--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Ilitek ILI9806E TFT LCD drm_panel driver.
+ *
+ * Copyright (C) 2022 Raspberry Pi Ltd
+ *
+ * Derived from drivers/drm/gpu/panel/panel-sitronix-st7789v.c
+ * Copyright (C) 2017 Free Electrons
+ */
+
+#include <drm/drm_modes.h>
+#include <drm/drm_panel.h>
+
+#include <linux/bitops.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 <video/mipi_display.h>
+#include <video/of_videomode.h>
+#include <video/videomode.h>
+
+struct ili9806 {
+ struct drm_panel panel;
+ struct spi_device *spi;
+ struct gpio_desc *reset;
+ struct regulator *power;
+ u32 bus_format;
+};
+
+#define ILI9806_DATA BIT(8)
+
+#define ILI9806_MAX_MSG_LEN 6
+
+struct ili9806e_msg {
+ unsigned int len;
+ u16 msg[ILI9806_MAX_MSG_LEN];
+};
+
+#define ILI9806_SET_PAGE(page) \
+ { \
+ .len = 6, \
+ .msg = { \
+ 0xFF, \
+ ILI9806_DATA | 0xFF, \
+ ILI9806_DATA | 0x98, \
+ ILI9806_DATA | 0x06, \
+ ILI9806_DATA | 0x04, \
+ ILI9806_DATA | (page) \
+ }, \
+ }
+
+#define ILI9806_SET_REG_PARAM(reg, data) \
+ { \
+ .len = 2, \
+ .msg = { \
+ (reg), \
+ ILI9806_DATA | (data), \
+ }, \
+ }
+
+#define ILI9806_SET_REG(reg) \
+ { \
+ .len = 1, \
+ .msg = { (reg) }, \
+ }
+
+static const struct ili9806e_msg panel_init[] = {
+ ILI9806_SET_PAGE(1),
+
+ /* interface mode
+ * SEPT_SDIO = 0 (spi interface transfer through SDA pin)
+ * SDO_STATUS = 1 (always output, but without output tri-state)
+ */
+ ILI9806_SET_REG_PARAM(0x08, 0x10),
+ /* display control
+ * VSPL = 1 (vertical sync polarity)
+ * HSPL = 0 (horizontal sync polarity)
+ * DPL = 0 (PCLK polarity)
+ * EPL = 1 (data enable polarity)
+ */
+ ILI9806_SET_REG_PARAM(0x21, 0x0d),
+ /* resolution control (0x02 = 480x800) */
+ ILI9806_SET_REG_PARAM(0x30, 0x02),
+ /* display inversion control (0x00 = column inversion) */
+ ILI9806_SET_REG_PARAM(0x31, 0x00),
+ /* power control
+ * EXB1T = 0 (internal charge pump)
+ * EXT_CPCK_SEL = 1 (pump clock control signal = output 2 x waveform)
+ * BT = 0 (DDVDH / DDVDL voltage = VCI x 2 / VCI x -2)
+ */
+ ILI9806_SET_REG_PARAM(0x40, 0x10),
+ /* power control
+ * DDVDH_CLP = 5.6 (DDVDH clamp leve)
+ * DDVDL_CLP = -5.6 (DDVDL clamp leve)
+ */
+ ILI9806_SET_REG_PARAM(0x41, 0x55),
+ /* power control
+ * VGH_CP = 2DDVDH - DDVDL (step up factor for VGH)
+ * VGL_CP = DDVDL + VCL - VCIP (step up factor for VGL)
+ */
+ ILI9806_SET_REG_PARAM(0x42, 0x02),
+ /* power control
+ * VGH_CLPEN = 0 (disable VGH clamp level)
+ * VGH_CLP = 9 (15.0 VGH clamp level - but this is disabled so not used?)
+ */
+ ILI9806_SET_REG_PARAM(0x43, 0x84),
+ /* power control
+ * VGL_CLPEN = 0 (disable VGL clamp level)
+ * VGL_CLP = 9 (-11.0 VGL clamp level - but this is disabled so not used?)
+ */
+ ILI9806_SET_REG_PARAM(0x44, 0x84),
+
+ /* power control
+ * VREG1OUT voltage for positive gamma?
