drm/panel: s6e63m0: Add DSI transport

This makes it possible to use the s6e63m0 panel with a
DSI host, such as in the Samsung GT-I8190 (Golden) mobile
phone.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Stephan Gerhold <stephan@gerhold.net>
Cc: Stephan Gerhold <stephan@gerhold.net>
Cc: Paweł Chmiel <pawel.mikolaj.chmiel@gmail.com>
Acked-by: Paul Cercueil <paul@crapouillou.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20200809215104.1830206-3-linus.walleij@linaro.org

drivers/gpu/drm/panel/Kconfig

@@ -341,6 +341,14 @@ config DRM_PANEL_SAMSUNG_S6E63M0_SPI
 	  Say Y here if you want to be able to access the Samsung
 	  S6E63M0 panel using SPI.
 
+config DRM_PANEL_SAMSUNG_S6E63M0_DSI
+	tristate "Samsung S6E63M0 RGB DSI interface"
+	depends on DRM_MIPI_DSI
+	depends on DRM_PANEL_SAMSUNG_S6E63M0
+	help
+	  Say Y here if you want to be able to access the Samsung
+	  S6E63M0 panel using DSI.
+
 config DRM_PANEL_SAMSUNG_S6E88A0_AMS452EF01
 	tristate "Samsung AMS452EF01 panel with S6E88A0 DSI video mode controller"
 	depends on OF

drivers/gpu/drm/panel/Makefile

@@ -35,6 +35,7 @@ obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E3HA2) += panel-samsung-s6e3ha2.o
 obj-$(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_AMS452EF01) += panel-samsung-s6e88a0-ams452ef01.o
 obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E8AA0) += panel-samsung-s6e8aa0.o
 obj-$(CONFIG_DRM_PANEL_SEIKO_43WVF1G) += panel-seiko-43wvf1g.o

drivers/gpu/drm/panel/panel-samsung-s6e63m0-dsi.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * DSI interface to the Samsung S6E63M0 panel.
+ * (C) 2019 Linus Walleij
+ */
+
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/of_device.h>
+
+#include <drm/drm_mipi_dsi.h>
+#include <drm/drm_print.h>
+
+#include "panel-samsung-s6e63m0.h"
+
+#define MCS_GLOBAL_PARAM	0xb0
+#define S6E63M0_DSI_MAX_CHUNK	15 /* CMD + 15 bytes max */
+
+static int s6e63m0_dsi_dcs_write(struct device *dev, const u8 *data, size_t len)
+{
+	struct mipi_dsi_device *dsi = to_mipi_dsi_device(dev);
+	const u8 *seqp = data;
+	u8 cmd;
+	u8 cmdwritten;
+	int remain;
+	int chunk;
+	int ret;
+
+	DRM_DEV_INFO(dev, "DSI writing dcs seq: %*ph\n", (int)len, data);
+
+	/* Pick out and skip past the DCS command */
+	cmd = *seqp;
+	seqp++;
+	cmdwritten = 0;
+	remain = len - 1;
+	chunk = remain;
+
+	/* Send max S6E63M0_DSI_MAX_CHUNK bytes at a time */
+	if (chunk > S6E63M0_DSI_MAX_CHUNK)
+		chunk = S6E63M0_DSI_MAX_CHUNK;
+	ret = mipi_dsi_dcs_write(dsi, cmd, seqp, chunk);
+	if (ret < 0) {
+		DRM_DEV_ERROR(dev,
+			      "error sending DCS command seq cmd %02x\n",
+			      cmd);
+		return ret;
+	}
+	cmdwritten += chunk;
+	seqp += chunk;
+
+	while (cmdwritten < remain) {
+		chunk = remain - cmdwritten;
+		if (chunk > S6E63M0_DSI_MAX_CHUNK)
+			chunk = S6E63M0_DSI_MAX_CHUNK;
+		ret = mipi_dsi_dcs_write(dsi, MCS_GLOBAL_PARAM, &cmdwritten, 1);
+		if (ret < 0) {
+			DRM_DEV_ERROR(dev,
+				      "error sending CMD %02x global param %02x\n",
+				      cmd, cmdwritten);
+			return ret;
+		}
+		ret = mipi_dsi_dcs_write(dsi, cmd, seqp, chunk);
+		if (ret < 0) {
+			DRM_DEV_ERROR(dev,
+				      "error sending CMD %02x chunk\n",
+				      cmd);
+			return ret;
+		}
+		cmdwritten += chunk;
+		seqp += chunk;
+	}
+	DRM_DEV_INFO(dev, "sent command %02x %02x bytes\n",
+		     cmd, cmdwritten);
+
+	usleep_range(8000, 9000);
+
+	return 0;
+}
+
+static int s6e63m0_dsi_probe(struct mipi_dsi_device *dsi)
+{
+	struct device *dev = &dsi->dev;
+	int ret;
+
+	dsi->lanes = 2;
+	dsi->format = MIPI_DSI_FMT_RGB888;
+	dsi->hs_rate = 349440000;
+	dsi->lp_rate = 9600000;
+	dsi->mode_flags = MIPI_DSI_MODE_VIDEO |
+		MIPI_DSI_MODE_EOT_PACKET |
+		MIPI_DSI_MODE_VIDEO_BURST;
+
+	ret = s6e63m0_probe(dev, s6e63m0_dsi_dcs_write, true);
+	if (ret)
+		return ret;
+
+	ret = mipi_dsi_attach(dsi);
+	if (ret < 0)
+		s6e63m0_remove(dev);
+
+	return ret;
+}
+
+static int s6e63m0_dsi_remove(struct mipi_dsi_device *dsi)
+{
+	mipi_dsi_detach(dsi);
+	return s6e63m0_remove(&dsi->dev);
+}
+
+static const struct of_device_id s6e63m0_dsi_of_match[] = {
+	{ .compatible = "samsung,s6e63m0" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, s6e63m0_dsi_of_match);
+
+static struct mipi_dsi_driver s6e63m0_dsi_driver = {
+	.probe			= s6e63m0_dsi_probe,
+	.remove			= s6e63m0_dsi_remove,
+	.driver			= {
+		.name		= "panel-samsung-s6e63m0",
+		.of_match_table = s6e63m0_dsi_of_match,
+	},
+};
+module_mipi_dsi_driver(s6e63m0_dsi_driver);
+
+MODULE_AUTHOR("Linus Walleij <linusw@kernel.org>");
+MODULE_DESCRIPTION("s6e63m0 LCD DSI Driver");
+MODULE_LICENSE("GPL v2");

