// SPDX-License-Identifier: GPL-2.0
/*
 * Sony ACX565AKM LCD Panel driver
 *
 * Copyright (C) 2019 Texas Instruments Incorporated
 *
 * Based on the omapdrm-specific panel-sony-acx565akm driver
 *
 * Copyright (C) 2010 Nokia Corporation
 * Author: Imre Deak <imre.deak@nokia.com>
 */

/*
 * TODO (to be addressed with hardware access to test the changes):
 *
 * - Update backlight support to use backlight_update_status() etc.
 * - Use prepare/unprepare for the basic power on/off of the backligt
 */

#include <linux/backlight.h>
#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/jiffies.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/sched.h>
#include <linux/spi/spi.h>
#include <video/mipi_display.h>

#include <drm/drm_connector.h>
#include <drm/drm_modes.h>
#include <drm/drm_panel.h>

#define CTRL_DISP_BRIGHTNESS_CTRL_ON            BIT(5)
#define CTRL_DISP_AMBIENT_LIGHT_CTRL_ON         BIT(4)
#define CTRL_DISP_BACKLIGHT_ON                  BIT(2)
#define CTRL_DISP_AUTO_BRIGHTNESS_ON            BIT(1)

#define MIPID_CMD_WRITE_CABC            0x55
#define MIPID_CMD_READ_CABC             0x56

#define MIPID_VER_LPH8923               3
#define MIPID_VER_LS041Y3               4
#define MIPID_VER_L4F00311              8
#define MIPID_VER_ACX565AKM             9

struct acx565akm_panel {
        struct drm_panel panel;

        struct spi_device *spi;
        struct gpio_desc *reset_gpio;
        struct backlight_device *backlight;

        struct mutex mutex;

        const char *name;
        u8 display_id[3];
        int model;
        int revision;
        bool has_bc;
        bool has_cabc;

        bool enabled;
        unsigned int cabc_mode;
        /*
         * Next value of jiffies when we can issue the next sleep in/out
         * command.
         */
        unsigned long hw_guard_end;
        unsigned long hw_guard_wait;            /* max guard time in jiffies */
};

#define to_acx565akm_device(p) container_of(p, struct acx565akm_panel, panel)

static void acx565akm_transfer(struct acx565akm_panel *lcd, int cmd,
                              const u8 *wbuf, int wlen, u8 *rbuf, int rlen)
{
        struct spi_message      m;
        struct spi_transfer     *x, xfer[5];
        int                     ret;

        spi_message_init(&m);

        memset(xfer, 0, sizeof(xfer));
        x = &xfer[0];

        cmd &=  0xff;
        x->tx_buf = &cmd;
        x->bits_per_word = 9;
        x->len = 2;

        if (rlen > 1 && wlen == 0) {
                /*
                 * Between the command and the response data there is a
                 * dummy clock cycle. Add an extra bit after the command
                 * word to account for this.
                 */
                x->bits_per_word = 10;
                cmd <<= 1;
        }
        spi_message_add_tail(x, &m);

        if (wlen) {
                x++;
                x->tx_buf = wbuf;
                x->len = wlen;
                x->bits_per_word = 9;
                spi_message_add_tail(x, &m);
        }

        if (rlen) {
                x++;
                x->rx_buf       = rbuf;
                x->len          = rlen;
                spi_message_add_tail(x, &m);
        }

        ret = spi_sync(lcd->spi, &m);
        if (ret < 0)
                dev_dbg(&lcd->spi->dev, "spi_sync %d\n", ret);
}

static inline void acx565akm_cmd(struct acx565akm_panel *lcd, int cmd)
{
        acx565akm_transfer(lcd, cmd, NULL, 0, NULL, 0);
}

static inline void acx565akm_write(struct acx565akm_panel *lcd,
                               int reg, const u8 *buf, int len)
{
        acx565akm_transfer(lcd, reg, buf, len, NULL, 0);
}

static inline void acx565akm_read(struct acx565akm_panel *lcd,
                              int reg, u8 *buf, int len)
{
        acx565akm_transfer(lcd, reg, NULL, 0, buf, len);
}

/* -----------------------------------------------------------------------------
 * Auto Brightness Control Via sysfs
 */

static unsigned int acx565akm_get_cabc_mode(struct acx565akm_panel *lcd)
{
        return lcd->cabc_mode;
}

static void acx565akm_set_cabc_mode(struct acx565akm_panel *lcd,
                                    unsigned int mode)
{
        u16 cabc_ctrl;

        lcd->cabc_mode = mode;
        if (!lcd->enabled)
                return;
        cabc_ctrl = 0;
        acx565akm_read(lcd, MIPID_CMD_READ_CABC, (u8 *)&cabc_ctrl, 1);
        cabc_ctrl &= ~3;
        cabc_ctrl |= (1 << 8) | (mode & 3);
        acx565akm_write(lcd, MIPID_CMD_WRITE_CABC, (u8 *)&cabc_ctrl, 2);
}

static unsigned int acx565akm_get_hw_cabc_mode(struct acx565akm_panel *lcd)
{
        u8 cabc_ctrl;

