// 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 (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 sysfs_emit(buf, "%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 sysfs_emit(buf, "%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,
        .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)
{
        struct drm_display_mode *mode;

        mode = drm_mode_duplicate(connector->dev, &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_drm_panel_alloc(&spi->dev, struct td043mtea1_panel, panel,
                                   &td043mtea1_funcs, DRM_MODE_CONNECTOR_DPI);
        if (IS_ERR(lcd))
                return PTR_ERR(lcd);

        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))
                return dev_err_probe(&spi->dev, PTR_ERR(lcd->vcc_reg),
                                     "failed to get VCC regulator\n");

        lcd->reset_gpio = devm_gpiod_get(&spi->dev, "reset", GPIOD_OUT_HIGH);
        if (IS_ERR(lcd->reset_gpio))
                return dev_err_probe(&spi->dev, PTR_ERR(lcd->reset_gpio),
                                     "failed to get reset GPIO\n");

        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_add(&lcd->panel);

        return 0;
}

static void 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);
}

static const struct of_device_id td043mtea1_of_match[] = {
        { .compatible = "tpo,td043mtea1", },
        { /* sentinel */ },
};

MODULE_DEVICE_TABLE(of, td043mtea1_of_match);

static const struct spi_device_id td043mtea1_ids[] = {
        { "td043mtea1", 0 },
        { /* sentinel */ }
};

MODULE_DEVICE_TABLE(spi, td043mtea1_ids);

static struct spi_driver td043mtea1_driver = {
        .probe          = td043mtea1_probe,
        .remove         = td043mtea1_remove,
        .id_table       = td043mtea1_ids,
        .driver         = {
                .name   = "panel-tpo-td043mtea1",
                .pm     = &td043mtea1_pm_ops,
                .of_match_table = td043mtea1_of_match,
        },
};

module_spi_driver(td043mtea1_driver);

MODULE_AUTHOR("Gražvydas Ignotas <notasas@gmail.com>");
MODULE_DESCRIPTION("TPO TD043MTEA1 Panel Driver");
MODULE_LICENSE("GPL");