[PATCH 0/4] Add new panel driver Samsung S6E88A0-AMS427AP24

[PATCH 0/4] 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.

Jakob Hauser (4):
  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

 .../panel/samsung,s6e88a0-ams427ap24.yaml     |  68 ++
 drivers/gpu/drm/panel/Kconfig                 |  10 +
 drivers/gpu/drm/panel/Makefile                |   1 +
 .../panel/panel-samsung-s6e88a0-ams427ap24.c  | 772 ++++++++++++++++++
 4 files changed, 851 insertions(+)
 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 1/4] 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 https://gitlab.freedesktop.org/drm/misc/kernel.git
current branch drm-misc-next.
---
 .../panel/samsung,s6e88a0-ams427ap24.yaml     | 68 +++++++++++++++++++
 1 file changed, 68 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..7010d3bbd07f
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/panel/samsung,s6e88a0-ams427ap24.yaml
@@ -0,0 +1,68 @@
+# 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
+
+  vdd3-supply:
+    description: core voltage supply
+
+  vci-supply:
+    description: voltage supply for analog circuits
+
+  flip-horizontal:
+    description: boolean to flip image horizontally
+    type: boolean
+
+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 1/4] dt-bindings: display: panel: Add Samsung S6E88A0-AMS427AP24 bindings

[Rob Herring]

On Thu, Oct 10, 2024 at 08:31:48PM +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 https://gitlab.freedesktop.org/drm/misc/kernel.git
> current branch drm-misc-next.
> ---
>  .../panel/samsung,s6e88a0-ams427ap24.yaml     | 68 +++++++++++++++++++
>  1 file changed, 68 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..7010d3bbd07f
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/display/panel/samsung,s6e88a0-ams427ap24.yaml
> @@ -0,0 +1,68 @@
> +# 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
> +
> +  vdd3-supply:
> +    description: core voltage supply
> +
> +  vci-supply:
> +    description: voltage supply for analog circuits
> +
> +  flip-horizontal:
> +    description: boolean to flip image horizontally
> +    type: boolean

This is already used in another panel. Please move it to 
panel-common.yaml.

> +
> +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 1/4] dt-bindings: display: panel: Add Samsung S6E88A0-AMS427AP24 bindings

[Jakob Hauser]

Hi Rob,

On 11.10.24 16:27, Rob Herring wrote:
> On Thu, Oct 10, 2024 at 08:31:48PM +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 https://gitlab.freedesktop.org/drm/misc/kernel.git
>> current branch drm-misc-next.
>> ---
>>   .../panel/samsung,s6e88a0-ams427ap24.yaml     | 68 +++++++++++++++++++
>>   1 file changed, 68 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..7010d3bbd07f
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/display/panel/samsung,s6e88a0-ams427ap24.yaml
>> @@ -0,0 +1,68 @@
>> +# 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
>> +
>> +  vdd3-supply:
>> +    description: core voltage supply
>> +
>> +  vci-supply:
>> +    description: voltage supply for analog circuits
>> +
>> +  flip-horizontal:
>> +    description: boolean to flip image horizontally
>> +    type: boolean
> 
> This is already used in another panel. Please move it to
> panel-common.yaml.
> 

I'll add a patch in v2 to move "flip-horizontal" and along with it also 
"flip-vertical" to "panel-common.yaml". File "samsung,s6e8aa0.yaml" 
needs to be changed accordingly.

@ Thierry, Laurent & Andrzej: CC'ing you as you're listed as maintainers 
of the affected files.

>> +
>> +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
>>

Kind regards,
Jakob

[PATCH 2/4] 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.

Coulnd't read out RAW EDID, /sys/class/drm/card0-DSI-1/edid is empty.

[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>
---
 drivers/gpu/drm/panel/Kconfig                 |   9 +
 drivers/gpu/drm/panel/Makefile                |   1 +
 .../panel/panel-samsung-s6e88a0-ams427ap24.c  | 261 ++++++++++++++++++
 3 files changed, 271 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 ddfaa99ea9dd..fa6a8c6cac5b 100644
--- a/drivers/gpu/drm/panel/Kconfig
+++ b/drivers/gpu/drm/panel/Kconfig
@@ -623,6 +623,15 @@ 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 4b5eaf111676..3002087c26d1 100644
--- a/drivers/gpu/drm/panel/Makefile
+++ b/drivers/gpu/drm/panel/Makefile
@@ -76,6 +76,7 @@ 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..182ba8c347e2
--- /dev/null
+++ b/drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams427ap24.c
@@ -0,0 +1,261 @@
+// 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;
+	bool prepared;
+};
+
+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 (ctx->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;
+	}
+
+	ctx->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 (!ctx->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);
+
+	ctx->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 2/4] drm/panel: samsung-s6e88a0-ams427ap24: Add initial driver