+ */
+ ILI9806_SET_REG_PARAM(0x50, 0x78),
+ /* power control
+ * VREG2OUT voltage for negative gamma?
+ */
+ ILI9806_SET_REG_PARAM(0x51, 0x78),
+
+ ILI9806_SET_REG_PARAM(0x52, 0x00),
+ ILI9806_SET_REG_PARAM(0x53, 0x77),
+ ILI9806_SET_REG_PARAM(0x57, 0x60),
+ ILI9806_SET_REG_PARAM(0x60, 0x07),
+ ILI9806_SET_REG_PARAM(0x61, 0x00),
+ ILI9806_SET_REG_PARAM(0x62, 0x08),
+ ILI9806_SET_REG_PARAM(0x63, 0x00),
+ ILI9806_SET_REG_PARAM(0xA0, 0x00),
+ ILI9806_SET_REG_PARAM(0xA1, 0x07),
+ ILI9806_SET_REG_PARAM(0xA2, 0x0C),
+ ILI9806_SET_REG_PARAM(0xA3, 0x0B),
+ ILI9806_SET_REG_PARAM(0xA4, 0x03),
+ ILI9806_SET_REG_PARAM(0xA5, 0x07),
+ ILI9806_SET_REG_PARAM(0xA6, 0x06),
+ ILI9806_SET_REG_PARAM(0xA7, 0x04),
+ ILI9806_SET_REG_PARAM(0xA8, 0x08),
+ ILI9806_SET_REG_PARAM(0xA9, 0x0C),
+ ILI9806_SET_REG_PARAM(0xAA, 0x13),
+ ILI9806_SET_REG_PARAM(0xAB, 0x06),
+ ILI9806_SET_REG_PARAM(0xAC, 0x0D),
+ ILI9806_SET_REG_PARAM(0xAD, 0x19),
+ ILI9806_SET_REG_PARAM(0xAE, 0x10),
+ ILI9806_SET_REG_PARAM(0xAF, 0x00),
+ /* negative gamma control
+ * set the gray scale voltage to adjust the gamma characteristics of the panel
+ */
+ ILI9806_SET_REG_PARAM(0xC0, 0x00),
+ ILI9806_SET_REG_PARAM(0xC1, 0x07),
+ ILI9806_SET_REG_PARAM(0xC2, 0x0C),
+ ILI9806_SET_REG_PARAM(0xC3, 0x0B),
+ ILI9806_SET_REG_PARAM(0xC4, 0x03),
+ ILI9806_SET_REG_PARAM(0xC5, 0x07),
+ ILI9806_SET_REG_PARAM(0xC6, 0x07),
+ ILI9806_SET_REG_PARAM(0xC7, 0x04),
+ ILI9806_SET_REG_PARAM(0xC8, 0x08),
+ ILI9806_SET_REG_PARAM(0xC9, 0x0C),
+ ILI9806_SET_REG_PARAM(0xCA, 0x13),
+ ILI9806_SET_REG_PARAM(0xCB, 0x06),
+ ILI9806_SET_REG_PARAM(0xCC, 0x0D),
+ ILI9806_SET_REG_PARAM(0xCD, 0x18),
+ ILI9806_SET_REG_PARAM(0xCE, 0x10),
+ ILI9806_SET_REG_PARAM(0xCF, 0x00),
+
+ ILI9806_SET_PAGE(6),
+
+ ILI9806_SET_REG_PARAM(0x00, 0x20),
+ ILI9806_SET_REG_PARAM(0x01, 0x0A),
+ ILI9806_SET_REG_PARAM(0x02, 0x00),
+ ILI9806_SET_REG_PARAM(0x03, 0x00),
+ ILI9806_SET_REG_PARAM(0x04, 0x01),
+ ILI9806_SET_REG_PARAM(0x05, 0x01),
+ ILI9806_SET_REG_PARAM(0x06, 0x98),
+ ILI9806_SET_REG_PARAM(0x07, 0x06),
+ ILI9806_SET_REG_PARAM(0x08, 0x01),
+ ILI9806_SET_REG_PARAM(0x09, 0x80),
+ ILI9806_SET_REG_PARAM(0x0A, 0x00),
+ ILI9806_SET_REG_PARAM(0x0B, 0x00),
+ ILI9806_SET_REG_PARAM(0x0C, 0x01),
+ ILI9806_SET_REG_PARAM(0x0D, 0x01),
+ ILI9806_SET_REG_PARAM(0x0E, 0x00),
+ ILI9806_SET_REG_PARAM(0x0F, 0x00),
+ ILI9806_SET_REG_PARAM(0x10, 0xF0),
+ ILI9806_SET_REG_PARAM(0x11, 0xF4),
+ ILI9806_SET_REG_PARAM(0x12, 0x01),
+ ILI9806_SET_REG_PARAM(0x13, 0x00),
+ ILI9806_SET_REG_PARAM(0x14, 0x00),
+ ILI9806_SET_REG_PARAM(0x15, 0xC0),
