drm/panel: Add driver for the LG Philips LB035Q02 panel

This panel is used on the Gumstix Overo Palo35.

The code is based on the omapdrm-specific panel-lgphilips-lb035q02
driver.
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/20190813201101.30980-5-laurent.pinchart@ideasonboard.com

drivers/gpu/drm/panel/Kconfig

@@ -103,6 +103,14 @@ config DRM_PANEL_SAMSUNG_LD9040
 	depends on OF && SPI
 	select VIDEOMODE_HELPERS
 
+config DRM_PANEL_LG_LB035Q02
+	tristate "LG LB035Q024573 RGB panel"
+	depends on GPIOLIB && OF && SPI
+	help
+	  Say Y here if you want to enable support for the LB035Q02 RGB panel
+	  (found on the Gumstix Overo Palo35 board). To compile this driver as
+	  a module, choose M here.
+
 config DRM_PANEL_LG_LG4573
 	tristate "LG4573 RGB/SPI panel"
 	depends on OF && SPI

drivers/gpu/drm/panel/Makefile

@@ -8,6 +8,7 @@ obj-$(CONFIG_DRM_PANEL_ILITEK_ILI9881C) += panel-ilitek-ili9881c.o
 obj-$(CONFIG_DRM_PANEL_INNOLUX_P079ZCA) += panel-innolux-p079zca.o
 obj-$(CONFIG_DRM_PANEL_JDI_LT070ME05000) += panel-jdi-lt070me05000.o
 obj-$(CONFIG_DRM_PANEL_KINGDISPLAY_KD097D04) += panel-kingdisplay-kd097d04.o
+obj-$(CONFIG_DRM_PANEL_LG_LB035Q02) += panel-lg-lb035q02.o
 obj-$(CONFIG_DRM_PANEL_LG_LG4573) += panel-lg-lg4573.o
 obj-$(CONFIG_DRM_PANEL_NOVATEK_NT39016) += panel-novatek-nt39016.o
 obj-$(CONFIG_DRM_PANEL_OLIMEX_LCD_OLINUXINO) += panel-olimex-lcd-olinuxino.o

