drm/panel: Add Magnachip D53E6EA8966 Panel Controller

From: Chris Morgan <[email protected]>

Add the Magnachip D53E6EA8966 panel IC controller for display panels such as the Samsung AMS495QA01 panel as found on the Anbernic RG503. This panel uses DSI to receive video signals, but 3-wire SPI to receive command signals using DBI.

Changes since V10:
- Guarded definition in drm_of.h with an additional #if statement.
- Narrowed focus of drm_of_get_dsi_bus() to only return dsi_host (no longer populates node on the mipi_dsi_device_info struct).

Changes since V9:
- Set an ifdef to not add the drm_of_get_dsi_bus when MIPI_DSI is not part of the current kernel config.
- Made "info" optional in the drm_of_get_dsi_bus() function.

Changes since V8:
- Set "placeholder" drm_of_get_dsi_bus in drm_of.h to static inline to hopefully eliminate the reported errors once and for all. Tested with 4 different kernel configurations provided by Intel's kernel test robot and no new warnings or errors were introduced.

Changes since V7:
- Removed Linus Walleij review note due to substantial changes.
- Corrected documentation of drm_of_get_dsi_bus function.
- Updated the drm_of_get_dsi_bus function to return pointer to mipi_dsi_host and use ERR_PTR macros.
- Refactored drm_panel_funcs so that the prepare function calls panel specific function for init sequence and uses generic functions otherwise.
- Renamed non-panel specific functions.
- Changed backlight value to int instead of u32.
- Corrected brightness function to use backlight_get_brightness().
- Fix an error reported when CONFIG_OF is selected but CONFIG_DRM_MIPI_DSI is not. Add an if function to drm_of_get_dsi_bus function to return -EINVAL in this instance.

Changes since V6:
- Fixed a trivial error with definition of drm_of_get_dsi_bus().

Changes since V5:
- Reverted dt binding documentation name back to samsung,ams495qa01.yaml.
- Removed no longer needed of_graph.h header file.
- Added backlight as a dependency.

Changes since V4:
- Renamed driver from the panel model to the panel IC controller per DRM team.
- Added a drm_of helper function of drm_of_get_dsi_bus() to handle finding and populating the DSI node when the DSI node is not the parent of the DSI controlled display.
- Converted the documented commands to constants to make it more readable.
- Reset GPIO is now required and documented as GPIO_ACTIVE_LOW.
- Removed "prepared" logic from panel.

Changes since V3:
- Updated documentation to add spi-peripheral-props.yaml per updates
made for similar devices. Note that I removed a "Reviewed-by" tag
from Rob Herring since this change probably needs to be confirmed.
- Added binding for RG503, since this device is now accepted with this
request: https://lore.kernel.org/linux-rockchip/[email protected]/

Changes since V2:
- Added 50hz mode at request of userspace devs.
- Renamed "dupa" to panel name. Good catch Maya.
- Added Maya's Signed-off-by.
- Removed check for max backlight, since it is already done by backlight_device_set_brightness.
- Fixed minor formatting issues on devicetree binding documentation and added port to provided example.

Changes since V1:
- Removed errant reference to backlight in documentation. This is an OLED panel.
- Made elvss regulator optional. In my case its hard wired and not controllable.
- Added "prepared" enum to track panel status to prevent unbalanced regulator enable/disable.

Chris Morgan (4):
drm: of: Add drm_of_get_dsi_bus helper function
dt-bindings: display: panel: Add Samsung AMS495QA01 drm/panel: Add Magnachip D53E6EA8966 Panel Driver
arm64: dts: rockchip: add display to RG503

 .../display/panel/samsung,ams495qa01.yaml     |  57 ++
 .../dts/rockchip/rk3566-anbernic-rg503.dts    |  55 ++
 drivers/gpu/drm/drm_of.c                      |  51 ++
 drivers/gpu/drm/panel/Kconfig                 |  11 +
 drivers/gpu/drm/panel/Makefile                |   1 +
 .../drm/panel/panel-magnachip-d53e6ea8966.c   | 522 ++++++++++++++++++
 include/drm/drm_of.h                          |  12 +
 7 files changed, 709 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/panel/samsung,ams495qa01.yaml
 create mode 100644 drivers/gpu/drm/panel/panel-magnachip-d53e6ea8966.c

2.34.1

From: Chris Morgan <[email protected]>

Add helper function to find DSI host for devices where DSI panel is not a minor of a DSI bus (such as the Samsung AMS495QA01 panel or the official Raspberry Pi touchscreen display).

