drm/panel: Add driver for the Toppoly TD043MTEA1 panel

This panel is used on the OMAP3 Pandora.

The code is based on the omapdrm-specific panel-tpo-td043mtea1 driver.

v2:
- fix checkpatch warnings
o (lcd == NULL) => (!lcd) (sam)
o alignment to open '(' (sam)

Signed-off-by: Laurent Pinchart <[e-mail]>
Reviewed-by: Sam Ravnborg <[e-mail]>
Signed-off-by: Sam Ravnborg <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/panel/Kconfig

···
 	  Say Y here if you want to enable support for TPO TD028TTEC1 480x640
 	  2.8" panel (found on the OpenMoko Neo FreeRunner and Neo 1973).
 
+config DRM_PANEL_TPO_TD043MTEA1
+	tristate "Toppoly (TPO) TD043MTEA1 panel driver"
+	depends on GPIOLIB && OF && REGULATOR && SPI
+	help
+	  Say Y here if you want to enable support for TPO TD043MTEA1 800x480
+	  4.3" panel (found on the OMAP3 Pandora board).
+
 config DRM_PANEL_TPO_TPG110
 	tristate "TPO TPG 800x400 panel"
 	depends on OF && SPI && GPIOLIB

drivers/gpu/drm/panel/Makefile

···
 obj-$(CONFIG_DRM_PANEL_SITRONIX_ST7789V) += panel-sitronix-st7789v.o
 obj-$(CONFIG_DRM_PANEL_SONY_ACX565AKM) += panel-sony-acx565akm.o
 obj-$(CONFIG_DRM_PANEL_TPO_TD028TTEC1) += panel-tpo-td028ttec1.o
+obj-$(CONFIG_DRM_PANEL_TPO_TD043MTEA1) += panel-tpo-td043mtea1.o
 obj-$(CONFIG_DRM_PANEL_TPO_TPG110) += panel-tpo-tpg110.o
 obj-$(CONFIG_DRM_PANEL_TRULY_NT35597_WQXGA) += panel-truly-nt35597.o

drivers/gpu/drm/panel/panel-tpo-td028ttec1.c

···
 	int ret;
 
 	lcd = devm_kzalloc(&spi->dev, sizeof(*lcd), GFP_KERNEL);
-	if (lcd == NULL)
+	if (!lcd)
 		return -ENOMEM;
 
 	spi_set_drvdata(spi, lcd);

