Add new panel driver Samsung S6E88A0-AMS427AP24

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

The discussion in v3 was not finished. I send v4 nonetheless as a new base to continue the discussion. I hope that's ok.

Changes in v4:

Patch 3
- Removed include <linux/of.h>, it's not needed.
- Added comments to the mipi_dsi_dcs_write_seq_multi() lines in function s6e88a0_ams427ap24_on().

Patch 4
- New defines for payload data length, thereof a fixed and a variable part.
- In the array s6e88a0_ams427ap24_br_to_cd[] made the comment about the columns more clear and added an additional column "brightness from".
- Array s6e88a0_ams427ap24_aid[] reduced from five to two columns and s6e88a0_ams427ap24_elvss[] from two to one column. Now they hold the variable data only. I kept s6e88a0_ams427ap24_elvss[] as a two-dimensional array to allow using the same memcopy procedure for all three buffers aid, elvss and gamma in function s6e88a0_ams427ap24_set_brightness().
- In function s6e88a0_ams427ap24_set_brightness() initialized prototype payload array for b2 and b6 commands. And in the memcpy commands below used the new defines for the fixed and variable data length.

Patch 5
- Added a comment to the mipi_dsi_dcs_write_seq_multi() line, according to the other lines before and after.

v1: https://lore.kernel.org/dri-devel/[email protected]/T/#t
v2: https://lore.kernel.org/dri-devel/[email protected]/T/#t
v3: https://lore.kernel.org/dri-devel/[email protected]/T/#t

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

 .../bindings/display/panel/panel-common.yaml  |   8 +
 .../panel/samsung,s6e88a0-ams427ap24.yaml     |  65 ++
 .../display/panel/samsung,s6e8aa0.yaml        |  10 +-
 drivers/gpu/drm/panel/Kconfig                 |  10 +
 drivers/gpu/drm/panel/Makefile                |   1 +
 .../panel/panel-samsung-s6e88a0-ams427ap24.c  | 766 ++++++++++++++++++
 6 files changed, 852 insertions(+), 8 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/display/panel/samsung,s6e88a0-ams427ap24.yaml
 create mode 100644 drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams427ap24.c

2.39.5

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

---
Patch is based on current branch drm-misc-next.

---
 .../bindings/display/panel/panel-common.yaml           |  8 ++++++++
 .../bindings/display/panel/samsung,s6e8aa0.yaml        | 10 ++--------
 2 files changed, 10 insertions(+), 8 deletions(-)

index 0a57a31f4f3d..087415753d60 100644
@@ -51,6 +51,14 @@ properties:
     $ref: /schemas/types.yaml#/definitions/uint32
     enum: [0, 90, 180, 270]
 
+  flip-horizontal:
+    description: boolean to flip image horizontally
+    type: boolean
+
+  flip-vertical:
+    description: boolean to flip image vertically
+    type: boolean
+
   # Display Timings
   panel-timing:
     description:

index 4601fa460680..19c8cc83db97 100644
@@ -21,6 +21,8 @@ properties:
 
   reset-gpios: true
   display-timings: true
+  flip-horizontal: true
+  flip-vertical: true
 
   vdd3-supply:
     description: core voltage supply

@@ -46,14 +48,6 @@ properties:
   panel-height-mm:
     description: physical panel height [mm]
 
-  flip-horizontal:
-    description: boolean to flip image horizontally
-    type: boolean
-
-  flip-vertical:
-    description: boolean to flip image vertically
-    type: boolean
-
 required:
   - compatible
   - reg

2.39.5

Add bindings for Samsung AMS427AP24 panel with S6E88A0 controller.

---
Patch is based on current branch drm-misc-next.

