[PATCH V2 4/6] board: rockchip: Add panel auto-detection for Anbernic RGxx3

[Chris Morgan <macroalpha82@gmail.com>]

From: Chris Morgan <macromorgan@hotmail.com>

Add support to automatically detect the panel for the Anbernic RGxx3.
This is done by creating a "pseudo driver" that provides only the bare
minimum to start the DSI controller and DSI DPHY. Once started, we then
can query the panel for its panel ID and compare it to a table of known
values. The panel compatible string (which corresponds to the upstream
Linux driver) is then defined as an environment variable "panel". The
panel compatible string is also changed automatically via an
ft_board_setup() call if what is detected differs from what is in the
loaded tree. This way, end users can use the same bootloader without
having to worry about which panel they have (as there is no obvious
way of knowing).

Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
---
 board/anbernic/rgxx3_rk3566/rgxx3-rk3566.c | 196 +++++++++++++++++++++
 1 file changed, 196 insertions(+)

diff --git a/board/anbernic/rgxx3_rk3566/rgxx3-rk3566.c b/board/anbernic/rgxx3_rk3566/rgxx3-rk3566.c
index 4d3c724b9c..3f1a42d184 100644
--- a/board/anbernic/rgxx3_rk3566/rgxx3-rk3566.c
+++ b/board/anbernic/rgxx3_rk3566/rgxx3-rk3566.c
@@ -6,21 +6,27 @@
 #include <abuf.h>
 #include <adc.h>
 #include <asm/io.h>
+#include <display.h>
 #include <dm.h>
 #include <dm/lists.h>
 #include <env.h>
 #include <fdt_support.h>
 #include <linux/delay.h>
+#include <mipi_dsi.h>
 #include <mmc.h>
+#include <panel.h>
 #include <pwm.h>
 #include <rng.h>
 #include <stdlib.h>
+#include <video_bridge.h>
 
 #define GPIO0_BASE		0xfdd60000
+#define GPIO4_BASE		0xfe770000
 #define GPIO_SWPORT_DR_L	0x0000
 #define GPIO_SWPORT_DR_H	0x0004
 #define GPIO_SWPORT_DDR_L	0x0008
 #define GPIO_SWPORT_DDR_H	0x000c
+#define GPIO_A0			BIT(0)
 #define GPIO_C5			BIT(5)
 #define GPIO_C6			BIT(6)
 #define GPIO_C7			BIT(7)
@@ -86,6 +92,16 @@ static const struct rg3xx_model rg3xx_model_details[] = {
 	},
 };
 
+struct rg353_panel {
+	const u16 id;
+	const char *panel_compat;
+};
+
+static const struct rg353_panel rg353_panel_details[] = {
+	{ .id = 0x3052, .panel_compat = "newvision,nv3051d"},
+	{ .id = 0x3821, .panel_compat = "anbernic,rg353v-panel-v2"},
+};
+
 /*
  * Start LED very early so user knows device is on. Set color
  * to red.
@@ -147,6 +163,150 @@ void __maybe_unused startup_buzz(void)
 	pwm_set_enable(dev, 0, 0);
 }
 