drivers/gpu/drm/panel/panel-tpo-td043mtea1.c

···
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Toppoly TD043MTEA1 Panel Driver
+ *
+ * Copyright (C) 2019 Texas Instruments Incorporated
+ *
+ * Based on the omapdrm-specific panel-tpo-td043mtea1 driver
+ *
+ * Author: Gražvydas Ignotas <[e-mail]>
+ */
+
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/regulator/consumer.h>
+#include <linux/spi/spi.h>
+
+#include <drm/drm_connector.h>
+#include <drm/drm_modes.h>
+#include <drm/drm_panel.h>
+
+#define TPO_R02_MODE(x)			((x) & 7)
+#define TPO_R02_MODE_800x480		7
+#define TPO_R02_NCLK_RISING		BIT(3)
+#define TPO_R02_HSYNC_HIGH		BIT(4)
+#define TPO_R02_VSYNC_HIGH		BIT(5)
+
+#define TPO_R03_NSTANDBY		BIT(0)
+#define TPO_R03_EN_CP_CLK		BIT(1)
+#define TPO_R03_EN_VGL_PUMP		BIT(2)
+#define TPO_R03_EN_PWM			BIT(3)
+#define TPO_R03_DRIVING_CAP_100		BIT(4)
+#define TPO_R03_EN_PRE_CHARGE		BIT(6)
+#define TPO_R03_SOFTWARE_CTL		BIT(7)
+
+#define TPO_R04_NFLIP_H			BIT(0)
+#define TPO_R04_NFLIP_V			BIT(1)
+#define TPO_R04_CP_CLK_FREQ_1H		BIT(2)
+#define TPO_R04_VGL_FREQ_1H		BIT(4)
+
+#define TPO_R03_VAL_NORMAL \
+	(TPO_R03_NSTANDBY | TPO_R03_EN_CP_CLK | TPO_R03_EN_VGL_PUMP | \
+	 TPO_R03_EN_PWM | TPO_R03_DRIVING_CAP_100 | TPO_R03_EN_PRE_CHARGE | \
+	 TPO_R03_SOFTWARE_CTL)
+
+#define TPO_R03_VAL_STANDBY \
+	(TPO_R03_DRIVING_CAP_100 | TPO_R03_EN_PRE_CHARGE | \
+	 TPO_R03_SOFTWARE_CTL)
+
+static const u16 td043mtea1_def_gamma[12] = {
+	105, 315, 381, 431, 490, 537, 579, 686, 780, 837, 880, 1023
+};
+
+struct td043mtea1_panel {
+	struct drm_panel panel;
+
+	struct spi_device *spi;
+	struct regulator *vcc_reg;
+	struct gpio_desc *reset_gpio;
+
+	unsigned int mode;
+	u16 gamma[12];
+	bool vmirror;
+	bool powered_on;
+	bool spi_suspended;
+	bool power_on_resume;
+};
+
+#define to_td043mtea1_device(p) container_of(p, struct td043mtea1_panel, panel)
+
+/* -----------------------------------------------------------------------------
+ * Hardware Access
+ */
+
+static int td043mtea1_write(struct td043mtea1_panel *lcd, u8 addr, u8 value)
+{
+	struct spi_message msg;
+	struct spi_transfer xfer;
+	u16 data;
+	int ret;
+
+	spi_message_init(&msg);
+
+	memset(&xfer, 0, sizeof(xfer));
+
+	data = ((u16)addr << 10) | (1 << 8) | value;
+	xfer.tx_buf = &data;
+	xfer.bits_per_word = 16;
+	xfer.len = 2;
+	spi_message_add_tail(&xfer, &msg);
+
+	ret = spi_sync(lcd->spi, &msg);
+	if (ret < 0)
+		dev_warn(&lcd->spi->dev, "failed to write to LCD reg (%d)\n",
+			 ret);
+
+	return ret;
+}
+
+static void td043mtea1_write_gamma(struct td043mtea1_panel *lcd)
+{
+	const u16 *gamma = lcd->gamma;
+	unsigned int i;
+	u8 val;
+
+	/* gamma bits [9:8] */
+	for (val = i = 0; i < 4; i++)
+		val |= (gamma[i] & 0x300) >> ((i + 1) * 2);
+	td043mtea1_write(lcd, 0x11, val);
+
+	for (val = i = 0; i < 4; i++)
+		val |= (gamma[i + 4] & 0x300) >> ((i + 1) * 2);
+	td043mtea1_write(lcd, 0x12, val);
+
+	for (val = i = 0; i < 4; i++)
+		val |= (gamma[i + 8] & 0x300) >> ((i + 1) * 2);
+	td043mtea1_write(lcd, 0x13, val);
+
+	/* gamma bits [7:0] */
