drm/panel: Add driver for the Sharp LS037V7DW01 panel

This panel is used on the TI SDP3430 board.

The code is based on the omapdrm-specific panel-sharp-ls037v7dw01
driver.

v2:
- fix checkpatch warning (lcd == NULL) => (!lcd) (sam)
- drop __exit_p() from remove. It caused a build warning.
  And no other panel drivers needs this (sam)

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190813201101.30980-7-laurent.pinchart@ideasonboard.com

drivers/gpu/drm/panel/Kconfig

@@ -282,6 +282,13 @@ config DRM_PANEL_SHARP_LQ101R1SX01
 	  To compile this driver as a module, choose M here: the module
 	  will be called panel-sharp-lq101r1sx01.
 
+config DRM_PANEL_SHARP_LS037V7DW01
+	tristate "Sharp LS037V7DW01 VGA LCD panel"
+	depends on GPIOLIB && OF && REGULATOR
+	help
+	  Say Y here if you want to enable support for Sharp LS037V7DW01 VGA
+	  (480x640) LCD panel (found on the TI SDP3430 board).
+
 config DRM_PANEL_SHARP_LS043T1LE01
 	tristate "Sharp LS043T1LE01 qHD video mode panel"
 	depends on OF

drivers/gpu/drm/panel/Makefile

@@ -29,6 +29,7 @@ obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E63M0) += panel-samsung-s6e63m0.o
 obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E8AA0) += panel-samsung-s6e8aa0.o
 obj-$(CONFIG_DRM_PANEL_SEIKO_43WVF1G) += panel-seiko-43wvf1g.o
 obj-$(CONFIG_DRM_PANEL_SHARP_LQ101R1SX01) += panel-sharp-lq101r1sx01.o
+obj-$(CONFIG_DRM_PANEL_SHARP_LS037V7DW01) += panel-sharp-ls037v7dw01.o
 obj-$(CONFIG_DRM_PANEL_SHARP_LS043T1LE01) += panel-sharp-ls043t1le01.o
 obj-$(CONFIG_DRM_PANEL_SITRONIX_ST7701) += panel-sitronix-st7701.o
 obj-$(CONFIG_DRM_PANEL_SITRONIX_ST7789V) += panel-sitronix-st7789v.o

drivers/gpu/drm/panel/panel-nec-nl8048hl11.c

@@ -180,7 +180,7 @@ static int nl8048_probe(struct spi_device *spi)
 	int ret;
 
 	lcd = devm_kzalloc(&spi->dev, sizeof(*lcd), GFP_KERNEL);
-	if (lcd == NULL)
+	if (!lcd)
 		return -ENOMEM;
 
 	spi_set_drvdata(spi, lcd);

