dsi_device *dsi)
+{
+	struct device *dev = &dsi->dev;
+	struct s6e88a0_ams427ap24 *ctx;
+	int ret;
+
+	ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+
+	ret = devm_regulator_bulk_get_const(dev,
+				      ARRAY_SIZE(s6e88a0_ams427ap24_supplies),
+				      s6e88a0_ams427ap24_supplies,
+				      &ctx->supplies);
+	if (ret < 0)
+		return ret;
+
+	ctx->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(ctx->reset_gpio))
+		return dev_err_probe(dev, PTR_ERR(ctx->reset_gpio),
+				     "Failed to get reset-gpios\n");
+
+	ctx->dsi = dsi;
+	mipi_dsi_set_drvdata(dsi, ctx);
+
+	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;
+
+	drm_panel_init(&ctx->panel, dev, &s6e88a0_ams427ap24_panel_funcs,
+		       DRM_MODE_CONNECTOR_DSI);
+	ctx->panel.prepare_prev_first = true;
+
+	drm_panel_add(&ctx->panel);
+
+	ret = mipi_dsi_attach(dsi);
+	if (ret < 0) {
+		dev_err(dev, "Failed to attach to DSI host: %d\n", ret);
+		drm_panel_remove(&ctx->panel);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void s6e88a0_ams427ap24_remove(struct mipi_dsi_device *dsi)
+{
+	struct s6e88a0_ams427ap24 *ctx = mipi_dsi_get_drvdata(dsi);
+	int ret;
+
+	ret = mipi_dsi_detach(dsi);
+	if (ret < 0)
+		dev_err(&dsi->dev, "Failed to detach from DSI host: %d\n", ret);
+
+	drm_panel_remove(&ctx->panel);
+}
+
+static const struct of_device_id s6e88a0_ams427ap24_of_match[] = {
+	{ .compatible = "samsung,s6e88a0-ams427ap24" },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, s6e88a0_ams427ap24_of_match);
+
+static struct mipi_dsi_driver s6e88a0_ams427ap24_driver = {
+	.probe = s6e88a0_ams427ap24_probe,
+	.remove = s6e88a0_ams427ap24_remove,
+	.driver = {
+		.name = "panel-s6e88a0-ams427ap24",
+		.of_match_table = s6e88a0_ams427ap24_of_match,
+	},
+};
+module_mipi_dsi_driver(s6e88a0_ams427ap24_driver);
+
+MODULE_AUTHOR("Jakob Hauser <jahau@rocketmail.com>");
+MODULE_DESCRIPTION("Samsung AMS427AP24 panel with S6E88A0 controller");
+MODULE_LICENSE("GPL v2");
-- 
2.39.5

Re: [PATCH v2 3/5] drm/panel: samsung-s6e88a0-ams427ap24: Add initial driver

[Neil Armstrong]

Hi,

On 22/10/2024 23:33, Jakob Hauser wrote:
> This initial part of the panel driver was mostly generated by the
> "linux-mdss-dsi-panel-driver-generator" tool [1], reading downstream
> Android kernel file "dsi_panel_S6E88A0_AMS427AP24_qhd_octa_video.dtsi" [2].
> 
> On top of the generic output of the tool, there were a couple of changes
> applied:
> - Added mipi_dsi_dcs_set_display_on() to function s6e88a0_ams427ap24_on(),
>    otherwise the display does not show up.
> - In functions s6e88a0_ams427ap24_on() and s6e88a0_ams427ap24_off()
>    changed DSI commands to multi context and used "accum_err" returns.
> - In functions s6e88a0_ams427ap24_on() and s6e88a0_ams427ap24_off() replaced
>    msleep() by mipi_dsi_msleep().
> - The function s6e88a0_ams427ap24_get_modes() was changed to make use of
>    drm_connector_helper_get_modes_fixed(). This also required to include
>    drm/drm_probe_helper.h.
> - In function s6e88a0_ams427ap24_probe() registring the regulators was changed
>    to devm_regulator_bulk_get_const(). This required to change supplies in struct
>    s6e88a0_ams427ap24 to a pointer.
> - Removed bool "prepared" from struct s6e88a0_ams427ap24 and instead used
>    framework-provided "panel->prepared" in functions s6e88a0_ams427ap24_prepare()
>    and s6e88a0_ams427ap24_unprepare().
> 
> [1] https://github.com/msm8916-mainline/linux-mdss-dsi-panel-driver-generator
> [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
> 
> Signed-off-by: Jakob Hauser <jahau@rocketmail.com>
> ---
> Coulnd't read out RAW EDID, /sys/class/drm/card0-DSI-1/edid is empty.

