[PATCH 4/4] drm/panel/ili9341: Support DPI panels

[Noralf Trønnes]

Add support for panels that use the DPI interface.
ILI9341 has onboard RAM so the assumption made here is that all such
panels support pixel upload over DBI.

The presence/absense of the Device Tree 'port' node decides which
interface is used for pixel transfer.

Signed-off-by: Noralf Trønnes <noralf at tronnes.org>
---
 drivers/gpu/drm/panel/panel-ilitek-ili9341.c | 56 ++++++++++++++++----
 1 file changed, 45 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/panel/panel-ilitek-ili9341.c b/drivers/gpu/drm/panel/panel-ilitek-ili9341.c
index f6082fa2a389..7cbfd739c7fd 100644
--- a/drivers/gpu/drm/panel/panel-ilitek-ili9341.c
+++ b/drivers/gpu/drm/panel/panel-ilitek-ili9341.c
@@ -11,6 +11,7 @@
 #include <linux/gpio/consumer.h>
 #include <linux/module.h>
 #include <linux/of_device.h>
+#include <linux/of_graph.h>
 #include <linux/pm.h>
 #include <linux/property.h>
 #include <linux/regulator/consumer.h>
@@ -53,11 +54,13 @@
 struct ili9341_config {
 	const struct drm_panel_funcs *funcs;
 	const struct drm_display_mode *mode;
+	bool no_dpi;
 };
 
 struct ili9341 {
 	struct mipi_dbi_dev dbidev; /* This must be the first entry */
 	struct drm_panel panel;
+	bool use_dpi;
 	struct regulator *regulator;
 	struct backlight_device *backlight;
 	const struct ili9341_config *conf;
@@ -174,6 +177,7 @@ static const struct drm_display_mode yx240qv29_mode = {
 static const struct ili9341_config yx240qv29_data = {
 	.funcs = &yx240qv29_funcs,
 	.mode = &yx240qv29_mode,
+	.no_dpi = true,
 };
 
 static int mi0283qt_prepare(struct drm_panel *panel)
@@ -291,6 +295,7 @@ static const struct drm_display_mode mi0283qt_mode = {
 static const struct ili9341_config mi0283qt_data = {
 	.funcs = &mi0283qt_drm_funcs,
 	.mode = &mi0283qt_mode,
+	.no_dpi = true,
 };
 
 /* Legacy, DRM driver name is ABI */
@@ -303,6 +308,7 @@ static int ili9341_probe(struct spi_device *spi)
 	const struct spi_device_id *spi_id;
 	struct device *dev = &spi->dev;
 	struct drm_driver *driver;
+	struct device_node *port;
 	struct mipi_dbi *dbi;
 	struct gpio_desc *dc;
 	struct ili9341 *ili;
@@ -357,21 +363,44 @@ static int ili9341_probe(struct spi_device *spi)
 	ili->panel.dev = dev;
 	ili->panel.funcs = ili->conf->funcs;
 
-	if (ili->conf == &mi0283qt_data)
-		driver = &mi0283qt_drm_driver;
-	else
-		driver = &ili9341_drm_driver;
 
-	return drm_mipi_dbi_panel_register(&ili->panel, &ili->dbidev, driver,
-					   ili->conf->mode, rotation);
+	port = of_get_child_by_name(dev->of_node, "port");
+	if (port) {
+		of_node_put(port);
+		ili->use_dpi = true;
+	}
+
+	if (ili->conf->no_dpi)
+		ili->use_dpi = false;
+
+	if (ili->use_dpi) {
+		ret = drm_panel_add(&ili->panel);
+	} else {
+		if (ili->conf == &mi0283qt_data)
+			driver = &mi0283qt_drm_driver;
+		else
+			driver = &ili9341_drm_driver;
+
+		ret = drm_mipi_dbi_panel_register(&ili->panel, &ili->dbidev, driver,
+						  ili->conf->mode, rotation);
+	}
+
+	return ret;
 }
 
 static int ili9341_remove(struct spi_device *spi)
 {
 	struct ili9341 *ili = spi_get_drvdata(spi);
 
-	drm_dev_unplug(&ili->dbidev.drm);
-	drm_atomic_helper_shutdown(&ili->dbidev.drm);
+	if (ili->use_dpi) {
+		drm_panel_remove(&ili->panel);
+		drm_panel_disable(&ili->panel);
+		drm_panel_unprepare(&ili->panel);
+		kfree(ili);
+	} else {
+		drm_dev_unplug(&ili->dbidev.drm);
+		drm_atomic_helper_shutdown(&ili->dbidev.drm);
+	}
 
 	return 0;
 }
@@ -380,21 +409,26 @@ static void ili9341_shutdown(struct spi_device *spi)
 {
 	struct ili9341 *ili = spi_get_drvdata(spi);
 
-	drm_atomic_helper_shutdown(&ili->dbidev.drm);
+	if (!ili->use_dpi)
+		drm_atomic_helper_shutdown(&ili->dbidev.drm);
 }
 
 static int __maybe_unused ili9341_pm_suspend(struct device *dev)
 {
 	struct ili9341 *ili = dev_get_drvdata(dev);
 
-	return drm_mode_config_helper_suspend(&ili->dbidev.drm);
+	if (!ili->use_dpi)
+		return drm_mode_config_helper_suspend(&ili->dbidev.drm);
+
+	return 0;
 }
 
 static int __maybe_unused ili9341_pm_resume(struct device *dev)
 {
 	struct ili9341 *ili = dev_get_drvdata(dev);
 
-	drm_mode_config_helper_resume(&ili->dbidev.drm);
+	if (!ili->use_dpi)
+		drm_mode_config_helper_resume(&ili->dbidev.drm);
 
 	return 0;
 }
-- 
2.20.1