--- /dev/null
+// 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 <notasas@gmail.com>
+ */
+
+#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 <notasas@gmail.com>");
+MODULE_DESCRIPTION("TPO TD043MTEA1 Panel Driver");
+MODULE_LICENSE("GPL");
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