drm/panel: Add driver for Samsung S6D16D0 panel

The Samsung S6D16D0 is a simple comman mode only DSI display
that is used on the ST-Ericsson Ux500 reference design
TVK1281618 user interface board (UIB).

Cc: Andrzej Hajda <a.hajda@samsung.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20181023074630.29186-2-linus.walleij@linaro.org

drivers/gpu/drm/panel/Kconfig

@@ -138,6 +138,12 @@ config DRM_PANEL_RAYDIUM_RM68200
 	  Say Y here if you want to enable support for Raydium RM68200
 	  720x1280 DSI video mode panel.
 
+config DRM_PANEL_SAMSUNG_S6D16D0
+	tristate "Samsung S6D16D0 DSI video mode panel"
+	depends on OF
+	depends on DRM_MIPI_DSI
+	select VIDEOMODE_HELPERS
+
 config DRM_PANEL_SAMSUNG_S6E3HA2
 	tristate "Samsung S6E3HA2 DSI video mode panel"
 	depends on OF

drivers/gpu/drm/panel/Makefile

@@ -13,6 +13,7 @@ obj-$(CONFIG_DRM_PANEL_PANASONIC_VVX10F034N00) += panel-panasonic-vvx10f034n00.o
 obj-$(CONFIG_DRM_PANEL_RASPBERRYPI_TOUCHSCREEN) += panel-raspberrypi-touchscreen.o
 obj-$(CONFIG_DRM_PANEL_RAYDIUM_RM68200) += panel-raydium-rm68200.o
 obj-$(CONFIG_DRM_PANEL_SAMSUNG_LD9040) += panel-samsung-ld9040.o
+obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6D16D0) += panel-samsung-s6d16d0.o
 obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E3HA2) += panel-samsung-s6e3ha2.o
 obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E63J0X03) += panel-samsung-s6e63j0x03.o
 obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E8AA0) += panel-samsung-s6e8aa0.o

