drm/panel: Add support for LG LG4573 480x800 4.3" panel

The LG4573 is used on the LG LCD LB043WV2-SD01, an industrial 4.3" TFT
panel with SPI control interface.
Signed-off-by: Heiko Schocher <hs@denx.de>
Signed-off-by: Thierry Reding <treding@nvidia.com>

Documentation/devicetree/bindings/panel/lg,lg4573.txt

+LG LG4573 TFT Liquid Crystal Display with SPI control bus
+
+Required properties:
+  - compatible: "lg,lg4573"
+  - reg: address of the panel on the SPI bus
+
+The panel must obey rules for SPI slave device specified in document [1].
+
+[1]: Documentation/devicetree/bindings/spi/spi-bus.txt
+
+Example:
+
+	lcd_panel: display@0 {
+		#address-cells = <1>;
+		#size-cells = <1>;
+		compatible = "lg,lg4573";
+		spi-max-frequency = <10000000>;
+		reg = <0>;
+	};

drivers/gpu/drm/panel/Kconfig

@@ -23,6 +23,14 @@ config DRM_PANEL_SAMSUNG_LD9040
 	depends on OF && SPI
 	select VIDEOMODE_HELPERS
 
+config DRM_PANEL_LG_LG4573
+	tristate "LG4573 RGB/SPI panel"
+	depends on OF && SPI
+	select VIDEOMODE_HELPERS
+	help
+	  Say Y here if you want to enable support for LG4573 RGB panel.
+	  To compile this driver as a module, choose M here.
+
 config DRM_PANEL_SAMSUNG_S6E8AA0
 	tristate "Samsung S6E8AA0 DSI video mode panel"
 	depends on OF

drivers/gpu/drm/panel/Makefile

 obj-$(CONFIG_DRM_PANEL_SIMPLE) += panel-simple.o
+obj-$(CONFIG_DRM_PANEL_LG_LG4573) += panel-lg-lg4573.o
 obj-$(CONFIG_DRM_PANEL_SAMSUNG_LD9040) += panel-samsung-ld9040.o
 obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E8AA0) += panel-samsung-s6e8aa0.o
 obj-$(CONFIG_DRM_PANEL_SHARP_LQ101R1SX01) += panel-sharp-lq101r1sx01.o

