[PATCH 1/2] drm/panel: Add driver for the AUO A030JTN01 TFT LCD

[Christophe Branchereau <cbranchereau@gmail.com>]

Add driver for the AUO A030JTN01 panel, which is a 320x480 3.0" 4:3
24-bit TFT LCD panel with non-square pixels and a delta-RGB 8-bit
interface.

Signed-off-by: Christophe Branchereau <cbranchereau@gmail.com>
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
---
 drivers/gpu/drm/panel/Kconfig               |   8 +
 drivers/gpu/drm/panel/Makefile              |   1 +
 drivers/gpu/drm/panel/panel-auo-a030jtn01.c | 295 ++++++++++++++++++++
 3 files changed, 304 insertions(+)
 create mode 100644 drivers/gpu/drm/panel/panel-auo-a030jtn01.c

diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
index a582ddd583c2..3db85c68d182 100644
--- a/drivers/gpu/drm/panel/Kconfig
+++ b/drivers/gpu/drm/panel/Kconfig
@@ -8,6 +8,14 @@ config DRM_PANEL
 menu "Display Panels"
 	depends on DRM && DRM_PANEL
 
+config DRM_PANEL_AUO_A030JTN01
+	tristate "AUO A030JTN01"
+	depends on OF && SPI
+	select REGMAP_SPI
+	help
+	  Say Y here to enable support for the AUO A030JTN01 320x480 3.0" panel
+	  as found in the YLM RS-97 handheld gaming console.
+
 config DRM_PANEL_ABT_Y030XX067A
 	tristate "ABT Y030XX067A 320x480 LCD panel"
 	depends on OF && SPI
diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
index 34e717382dbb..f425599c2717 100644
--- a/drivers/gpu/drm/panel/Makefile
+++ b/drivers/gpu/drm/panel/Makefile
@@ -1,4 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_DRM_PANEL_AUO_A030JTN01) += panel-auo-a030jtn01.o
 obj-$(CONFIG_DRM_PANEL_ABT_Y030XX067A) += panel-abt-y030xx067a.o
 obj-$(CONFIG_DRM_PANEL_ARM_VERSATILE) += panel-arm-versatile.o
 obj-$(CONFIG_DRM_PANEL_ASUS_Z00T_TM5P5_NT35596) += panel-asus-z00t-tm5p5-n35596.o
diff --git a/drivers/gpu/drm/panel/panel-auo-a030jtn01.c b/drivers/gpu/drm/panel/panel-auo-a030jtn01.c
new file mode 100644
index 000000000000..1c4f812e9483
--- /dev/null
+++ b/drivers/gpu/drm/panel/panel-auo-a030jtn01.c
@@ -0,0 +1,295 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * AU Optronics A030JTN01.0 TFT LCD panel driver
+ *
+ * Copyright (C) 2020, Paul Cercueil <paul@crapouillou.net>
+ * Copyright (C) 2020, Christophe Branchereau <cbranchereau@gmail.com>
+ */
+
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/gpio/consumer.h>
+#include <linux/media-bus-format.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+#include <linux/spi/spi.h>
+
+#include <drm/drm_modes.h>
+#include <drm/drm_panel.h>
+
+struct a030jtn01_info {
+	const struct drm_display_mode *display_modes;
+	unsigned int num_modes;
+	u16 width_mm, height_mm;
+	u32 bus_format, bus_flags;
+};
+
+struct a030jtn01 {
+	struct drm_panel panel;
+	struct spi_device *spi;
+	struct regmap *map;
+
+	const struct a030jtn01_info *panel_info;
+
+	struct regulator *supply;
+	struct gpio_desc *reset_gpio;
+};
+
+static inline struct a030jtn01 *to_a030jtn01(struct drm_panel *panel)
+{
+	return container_of(panel, struct a030jtn01, panel);
+}
+
+static int a030jtn01_prepare(struct drm_panel *panel)
+{
+	struct a030jtn01 *priv = to_a030jtn01(panel);
+	struct device *dev = &priv->spi->dev;