[Jessica Zhang]

On 10/10/2024 11:31 AM, 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.
> 
> Coulnd't read out RAW EDID, /sys/class/drm/card0-DSI-1/edid is empty.
> 
> [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>
> ---
>   drivers/gpu/drm/panel/Kconfig                 |   9 +
>   drivers/gpu/drm/panel/Makefile                |   1 +
>   .../panel/panel-samsung-s6e88a0-ams427ap24.c  | 261 ++++++++++++++++++
>   3 files changed, 271 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 ddfaa99ea9dd..fa6a8c6cac5b 100644
> --- a/drivers/gpu/drm/panel/Kconfig
> +++ b/drivers/gpu/drm/panel/Kconfig
> @@ -623,6 +623,15 @@ 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 4b5eaf111676..3002087c26d1 100644
> --- a/drivers/gpu/drm/panel/Makefile
> +++ b/drivers/gpu/drm/panel/Makefile
> @@ -76,6 +76,7 @@ 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..182ba8c347e2
> --- /dev/null
> +++ b/drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams427ap24.c
> @@ -0,0 +1,261 @@
> +// 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;
> +	bool prepared;

Hi Jakob,

I think you can drop the `prepared` here as it should be handled by 
framework now [1]

Thanks,

Jessica Zhang

[1] 
https://elixir.bootlin.com/linux/v6.11.3/source/include/drm/drm_panel.h#L262

> +};
> +
> +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 (ctx->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;
> +	}
> +
> +	ctx->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 (!ctx->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);
> +
> +	ctx->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 2/4] drm/panel: samsung-s6e88a0-ams427ap24: Add initial driver

[Jakob Hauser]

Hi Jessica,

On 11.10.24 18:52, Jessica Zhang wrote:
> 
> 
> On 10/10/2024 11:31 AM, Jakob Hauser wrote:

...

>> +struct s6e88a0_ams427ap24 {
>> +    struct drm_panel panel;
>> +    struct mipi_dsi_device *dsi;
>> +    struct regulator_bulk_data *supplies;
>> +    struct gpio_desc *reset_gpio;
>> +    bool prepared;
> 
> Hi Jakob,
> 
> I think you can drop the `prepared` here as it should be handled by 
> framework now [1]
> 
> Thanks,
> 
> Jessica Zhang
> 
> [1] 
> https://elixir.bootlin.com/linux/v6.11.3/source/include/drm/drm_panel.h#L262
> 
>> +};

Thanks for the hint. I'll change that in v2.

...

Kind regards,
Jakob

[PATCH 3/4] 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>
---
 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 fa6a8c6cac5b..9b150eabc4e3 100644
--- a/drivers/gpu/drm/panel/Kconfig
+++ b/drivers/gpu/drm/panel/Kconfig
@@ -627,6 +627,7 @@ 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 182ba8c347e2..657120d7dd33 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;
@@ -36,6 +46,464 @@ 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 40,00 %, 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);
@@ -50,6 +518,8 @@ 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;
 
@@ -69,20 +539,15 @@ 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;
@@ -182,6 +647,32 @@ 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;
@@ -210,12 +701,16 @@ 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

[PATCH 4/4] 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 657120d7dd33..4d5c494e03ae 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;
 	bool prepared;
 };
 
@@ -539,6 +540,10 @@ 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);
 
@@ -673,6 +678,15 @@ 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;
@@ -707,6 +721,8 @@ 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 4/4] drm/panel: samsung-s6e88a0-ams427ap24: Add flip option

[Jessica Zhang]

On 10/10/2024 11:31 AM, 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

Hi Jakob,

I'm a bit confused by the wording here. Do you mean that even though the 
downstream driver comments state the panel is in a non-flipped state by 
default, your observations suggest that it's actually defaulting to a 
flipped state?

Thanks,

Jessica Zhang

> 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 657120d7dd33..4d5c494e03ae 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;
>   	bool prepared;
>   };
>   
> @@ -539,6 +540,10 @@ 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);
>   
> @@ -673,6 +678,15 @@ 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;
> @@ -707,6 +721,8 @@ 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 4/4] drm/panel: samsung-s6e88a0-ams427ap24: Add flip option

[Jakob Hauser]

Hi Jessica,

On 11.10.24 19:17, Jessica Zhang wrote:
> 
> On 10/10/2024 11:31 AM, 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
> 
> Hi Jakob,
> 
> I'm a bit confused by the wording here. Do you mean that even though the 
> downstream driver comments state the panel is in a non-flipped state by 
> default, your observations suggest that it's actually defaulting to a 
> flipped state?
> 
> Thanks,
> 
> Jessica Zhang
> 
>> 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

In the commit message I'm referencing another downstream driver for a 
different (similar but older) panel. The commit message is very 
summarized. I'll try to describe the situation more detailed here. Maybe 
this is going too far but I don't know how to dissolve it otherwise.