DSI panels doesn't have EDID, you can drop this comment

> 
> Changes in v2:
>   - Removed bool "prepared" from struct s6e88a0_ams427ap24 and instead used
>     framework-provided "panel->prepared" in functions s6e88a0_ams427ap24_prepare()
>     and s6e88a0_ams427ap24_unprepare(). Mentioned this in the commit message.
> ---
>   drivers/gpu/drm/panel/Kconfig                 |   9 +
>   drivers/gpu/drm/panel/Makefile                |   1 +
>   .../panel/panel-samsung-s6e88a0-ams427ap24.c  | 260 ++++++++++++++++++
>   3 files changed, 270 insertions(+)
>   create mode 100644 drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams427ap24.c
> 
> diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
> index bce4cb64184a..f8adc38447fb 100644
> --- a/drivers/gpu/drm/panel/Kconfig
> +++ b/drivers/gpu/drm/panel/Kconfig
> @@ -632,6 +632,15 @@ config DRM_PANEL_SAMSUNG_AMS639RQ08
>   	  Say Y or M here if you want to enable support for the
>   	  Samsung AMS639RQ08 FHD Plus (2340x1080@60Hz) CMD mode panel.
>   
> +config DRM_PANEL_SAMSUNG_S6E88A0_AMS427AP24
> +	tristate "Samsung AMS427AP24 panel with S6E88A0 controller"
> +	depends on GPIOLIB && OF && REGULATOR
> +	depends on DRM_MIPI_DSI
> +	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
> +	  GT-I9195I). To compile this driver as a module, choose M here.
> +
>   config DRM_PANEL_SAMSUNG_S6E88A0_AMS452EF01
>   	tristate "Samsung AMS452EF01 panel with S6E88A0 DSI video mode controller"
>   	depends on OF
> diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
> index 4db02c2411ae..7dcf72646cac 100644
> --- a/drivers/gpu/drm/panel/Makefile
> +++ b/drivers/gpu/drm/panel/Makefile
> @@ -77,6 +77,7 @@ obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E63J0X03) += panel-samsung-s6e63j0x03.o
>   obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E63M0) += panel-samsung-s6e63m0.o
>   obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E63M0_SPI) += panel-samsung-s6e63m0-spi.o
>   obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E63M0_DSI) += panel-samsung-s6e63m0-dsi.o
> +obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E88A0_AMS427AP24) += panel-samsung-s6e88a0-ams427ap24.o
>   obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E88A0_AMS452EF01) += panel-samsung-s6e88a0-ams452ef01.o
>   obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E8AA0) += panel-samsung-s6e8aa0.o
>   obj-$(CONFIG_DRM_PANEL_SAMSUNG_SOFEF00) += panel-samsung-sofef00.o
> diff --git a/drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams427ap24.c b/drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams427ap24.c
> new file mode 100644
> index 000000000000..0ab2768e0e2b
> --- /dev/null
> +++ b/drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams427ap24.c
> @@ -0,0 +1,260 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Samsung AMS427AP24 panel with S6E88A0 controller
> + * Copyright (c) 2024 Jakob Hauser <jahau@rocketmail.com>
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/regulator/consumer.h>
> +
> +#include <video/mipi_display.h>
> +
> +#include <drm/drm_mipi_dsi.h>
> +#include <drm/drm_modes.h>
> +#include <drm/drm_panel.h>
> +#include <drm/drm_probe_helper.h>
> +
> +struct s6e88a0_ams427ap24 {
> +	struct drm_panel panel;
> +	struct mipi_dsi_device *dsi;
> +	struct regulator_bulk_data *supplies;
> +	struct gpio_desc *reset_gpio;
> +};
> +
> +const struct regulator_bulk_data s6e88a0_ams427ap24_supplies[] = {