drivers/gpu/drm/panel/panel-lg-lg4573.c

+/*
+ * Copyright (C) 2015 Heiko Schocher <hs@denx.de>
+ *
+ * from:
+ * drivers/gpu/drm/panel/panel-ld9040.c
+ * ld9040 AMOLED LCD drm_panel driver.
+ *
+ * Copyright (c) 2014 Samsung Electronics Co., Ltd
+ * Derived from drivers/video/backlight/ld9040.c
+ *
+ * Andrzej Hajda <a.hajda@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+*/
+
+#include <drm/drmP.h>
+#include <drm/drm_panel.h>
+
+#include <linux/gpio/consumer.h>
+#include <linux/regulator/consumer.h>
+#include <linux/spi/spi.h>
+
+#include <video/mipi_display.h>
+#include <video/of_videomode.h>
+#include <video/videomode.h>
+
+struct lg4573 {
+	struct drm_panel panel;
+	struct spi_device *spi;
+	struct videomode vm;
+};
+
+static inline struct lg4573 *panel_to_lg4573(struct drm_panel *panel)
+{
+	return container_of(panel, struct lg4573, panel);
+}
+
+static int lg4573_spi_write_u16(struct lg4573 *ctx, u16 data)
+{
+	struct spi_transfer xfer = {
+		.len = 2,
+	};
+	u16 temp = cpu_to_be16(data);
+	struct spi_message msg;
+
+	dev_dbg(ctx->panel.dev, "writing data: %x\n", data);
+	xfer.tx_buf = &temp;
+	spi_message_init(&msg);
+	spi_message_add_tail(&xfer, &msg);
+
+	return spi_sync(ctx->spi, &msg);
+}
+
+static int lg4573_spi_write_u16_array(struct lg4573 *ctx, const u16 *buffer,
+				      unsigned int count)
+{
+	unsigned int i;
+	int ret;
+
+	for (i = 0; i < count; i++) {
+		ret = lg4573_spi_write_u16(ctx, buffer[i]);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int lg4573_spi_write_dcs(struct lg4573 *ctx, u8 dcs)
+{
+	return lg4573_spi_write_u16(ctx, (0x70 << 8 | dcs));
+}
+
+static int lg4573_display_on(struct lg4573 *ctx)
+{
+	int ret;
+
+	ret = lg4573_spi_write_dcs(ctx, MIPI_DCS_EXIT_SLEEP_MODE);
+	if (ret)
+		return ret;
+
+	msleep(5);
+
+	return lg4573_spi_write_dcs(ctx, MIPI_DCS_SET_DISPLAY_ON);
+}
+
+static int lg4573_display_off(struct lg4573 *ctx)
+{
+	int ret;
+
+	ret = lg4573_spi_write_dcs(ctx, MIPI_DCS_SET_DISPLAY_OFF);
+	if (ret)
+		return ret;
+
+	msleep(120);
+
+	return lg4573_spi_write_dcs(ctx, MIPI_DCS_ENTER_SLEEP_MODE);
+}
+
+static int lg4573_display_mode_settings(struct lg4573 *ctx)
+{
+	static const u16 display_mode_settings[] = {
+		0x703A, 0x7270, 0x70B1, 0x7208,
+		0x723B, 0x720F, 0x70B2, 0x7200,
+		0x72C8, 0x70B3, 0x7200, 0x70B4,
+		0x7200, 0x70B5, 0x7242, 0x7210,
+		0x7210, 0x7200, 0x7220, 0x70B6,
+		0x720B, 0x720F, 0x723C, 0x7213,
+		0x7213, 0x72E8, 0x70B7, 0x7246,
+		0x7206, 0x720C, 0x7200, 0x7200,
+	};
+
+	dev_dbg(ctx->panel.dev, "transfer display mode settings\n");
+	return lg4573_spi_write_u16_array(ctx, display_mode_settings,
+					  ARRAY_SIZE(display_mode_settings));
+}
+
+static int lg4573_power_settings(struct lg4573 *ctx)
+{
+	static const u16 power_settings[] = {
+		0x70C0, 0x7201, 0x7211, 0x70C3,
+		0x7207, 0x7203, 0x7204, 0x7204,
+		0x7204, 0x70C4, 0x7212, 0x7224,
+		0x7218, 0x7218, 0x7202, 0x7249,
+		0x70C5, 0x726F, 0x70C6, 0x7241,
+		0x7263,
+	};
+
+	dev_dbg(ctx->panel.dev, "transfer power settings\n");
+	return lg4573_spi_write_u16_array(ctx, power_settings,
+					  ARRAY_SIZE(power_settings));
+}
+
+static int lg4573_gamma_settings(struct lg4573 *ctx)
+{
+	static const u16 gamma_settings[] = {
+		0x70D0, 0x7203, 0x7207, 0x7273,
+		0x7235, 0x7200, 0x7201, 0x7220,
+		0x7200, 0x7203, 0x70D1, 0x7203,
+		0x7207, 0x7273, 0x7235, 0x7200,
+		0x7201, 0x7220, 0x7200, 0x7203,
+		0x70D2, 0x7203, 0x7207, 0x7273,
+		0x7235, 0x7200, 0x7201, 0x7220,
