drm/panel: ilitek-ili9806e: add Rocktech RK050HR345-CT106A SPI panel

Add support for the Rocktech RK050HR345-CT106A panel based on the
Ilitek ILI9806E controller using the SPI bus.

The driver is designed to be easily extensible to support other panels
with different initialization sequences and display timings by
providing a specific descriptor structure for each model.

Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patch.msgid.link/20260318073346.18041-5-dario.binacchi@amarulasolutions.com

Author: passgat

MAINTAINERS

@@ -8027,6 +8027,7 @@ F:	drivers/gpu/drm/panel/panel-ilitek-ili9805.c
 
 DRM DRIVER FOR ILITEK ILI9806E PANELS
 M:	Michael Walle <mwalle@kernel.org>
+M:	Dario Binacchi <dario.binacchi@amarulasolutions.com>
 S:	Maintained
 F:	drivers/gpu/drm/panel/panel-ilitek-ili9806e-*
 

drivers/gpu/drm/panel/Kconfig

@@ -281,6 +281,18 @@ config DRM_PANEL_ILITEK_ILI9806E_DSI
 	  Say Y if you want to enable support for panels based on the
 	  Ilitek ILI9806E controller using DSI.
 
+config DRM_PANEL_ILITEK_ILI9806E_SPI
+	tristate "Ilitek ILI9806E-based RGB SPI panel"
+	depends on OF
+	depends on SPI
+	depends on BACKLIGHT_CLASS_DEVICE
+	select DRM_MIPI_DBI
+	select VIDEOMODE_HELPERS
+	select DRM_PANEL_ILITEK_ILI9806E_CORE
+	help
+	  Say Y if you want to enable support for panels based on the
+	  Ilitek ILI9806E controller using SPI.
+
 config DRM_PANEL_ILITEK_ILI9881C
 	tristate "Ilitek ILI9881C-based panels"
 	depends on OF

drivers/gpu/drm/panel/Makefile

@@ -29,6 +29,7 @@ obj-$(CONFIG_DRM_PANEL_ILITEK_ILI9341) += panel-ilitek-ili9341.o
 obj-$(CONFIG_DRM_PANEL_ILITEK_ILI9805) += panel-ilitek-ili9805.o
 obj-$(CONFIG_DRM_PANEL_ILITEK_ILI9806E_CORE) += panel-ilitek-ili9806e-core.o
 obj-$(CONFIG_DRM_PANEL_ILITEK_ILI9806E_DSI) += panel-ilitek-ili9806e-dsi.o
+obj-$(CONFIG_DRM_PANEL_ILITEK_ILI9806E_SPI) += panel-ilitek-ili9806e-spi.o
 obj-$(CONFIG_DRM_PANEL_ILITEK_ILI9881C) += panel-ilitek-ili9881c.o
 obj-$(CONFIG_DRM_PANEL_ILITEK_ILI9882T) += panel-ilitek-ili9882t.o
 obj-$(CONFIG_DRM_PANEL_INNOLUX_EJ030NA) += panel-innolux-ej030na.o

drivers/gpu/drm/panel/panel-ilitek-ili9806e-core.c

@@ -11,6 +11,7 @@
 #include <linux/export.h>
 #include <linux/gpio/consumer.h>
 #include <linux/module.h>
+#include <linux/of.h>
 #include <linux/property.h>
 #include <linux/regulator/consumer.h>
 
@@ -20,15 +21,11 @@ struct ili9806e {
 	void *transport;
 	struct drm_panel panel;
 
+	unsigned int num_supplies;
 	struct regulator_bulk_data supplies[2];
 	struct gpio_desc *reset_gpio;
 };
 
-static const char * const regulator_names[] = {
-	"vdd",
-	"vccio",
-};
-
 void *ili9806e_get_transport(struct drm_panel *panel)
 {
 	struct ili9806e *ctx = container_of(panel, struct ili9806e, panel);
@@ -44,7 +41,7 @@ int ili9806e_power_on(struct device *dev)
 
 	gpiod_set_value(ctx->reset_gpio, 1);
 
-	ret = regulator_bulk_enable(ARRAY_SIZE(ctx->supplies), ctx->supplies);
+	ret = regulator_bulk_enable(ctx->num_supplies, ctx->supplies);
 	if (ret) {
 		dev_err(dev, "regulator bulk enable failed: %d\n", ret);
 		return ret;
@@ -65,7 +62,7 @@ int ili9806e_power_off(struct device *dev)
 
 	gpiod_set_value(ctx->reset_gpio, 1);
 
-	ret = regulator_bulk_disable(ARRAY_SIZE(ctx->supplies), ctx->supplies);
+	ret = regulator_bulk_disable(ctx->num_supplies, ctx->supplies);
 	if (ret)
 		dev_err(dev, "regulator bulk disable failed: %d\n", ret);
 
@@ -78,7 +75,8 @@ int ili9806e_probe(struct device *dev, void *transport,
 		  int connector_type)
 {
 	struct ili9806e *ctx;
-	int i, ret;
+	bool set_prepare_prev_first = false;
+	int ret;
 
 	ctx = devm_kzalloc(dev, sizeof(struct ili9806e), GFP_KERNEL);
 	if (!ctx)
@@ -87,11 +85,16 @@ int ili9806e_probe(struct device *dev, void *transport,
 	dev_set_drvdata(dev, ctx);
 	ctx->transport = transport;
 
-	for (i = 0; i < ARRAY_SIZE(ctx->supplies); i++)
-		ctx->supplies[i].supply = regulator_names[i];
+	ctx->supplies[ctx->num_supplies++].supply = "vdd";
+	if (of_device_is_compatible(dev->of_node,
+				    "densitron,dmt028vghmcmi-1d") ||
+	    of_device_is_compatible(dev->of_node,
+				    "ortustech,com35h3p70ulc")) {
+		ctx->supplies[ctx->num_supplies++].supply = "vccio";
+		set_prepare_prev_first = true;
+	}
 
-	ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(ctx->supplies),
-				      ctx->supplies);
+	ret = devm_regulator_bulk_get(dev, ctx->num_supplies, ctx->supplies);
 	if (ret)
 		return dev_err_probe(dev, ret, "failed to get regulators\n");
 
@@ -106,7 +109,9 @@ int ili9806e_probe(struct device *dev, void *transport,
 	if (ret)
 		return dev_err_probe(dev, ret, "Failed to get backlight\n");
 
-	ctx->panel.prepare_prev_first = true;
+	if (set_prepare_prev_first)
+		ctx->panel.prepare_prev_first = true;
+
 	drm_panel_add(&ctx->panel);
 
 	return 0;