+ ILI9806_SET_REG_PARAM(0x16, 0x08),
+ ILI9806_SET_REG_PARAM(0x17, 0x00),
+ ILI9806_SET_REG_PARAM(0x18, 0x00),
+ ILI9806_SET_REG_PARAM(0x19, 0x00),
+ ILI9806_SET_REG_PARAM(0x1A, 0x00),
+ ILI9806_SET_REG_PARAM(0x1B, 0x00),
+ ILI9806_SET_REG_PARAM(0x1C, 0x00),
+ ILI9806_SET_REG_PARAM(0x1D, 0x00),
+ ILI9806_SET_REG_PARAM(0x20, 0x01),
+ ILI9806_SET_REG_PARAM(0x21, 0x23),
+ ILI9806_SET_REG_PARAM(0x22, 0x45),
+ ILI9806_SET_REG_PARAM(0x23, 0x67),
+ ILI9806_SET_REG_PARAM(0x24, 0x01),
+ ILI9806_SET_REG_PARAM(0x25, 0x23),
+ ILI9806_SET_REG_PARAM(0x26, 0x45),
+ ILI9806_SET_REG_PARAM(0x27, 0x67),
+ ILI9806_SET_REG_PARAM(0x30, 0x11),
+ ILI9806_SET_REG_PARAM(0x31, 0x11),
+ ILI9806_SET_REG_PARAM(0x32, 0x00),
+ ILI9806_SET_REG_PARAM(0x33, 0xEE),
+ ILI9806_SET_REG_PARAM(0x34, 0xFF),
+ ILI9806_SET_REG_PARAM(0x35, 0xBB),
+ ILI9806_SET_REG_PARAM(0x36, 0xAA),
+ ILI9806_SET_REG_PARAM(0x37, 0xDD),
+ ILI9806_SET_REG_PARAM(0x38, 0xCC),
+ ILI9806_SET_REG_PARAM(0x39, 0x66),
+ ILI9806_SET_REG_PARAM(0x3A, 0x77),
+ ILI9806_SET_REG_PARAM(0x3B, 0x22),
+ ILI9806_SET_REG_PARAM(0x3C, 0x22),
+ ILI9806_SET_REG_PARAM(0x3D, 0x22),
+ ILI9806_SET_REG_PARAM(0x3E, 0x22),
+ ILI9806_SET_REG_PARAM(0x3F, 0x22),
+ ILI9806_SET_REG_PARAM(0x40, 0x22),
+ /* register doesn't exist on page 6? */
+ ILI9806_SET_REG_PARAM(0x52, 0x10),
+ /* doesn't make sense, not valid according to datasheet */
+ ILI9806_SET_REG_PARAM(0x53, 0x10),
+ /* doesn't make sense, not valid according to datasheet */
+ ILI9806_SET_REG_PARAM(0x54, 0x13),
+
+ ILI9806_SET_PAGE(7),
+
+ /* enable VREG */
+ ILI9806_SET_REG_PARAM(0x18, 0x1D),
+ /* enable VGL_REG */
+ ILI9806_SET_REG_PARAM(0x17, 0x22),
+ /* register doesn't exist on page 7? */
+ ILI9806_SET_REG_PARAM(0x02, 0x77),
+ /* register doesn't exist on page 7? */
+ ILI9806_SET_REG_PARAM(0x26, 0xB2),
+ /* register doesn't exist on page 7? */
+ ILI9806_SET_REG_PARAM(0xE1, 0x79),
+
+ ILI9806_SET_PAGE(0),
+
+ ILI9806_SET_REG_PARAM(MIPI_DCS_SET_PIXEL_FORMAT,
+ MIPI_DCS_PIXEL_FMT_18BIT << 4),
+ ILI9806_SET_REG_PARAM(MIPI_DCS_SET_TEAR_ON, 0x00),
+ ILI9806_SET_REG(MIPI_DCS_EXIT_SLEEP_MODE),
+};
+
+#define NUM_INIT_REGS ARRAY_SIZE(panel_init)
+
+static inline struct ili9806 *panel_to_ili9806(struct drm_panel *panel)
+{
+ return container_of(panel, struct ili9806, panel);
+}
+
+static int ili9806_write_msg(struct ili9806 *ctx, const struct ili9806e_msg *msg)
+{
+ struct spi_transfer xfer = { };
+ struct spi_message spi;
+ //u16 txbuf[] = { msg->, ILI9806_DATA | data };
+
+ spi_message_init(&spi);
+
+ xfer.tx_buf = msg->msg;
+ xfer.bits_per_word = 9;