+	int err;
+
+	err = regulator_enable(priv->supply);
+	if (err) {
+		dev_err(dev, "Failed to enable power supply: %d\n", err);
+		return err;
+	}
+
+	usleep_range(1000, 8000);
+
+	/* Reset the chip */
+	gpiod_set_value_cansleep(priv->reset_gpio, 1);
+	usleep_range(100, 8000);
+	gpiod_set_value_cansleep(priv->reset_gpio, 0);
+	usleep_range(2000, 8000);
+
+	/*
+	 * No idea why two writes are needed. If this write is commented,
+	 * the colors are wrong. Doesn't seem to be timing-related, since
+	 * a msleep(200) doesn't fix it.
+	 */
+	regmap_write(priv->map, 0x06, 0x00);
+
+	/* Use (24 + 6) == 0x1e as the vertical back porch */
+	err = regmap_write(priv->map, 0x06, 0x1e);
+	if (err)
+		goto err_disable_regulator;
+
+	/* Use (42 + 30) * 3 == 0xd8 as the horizontal back porch */
+	err = regmap_write(priv->map, 0x07, 0xd8);
+	if (err)
+		goto err_disable_regulator;
+
+	regmap_write(priv->map, 0x05, 0x74);
+
+	return 0;
+
+err_disable_regulator:
+	gpiod_set_value_cansleep(priv->reset_gpio, 1);
+	regulator_disable(priv->supply);
+	return err;
+}
+
+static int a030jtn01_unprepare(struct drm_panel *panel)
+{
+	struct a030jtn01 *priv = to_a030jtn01(panel);
+
+	gpiod_set_value_cansleep(priv->reset_gpio, 1);
+	regulator_disable(priv->supply);
+
+	return 0;
+}
+
+static int a030jtn01_enable(struct drm_panel *panel)
+{
+	struct a030jtn01 *priv = to_a030jtn01(panel);
+	int ret;
+
+	ret = regmap_write(priv->map, 0x05, 0x75);
+	if (ret)
+		return ret;
+
+	/* Wait for the picture to be stable */
+	if (panel->backlight)
+		msleep(100);
+
+	return 0;
+}
+
+static int a030jtn01_disable(struct drm_panel *panel)
+{
+	struct a030jtn01 *priv = to_a030jtn01(panel);
+
+	return regmap_write(priv->map, 0x05, 0x74);
+}
+
+static int a030jtn01_get_modes(struct drm_panel *panel,
+				struct drm_connector *connector)
+{
+	struct a030jtn01 *priv = to_a030jtn01(panel);
+	const struct a030jtn01_info *panel_info = priv->panel_info;
+	struct drm_display_mode *mode;
+	unsigned int i;
+
+	for (i = 0; i < panel_info->num_modes; i++) {
+		mode = drm_mode_duplicate(connector->dev,
+					  &panel_info->display_modes[i]);
+		if (!mode)
+			return -ENOMEM;
+
+		drm_mode_set_name(mode);
+
+		mode->type = DRM_MODE_TYPE_DRIVER;
+		if (panel_info->num_modes == 1)
+			mode->type |= DRM_MODE_TYPE_PREFERRED;
+
+		drm_mode_probed_add(connector, mode);
+	}
+
+	connector->display_info.bpc = 8;
+	connector->display_info.width_mm = panel_info->width_mm;
+	connector->display_info.height_mm = panel_info->height_mm;
+
+	drm_display_info_set_bus_formats(&connector->display_info,
+					 &panel_info->bus_format, 1);
+	connector->display_info.bus_flags = panel_info->bus_flags;
+
+	return panel_info->num_modes;
+}
+
+static const struct drm_panel_funcs a030jtn01_funcs = {
+	.prepare	= a030jtn01_prepare,
+	.unprepare	= a030jtn01_unprepare,
+	.enable		= a030jtn01_enable,
+	.disable	= a030jtn01_disable,
+	.get_modes	= a030jtn01_get_modes,
+};
+
+static bool a030jtn01_has_reg(struct device *dev, unsigned int reg)
+{
+	static const u32 a030jtn01_regs_mask = 0x001823f1fb;
+
+	return a030jtn01_regs_mask & BIT(reg);
+};
+
