dt-bindings: display: panel: Add Samsung S6E88A0-AMS427AP24 bindings

Add bindings for Samsung AMS427AP24 panel with S6E88A0 controller.

Signed-off-by Jakob Hauser <[email protected]>

---
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

Documentation/devicetree/bindings/display/panel/samsung,s6e88a0-ams427ap24.yaml new file +23 -0

new file mode 100644
index 000000000000..7010d3bbd07f
@@ -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 <[email protected]>
+
+allOf:
+  - $ref: panel-common.yaml#
+
+properties:
+  compatible:
+    const: samsung,s6e88a0-ams427ap24
+
+  reg:
+    maxItems: 1
+
+  port: true
+  reset-gpios: true

Documentation/devicetree/bindings/display/panel/samsung,s6e88a0-ams427ap24.yaml new file +35 -0

+
+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>;
+                            };
+                    };
+            };
+    };

Signature · 1 line

2.39.5

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 <[email protected]>

---
  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

drivers/gpu/drm/panel/Kconfig +9 -0

index ddfaa99ea9dd..fa6a8c6cac5b 100644
@@ -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

drivers/gpu/drm/panel/Makefile +1 -0

index 4b5eaf111676..3002087c26d1 100644
@@ -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

drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams427ap24.c new file +15 -0

new file mode 100644
index 000000000000..182ba8c347e2
@@ -0,0 +1,261 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Samsung AMS427AP24 panel with S6E88A0 controller
+ * Copyright (c) 2024 Jakob Hauser <[email protected]>
+ */
+
+#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>

drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams427ap24.c new file +236 -0

+};
+
+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 <[email protected]>");
+MODULE_DESCRIPTION("Samsung AMS427AP24 panel with S6E88A0 controller");
+MODULE_LICENSE("GPL v2");

Signature · 1 line

2.39.5

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 <[email protected]>

---
  .../drm/panel/panel-samsung-s6e88a0-ams427ap24.c | 16 ++++++++++++++++
  1 file changed, 16 insertions(+)

drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams427ap24.c +16 -0

index 657120d7dd33..4d5c494e03ae 100644
@@ -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;

Signature · 1 line

2.39.5

Quoted 45 lines · Jakob Hauser

Add bindings for Samsung AMS427AP24 panel with S6E88A0 controller.

Signed-off-by Jakob Hauser <[email protected]>

---
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

Documentation/devicetree/bindings/display/panel/samsung,s6e88a0-ams427ap24.yaml new file +28 -0

new file mode 100644
index 000000000000..7010d3bbd07f
@@ -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 <[email protected]>
+
+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:

Documentation/devicetree/bindings/display/panel/samsung,s6e88a0-ams427ap24.yaml line 33

Quoted 5 lines

Documentation/devicetree/bindings/display/panel/samsung,s6e88a0-ams427ap24.yaml new file +5 -0

+    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.

Quoted 30 lines

Documentation/devicetree/bindings/display/panel/samsung,s6e88a0-ams427ap24.yaml new file +30 -0

+
+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 {

Quoted 8 lines

Documentation/devicetree/bindings/display/panel/samsung,s6e88a0-ams427ap24.yaml new file +5 -0

+                                    remote-endpoint = <&mdss_dsi0_out>;
+                            };
+                    };
+            };
+    };

Signature · 1 line

2.39.5

On 10/10/2024 11:31 AM, Jakob Hauser wrote:

Quoted 6 lines

+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

Quoted 1 line

+};

Quoted 9 lines · 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

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

Quoted 11 lines

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