---
 .../panel/samsung,s6e88a0-ams427ap24.yaml     | 65 +++++++++++++++++++
 1 file changed, 65 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/panel/samsung,s6e88a0-ams427ap24.yaml

new file mode 100644
index 000000000000..db284ba5be20
@@ -0,0 +1,65 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/panel/samsung,s6e88a0-ams427ap24.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Samsung AMS427AP24 panel with S6E88A0 controller
+
+maintainers:
+  - Jakob Hauser <[email protected]>
+
+allOf:
+  - $ref: panel-common.yaml#
+
+properties:
+  compatible:
+    const: samsung,s6e88a0-ams427ap24
+
+  reg:
+    maxItems: 1
+
+  port: true
+  reset-gpios: true
+  flip-horizontal: true
+
+  vdd3-supply:
+    description: core voltage supply
+
+  vci-supply:
+    description: voltage supply for analog circuits
+
+required:
+  - compatible
+  - reg
+  - port
+  - reset-gpios
+  - vdd3-supply
+  - vci-supply
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+
+    dsi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        panel@0 {
+            compatible = "samsung,s6e88a0-ams427ap24";
+            reg = <0>;
+
+            vdd3-supply = <&pm8916_l17>;
+            vci-supply = <&pm8916_l6>;
+            reset-gpios = <&tlmm 25 GPIO_ACTIVE_LOW>;
+            flip-horizontal;
+
+            port {
+                panel_in: endpoint {
+                    remote-endpoint = <&mdss_dsi0_out>;
+                };
+            };
+        };
+    };

2.39.5

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

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

[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

---
Changes in v4:
- Removed include <linux/of.h>, it's not needed.
- Added comments to the mipi_dsi_dcs_write_seq_multi() lines in function s6e88a0_ams427ap24_on().

---
 drivers/gpu/drm/panel/Kconfig                 |   9 +
 drivers/gpu/drm/panel/Makefile                |   1 +
 .../panel/panel-samsung-s6e88a0-ams427ap24.c  | 251 ++++++++++++++++++
 3 files changed, 261 insertions(+)
 create mode 100644 drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams427ap24.c

index bce4cb64184a..f8adc38447fb 100644
@@ -632,6 +632,15 @@ config DRM_PANEL_SAMSUNG_AMS639RQ08
 	  Say Y or M here if you want to enable support for the
 	  Samsung AMS639RQ08 FHD Plus (2340x1080@60Hz) CMD mode panel.
 
+config DRM_PANEL_SAMSUNG_S6E88A0_AMS427AP24
+	tristate "Samsung AMS427AP24 panel with S6E88A0 controller"
+	depends on GPIOLIB && OF && REGULATOR
+	depends on DRM_MIPI_DSI
+	help
+	  Say Y here if you want to enable support for Samsung AMS427AP24 panel
+	  with S6E88A0 controller (found in Samsung Galaxy S4 Mini Value Edition
+	  GT-I9195I). To compile this driver as a module, choose M here.
+
 config DRM_PANEL_SAMSUNG_S6E88A0_AMS452EF01
 	tristate "Samsung AMS452EF01 panel with S6E88A0 DSI video mode controller"
 	depends on OF

index 4db02c2411ae..7dcf72646cac 100644
@@ -77,6 +77,7 @@ obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E63J0X03) += panel-samsung-s6e63j0x03.o
 obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E63M0) += panel-samsung-s6e63m0.o
 obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E63M0_SPI) += panel-samsung-s6e63m0-spi.o
 obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E63M0_DSI) += panel-samsung-s6e63m0-dsi.o
+obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E88A0_AMS427AP24) += panel-samsung-s6e88a0-ams427ap24.o
 obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E88A0_AMS452EF01) += panel-samsung-s6e88a0-ams452ef01.o
 obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E8AA0) += panel-samsung-s6e8aa0.o
 obj-$(CONFIG_DRM_PANEL_SAMSUNG_SOFEF00) += panel-samsung-sofef00.o

2.39.5

Comments instead of #defines?

OK then, it's readable too.

Yours,
Linus Walleij

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

---
Changes in v4:
- New defines for payload data length, thereof a fixed and a variable part.
- In the array s6e88a0_ams427ap24_br_to_cd[] made the comment about the columns more clear and added an additional column "brightness from".
- Array s6e88a0_ams427ap24_aid[] reduced from five to two columns and s6e88a0_ams427ap24_elvss[] from two to one column. Now they hold the variable data only. I kept s6e88a0_ams427ap24_elvss[] as a two-dimensional array to allow using the same memcopy procedure for all three buffers aid, elvss and gamma in function s6e88a0_ams427ap24_set_brightness().
- In function s6e88a0_ams427ap24_set_brightness() initialized prototype payload array for b2 and b6 commands. And in the memcpy commands below used the new defines for the fixed and variable data length.