drivers/gpu/drm/panel/panel-samsung-s6e63m0-spi.c

@@ -60,7 +60,7 @@ static int s6e63m0_spi_probe(struct spi_device *spi)
 		DRM_DEV_ERROR(dev, "spi setup failed.\n");
 		return ret;
 	}
-	return s6e63m0_probe(dev, s6e63m0_spi_dcs_write);
+	return s6e63m0_probe(dev, s6e63m0_spi_dcs_write, false);
 }
 
 static int s6e63m0_spi_remove(struct spi_device *spi)

drivers/gpu/drm/panel/panel-samsung-s6e63m0.c

@@ -400,7 +400,8 @@ static int s6e63m0_backlight_register(struct s6e63m0 *ctx)
 }
 
 int s6e63m0_probe(struct device *dev,
-		  int (*dcs_write)(struct device *dev, const u8 *data, size_t len))
+		  int (*dcs_write)(struct device *dev, const u8 *data, size_t len),
+		  bool dsi_mode)
 {
 	struct s6e63m0 *ctx;
 	int ret;
@@ -432,6 +433,7 @@ int s6e63m0_probe(struct device *dev,
 	}
 
 	drm_panel_init(&ctx->panel, dev, &s6e63m0_drm_funcs,
+		       dsi_mode ? DRM_MODE_CONNECTOR_DSI :
 		       DRM_MODE_CONNECTOR_DPI);
 
 	ret = s6e63m0_backlight_register(ctx);

drivers/gpu/drm/panel/panel-samsung-s6e63m0.h

@@ -4,7 +4,9 @@
 #define _PANEL_SAMSUNG_S6E63M0_H
 
 int s6e63m0_probe(struct device *dev,
-		  int (*dcs_write)(struct device *dev, const u8 *data, size_t len));
+		  int (*dcs_write)(struct device *dev, const u8 *data,
+				   size_t len),
+		  bool dsi_mode);
 int s6e63m0_remove(struct device *dev);
 
 #endif /* _PANEL_SAMSUNG_S6E63M0_H */