Please add static

> +	{ .supply = "vdd3" },
> +	{ .supply = "vci" },
> +};
> +
> +static inline
> +struct s6e88a0_ams427ap24 *to_s6e88a0_ams427ap24(struct drm_panel *panel)
> +{
> +	return container_of(panel, struct s6e88a0_ams427ap24, panel);
> +}
> +
> +static void s6e88a0_ams427ap24_reset(struct s6e88a0_ams427ap24 *ctx)
> +{
> +	gpiod_set_value_cansleep(ctx->reset_gpio, 0);
> +	usleep_range(5000, 6000);
> +	gpiod_set_value_cansleep(ctx->reset_gpio, 1);
> +	usleep_range(1000, 2000);
> +	gpiod_set_value_cansleep(ctx->reset_gpio, 0);
> +	usleep_range(18000, 19000);
> +}
> +
> +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 };
> +
> +	dsi->mode_flags |= MIPI_DSI_MODE_LPM;
> +
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf0, 0x5a, 0x5a);
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xfc, 0x5a, 0x5a);
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xb0, 0x11);
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xfd, 0x11);
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xb0, 0x13);
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xfd, 0x18);
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xb0, 0x02);
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xb8, 0x30);
> +
> +	mipi_dsi_dcs_exit_sleep_mode_multi(&dsi_ctx);
> +	mipi_dsi_msleep(&dsi_ctx, 20);
> +
> +	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf1, 0x5a, 0x5a);
> +	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);
> +
> +	mipi_dsi_dcs_set_display_on_multi(&dsi_ctx);
> +
> +	return dsi_ctx.accum_err;
> +}
> +
> +static int s6e88a0_ams427ap24_off(struct s6e88a0_ams427ap24 *ctx)
> +{
> +	struct mipi_dsi_device *dsi = ctx->dsi;
> +	struct mipi_dsi_multi_context dsi_ctx = { .dsi = dsi };
> +
> +	dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;
> +
> +	mipi_dsi_dcs_set_display_off_multi(&dsi_ctx);
> +	mipi_dsi_dcs_enter_sleep_mode_multi(&dsi_ctx);
> +	mipi_dsi_msleep(&dsi_ctx, 120);
> +
> +	return dsi_ctx.accum_err;
> +}
> +
> +static int s6e88a0_ams427ap24_prepare(struct drm_panel *panel)
> +{
> +	struct s6e88a0_ams427ap24 *ctx = to_s6e88a0_ams427ap24(panel);
> +	struct device *dev = &ctx->dsi->dev;
> +	int ret;
> +
> +	if (panel->prepared)
> +		return 0;

You can drop these, _prepare won't be called twice, the framework controls that.

> +
> +	ret = regulator_bulk_enable(ARRAY_SIZE(s6e88a0_ams427ap24_supplies),
> +				    ctx->supplies);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to enable regulators: %d\n", ret);
> +		return ret;
> +	}
> +
> +	s6e88a0_ams427ap24_reset(ctx);
> +
> +	ret = s6e88a0_ams427ap24_on(ctx);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to initialize panel: %d\n", ret);
> +		gpiod_set_value_cansleep(ctx->reset_gpio, 1);
> +		regulator_bulk_disable(ARRAY_SIZE(s6e88a0_ams427ap24_supplies),
> +				       ctx->supplies);
> +		return ret;
> +	}
> +
> +	panel->prepared = true;

Ditto

> +	return 0;
> +}
> +
> +static int s6e88a0_ams427ap24_unprepare(struct drm_panel *panel)
> +{
> +	struct s6e88a0_ams427ap24 *ctx = to_s6e88a0_ams427ap24(panel);
> +	struct device *dev = &ctx->dsi->dev;
> +	int ret;
> +
> +	if (!panel->prepared)
> +		return 0;

Ditto

> +
> +	ret = s6e88a0_ams427ap24_off(ctx);
> +	if (ret < 0)
> +		dev_err(dev, "Failed to un-initialize panel: %d\n", ret);
> +
> +	gpiod_set_value_cansleep(ctx->reset_gpio, 1);
> +	regulator_bulk_disable(ARRAY_SIZE(s6e88a0_ams427ap24_supplies),
> +			       ctx->supplies);
> +
> +	panel->prepared = false;