+ xfer.len = sizeof(u16) * msg->len;
+
+ spi_message_add_tail(&xfer, &spi);
+ return spi_sync(ctx->spi, &spi);
+}
+
+static int ili9806e_write_msg_list(struct ili9806 *ctx,
+ const struct ili9806e_msg msgs[],
+ unsigned int num_msgs)
+{
+ int ret, i;
+
+ for (i = 0; i < num_msgs; i++) {
+ ret = ili9806_write_msg(ctx, &msgs[i]);
+ if (ret)
+ break;
+ }
+
+ return ret;
+}
+
+static const struct drm_display_mode ili9806e_480x800_mode = {
+ .clock = 32000,
+ .hdisplay = 480,
+ .hsync_start = 480 + 10,
+ .hsync_end = 480 + 10 + 16,
+ .htotal = 480 + 10 + 16 + 59,
+ .vdisplay = 800,
+ .vsync_start = 800 + 15,
+ .vsync_end = 800 + 15 + 113,
+ .vtotal = 800 + 15 + 113 + 15,
+ .flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
+};
+
+static int ili9806_get_modes(struct drm_panel *panel,
+ struct drm_connector *connector)
+{
+ struct ili9806 *ctx = panel_to_ili9806(panel);
+ struct drm_display_mode *mode;
+
+ mode = drm_mode_duplicate(connector->dev, &ili9806e_480x800_mode);
+ if (!mode) {
+ dev_err(panel->dev, "failed to add mode %ux%ux@%u\n",
+ ili9806e_480x800_mode.hdisplay,
+ ili9806e_480x800_mode.vdisplay,
+ drm_mode_vrefresh(&ili9806e_480x800_mode));
+ return -ENOMEM;
+ }
+
+ drm_mode_set_name(mode);
+
+ mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;
+ drm_mode_probed_add(connector, mode);
+
+ connector->display_info.width_mm = 61;
+ connector->display_info.height_mm = 103;
+ drm_display_info_set_bus_formats(&connector->display_info,
+ &ctx->bus_format, 1);
+ connector->display_info.bus_flags =
+ DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE;
+
+ return 1;
+}
+
+static int ili9806_prepare(struct drm_panel *panel)
+{
+ struct ili9806 *ctx = panel_to_ili9806(panel);
+ int ret;
+
+ ret = regulator_enable(ctx->power);
+ if (ret)
+ return ret;
+
+ ret = ili9806e_write_msg_list(ctx, panel_init, NUM_INIT_REGS);
+
+ return ret;
+}
+
+static int ili9806_enable(struct drm_panel *panel)
+{
+ struct ili9806 *ctx = panel_to_ili9806(panel);
+ const struct ili9806e_msg msg = ILI9806_SET_REG(MIPI_DCS_SET_DISPLAY_ON);
+ int ret;
+
+ ret = ili9806_write_msg(ctx, &msg);
+
+ return ret;
+}
+
+static int ili9806_disable(struct drm_panel *panel)
+{
+ struct ili9806 *ctx = panel_to_ili9806(panel);
+ const struct ili9806e_msg msg = ILI9806_SET_REG(MIPI_DCS_SET_DISPLAY_OFF);
+ int ret;
+
+ ret = ili9806_write_msg(ctx, &msg);
+
+ return ret;
+}
+
+static int ili9806_unprepare(struct drm_panel *panel)
+{
+ struct ili9806 *ctx = panel_to_ili9806(panel);
+ const struct ili9806e_msg msg = ILI9806_SET_REG(MIPI_DCS_ENTER_SLEEP_MODE);