+	for (val = i = 0; i < 12; i++)
+		td043mtea1_write(lcd, 0x14 + i, gamma[i] & 0xff);
+}
+
+static int td043mtea1_write_mirror(struct td043mtea1_panel *lcd)
+{
+	u8 reg4 = TPO_R04_NFLIP_H | TPO_R04_NFLIP_V |
+		TPO_R04_CP_CLK_FREQ_1H | TPO_R04_VGL_FREQ_1H;
+	if (lcd->vmirror)
+		reg4 &= ~TPO_R04_NFLIP_V;
+
+	return td043mtea1_write(lcd, 4, reg4);
+}
+
+static int td043mtea1_power_on(struct td043mtea1_panel *lcd)
+{
+	int ret;
+
+	if (lcd->powered_on)
+		return 0;
+
+	ret = regulator_enable(lcd->vcc_reg);
+	if (ret < 0)
+		return ret;
+
+	/* Wait for the panel to stabilize. */
+	msleep(160);
+
+	gpiod_set_value(lcd->reset_gpio, 0);
+
+	td043mtea1_write(lcd, 2, TPO_R02_MODE(lcd->mode) | TPO_R02_NCLK_RISING);
+	td043mtea1_write(lcd, 3, TPO_R03_VAL_NORMAL);
+	td043mtea1_write(lcd, 0x20, 0xf0);
+	td043mtea1_write(lcd, 0x21, 0xf0);
+	td043mtea1_write_mirror(lcd);
+	td043mtea1_write_gamma(lcd);
+
+	lcd->powered_on = true;
+
+	return 0;
+}
+
+static void td043mtea1_power_off(struct td043mtea1_panel *lcd)
+{
+	if (!lcd->powered_on)
+		return;
+
+	td043mtea1_write(lcd, 3, TPO_R03_VAL_STANDBY | TPO_R03_EN_PWM);
+
+	gpiod_set_value(lcd->reset_gpio, 1);
+
+	/* wait for at least 2 vsyncs before cutting off power */
+	msleep(50);
+
+	td043mtea1_write(lcd, 3, TPO_R03_VAL_STANDBY);
+
+	regulator_disable(lcd->vcc_reg);
+
+	lcd->powered_on = false;
+}
+
+/* -----------------------------------------------------------------------------
+ * sysfs
+ */
+
+static ssize_t vmirror_show(struct device *dev, struct device_attribute *attr,
+			    char *buf)
+{
+	struct td043mtea1_panel *lcd = dev_get_drvdata(dev);
+
+	return snprintf(buf, PAGE_SIZE, "%d\n", lcd->vmirror);
+}
+
+static ssize_t vmirror_store(struct device *dev, struct device_attribute *attr,
+			     const char *buf, size_t count)
+{
+	struct td043mtea1_panel *lcd = dev_get_drvdata(dev);
+	int val;
+	int ret;
+
+	ret = kstrtoint(buf, 0, &val);
+	if (ret < 0)
+		return ret;
+
+	lcd->vmirror = !!val;
+
+	ret = td043mtea1_write_mirror(lcd);
+	if (ret < 0)
+		return ret;
+
+	return count;
+}
+
+static ssize_t mode_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct td043mtea1_panel *lcd = dev_get_drvdata(dev);
+
+	return snprintf(buf, PAGE_SIZE, "%d\n", lcd->mode);
+}
+
+static ssize_t mode_store(struct device *dev, struct device_attribute *attr,
+			  const char *buf, size_t count)
+{
+	struct td043mtea1_panel *lcd = dev_get_drvdata(dev);
+	long val;
+	int ret;
+
+	ret = kstrtol(buf, 0, &val);
+	if (ret != 0 || val & ~7)
+		return -EINVAL;
+
+	lcd->mode = val;
+
+	val |= TPO_R02_NCLK_RISING;
+	td043mtea1_write(lcd, 2, val);
+
+	return count;
+}
+
+static ssize_t gamma_show(struct device *dev, struct device_attribute *attr,
+			  char *buf)
+{
+	struct td043mtea1_panel *lcd = dev_get_drvdata(dev);
+	ssize_t len = 0;
+	unsigned int i;
+	int ret;
+
+	for (i = 0; i < ARRAY_SIZE(lcd->gamma); i++) {
+		ret = snprintf(buf + len, PAGE_SIZE - len, "%u ",
+			       lcd->gamma[i]);
+		if (ret < 0)
+			return ret;
+		len += ret;
+	}
+	buf[len - 1] = '\n';
+
+	return len;
+}
