Add new panel driver Samsung S6E88A0-AMS427AP24

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

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

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

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

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

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

Comments instead of #defines?

OK then, it's readable too.

Yours,
Linus Walleij

Yours,
Linus Walleij

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