Ditto

> +	return 0;
> +}
> +
> +static const struct drm_display_mode s6e88a0_ams427ap24_mode = {
> +	.clock = (540 + 94 + 4 + 18) * (960 + 12 + 1 + 3) * 60 / 1000,
> +	.hdisplay = 540,
> +	.hsync_start = 540 + 94,
> +	.hsync_end = 540 + 94 + 4,
> +	.htotal = 540 + 94 + 4 + 18,
> +	.vdisplay = 960,
> +	.vsync_start = 960 + 12,
> +	.vsync_end = 960 + 12 + 1,
> +	.vtotal = 960 + 12 + 1 + 3,
> +	.width_mm = 55,
> +	.height_mm = 95,
> +	.type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED,
> +};
> +
> +static int s6e88a0_ams427ap24_get_modes(struct drm_panel *panel,
> +					struct drm_connector *connector)
> +{
> +	return drm_connector_helper_get_modes_fixed(connector,
> +						    &s6e88a0_ams427ap24_mode);
> +}
> +
> +static const struct drm_panel_funcs s6e88a0_ams427ap24_panel_funcs = {
> +	.prepare = s6e88a0_ams427ap24_prepare,
> +	.unprepare = s6e88a0_ams427ap24_unprepare,
> +	.get_modes = s6e88a0_ams427ap24_get_modes,
> +};
> +
> +static int s6e88a0_ams427ap24_probe(struct mipi_dsi_device *dsi)
> +{
> +	struct device *dev = &dsi->dev;
> +	struct s6e88a0_ams427ap24 *ctx;
> +	int ret;
> +
> +	ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
> +	if (!ctx)
> +		return -ENOMEM;
> +
> +	ret = devm_regulator_bulk_get_const(dev,
> +				      ARRAY_SIZE(s6e88a0_ams427ap24_supplies),
> +				      s6e88a0_ams427ap24_supplies,
> +				      &ctx->supplies);
> +	if (ret < 0)
> +		return ret;
> +
> +	ctx->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
> +	if (IS_ERR(ctx->reset_gpio))
> +		return dev_err_probe(dev, PTR_ERR(ctx->reset_gpio),
> +				     "Failed to get reset-gpios\n");
> +
> +	ctx->dsi = dsi;
> +	mipi_dsi_set_drvdata(dsi, ctx);
> +
> +	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;
> +
> +	drm_panel_init(&ctx->panel, dev, &s6e88a0_ams427ap24_panel_funcs,
> +		       DRM_MODE_CONNECTOR_DSI);
> +	ctx->panel.prepare_prev_first = true;
> +
> +	drm_panel_add(&ctx->panel);
> +
> +	ret = mipi_dsi_attach(dsi);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to attach to DSI host: %d\n", ret);
> +		drm_panel_remove(&ctx->panel);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static void s6e88a0_ams427ap24_remove(struct mipi_dsi_device *dsi)
> +{
> +	struct s6e88a0_ams427ap24 *ctx = mipi_dsi_get_drvdata(dsi);
> +	int ret;
> +
> +	ret = mipi_dsi_detach(dsi);
> +	if (ret < 0)
> +		dev_err(&dsi->dev, "Failed to detach from DSI host: %d\n", ret);
> +
> +	drm_panel_remove(&ctx->panel);
> +}
> +
> +static const struct of_device_id s6e88a0_ams427ap24_of_match[] = {
> +	{ .compatible = "samsung,s6e88a0-ams427ap24" },
> +	{ /* sentinel */ },
> +};
> +MODULE_DEVICE_TABLE(of, s6e88a0_ams427ap24_of_match);
> +
> +static struct mipi_dsi_driver s6e88a0_ams427ap24_driver = {
> +	.probe = s6e88a0_ams427ap24_probe,
> +	.remove = s6e88a0_ams427ap24_remove,
> +	.driver = {
> +		.name = "panel-s6e88a0-ams427ap24",
> +		.of_match_table = s6e88a0_ams427ap24_of_match,
> +	},
> +};
> +module_mipi_dsi_driver(s6e88a0_ams427ap24_driver);
> +
> +MODULE_AUTHOR("Jakob Hauser <jahau@rocketmail.com>");
> +MODULE_DESCRIPTION("Samsung AMS427AP24 panel with S6E88A0 controller");
> +MODULE_LICENSE("GPL v2");


Thanks,
Neil

[PATCH v2 4/5] drm/panel: samsung-s6e88a0-ams427ap24: Add brightness control

[Jakob Hauser]

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>
---
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 <jahau@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

Re: [PATCH v2 4/5] drm/panel: samsung-s6e88a0-ams427ap24: Add brightness control

[Neil Armstrong]

On 22/10/2024 23:33, Jakob Hauser wrote:
> 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>
> ---
> 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 <jahau@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);


Wow this looks complex, anything this looks good overall, good work making it clean.

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>

[PATCH v2 5/5] drm/panel: samsung-s6e88a0-ams427ap24: Add flip option

[Jakob Hauser]

The way of implementing a flip option follows the existing
panel-samsung-s6e8aa0.c [1][2][3].