drivers/gpu/drm/panel/panel-lg-lb035q02.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * LG.Philips LB035Q02 LCD Panel Driver
+ *
+ * Copyright (C) 2019 Texas Instruments Incorporated
+ *
+ * Based on the omapdrm-specific panel-lgphilips-lb035q02 driver
+ *
+ * Copyright (C) 2013 Texas Instruments Incorporated
+ * Author: Tomi Valkeinen <tomi.valkeinen@ti.com>
+ *
+ * Based on a driver by: Steve Sakoman <steve@sakoman.com>
+ */
+
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+#include <linux/spi/spi.h>
+
+#include <drm/drm_connector.h>
+#include <drm/drm_modes.h>
+#include <drm/drm_panel.h>
+
+struct lb035q02_device {
+	struct drm_panel panel;
+
+	struct spi_device *spi;
+	struct gpio_desc *enable_gpio;
+};
+
+#define to_lb035q02_device(p) container_of(p, struct lb035q02_device, panel)
+
+static int lb035q02_write(struct lb035q02_device *lcd, u16 reg, u16 val)
+{
+	struct spi_message msg;
+	struct spi_transfer index_xfer = {
+		.len		= 3,
+		.cs_change	= 1,
+	};
+	struct spi_transfer value_xfer = {
+		.len		= 3,
+	};
+	u8	buffer[16];
+
+	spi_message_init(&msg);
+
+	/* register index */
+	buffer[0] = 0x70;
+	buffer[1] = 0x00;
+	buffer[2] = reg & 0x7f;
+	index_xfer.tx_buf = buffer;
+	spi_message_add_tail(&index_xfer, &msg);
+
+	/* register value */
+	buffer[4] = 0x72;
+	buffer[5] = val >> 8;
+	buffer[6] = val;
+	value_xfer.tx_buf = buffer + 4;
+	spi_message_add_tail(&value_xfer, &msg);
+
+	return spi_sync(lcd->spi, &msg);
+}
+
+static int lb035q02_init(struct lb035q02_device *lcd)
+{
+	/* Init sequence from page 28 of the lb035q02 spec. */
+	static const struct {
+		u16 index;
+		u16 value;
+	} init_data[] = {
+		{ 0x01, 0x6300 },
+		{ 0x02, 0x0200 },
+		{ 0x03, 0x0177 },
+		{ 0x04, 0x04c7 },
+		{ 0x05, 0xffc0 },
+		{ 0x06, 0xe806 },
+		{ 0x0a, 0x4008 },
+		{ 0x0b, 0x0000 },
+		{ 0x0d, 0x0030 },
+		{ 0x0e, 0x2800 },
+		{ 0x0f, 0x0000 },
+		{ 0x16, 0x9f80 },
+		{ 0x17, 0x0a0f },
+		{ 0x1e, 0x00c1 },
+		{ 0x30, 0x0300 },
+		{ 0x31, 0x0007 },
+		{ 0x32, 0x0000 },
+		{ 0x33, 0x0000 },
+		{ 0x34, 0x0707 },
+		{ 0x35, 0x0004 },
+		{ 0x36, 0x0302 },
+		{ 0x37, 0x0202 },
+		{ 0x3a, 0x0a0d },
+		{ 0x3b, 0x0806 },
+	};
+
+	unsigned int i;
+	int ret;
+
+	for (i = 0; i < ARRAY_SIZE(init_data); ++i) {
+		ret = lb035q02_write(lcd, init_data[i].index,
+				     init_data[i].value);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int lb035q02_disable(struct drm_panel *panel)
+{
+	struct lb035q02_device *lcd = to_lb035q02_device(panel);
+
+	gpiod_set_value_cansleep(lcd->enable_gpio, 0);
+
+	return 0;
+}
+
+static int lb035q02_enable(struct drm_panel *panel)
+{
+	struct lb035q02_device *lcd = to_lb035q02_device(panel);
+
+	gpiod_set_value_cansleep(lcd->enable_gpio, 1);
+
+	return 0;
+}
+
+static const struct drm_display_mode lb035q02_mode = {
+	.clock = 6500,
+	.hdisplay = 320,
+	.hsync_start = 320 + 20,
+	.hsync_end = 320 + 20 + 2,
+	.htotal = 320 + 20 + 2 + 68,
+	.vdisplay = 240,
+	.vsync_start = 240 + 4,
+	.vsync_end = 240 + 4 + 2,
+	.vtotal = 240 + 4 + 2 + 18,
+	.vrefresh = 60,
+	.type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED,
+	.flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
+	.width_mm = 70,
+	.height_mm = 53,
+};
+
+static int lb035q02_get_modes(struct drm_panel *panel)
+{
+	struct drm_connector *connector = panel->connector;
+	struct drm_display_mode *mode;
+
+	mode = drm_mode_duplicate(panel->drm, &lb035q02_mode);
+	if (!mode)
+		return -ENOMEM;
+
+	drm_mode_set_name(mode);
+	drm_mode_probed_add(connector, mode);
+
+	connector->display_info.width_mm = lb035q02_mode.width_mm;
+	connector->display_info.height_mm = lb035q02_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 Gumstix Overo
+	 * Palo35 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 lb035q02_funcs = {
+	.disable = lb035q02_disable,
+	.enable = lb035q02_enable,
+	.get_modes = lb035q02_get_modes,
+};
+
+static int lb035q02_probe(struct spi_device *spi)
+{
+	struct lb035q02_device *lcd;
+	int ret;
+
+	lcd = devm_kzalloc(&spi->dev, sizeof(*lcd), GFP_KERNEL);
+	if (lcd == NULL)
+		return -ENOMEM;
+
+	spi_set_drvdata(spi, lcd);
+	lcd->spi = spi;
+
+	lcd->enable_gpio = devm_gpiod_get(&spi->dev, "enable", GPIOD_OUT_LOW);
+	if (IS_ERR(lcd->enable_gpio)) {
+		dev_err(&spi->dev, "failed to parse enable gpio\n");
+		return PTR_ERR(lcd->enable_gpio);
+	}
+
+	ret = lb035q02_init(lcd);
+	if (ret < 0)
+		return ret;
+
+	drm_panel_init(&lcd->panel);
+	lcd->panel.dev = &lcd->spi->dev;
+	lcd->panel.funcs = &lb035q02_funcs;
+
+	return drm_panel_add(&lcd->panel);
+}
+
+static int lb035q02_remove(struct spi_device *spi)
+{
+	struct lb035q02_device *lcd = spi_get_drvdata(spi);
+
+	drm_panel_remove(&lcd->panel);
+	drm_panel_disable(&lcd->panel);
+
+	return 0;
+}
+
+static const struct of_device_id lb035q02_of_match[] = {
+	{ .compatible = "lgphilips,lb035q02", },
+	{ /* sentinel */ },
+};
+
+MODULE_DEVICE_TABLE(of, lb035q02_of_match);
+
+static struct spi_driver lb035q02_driver = {
+	.probe		= lb035q02_probe,
+	.remove		= lb035q02_remove,
+	.driver		= {
+		.name	= "panel-lg-lb035q02",
+		.of_match_table = lb035q02_of_match,
+	},
+};
+
+module_spi_driver(lb035q02_driver);
+
+MODULE_ALIAS("spi:lgphilips,lb035q02");
+MODULE_AUTHOR("Tomi Valkeinen <tomi.valkeinen@ti.com>");
+MODULE_DESCRIPTION("LG.Philips LB035Q02 LCD Panel driver");
+MODULE_LICENSE("GPL");