---
 drivers/gpu/drm/drm_of.c | 51 ++++++++++++++++++++++++++++++++++++++++
 include/drm/drm_of.h     | 12 ++++++++++
 2 files changed, 63 insertions(+)

index 7bbcb999bb75..177b600895d3 100644
@@ -10,6 +10,7 @@
 #include <drm/drm_crtc.h>
 #include <drm/drm_device.h>
 #include <drm/drm_encoder.h>
+#include <drm/drm_mipi_dsi.h>
 #include <drm/drm_of.h>
 #include <drm/drm_panel.h>
 

@@ -493,3 +494,53 @@ int drm_of_get_data_lanes_count_ep(const struct device_node *port,
 	return ret;
 }
 EXPORT_SYMBOL_GPL(drm_of_get_data_lanes_count_ep);
+
+#if IS_ENABLED(CONFIG_DRM_MIPI_DSI)
+
+/**
+ * drm_of_get_dsi_bus - find the DSI bus for a given device
+ * @dev: parent device of display (SPI, I2C)
+ *
+ * Gets parent DSI bus for a DSI device controlled through a bus other
+ * than MIPI-DCS (SPI, I2C, etc.) using the Device Tree.
+ *
+ * Returns pointer to mipi_dsi_host if successful, -EINVAL if the
+ * request is unsupported, -EPROBE_DEFER if the DSI host is found but
+ * not available, or -ENODEV otherwise.
+ */
+struct mipi_dsi_host *drm_of_get_dsi_bus(struct device *dev)
+{
+	struct mipi_dsi_host *dsi_host;
+	struct device_node *endpoint, *dsi_host_node;
+
+	/*
+	 * Get first endpoint child from device.
+	 */
+	endpoint = of_graph_get_next_endpoint(dev->of_node, NULL);
+	if (!endpoint)
+		return ERR_PTR(-ENODEV);
+
+	/*
+	 * Follow the first endpoint to get the DSI host node and then
+	 * release the endpoint since we no longer need it.
+	 */
+	dsi_host_node = of_graph_get_remote_port_parent(endpoint);
+	of_node_put(endpoint);
+	if (!dsi_host_node)
+		return ERR_PTR(-ENODEV);
+
+	/*
+	 * Get the DSI host from the DSI host node. If we get an error
+	 * or the return is null assume we're not ready to probe just
+	 * yet. Release the DSI host node since we're done with it.
+	 */
+	dsi_host = of_find_mipi_dsi_host_by_node(dsi_host_node);
+	of_node_put(dsi_host_node);
+	if (IS_ERR_OR_NULL(dsi_host))
+		return ERR_PTR(-EPROBE_DEFER);
+
+	return dsi_host;
+}
+EXPORT_SYMBOL_GPL(drm_of_get_dsi_bus);
+
+#endif /* CONFIG_DRM_MIPI_DSI */

index 10ab58c40746..082a6e980d01 100644
@@ -15,6 +15,8 @@ struct drm_encoder;
 struct drm_panel;
 struct drm_bridge;
 struct device_node;
+struct mipi_dsi_device_info;
+struct mipi_dsi_host;
 
 /**
  * enum drm_lvds_dual_link_pixels - Pixel order of an LVDS dual-link connection

@@ -129,6 +131,16 @@ drm_of_get_data_lanes_count_ep(const struct device_node *port,
 }
 #endif
 
+#if IS_ENABLED(CONFIG_OF) && IS_ENABLED(CONFIG_DRM_MIPI_DSI)
+struct mipi_dsi_host *drm_of_get_dsi_bus(struct device *dev);
+#else
+static inline struct
+mipi_dsi_host *drm_of_get_dsi_bus(struct device *dev)
+{
+	return ERR_PTR(-EINVAL);
+}
+#endif /* CONFIG_OF && CONFIG_DRM_MIPI_DSI */
+
 /*
  * drm_of_panel_bridge_remove - remove panel bridge
  * @np: device tree node containing panel bridge output ports

2.34.1

Hi,

Sorry for not noticing this earlier, but this is a bit confusing. Signed-off-by is there usually to follow either the authors or the maintainers (or people that passed the patch along).