---
 drivers/gpu/drm/panel/Kconfig                 |   1 +
 .../panel/panel-samsung-s6e88a0-ams427ap24.c  | 532 +++++++++++++++++-
 2 files changed, 521 insertions(+), 12 deletions(-)

index f8adc38447fb..d7469c565d1d 100644
@@ -636,6 +636,7 @@ config DRM_PANEL_SAMSUNG_S6E88A0_AMS427AP24
 	tristate "Samsung AMS427AP24 panel with S6E88A0 controller"
 	depends on GPIOLIB && OF && REGULATOR
 	depends on DRM_MIPI_DSI
+	depends on BACKLIGHT_CLASS_DEVICE
 	help
 	  Say Y here if you want to enable support for Samsung AMS427AP24 panel
 	  with S6E88A0 controller (found in Samsung Galaxy S4 Mini Value Edition

2.39.5

Yours,
Linus Walleij

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

---
Changes in v4:
- Added a comment to the mipi_dsi_dcs_write_seq_multi() line, according to the other lines before and after.

---
 drivers/gpu/drm/panel/panel-samsung-s6e88a0-ams427ap24.c | 7 +++++++
 1 file changed, 7 insertions(+)

index 4b8aa088f445..e92e95158d1f 100644
@@ -38,6 +38,7 @@ struct s6e88a0_ams427ap24 {
 	struct mipi_dsi_device *dsi;
 	struct regulator_bulk_data *supplies;
 	struct gpio_desc *reset_gpio;
+	bool flip_horizontal;
 };
 
 static const struct regulator_bulk_data s6e88a0_ams427ap24_supplies[] = {

@@ -550,6 +551,10 @@ static int s6e88a0_ams427ap24_on(struct s6e88a0_ams427ap24 *ctx)
 	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xcc, 0x4c); // pixel clock divider pol.
 	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf2, 0x03, 0x0d); // unknown
 	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf1, 0xa5, 0xa5); // level 3 key off
+
+	if (ctx->flip_horizontal)
+		mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xcb, 0x0e); // flip display
+
 	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xf0, 0xa5, 0xa5); // level 1 key off
 	mipi_dsi_dcs_write_seq_multi(&dsi_ctx, 0xfc, 0xa5, 0xa5); // level 2 key off
 

@@ -710,6 +715,8 @@ static int s6e88a0_ams427ap24_probe(struct mipi_dsi_device *dsi)
 		       DRM_MODE_CONNECTOR_DSI);
 	ctx->panel.prepare_prev_first = true;
 
+	ctx->flip_horizontal = device_property_read_bool(dev, "flip-horizontal");
+
 	ret = s6e88a0_ams427ap24_register_backlight(ctx);
 	if (ret < 0)
 		return ret;

2.39.5

Yours,
Linus Walleij

Hi,

Thanks, Applied to https://gitlab.freedesktop.org/drm/misc/kernel.git (drm-misc-next)

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

      https://gitlab.freedesktop.org/drm/misc/kernel/-/commit/3c0ecd83eee9b8584588f629e01d209f2c3a632b
[2/5] dt-bindings: display: panel: Add Samsung S6E88A0-AMS427AP24
      https://gitlab.freedesktop.org/drm/misc/kernel/-/commit/4998d53df6753c3dbb6e960291715027518c61df
[3/5] drm/panel: samsung-s6e88a0-ams427ap24: Add initial driver
      https://gitlab.freedesktop.org/drm/misc/kernel/-/commit/d5658db2a0768a73a862f8b5fe6daae10d3abfec
[4/5] drm/panel: samsung-s6e88a0-ams427ap24: Add brightness control
      https://gitlab.freedesktop.org/drm/misc/kernel/-/commit/5b67fdf1668fc373b1e492e33ce7d17f7056a609
[5/5] drm/panel: samsung-s6e88a0-ams427ap24: Add flip option
      https://gitlab.freedesktop.org/drm/misc/kernel/-/commit/e70d4f8e242bbc4fd39f3a867dc3e33122d7e559

Neil