drivers/gpu/drm/panel/panel-sharp-ls037v7dw01.c

@@ -0,0 +1,226 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Sharp LS037V7DW01 LCD Panel Driver
+ *
+ * Copyright (C) 2019 Texas Instruments Incorporated
+ *
+ * Based on the omapdrm-specific panel-sharp-ls037v7dw01 driver
+ *
+ * Copyright (C) 2013 Texas Instruments Incorporated
+ * Author: Tomi Valkeinen <tomi.valkeinen@ti.com>
+ */
+
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+
+#include <drm/drm_connector.h>
+#include <drm/drm_modes.h>
+#include <drm/drm_panel.h>
+
+struct ls037v7dw01_panel {
+	struct drm_panel panel;
+	struct platform_device *pdev;
+
+	struct regulator *vdd;
+	struct gpio_desc *resb_gpio;	/* low = reset active min 20 us */
+	struct gpio_desc *ini_gpio;	/* high = power on */
+	struct gpio_desc *mo_gpio;	/* low = 480x640, high = 240x320 */
+	struct gpio_desc *lr_gpio;	/* high = conventional horizontal scanning */
+	struct gpio_desc *ud_gpio;	/* high = conventional vertical scanning */
+};
+
+#define to_ls037v7dw01_device(p) \
+	container_of(p, struct ls037v7dw01_panel, panel)
+
+static int ls037v7dw01_disable(struct drm_panel *panel)
+{
+	struct ls037v7dw01_panel *lcd = to_ls037v7dw01_device(panel);
+
+	gpiod_set_value_cansleep(lcd->ini_gpio, 0);
+	gpiod_set_value_cansleep(lcd->resb_gpio, 0);
+
+	/* Wait at least 5 vsyncs after disabling the LCD. */
+	msleep(100);
+
+	return 0;
+}
+
+static int ls037v7dw01_unprepare(struct drm_panel *panel)
+{
+	struct ls037v7dw01_panel *lcd = to_ls037v7dw01_device(panel);
+
+	regulator_disable(lcd->vdd);
+	return 0;
+}
+
+static int ls037v7dw01_prepare(struct drm_panel *panel)
+{
+	struct ls037v7dw01_panel *lcd = to_ls037v7dw01_device(panel);
+	int ret;
+
+	ret = regulator_enable(lcd->vdd);
+	if (ret < 0)
+		dev_err(&lcd->pdev->dev, "%s: failed to enable regulator\n",
+			__func__);
+
+	return ret;
+}
+
+static int ls037v7dw01_enable(struct drm_panel *panel)
+{
+	struct ls037v7dw01_panel *lcd = to_ls037v7dw01_device(panel);
+
+	/* Wait couple of vsyncs before enabling the LCD. */
+	msleep(50);
+
+	gpiod_set_value_cansleep(lcd->resb_gpio, 1);
+	gpiod_set_value_cansleep(lcd->ini_gpio, 1);
+
+	return 0;
+}
+
+static const struct drm_display_mode ls037v7dw01_mode = {
+	.clock = 19200,
+	.hdisplay = 480,
+	.hsync_start = 480 + 1,
+	.hsync_end = 480 + 1 + 2,
+	.htotal = 480 + 1 + 2 + 28,
+	.vdisplay = 640,
+	.vsync_start = 640 + 1,
+	.vsync_end = 640 + 1 + 1,
+	.vtotal = 640 + 1 + 1 + 1,
+	.vrefresh = 58,
+	.type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED,
+	.flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
+	.width_mm = 56,
+	.height_mm = 75,
+};
+
+static int ls037v7dw01_get_modes(struct drm_panel *panel)
+{
+	struct drm_connector *connector = panel->connector;
+	struct drm_display_mode *mode;
+
+	mode = drm_mode_duplicate(panel->drm, &ls037v7dw01_mode);
+	if (!mode)
+		return -ENOMEM;
+
+	drm_mode_set_name(mode);
+	drm_mode_probed_add(connector, mode);
+
+	connector->display_info.width_mm = ls037v7dw01_mode.width_mm;
+	connector->display_info.height_mm = ls037v7dw01_mode.height_mm;
+	/*
+	 * FIXME: According to the datasheet pixel data is sampled on the
+	 * rising edge of the clock, but the code running on the SDP3430
+	 * indicates sampling on the negative edge. This should be tested on a
+	 * real device.
+	 */
+	connector->display_info.bus_flags = DRM_BUS_FLAG_DE_HIGH
+					  | DRM_BUS_FLAG_SYNC_SAMPLE_POSEDGE
+					  | DRM_BUS_FLAG_PIXDATA_SAMPLE_NEGEDGE;
+
+	return 1;
+}
+
+static const struct drm_panel_funcs ls037v7dw01_funcs = {
+	.disable = ls037v7dw01_disable,
+	.unprepare = ls037v7dw01_unprepare,
+	.prepare = ls037v7dw01_prepare,
+	.enable = ls037v7dw01_enable,
+	.get_modes = ls037v7dw01_get_modes,
+};
+
+static int ls037v7dw01_probe(struct platform_device *pdev)
+{
+	struct ls037v7dw01_panel *lcd;
+
+	lcd = devm_kzalloc(&pdev->dev, sizeof(*lcd), GFP_KERNEL);
+	if (lcd == NULL)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, lcd);
+	lcd->pdev = pdev;
+
+	lcd->vdd = devm_regulator_get(&pdev->dev, "envdd");
+	if (IS_ERR(lcd->vdd)) {
+		dev_err(&pdev->dev, "failed to get regulator\n");
+		return PTR_ERR(lcd->vdd);
+	}
+
+	lcd->ini_gpio = devm_gpiod_get(&pdev->dev, "enable", GPIOD_OUT_LOW);
+	if (IS_ERR(lcd->ini_gpio)) {
+		dev_err(&pdev->dev, "failed to get enable gpio\n");
+		return PTR_ERR(lcd->ini_gpio);
+	}
+
+	lcd->resb_gpio = devm_gpiod_get(&pdev->dev, "reset", GPIOD_OUT_LOW);
+	if (IS_ERR(lcd->resb_gpio)) {
+		dev_err(&pdev->dev, "failed to get reset gpio\n");
+		return PTR_ERR(lcd->resb_gpio);
+	}
+
+	lcd->mo_gpio = devm_gpiod_get_index(&pdev->dev, "mode", 0,
+					    GPIOD_OUT_LOW);
+	if (IS_ERR(lcd->mo_gpio)) {
+		dev_err(&pdev->dev, "failed to get mode[0] gpio\n");
+		return PTR_ERR(lcd->mo_gpio);
+	}
+
+	lcd->lr_gpio = devm_gpiod_get_index(&pdev->dev, "mode", 1,
+					    GPIOD_OUT_LOW);
+	if (IS_ERR(lcd->lr_gpio)) {
+		dev_err(&pdev->dev, "failed to get mode[1] gpio\n");
+		return PTR_ERR(lcd->lr_gpio);
+	}
+
+	lcd->ud_gpio = devm_gpiod_get_index(&pdev->dev, "mode", 2,
+					    GPIOD_OUT_LOW);
+	if (IS_ERR(lcd->ud_gpio)) {
+		dev_err(&pdev->dev, "failed to get mode[2] gpio\n");
+		return PTR_ERR(lcd->ud_gpio);
+	}
+
+	drm_panel_init(&lcd->panel);
+	lcd->panel.dev = &pdev->dev;
+	lcd->panel.funcs = &ls037v7dw01_funcs;
+
+	return drm_panel_add(&lcd->panel);
+}
+
+static int ls037v7dw01_remove(struct platform_device *pdev)
+{
+	struct ls037v7dw01_panel *lcd = platform_get_drvdata(pdev);
+
+	drm_panel_remove(&lcd->panel);
+	drm_panel_disable(&lcd->panel);
+	drm_panel_unprepare(&lcd->panel);
+
+	return 0;
+}
+
+static const struct of_device_id ls037v7dw01_of_match[] = {
+	{ .compatible = "sharp,ls037v7dw01", },
+	{ /* sentinel */ },
+};
+
+MODULE_DEVICE_TABLE(of, ls037v7dw01_of_match);
+
+static struct platform_driver ls037v7dw01_driver = {
+	.probe		= ls037v7dw01_probe,
+	.remove		= ls037v7dw01_remove,
+	.driver		= {
+		.name = "panel-sharp-ls037v7dw01",
+		.of_match_table = ls037v7dw01_of_match,
+	},
+};
+
+module_platform_driver(ls037v7dw01_driver);
+
+MODULE_AUTHOR("Tomi Valkeinen <tomi.valkeinen@ti.com>");
+MODULE_DESCRIPTION("Sharp LS037V7DW01 Panel Driver");
+MODULE_LICENSE("GPL");