The value to flip the screen is taken from a downstream kernel file of
a similar but older panel [4]. The mipi clock [5] for the new panel
samsung-s6e88a0-ams427ap24 matches 461 MHz and a hardware read-out of the
0xcb values corresponds to revision R01 of that older panel [6]. Although
for samsung-s6e88a0-ams427ap24 that's in non-flipped state while in this
older driver it seems to be the other way around. Further up there is a
hint [7] basically saying for revision R01 to change the first word of the
0xcb command from 0x06 to 0x0e, which is actually setting BIT(3) of that
word. This causes a horizontal flip.

[1] https://github.com/torvalds/linux/blob/v6.11/drivers/gpu/drm/panel/panel-samsung-s6e8aa0.c#L103
[2] https://github.com/torvalds/linux/blob/v6.11/drivers/gpu/drm/panel/panel-samsung-s6e8aa0.c#L207-L211
[3] https://github.com/torvalds/linux/blob/v6.11/drivers/gpu/drm/panel/panel-samsung-s6e8aa0.c#L954-L974
[4] https://github.com/LineageOS/android_kernel_samsung_msm8930-common/blob/lineage-15.1/drivers/video/msm/mipi_samsung_oled_video_qhd_pt-8930.c
[5] https://github.com/LineageOS/android_kernel_samsung_msm8930-common/blob/lineage-15.1/drivers/video/msm/mipi_samsung_oled_video_qhd_pt-8930.c#L2027-L2028
[6] https://github.com/LineageOS/android_kernel_samsung_msm8930-common/blob/lineage-15.1/drivers/video/msm/mipi_samsung_oled_video_qhd_pt-8930.c#L137-L151
[7] https://github.com/LineageOS/android_kernel_samsung_msm8930-common/blob/lineage-15.1/drivers/video/msm/mipi_samsung_oled_video_qhd_pt-8930.c#L66-L74

Signed-off-by: Jakob Hauser <jahau@rocketmail.com>
---
 .../drm/panel/panel-samsung-s6e88a0-ams427ap24.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams427ap24.c b/drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams427ap24.c
index 6e02b881434d..8372d0d307c8 100644
--- a/drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams427ap24.c
+++ b/drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams427ap24.c
@@ -32,6 +32,7 @@ struct s6e88a0_ams427ap24 {
 	struct mipi_dsi_device *dsi;
 	struct regulator_bulk_data *supplies;
 	struct gpio_desc *reset_gpio;
+	bool flip_horizontal;
 };
 
 const struct regulator_bulk_data s6e88a0_ams427ap24_supplies[] = {
@@ -538,6 +539,10 @@ 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);
+
+	if (ctx->flip_horizontal)
+		mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xcb, 0x0e);
+
 	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf0, 0xa5, 0xa5);
 	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xfc, 0xa5, 0xa5);
 
@@ -672,6 +677,15 @@ static int s6e88a0_ams427ap24_register_backlight(struct s6e88a0_ams427ap24 *ctx)
 	return ret;
 }
 
+static void s6e88a0_ams427ap24_parse_dt(struct s6e88a0_ams427ap24 *ctx)
+{
+	struct mipi_dsi_device *dsi = ctx->dsi;
+	struct device *dev = &dsi->dev;
+	struct device_node *np = dev->of_node;
+
+	ctx->flip_horizontal = of_property_read_bool(np, "flip-horizontal");
+}
+
 static int s6e88a0_ams427ap24_probe(struct mipi_dsi_device *dsi)
 {
 	struct device *dev = &dsi->dev;
@@ -706,6 +720,8 @@ static int s6e88a0_ams427ap24_probe(struct mipi_dsi_device *dsi)
 		       DRM_MODE_CONNECTOR_DSI);
 	ctx->panel.prepare_prev_first = true;
 
+	s6e88a0_ams427ap24_parse_dt(ctx);
+
 	ret = s6e88a0_ams427ap24_register_backlight(ctx);
 	if (ret < 0)
 		return ret;
-- 
2.39.5

Re: [PATCH v2 5/5] drm/panel: samsung-s6e88a0-ams427ap24: Add flip option

[Neil Armstrong]