+ int ret;
+
+ ret = ili9806_write_msg(ctx, &msg);
+
+ return ret;
+}
+
+static const struct drm_panel_funcs ili9806_drm_funcs = {
+ .disable = ili9806_disable,
+ .enable = ili9806_enable,
+ .get_modes = ili9806_get_modes,
+ .prepare = ili9806_prepare,
+ .unprepare = ili9806_unprepare,
+};
+
+static const struct of_device_id ili9806_of_match[] = {
+ { .compatible = "txw,txw397017s2",
+ .data = (void *)MEDIA_BUS_FMT_RGB888_1X24,
+ }, {
+ .compatible = "pimoroni,hyperpixel4",
+ .data = (void *)MEDIA_BUS_FMT_RGB666_1X24_CPADHI,
+ }, {
+ .compatible = "ilitek,ili9806e",
+ .data = (void *)MEDIA_BUS_FMT_RGB888_1X24,
+ }, {
+ /* sentinel */
+ }
+};
+MODULE_DEVICE_TABLE(of, ili9806_of_match);
+
+static int ili9806_probe(struct spi_device *spi)
+{
+ const struct ili9806e_msg panel_reset[] = {
+ ILI9806_SET_PAGE(0),
+ ILI9806_SET_REG_PARAM(0x01, 0x00)
+ };
+ const struct of_device_id *id;
+ struct ili9806 *ctx;
+ int ret;
+
+ ctx = devm_kzalloc(&spi->dev, sizeof(*ctx), GFP_KERNEL);
+ if (!ctx)
+ return -ENOMEM;
+
+ id = of_match_node(ili9806_of_match, spi->dev.of_node);
+ if (!id)
+ return -ENODEV;
+
+ ctx->bus_format = (u32)id->data;
+
+ spi_set_drvdata(spi, ctx);
+ ctx->spi = spi;
+
+ drm_panel_init(&ctx->panel, &spi->dev, &ili9806_drm_funcs,
+ DRM_MODE_CONNECTOR_DPI);
+
+ ctx->power = devm_regulator_get(&spi->dev, "power");
+ if (IS_ERR(ctx->power))
+ return PTR_ERR(ctx->power);
+
+ ctx->reset = devm_gpiod_get_optional(&spi->dev, "reset", GPIOD_OUT_LOW);
+ if (IS_ERR(ctx->reset)) {
+ dev_err(&spi->dev, "Couldn't get our reset line\n");
+ return PTR_ERR(ctx->reset);
+ }
+
+ /* Soft reset */
+ ili9806e_write_msg_list(ctx, panel_reset, ARRAY_SIZE(panel_reset));
+ msleep(200);
+
+ ret = drm_panel_of_backlight(&ctx->panel);
+ if (ret)
+ return ret;
+
+ drm_panel_add(&ctx->panel);
+
+ return 0;
+}
+
+static int ili9806_remove(struct spi_device *spi)
+{
+ struct ili9806 *ctx = spi_get_drvdata(spi);
+
+ drm_panel_remove(&ctx->panel);
+
+ return 0;
+}
+
+static const struct spi_device_id ili9806_ids[] = {
+ { "txw397017s2", 0 },
+ { "ili9806e", 0 },
+ { "hyperpixel4", 0 },
+ { /* sentinel */ }
+};
+
+MODULE_DEVICE_TABLE(spi, ili9806_ids);
+
+static struct spi_driver ili9806_driver = {
+ .probe = ili9806_probe,
+ .remove = ili9806_remove,
+ .driver = {
+ .name = "ili9806e",
+ .of_match_table = ili9806_of_match,
+ },
+ .id_table = ili9806_ids,
+};
+module_spi_driver(ili9806_driver);
+
+MODULE_AUTHOR("Dave Stevenson <dave.stevenson@raspberrypi.com>");
+MODULE_DESCRIPTION("ili9806 LCD panel driver");
+MODULE_LICENSE("GPL v2");