Given the order, the SoB here indicates that it's Maya Matuszczyk that committed/submitted that patch, while you are the author. Obviously, that isn't the case since you are both the author and submitter.

So what's going on?

Maxime

I borrowed a few lines of code from her, which is why she is listed here. If this is not correct let me know.

Thank you.

I see, then the usage is that:
* You add a Co-developed-by tag with their name
* You add your Signed-off-by last

Maxime

From: Chris Morgan <[email protected]>

Add documentation for Samsung AMS495QA01 panel (with Magnachip D53E6EA8966 controller IC).

---
 .../display/panel/samsung,ams495qa01.yaml     | 57 +++++++++++++++++++
 1 file changed, 57 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/panel/samsung,ams495qa01.yaml

new file mode 100644
index 000000000000..58fa073ce258
@@ -0,0 +1,57 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/panel/samsung,ams495qa01.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Samsung AMS495QA01 panel with Magnachip D53E6EA8966 controller
+
+maintainers:
+  - Chris Morgan <[email protected]>
+
+allOf:
+  - $ref: panel-common.yaml#
+
+properties:
+  compatible:
+    const: samsung,ams495qa01
+
+  reg: true
+  reset-gpios:
+    description: reset gpio, must be GPIO_ACTIVE_LOW
+  elvdd-supply:
+    description: regulator that supplies voltage to the panel display
+  enable-gpios: true
+  port: true
+  vdd-supply:
+    description: regulator that supplies voltage to panel logic
+
+required:
+  - compatible
+  - reg
+  - reset-gpios
+  - vdd-supply
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    spi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+        panel@0 {
+            compatible = "samsung,ams495qa01";
+            reg = <0>;
+            reset-gpios = <&gpio4 0 GPIO_ACTIVE_LOW>;
+            vdd-supply = <&vcc_3v3>;
+
+            port {
+                mipi_in_panel: endpoint {
+                  remote-endpoint = <&mipi_out_panel>;
+                };
+            };
+        };
+    };
+
+...

2.34.1

From: Chris Morgan <[email protected]>

Support Magnachip D53E6EA8966 based panels such as the Samsung AMS495QA01 panel as found on the Anbernic RG503. Note this driver supports only the AMS495QA01 today which receives video signals via DSI, however it receives commands via 3-wire SPI using DBI.

---
 drivers/gpu/drm/panel/Kconfig                 |  11 +
 drivers/gpu/drm/panel/Makefile                |   1 +
 .../drm/panel/panel-magnachip-d53e6ea8966.c   | 522 ++++++++++++++++++
 3 files changed, 534 insertions(+)
 create mode 100644 drivers/gpu/drm/panel/panel-magnachip-d53e6ea8966.c

index 737edcdf9eef..204b84a83604 100644
@@ -298,6 +298,17 @@ config DRM_PANEL_LG_LG4573
 	  Say Y here if you want to enable support for LG4573 RGB panel.
 	  To compile this driver as a module, choose M here.
 
+config DRM_PANEL_MAGNACHIP_D53E6EA8966
+	tristate "Magnachip D53E6EA8966 DSI panel"
+	depends on OF && SPI
+	depends on DRM_MIPI_DSI
+	depends on BACKLIGHT_CLASS_DEVICE
+	select DRM_MIPI_DBI
+	help
+	  DRM panel driver for the Samsung AMS495QA01 panel controlled
+	  with the Magnachip D53E6EA8966 panel IC. This panel receives
+	  video data via DSI but commands via 9-bit SPI using DBI.
+
 config DRM_PANEL_NEC_NL8048HL11
 	tristate "NEC NL8048HL11 RGB panel"
 	depends on GPIOLIB && OF && SPI