+/*
+ * Provide the bare minimum to identify the panel for the RG353
+ * series. Since we don't have a working framebuffer device, no
+ * need to init the panel; just identify it and provide the
+ * clocks so we know what to set the different clock values to.
+ */
+
+static const struct display_timing rg353_default_timing = {
+	.pixelclock.typ		= 24150000,
+	.hactive.typ		= 640,
+	.hfront_porch.typ	= 40,
+	.hback_porch.typ	= 80,
+	.hsync_len.typ		= 2,
+	.vactive.typ		= 480,
+	.vfront_porch.typ	= 18,
+	.vback_porch.typ	= 28,
+	.vsync_len.typ		= 2,
+	.flags			= DISPLAY_FLAGS_HSYNC_HIGH |
+				  DISPLAY_FLAGS_VSYNC_HIGH,
+};
+
+static int anbernic_rg353_panel_get_timing(struct udevice *dev,
+					   struct display_timing *timings)
+{
+	memcpy(timings, &rg353_default_timing, sizeof(*timings));
+
+	return 0;
+}
+
+static int anbernic_rg353_panel_probe(struct udevice *dev)
+{
+	struct mipi_dsi_panel_plat *plat = dev_get_plat(dev);
+
+	plat->lanes = 4;
+	plat->format = MIPI_DSI_FMT_RGB888;
+	plat->mode_flags = MIPI_DSI_MODE_VIDEO |
+			   MIPI_DSI_MODE_VIDEO_BURST |
+			   MIPI_DSI_MODE_EOT_PACKET |
+			   MIPI_DSI_MODE_LPM;
+
+	return 0;
+}
+
+static const struct panel_ops anbernic_rg353_panel_ops = {
+	.get_display_timing = anbernic_rg353_panel_get_timing,
+};
+
+U_BOOT_DRIVER(anbernic_rg353_panel) = {
+	.name		= "anbernic_rg353_panel",
+	.id		= UCLASS_PANEL,
+	.ops		= &anbernic_rg353_panel_ops,
+	.probe		= anbernic_rg353_panel_probe,
+	.plat_auto	= sizeof(struct mipi_dsi_panel_plat),
+};
+
+int rgxx3_detect_display(void)
+{
+	struct udevice *dev;
+	struct mipi_dsi_device *dsi;
+	struct mipi_dsi_panel_plat *mplat;
+	const struct rg353_panel *panel;
+	int ret = 0;
+	int i;
+	u8 panel_id[2];
+
+	/*
+	 * Take panel out of reset status.
+	 * Set GPIO4_A0 to output.
+	 */
+	writel(GPIO_WRITEMASK(GPIO_A0) | GPIO_A0,
+	       (GPIO4_BASE + GPIO_SWPORT_DDR_L));
+	/* Set GPIO4_A0 to 1. */
+	writel(GPIO_WRITEMASK(GPIO_A0) | GPIO_A0,
+	       (GPIO4_BASE + GPIO_SWPORT_DR_L));
+
+	/* Probe the DSI controller. */
+	ret = uclass_get_device_by_name(UCLASS_VIDEO_BRIDGE,
+					"dsi@fe060000", &dev);
+	if (ret) {
+		printf("DSI host not probed: %d\n", ret);
+		return ret;
+	}
+
+	/* Probe the DSI panel. */
+	ret = device_bind_driver_to_node(dev, "anbernic_rg353_panel",
+					 "anbernic_rg353_panel",
+					 dev_ofnode(dev), NULL);
+	if (ret) {
+		printf("Failed to probe RG353 panel: %d\n", ret);
+		return ret;
+	}
+
+	/*
+	 * Attach the DSI controller which will also probe and attach
+	 * the DSIDPHY.
+	 */
+	ret = video_bridge_attach(dev);
+	if (ret) {
+		printf("Failed to attach DSI controller: %d\n", ret);
+		return ret;
+	}
+
+	/*
+	 * Get the panel which should have already been probed by the
+	 * video_bridge_attach() function.
+	 */
+	ret = uclass_first_device_err(UCLASS_PANEL, &dev);
+	if (ret) {
+		printf("Panel device error: %d\n", ret);
+		return ret;
+	}
+
+	/* Now call the panel via DSI commands to get the panel ID. */
+	mplat = dev_get_plat(dev);
+	dsi = mplat->device;
+	mipi_dsi_set_maximum_return_packet_size(dsi, sizeof(panel_id));
+	ret = mipi_dsi_dcs_read(dsi, MIPI_DCS_GET_DISPLAY_ID, &panel_id,
+				sizeof(panel_id));
+	if (ret < 0) {
+		printf("Unable to read panel ID: %d\n", ret);
+		return ret;
+	}
+
+	/* Get the correct panel compatible from the table. */
+	for (i = 0; i < ARRAY_SIZE(rg353_panel_details); i++) {
+		if (rg353_panel_details[i].id == ((panel_id[0] << 8) |
+						 panel_id[1])) {
+			panel = &rg353_panel_details[i];
+			break;
+		}
+	}
+
+	if (!panel) {
+		printf("Unable to identify panel_id %x\n",
+		       (panel_id[0] << 8) | panel_id[1]);
+		env_set("panel", "unknown");
+		return -EINVAL;
+	}
+
+	env_set("panel", panel->panel_compat);
+
+	return 0;
+}
+
 /* Detect which Anbernic RGXX3 device we are using so as to load the
  * correct devicetree for Linux. Set an environment variable once
  * found. The detection depends on the value of ADC channel 1, the
@@ -207,6 +367,14 @@ int rgxx3_detect_device(void)
 		rg3xx_model_details[board_id].board_name);
 	env_set("fdtfile", rg3xx_model_details[board_id].fdtfile);
 
+	/* Detect the panel type for any device that isn't a 503. */
+	if (board_id == RG503)
+		return 0;
+
+	ret = rgxx3_detect_display();
+	if (ret)
+		return ret;
+
 	return 0;
 }
 
@@ -232,6 +400,7 @@ int rk_board_late_init(void)
 
 int ft_board_setup(void *blob, struct bd_info *bd)
 {
+	int node, ret;
 	char *env;
 
 	/* No fixups necessary for the RG503 */
@@ -245,5 +414,32 @@ int ft_board_setup(void *blob, struct bd_info *bd)
 			    rg3xx_model_details[RG353M].board_name,
 			    sizeof(rg3xx_model_details[RG353M].board_name));
 
+	/*
+	 * Check if the environment variable doesn't equal the panel.
+	 * If it doesn't, update the devicetree to the correct panel.
+	 */
+	node = fdt_path_offset(blob, "/dsi@fe060000/panel@0");
+	if (!(node > 0)) {
+		printf("Can't find the DSI node\n");
+		return -ENODEV;
+	}
+
+	env = env_get("panel");
+	if (!env) {
+		printf("Can't get panel env\n");
+		return -ENODEV;
+	}
+
+	ret = fdt_node_check_compatible(blob, node, env);
+	if (ret < 0)
+		return -ENODEV;
+
+	/* Panels match, return 0. */
+	if (!ret)
+		return 0;
+
+	do_fixup_by_path_string(blob, "/dsi@fe060000/panel@0",
+				"compatible", env);
+
 	return 0;
 }
-- 
2.34.1