+
+static ssize_t gamma_store(struct device *dev, struct device_attribute *attr,
+			   const char *buf, size_t count)
+{
+	struct td043mtea1_panel *lcd = dev_get_drvdata(dev);
+	unsigned int g[12];
+	unsigned int i;
+	int ret;
+
+	ret = sscanf(buf, "%u %u %u %u %u %u %u %u %u %u %u %u",
+		     &g[0], &g[1], &g[2], &g[3], &g[4], &g[5],
+		     &g[6], &g[7], &g[8], &g[9], &g[10], &g[11]);
+	if (ret != 12)
+		return -EINVAL;
+
+	for (i = 0; i < 12; i++)
+		lcd->gamma[i] = g[i];
+
+	td043mtea1_write_gamma(lcd);
+
+	return count;
+}
+
+static DEVICE_ATTR_RW(vmirror);
+static DEVICE_ATTR_RW(mode);
+static DEVICE_ATTR_RW(gamma);
+
+static struct attribute *td043mtea1_attrs[] = {
+	&dev_attr_vmirror.attr,
+	&dev_attr_mode.attr,
+	&dev_attr_gamma.attr,
+	NULL,
+};
+
+static const struct attribute_group td043mtea1_attr_group = {
+	.attrs = td043mtea1_attrs,
+};
+
+/* -----------------------------------------------------------------------------
+ * Panel Operations
+ */
+
+static int td043mtea1_unprepare(struct drm_panel *panel)
+{
+	struct td043mtea1_panel *lcd = to_td043mtea1_device(panel);
+
+	if (!lcd->spi_suspended)
+		td043mtea1_power_off(lcd);
+
+	return 0;
+}
+
+static int td043mtea1_prepare(struct drm_panel *panel)
+{
+	struct td043mtea1_panel *lcd = to_td043mtea1_device(panel);
+	int ret;
+
+	/*
+	 * If we are resuming from system suspend, SPI might not be enabled
+	 * yet, so we'll program the LCD from SPI PM resume callback.
+	 */
+	if (lcd->spi_suspended)
+		return 0;
+
+	ret = td043mtea1_power_on(lcd);
+	if (ret) {
+		dev_err(&lcd->spi->dev, "%s: power on failed (%d)\n",
+			__func__, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static const struct drm_display_mode td043mtea1_mode = {
+	.clock = 36000,
+	.hdisplay = 800,
+	.hsync_start = 800 + 68,
+	.hsync_end = 800 + 68 + 1,
+	.htotal = 800 + 68 + 1 + 214,
+	.vdisplay = 480,
+	.vsync_start = 480 + 39,
+	.vsync_end = 480 + 39 + 1,
+	.vtotal = 480 + 39 + 1 + 34,
+	.vrefresh = 60,
+	.type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED,
+	.flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
+	.width_mm = 94,
+	.height_mm = 56,
+};
+
+static int td043mtea1_get_modes(struct drm_panel *panel)
+{
+	struct drm_connector *connector = panel->connector;
+	struct drm_display_mode *mode;
+
+	mode = drm_mode_duplicate(panel->drm, &td043mtea1_mode);
+	if (!mode)
+		return -ENOMEM;
+
+	drm_mode_set_name(mode);
+	drm_mode_probed_add(connector, mode);
+
+	connector->display_info.width_mm = td043mtea1_mode.width_mm;
+	connector->display_info.height_mm = td043mtea1_mode.height_mm;
+	/*
+	 * FIXME: According to the datasheet sync signals are sampled on the
+	 * rising edge of the clock, but the code running on the OMAP3 Pandora
+	 * indicates sampling on the falling edge. This should be tested on a
+	 * real device.
+	 */
+	connector->display_info.bus_flags = DRM_BUS_FLAG_DE_HIGH
+					  | DRM_BUS_FLAG_SYNC_SAMPLE_NEGEDGE
+					  | DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE;
+
+	return 1;
+}
+
+static const struct drm_panel_funcs td043mtea1_funcs = {
