@@ -0,0 +1,297 @@
+// 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 int 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);
+
+ return 0;
+}
+
+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");