index f8f9d9f6a307..20de312aa5e9 100644
@@ -27,6 +27,7 @@ obj-$(CONFIG_DRM_PANEL_LEADTEK_LTK050H3146W) += panel-leadtek-ltk050h3146w.o
 obj-$(CONFIG_DRM_PANEL_LEADTEK_LTK500HD1829) += panel-leadtek-ltk500hd1829.o
 obj-$(CONFIG_DRM_PANEL_LG_LB035Q02) += panel-lg-lb035q02.o
 obj-$(CONFIG_DRM_PANEL_LG_LG4573) += panel-lg-lg4573.o
+obj-$(CONFIG_DRM_PANEL_MAGNACHIP_D53E6EA8966) += panel-magnachip-d53e6ea8966.o
 obj-$(CONFIG_DRM_PANEL_NEC_NL8048HL11) += panel-nec-nl8048hl11.o
 obj-$(CONFIG_DRM_PANEL_NEWVISION_NV3051D) += panel-newvision-nv3051d.o
 obj-$(CONFIG_DRM_PANEL_NEWVISION_NV3052C) += panel-newvision-nv3052c.o

2.34.1

From: Chris Morgan <[email protected]>

Add Samsung AMS495QA01 panel to RG503.

---
 .../dts/rockchip/rk3566-anbernic-rg503.dts    | 55 +++++++++++++++++++
 1 file changed, 55 insertions(+)

index 5dafcc86296b..b4b2df821cba 100644
@@ -47,6 +47,21 @@ gpio_spi: spi {
 		mosi-gpios = <&gpio4 RK_PB0 GPIO_ACTIVE_HIGH>;
 		cs-gpios = <&gpio4 RK_PA7 GPIO_ACTIVE_HIGH>;
 		num-chipselects = <0>;
+
+		panel@0 {
+			compatible = "samsung,ams495qa01";
+			reg = <0>;
+			pinctrl-names = "default";
+			pinctrl-0 = <&lcd_reset>;
+			reset-gpios = <&gpio4 RK_PA0 GPIO_ACTIVE_LOW>;
+			vdd-supply = <&vcc_3v3>;
+
+			port {
+				mipi_in_panel: endpoint {
+					remote-endpoint = <&mipi_out_panel>;
+				};
+			};
+		};
 	};
 
 	/* Channels reversed for both headphones and speakers. */

@@ -94,6 +109,32 @@ &cru {
 	assigned-clock-rates = <1200000000>, <200000000>, <500000000>;
 };
 
+&dsi_dphy0 {
+	status = "okay";
+};
+
+&dsi0 {
+	status = "okay";
+
+	ports {
+		dsi0_in: port@0 {
+			reg = <0>;
+
+			dsi0_in_vp1: endpoint {
+				remote-endpoint = <&vp1_out_dsi0>;
+			};
+		};
+
+		dsi0_out: port@1 {
+			reg = <1>;
+
+			mipi_out_panel: endpoint {
+				remote-endpoint = <&mipi_in_panel>;
+			};
+		};
+	};
+};
+
 &gpio_keys_control {
 	button-a {
 		gpios = <&gpio3 RK_PC1 GPIO_ACTIVE_LOW>;

@@ -146,6 +187,13 @@ spk_amp_enable_h: spk-amp-enable-h {
 		};
 	};
 
+	gpio-lcd {
+		lcd_reset: lcd-reset {
+			rockchip,pins =
+				<4 RK_PA0 RK_FUNC_GPIO &pcfg_pull_none>;
+		};
+	};
+
 	gpio-spi {
 		spi_pins: spi-pins {
 			rockchip,pins =

@@ -164,3 +212,10 @@ rk817_charger: charger {
 		rockchip,sleep-filter-current-microamp = <100000>;
 	};
 };
+
+&vp1 {
+	vp1_out_dsi0: endpoint@ROCKCHIP_VOP2_EP_MIPI0 {
+		reg = <ROCKCHIP_VOP2_EP_MIPI0>;
+		remote-endpoint = <&dsi0_in_vp1>;
+	};
+};

2.34.1