+	.unprepare = td043mtea1_unprepare,
+	.prepare = td043mtea1_prepare,
+	.get_modes = td043mtea1_get_modes,
+};
+
+/* -----------------------------------------------------------------------------
+ * Power Management, Probe and Remove
+ */
+
+static int __maybe_unused td043mtea1_suspend(struct device *dev)
+{
+	struct td043mtea1_panel *lcd = dev_get_drvdata(dev);
+
+	if (lcd->powered_on) {
+		td043mtea1_power_off(lcd);
+		lcd->powered_on = true;
+	}
+
+	lcd->spi_suspended = true;
+
+	return 0;
+}
+
+static int __maybe_unused td043mtea1_resume(struct device *dev)
+{
+	struct td043mtea1_panel *lcd = dev_get_drvdata(dev);
+	int ret;
+
+	lcd->spi_suspended = false;
+
+	if (lcd->powered_on) {
+		lcd->powered_on = false;
+		ret = td043mtea1_power_on(lcd);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(td043mtea1_pm_ops, td043mtea1_suspend,
+			 td043mtea1_resume);
+
+static int td043mtea1_probe(struct spi_device *spi)
+{
+	struct td043mtea1_panel *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->mode = TPO_R02_MODE_800x480;
+	memcpy(lcd->gamma, td043mtea1_def_gamma, sizeof(lcd->gamma));
+
+	lcd->vcc_reg = devm_regulator_get(&spi->dev, "vcc");
+	if (IS_ERR(lcd->vcc_reg)) {
+		dev_err(&spi->dev, "failed to get VCC regulator\n");
+		return PTR_ERR(lcd->vcc_reg);
+	}
+
+	lcd->reset_gpio = devm_gpiod_get(&spi->dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(lcd->reset_gpio)) {
+		dev_err(&spi->dev, "failed to get reset GPIO\n");
+		return PTR_ERR(lcd->reset_gpio);
+	}
+
+	spi->bits_per_word = 16;
+	spi->mode = SPI_MODE_0;
+
+	ret = spi_setup(spi);
+	if (ret < 0) {
+		dev_err(&spi->dev, "failed to setup SPI: %d\n", ret);
+		return ret;
+	}
+
+	ret = sysfs_create_group(&spi->dev.kobj, &td043mtea1_attr_group);
+	if (ret < 0) {
+		dev_err(&spi->dev, "failed to create sysfs files\n");
+		return ret;
+	}
+
+	drm_panel_init(&lcd->panel);
+	lcd->panel.dev = &lcd->spi->dev;
+	lcd->panel.funcs = &td043mtea1_funcs;
+
+	ret = drm_panel_add(&lcd->panel);
+	if (ret < 0) {
+		sysfs_remove_group(&spi->dev.kobj, &td043mtea1_attr_group);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int td043mtea1_remove(struct spi_device *spi)
+{
+	struct td043mtea1_panel *lcd = spi_get_drvdata(spi);
+
+	drm_panel_remove(&lcd->panel);
+	drm_panel_disable(&lcd->panel);
+	drm_panel_unprepare(&lcd->panel);
+
+	sysfs_remove_group(&spi->dev.kobj, &td043mtea1_attr_group);
+
+	return 0;
+}
+
+static const struct of_device_id td043mtea1_of_match[] = {
+	{ .compatible = "tpo,td043mtea1", },
+	{ /* sentinel */ },
+};
+
+MODULE_DEVICE_TABLE(of, td043mtea1_of_match);
+
+static struct spi_driver td043mtea1_driver = {
+	.probe		= td043mtea1_probe,
+	.remove		= td043mtea1_remove,
+	.driver		= {
+		.name	= "panel-tpo-td043mtea1",
+		.pm	= &td043mtea1_pm_ops,
+		.of_match_table = td043mtea1_of_match,
+	},
+};
+
+module_spi_driver(td043mtea1_driver);
+
+MODULE_ALIAS("spi:tpo,td043mtea1");
+MODULE_AUTHOR("Gražvydas Ignotas <[e-mail]>");
+MODULE_DESCRIPTION("TPO TD043MTEA1 Panel Driver");
+MODULE_LICENSE("GPL");