drivers/gpu/drm/panel/panel-samsung-s6d16d0.c

@@ -0,0 +1,264 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * MIPI-DSI Samsung s6d16d0 panel driver. This is a 864x480
+ * AMOLED panel with a command-only DSI interface.
+ */
+
+#include <drm/drm_modes.h>
+#include <drm/drm_mipi_dsi.h>
+#include <drm/drm_panel.h>
+#include <drm/drm_print.h>
+
+#include <linux/gpio/consumer.h>
+#include <linux/regulator/consumer.h>
+#include <linux/delay.h>
+#include <linux/of_device.h>
+#include <linux/module.h>
+
+struct s6d16d0 {
+	struct device *dev;
+	struct drm_panel panel;
+	struct regulator *supply;
+	struct gpio_desc *reset_gpio;
+};
+
+/*
+ * The timings are not very helpful as the display is used in
+ * command mode.
+ */
+static const struct drm_display_mode samsung_s6d16d0_mode = {
+	/* HS clock, (htotal*vtotal*vrefresh)/1000 */
+	.clock = 420160,
+	.hdisplay = 864,
+	.hsync_start = 864 + 154,
+	.hsync_end = 864 + 154 + 16,
+	.htotal = 864 + 154 + 16 + 32,
+	.vdisplay = 480,
+	.vsync_start = 480 + 1,
+	.vsync_end = 480 + 1 + 1,
+	.vtotal = 480 + 1 + 1 + 1,
+	/*
+	 * This depends on the clocking HS vs LP rate, this value
+	 * is calculated as:
+	 * vrefresh = (clock * 1000) / (htotal*vtotal)
+	 */
+	.vrefresh = 816,
+	.width_mm = 84,
+	.height_mm = 48,
+};
+
+static inline struct s6d16d0 *panel_to_s6d16d0(struct drm_panel *panel)
+{
+	return container_of(panel, struct s6d16d0, panel);
+}
+
+static int s6d16d0_unprepare(struct drm_panel *panel)
+{
+	struct s6d16d0 *s6 = panel_to_s6d16d0(panel);
+	struct mipi_dsi_device *dsi = to_mipi_dsi_device(s6->dev);
+	int ret;
+
+	/* Enter sleep mode */
+	ret = mipi_dsi_dcs_enter_sleep_mode(dsi);
+	if (ret) {
+		DRM_DEV_ERROR(s6->dev, "failed to enter sleep mode (%d)\n",
+			      ret);
+		return ret;
+	}
+
+	/* Assert RESET */
+	gpiod_set_value_cansleep(s6->reset_gpio, 1);
+	regulator_disable(s6->supply);
+
+	return 0;
+}
+
+static int s6d16d0_prepare(struct drm_panel *panel)
+{
+	struct s6d16d0 *s6 = panel_to_s6d16d0(panel);
+	struct mipi_dsi_device *dsi = to_mipi_dsi_device(s6->dev);
+	int ret;
+
+	ret = regulator_enable(s6->supply);
+	if (ret) {
+		DRM_DEV_ERROR(s6->dev, "failed to enable supply (%d)\n", ret);
+		return ret;
+	}
+
+	/* Assert RESET */
+	gpiod_set_value_cansleep(s6->reset_gpio, 1);
+	udelay(10);
+	/* De-assert RESET */
+	gpiod_set_value_cansleep(s6->reset_gpio, 0);
+	msleep(120);
+
+	/* Enabe tearing mode: send TE (tearing effect) at VBLANK */
+	ret = mipi_dsi_dcs_set_tear_on(dsi,
+				       MIPI_DSI_DCS_TEAR_MODE_VBLANK);
+	if (ret) {
+		DRM_DEV_ERROR(s6->dev, "failed to enble vblank TE (%d)\n",
+			      ret);
+		return ret;
+	}
+	/* Exit sleep mode and power on */
+	ret = mipi_dsi_dcs_exit_sleep_mode(dsi);
+	if (ret) {
+		DRM_DEV_ERROR(s6->dev, "failed to exit sleep mode (%d)\n",
+			      ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int s6d16d0_enable(struct drm_panel *panel)
+{
+	struct s6d16d0 *s6 = panel_to_s6d16d0(panel);
+	struct mipi_dsi_device *dsi = to_mipi_dsi_device(s6->dev);
+	int ret;
+
+	ret = mipi_dsi_dcs_set_display_on(dsi);
+	if (ret) {
+		DRM_DEV_ERROR(s6->dev, "failed to turn display on (%d)\n",
+			      ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int s6d16d0_disable(struct drm_panel *panel)
+{
+	struct s6d16d0 *s6 = panel_to_s6d16d0(panel);
+	struct mipi_dsi_device *dsi = to_mipi_dsi_device(s6->dev);
+	int ret;
+
+	ret = mipi_dsi_dcs_set_display_off(dsi);
+	if (ret) {
+		DRM_DEV_ERROR(s6->dev, "failed to turn display off (%d)\n",
+			      ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int s6d16d0_get_modes(struct drm_panel *panel)
+{
+	struct drm_connector *connector = panel->connector;
+	struct drm_display_mode *mode;
+
+	strncpy(connector->display_info.name, "Samsung S6D16D0\0",
+		DRM_DISPLAY_INFO_LEN);
+
+	mode = drm_mode_duplicate(panel->drm, &samsung_s6d16d0_mode);
+	if (!mode) {
+		DRM_ERROR("bad mode or failed to add mode\n");
+		return -EINVAL;
+	}
+	drm_mode_set_name(mode);
+	mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;
+
+	connector->display_info.width_mm = mode->width_mm;
+	connector->display_info.height_mm = mode->height_mm;
+
+	drm_mode_probed_add(connector, mode);
+
+	return 1; /* Number of modes */
+}
+
+static const struct drm_panel_funcs s6d16d0_drm_funcs = {
+	.disable = s6d16d0_disable,
+	.unprepare = s6d16d0_unprepare,
+	.prepare = s6d16d0_prepare,
+	.enable = s6d16d0_enable,
+	.get_modes = s6d16d0_get_modes,
+};
+
+static int s6d16d0_probe(struct mipi_dsi_device *dsi)
+{
+	struct device *dev = &dsi->dev;
+	struct s6d16d0 *s6;
+	int ret;
+
+	s6 = devm_kzalloc(dev, sizeof(struct s6d16d0), GFP_KERNEL);
+	if (!s6)
+		return -ENOMEM;
+
+	mipi_dsi_set_drvdata(dsi, s6);
+	s6->dev = dev;
+
+	dsi->lanes = 2;
+	dsi->format = MIPI_DSI_FMT_RGB888;
+	dsi->hs_rate = 420160000;
+	dsi->lp_rate = 19200000;
+	/*
+	 * This display uses command mode so no MIPI_DSI_MODE_VIDEO
+	 * or MIPI_DSI_MODE_VIDEO_SYNC_PULSE
+	 *
+	 * As we only send commands we do not need to be continuously
+	 * clocked.
+	 */
+	dsi->mode_flags =
+		MIPI_DSI_CLOCK_NON_CONTINUOUS |
+		MIPI_DSI_MODE_EOT_PACKET;
+
+	s6->supply = devm_regulator_get(dev, "vdd1");
+	if (IS_ERR(s6->supply))
+		return PTR_ERR(s6->supply);
+
+	/* This asserts RESET by default */
+	s6->reset_gpio = devm_gpiod_get_optional(dev, "reset",
+						 GPIOD_OUT_HIGH);
+	if (IS_ERR(s6->reset_gpio)) {
+		ret = PTR_ERR(s6->reset_gpio);
+		if (ret != -EPROBE_DEFER)
+			DRM_DEV_ERROR(dev, "failed to request GPIO (%d)\n",
+				      ret);
+		return ret;
+	}
+
+	drm_panel_init(&s6->panel);
+	s6->panel.dev = dev;
+	s6->panel.funcs = &s6d16d0_drm_funcs;
+
+	ret = drm_panel_add(&s6->panel);
+	if (ret < 0)
+		return ret;
+
+	ret = mipi_dsi_attach(dsi);
+	if (ret < 0)
+		drm_panel_remove(&s6->panel);
+
+	return ret;
+}
+
+static int s6d16d0_remove(struct mipi_dsi_device *dsi)
+{
+	struct s6d16d0 *s6 = mipi_dsi_get_drvdata(dsi);
+
+	mipi_dsi_detach(dsi);
+	drm_panel_remove(&s6->panel);
+
+	return 0;
+}
+
+static const struct of_device_id s6d16d0_of_match[] = {
+	{ .compatible = "samsung,s6d16d0" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, s6d16d0_of_match);
+
+static struct mipi_dsi_driver s6d16d0_driver = {
+	.probe = s6d16d0_probe,
+	.remove = s6d16d0_remove,
+	.driver = {
+		.name = "panel-samsung-s6d16d0",
+		.of_match_table = s6d16d0_of_match,
+	},
+};
+module_mipi_dsi_driver(s6d16d0_driver);
+
+MODULE_AUTHOR("Linus Wallei <linus.walleij@linaro.org>");
+MODULE_DESCRIPTION("MIPI-DSI s6d16d0 Panel Driver");
+MODULE_LICENSE("GPL v2");