+		0x7200, 0x7203, 0x70D3, 0x7203,
+		0x7207, 0x7273, 0x7235, 0x7200,
+		0x7201, 0x7220, 0x7200, 0x7203,
+		0x70D4, 0x7203, 0x7207, 0x7273,
+		0x7235, 0x7200, 0x7201, 0x7220,
+		0x7200, 0x7203, 0x70D5, 0x7203,
+		0x7207, 0x7273, 0x7235, 0x7200,
+		0x7201, 0x7220, 0x7200, 0x7203,
+	};
+
+	dev_dbg(ctx->panel.dev, "transfer gamma settings\n");
+	return lg4573_spi_write_u16_array(ctx, gamma_settings,
+					  ARRAY_SIZE(gamma_settings));
+}
+
+static int lg4573_init(struct lg4573 *ctx)
+{
+	int ret;
+
+	dev_dbg(ctx->panel.dev, "initializing LCD\n");
+
+	ret = lg4573_display_mode_settings(ctx);
+	if (ret)
+		return ret;
+
+	ret = lg4573_power_settings(ctx);
+	if (ret)
+		return ret;
+
+	return lg4573_gamma_settings(ctx);
+}
+
+static int lg4573_power_on(struct lg4573 *ctx)
+{
+	return lg4573_display_on(ctx);
+}
+
+static int lg4573_disable(struct drm_panel *panel)
+{
+	struct lg4573 *ctx = panel_to_lg4573(panel);
+
+	return lg4573_display_off(ctx);
+}
+
+static int lg4573_enable(struct drm_panel *panel)
+{
+	struct lg4573 *ctx = panel_to_lg4573(panel);
+
+	lg4573_init(ctx);
+
+	return lg4573_power_on(ctx);
+}
+
+static const struct drm_display_mode default_mode = {
+	.clock = 27000,
+	.hdisplay = 480,
+	.hsync_start = 480 + 10,
+	.hsync_end = 480 + 10 + 59,
+	.htotal = 480 + 10 + 59 + 10,
+	.vdisplay = 800,
+	.vsync_start = 800 + 15,
+	.vsync_end = 800 + 15 + 15,
+	.vtotal = 800 + 15 + 15 + 15,
+	.vrefresh = 60,
+};
+
+static int lg4573_get_modes(struct drm_panel *panel)
+{
+	struct drm_connector *connector = panel->connector;
+	struct drm_display_mode *mode;
+
+	mode = drm_mode_duplicate(panel->drm, &default_mode);
+	if (!mode) {
+		dev_err(panel->drm->dev, "failed to add mode %ux%ux@%u\n",
+			default_mode.hdisplay, default_mode.vdisplay,
+			default_mode.vrefresh);
+		return -ENOMEM;
+	}
+
+	drm_mode_set_name(mode);
+
+	mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;
+	drm_mode_probed_add(connector, mode);
+
+	panel->connector->display_info.width_mm = 61;
+	panel->connector->display_info.height_mm = 103;
+
+	return 1;
+}
+
+static const struct drm_panel_funcs lg4573_drm_funcs = {
+	.disable = lg4573_disable,
+	.enable = lg4573_enable,
+	.get_modes = lg4573_get_modes,
+};
+
+static int lg4573_probe(struct spi_device *spi)
+{
+	struct lg4573 *ctx;
+	int ret;
+
+	ctx = devm_kzalloc(&spi->dev, sizeof(*ctx), GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+
+	ctx->spi = spi;
+
+	spi_set_drvdata(spi, ctx);
+	spi->bits_per_word = 8;
+
+	ret = spi_setup(spi);
+	if (ret < 0) {
+		dev_err(&spi->dev, "SPI setup failed: %d\n", ret);
+		return ret;
+	}
+
+	drm_panel_init(&ctx->panel);
+	ctx->panel.dev = &spi->dev;
+	ctx->panel.funcs = &lg4573_drm_funcs;
+
+	return drm_panel_add(&ctx->panel);
+}
+
+static int lg4573_remove(struct spi_device *spi)
+{
+	struct lg4573 *ctx = spi_get_drvdata(spi);
+
+	lg4573_display_off(ctx);
+	drm_panel_remove(&ctx->panel);
+
+	return 0;
+}
+
+static const struct of_device_id lg4573_of_match[] = {
+	{ .compatible = "lg,lg4573" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, lg4573_of_match);
+
+static struct spi_driver lg4573_driver = {
+	.probe = lg4573_probe,
+	.remove = lg4573_remove,
+	.driver = {
+		.name = "lg4573",
+		.owner = THIS_MODULE,
+		.of_match_table = lg4573_of_match,
+	},
+};
+module_spi_driver(lg4573_driver);
+
+MODULE_AUTHOR("Heiko Schocher <hs@denx.de>");
+MODULE_DESCRIPTION("lg4573 LCD Driver");
+MODULE_LICENSE("GPL v2");