The panel AMS427AP24 of this patchset is mounted in device 
samsung-serranove "Samsung Galaxy S4 Mini Value Edition". On this device 
the picture by default is the wrong way around (flipped/mirrored). So it 
needs horizontal flip to get it right. In the downstream Android kernel 
this is done in the panel controller. Following links are just for 
reference, no need to study them in deep: "hflip" in dtsi file [a], 
reading "hflip" in mdss_dsi_panel.c [b], and then I'm fully not sure how 
it continues... processing in mdss_mdp_overlay.c [d] or in 
mdss_mdp_rotator.c [e] or in mdss_mdp_pipe.c [f].

I noticed that in another downstream panel driver used by the similar 
but older device samsung-serranolte ("Samsung Galaxy S4 Mini LTE", not 
the "ve" Value Edition) the flip is done directly in the panel driver. 
That driver is labelled "AMS427AP01" [f] but it seems to serve a couple 
of different dimensions [g] and also distinguishes between an original 
revision and a revision "r01". This driver contains a section "#if 
defined(CONFIG_FEATURE_FLIPLR)" [h]. FLIPLR means flip left-right. That 
section holds values for the 0xcb command for different sizes (different 
mipi clocks) and the two different revisions.

When reading out the default values of the 0xcb command on the newer 
device samsung-serranove ("ve" Value Edition") with panel AMS427AP24, 
they match with the values of the older driver AMS427AP01 for mipi clock 
461 MHz revision r01 [i].

However, for the newer device samsung-serranove ("ve" Value Edition") 
with panel AMS427AP24 that's the default value. Now it needs a 
horizontal flip to get the picture right. This can be achieved by 
changing the first value of 0xcb command from 0x06 to 0x0e. That's what 
I implemented in the patch as an option.

For the older device samsung-serranolte (LTE, not "ve" Value Edition) 
with panel AMS427AP01 I can't say much. That's possibly where the 
confusion comes from. In that driver for that older panel the hint on 
value 0x0e is just a comment [j] while the value 0x06 [k] is part of the 
"#if defined(CONFIG_FEATURE_FLIPLR)" section. Therefore I assume that on 
the older panel AMS427AP01 it's the other way around: value 0x0e as 
default and 0x06 as flip option.

I hope this more detailed description is comprehensible. Let me know if 
you have questions. Also feel free to suggest improvements on the commit 
message.

[a] 
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#L112
[b] 
https://github.com/msm8916-mainline/linux-downstream/blob/GT-I9195I/drivers/video/msm/mdss/mdss_dsi_panel.c#L1290-L1291
[c] 
https://github.com/msm8916-mainline/linux-downstream/blob/GT-I9195I/drivers/video/msm/mdss/mdss_mdp_overlay.c#L709-L711
[d] 
https://github.com/msm8916-mainline/linux-downstream/blob/GT-I9195I/drivers/video/msm/mdss/mdss_mdp_rotator.c#L590-L591
[e] 
https://github.com/msm8916-mainline/linux-downstream/blob/GT-I9195I/drivers/video/msm/mdss/mdss_mdp_pipe.c#L1309-L1310
[f] 
https://github.com/LineageOS/android_kernel_samsung_msm8930-common/blob/lineage-15.1/drivers/video/msm/mipi_samsung_oled_video_qhd_pt-8930.c#L1867
[g] 
https://github.com/LineageOS/android_kernel_samsung_msm8930-common/blob/lineage-15.1/drivers/video/msm/mipi_samsung_oled_video_qhd_pt-8930.c#L1980-L1995
[h] 
https://github.com/LineageOS/android_kernel_samsung_msm8930-common/blob/lineage-15.1/drivers/video/msm/mipi_samsung_oled_video_qhd_pt-8930.c#L65-L246
[i] 
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
[j] 
https://github.com/LineageOS/android_kernel_samsung_msm8930-common/blob/lineage-15.1/drivers/video/msm/mipi_samsung_oled_video_qhd_pt-8930.c#L68
[k] 
https://github.com/LineageOS/android_kernel_samsung_msm8930-common/blob/lineage-15.1/drivers/video/msm/mipi_samsung_oled_video_qhd_pt-8930.c#L139-L140

...

Kind regards,
Jakob