On 22/10/2024 23:33, Jakob Hauser wrote:
> The way of implementing a flip option follows the existing
> panel-samsung-s6e8aa0.c [1][2][3].
> 
> The value to flip the screen is taken from a downstream kernel file of
> a similar but older panel [4]. The mipi clock [5] for the new panel
> samsung-s6e88a0-ams427ap24 matches 461 MHz and a hardware read-out of the
> 0xcb values corresponds to revision R01 of that older panel [6]. Although
> for samsung-s6e88a0-ams427ap24 that's in non-flipped state while in this
> older driver it seems to be the other way around. Further up there is a
> hint [7] basically saying for revision R01 to change the first word of the
> 0xcb command from 0x06 to 0x0e, which is actually setting BIT(3) of that
> word. This causes a horizontal flip.
> 
> [1] https://github.com/torvalds/linux/blob/v6.11/drivers/gpu/drm/panel/panel-samsung-s6e8aa0.c#L103
> [2] https://github.com/torvalds/linux/blob/v6.11/drivers/gpu/drm/panel/panel-samsung-s6e8aa0.c#L207-L211
> [3] https://github.com/torvalds/linux/blob/v6.11/drivers/gpu/drm/panel/panel-samsung-s6e8aa0.c#L954-L974
> [4] https://github.com/LineageOS/android_kernel_samsung_msm8930-common/blob/lineage-15.1/drivers/video/msm/mipi_samsung_oled_video_qhd_pt-8930.c
> [5] https://github.com/LineageOS/android_kernel_samsung_msm8930-common/blob/lineage-15.1/drivers/video/msm/mipi_samsung_oled_video_qhd_pt-8930.c#L2027-L2028
> [6] https://github.com/LineageOS/android_kernel_samsung_msm8930-common/blob/lineage-15.1/drivers/video/msm/mipi_samsung_oled_video_qhd_pt-8930.c#L137-L151
> [7] https://github.com/LineageOS/android_kernel_samsung_msm8930-common/blob/lineage-15.1/drivers/video/msm/mipi_samsung_oled_video_qhd_pt-8930.c#L66-L74
> 
> Signed-off-by: Jakob Hauser <jahau@rocketmail.com>
> ---
>   .../drm/panel/panel-samsung-s6e88a0-ams427ap24.c | 16 ++++++++++++++++
>   1 file changed, 16 insertions(+)
> 
> diff --git a/drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams427ap24.c b/drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams427ap24.c
> index 6e02b881434d..8372d0d307c8 100644
> --- a/drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams427ap24.c
> +++ b/drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams427ap24.c
> @@ -32,6 +32,7 @@ struct s6e88a0_ams427ap24 {
>   	struct mipi_dsi_device *dsi;
>   	struct regulator_bulk_data *supplies;
>   	struct gpio_desc *reset_gpio;
> +	bool flip_horizontal;
>   };
>   
>   const struct regulator_bulk_data s6e88a0_ams427ap24_supplies[] = {
> @@ -538,6 +539,10 @@ 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);
> +
> +	if (ctx->flip_horizontal)
> +		mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xcb, 0x0e);
> +
>   	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf0, 0xa5, 0xa5);
>   	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xfc, 0xa5, 0xa5);
>   
> @@ -672,6 +677,15 @@ static int s6e88a0_ams427ap24_register_backlight(struct s6e88a0_ams427ap24 *ctx)
>   	return ret;
>   }
>   
> +static void s6e88a0_ams427ap24_parse_dt(struct s6e88a0_ams427ap24 *ctx)
> +{
> +	struct mipi_dsi_device *dsi = ctx->dsi;
> +	struct device *dev = &dsi->dev;
> +	struct device_node *np = dev->of_node;
> +
> +	ctx->flip_horizontal = of_property_read_bool(np, "flip-horizontal");


Please use device_property_read_bool() instead

> +}
> +
>   static int s6e88a0_ams427ap24_probe(struct mipi_dsi_device *dsi)
>   {
>   	struct device *dev = &dsi->dev;
> @@ -706,6 +720,8 @@ static int s6e88a0_ams427ap24_probe(struct mipi_dsi_device *dsi)
>   		       DRM_MODE_CONNECTOR_DSI);
>   	ctx->panel.prepare_prev_first = true;
>   
> +	s6e88a0_ams427ap24_parse_dt(ctx);

I don't think this deserves a separate function, just move it probe.

> +
>   	ret = s6e88a0_ams427ap24_register_backlight(ctx);
>   	if (ret < 0)
>   		return ret;

With that changed:

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>