+static const struct regmap_config a030jtn01_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.read_flag_mask = 0x40,
+	.max_register = 0x1c,
+	.readable_reg = a030jtn01_has_reg,
+	.writeable_reg = a030jtn01_has_reg,
+};
+
+static int a030jtn01_probe(struct spi_device *spi)
+{
+	struct device *dev = &spi->dev;
+	struct a030jtn01 *priv;
+	int err;
+
+	spi->mode |= SPI_MODE_3 | SPI_3WIRE;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->spi = spi;
+	spi_set_drvdata(spi, priv);
+
+	priv->map = devm_regmap_init_spi(spi, &a030jtn01_regmap_config);
+	if (IS_ERR(priv->map)) {
+		dev_err(dev, "Unable to init regmap\n");
+		return PTR_ERR(priv->map);
+	}
+
+	priv->panel_info = of_device_get_match_data(dev);
+	if (!priv->panel_info)
+		return -EINVAL;
+
+	priv->supply = devm_regulator_get(dev, "power");
+	if (IS_ERR(priv->supply)) {
+		dev_err(dev, "Failed to get power supply\n");
+		return PTR_ERR(priv->supply);
+	}
+
+	priv->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(priv->reset_gpio)) {
+		dev_err(dev, "Failed to get reset GPIO\n");
+		return PTR_ERR(priv->reset_gpio);
+	}
+
+	drm_panel_init(&priv->panel, dev, &a030jtn01_funcs,
+		       DRM_MODE_CONNECTOR_DPI);
+
+	err = drm_panel_of_backlight(&priv->panel);
+	if (err)
+		return err;
+
+	drm_panel_add(&priv->panel);
+
+	return 0;
+}
+
+static void a030jtn01_remove(struct spi_device *spi)
+{
+	struct a030jtn01 *priv = spi_get_drvdata(spi);
+
+	drm_panel_remove(&priv->panel);
+	drm_panel_disable(&priv->panel);
+	drm_panel_unprepare(&priv->panel);
+}
+
+static const struct drm_display_mode a030jtn01_modes[] = {
+	{ /* 60 Hz */
+		.clock = 14400,
+		.hdisplay = 320,
+		.hsync_start = 320 + 8,
+		.hsync_end = 320 + 8 + 42,
+		.htotal = 320 + 8 + 42 + 30,
+		.vdisplay = 480,
+		.vsync_start = 480 + 90,
+		.vsync_end = 480 + 90 + 24,
+		.vtotal = 480 + 90 + 24 + 6,
+		.flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
+	},
+	{ /* 50 Hz */
+		.clock = 12000,
+		.hdisplay = 320,
+		.hsync_start = 320 + 8,
+		.hsync_end = 320 + 8 + 42,
+		.htotal = 320 + 8 + 42 + 30,
+		.vdisplay = 480,
+		.vsync_start = 480 + 90,
+		.vsync_end = 480 + 90 + 24,
+		.vtotal = 480 + 90 + 24 + 6,
+		.flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
+	},
+};
+
+static const struct a030jtn01_info a030jtn01_info = {
+	.display_modes = a030jtn01_modes,
+	.num_modes = ARRAY_SIZE(a030jtn01_modes),
+	.width_mm = 70,
+	.height_mm = 51,
+	.bus_format = MEDIA_BUS_FMT_RGB888_3X8_DELTA,
+	.bus_flags = DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE,
+};
+
+static const struct of_device_id a030jtn01_of_match[] = {
+	{ .compatible = "auo,a030jtn01", .data = &a030jtn01_info },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, a030jtn01_of_match);
+
+static struct spi_driver a030jtn01_driver = {
+	.driver = {
+		.name = "auo-a030jtn01",
+		.of_match_table = a030jtn01_of_match,
+	},
+	.probe = a030jtn01_probe,
+	.remove = a030jtn01_remove,
+};
+module_spi_driver(a030jtn01_driver);
+
+MODULE_AUTHOR("Paul Cercueil <paul@crapouillou.net>");
+MODULE_AUTHOR("Christophe Branchereau <cbranchereau@gmail.com>");
+MODULE_LICENSE("GPL v2");
-- 
2.35.1