        acx565akm_read(lcd, MIPID_CMD_READ_CABC, &cabc_ctrl, 1);
        return cabc_ctrl & 3;
}

static const char * const acx565akm_cabc_modes[] = {
        "off",          /* always used when CABC is not supported */
        "ui",
        "still-image",
        "moving-image",
};

static ssize_t cabc_mode_show(struct device *dev,
                              struct device_attribute *attr,
                              char *buf)
{
        struct acx565akm_panel *lcd = dev_get_drvdata(dev);
        const char *mode_str;
        int mode;

        if (!lcd->has_cabc)
                mode = 0;
        else
                mode = acx565akm_get_cabc_mode(lcd);

        mode_str = "unknown";
        if (mode >= 0 && mode < ARRAY_SIZE(acx565akm_cabc_modes))
                mode_str = acx565akm_cabc_modes[mode];

        return sprintf(buf, "%s\n", mode_str);
}

static ssize_t cabc_mode_store(struct device *dev,
                               struct device_attribute *attr,
                               const char *buf, size_t count)
{
        struct acx565akm_panel *lcd = dev_get_drvdata(dev);
        unsigned int i;

        for (i = 0; i < ARRAY_SIZE(acx565akm_cabc_modes); i++) {
                const char *mode_str = acx565akm_cabc_modes[i];
                int cmp_len = strlen(mode_str);

                if (count > 0 && buf[count - 1] == '\n')
                        count--;
                if (count != cmp_len)
                        continue;

                if (strncmp(buf, mode_str, cmp_len) == 0)
                        break;
        }

        if (i == ARRAY_SIZE(acx565akm_cabc_modes))
                return -EINVAL;

        if (!lcd->has_cabc && i != 0)
                return -EINVAL;

        mutex_lock(&lcd->mutex);
        acx565akm_set_cabc_mode(lcd, i);
        mutex_unlock(&lcd->mutex);

        return count;
}

static ssize_t cabc_available_modes_show(struct device *dev,
                                         struct device_attribute *attr,
                                         char *buf)
{
        struct acx565akm_panel *lcd = dev_get_drvdata(dev);
        unsigned int i;
        size_t len = 0;

        if (!lcd->has_cabc)
                return sprintf(buf, "%s\n", acx565akm_cabc_modes[0]);

        for (i = 0; i < ARRAY_SIZE(acx565akm_cabc_modes); i++)
                len += sprintf(&buf[len], "%s%s", i ? " " : "",
                               acx565akm_cabc_modes[i]);

        buf[len++] = '\n';

        return len;
}

static DEVICE_ATTR_RW(cabc_mode);
static DEVICE_ATTR_RO(cabc_available_modes);

static struct attribute *acx565akm_cabc_attrs[] = {
        &dev_attr_cabc_mode.attr,
        &dev_attr_cabc_available_modes.attr,
        NULL,
};

static const struct attribute_group acx565akm_cabc_attr_group = {
        .attrs = acx565akm_cabc_attrs,
};

/* -----------------------------------------------------------------------------
 * Backlight Device
 */

static int acx565akm_get_actual_brightness(struct acx565akm_panel *lcd)
{
        u8 bv;

        acx565akm_read(lcd, MIPI_DCS_GET_DISPLAY_BRIGHTNESS, &bv, 1);

        return bv;
}

static void acx565akm_set_brightness(struct acx565akm_panel *lcd, int level)
{
        u16 ctrl;
        int bv;

        bv = level | (1 << 8);
        acx565akm_write(lcd, MIPI_DCS_SET_DISPLAY_BRIGHTNESS, (u8 *)&bv, 2);

        acx565akm_read(lcd, MIPI_DCS_GET_CONTROL_DISPLAY, (u8 *)&ctrl, 1);
        if (level)
                ctrl |= CTRL_DISP_BRIGHTNESS_CTRL_ON |
                        CTRL_DISP_BACKLIGHT_ON;
        else
                ctrl &= ~(CTRL_DISP_BRIGHTNESS_CTRL_ON |
                          CTRL_DISP_BACKLIGHT_ON);

        ctrl |= 1 << 8;
        acx565akm_write(lcd, MIPI_DCS_WRITE_CONTROL_DISPLAY, (u8 *)&ctrl, 2);
}

static int acx565akm_bl_update_status_locked(struct backlight_device *dev)
{
        struct acx565akm_panel *lcd = dev_get_drvdata(&dev->dev);
        int level = backlight_get_brightness(dev);

        acx565akm_set_brightness(lcd, level);

        return 0;
}

static int acx565akm_bl_update_status(struct backlight_device *dev)
{
        struct acx565akm_panel *lcd = dev_get_drvdata(&dev->dev);
        int ret;

        mutex_lock(&lcd->mutex);
        ret = acx565akm_bl_update_status_locked(dev);
        mutex_unlock(&lcd->mutex);

        return ret;
}

static int acx565akm_bl_get_intensity(struct backlight_device *dev)
{
        struct acx565akm_panel *lcd = dev_get_drvdata(&dev->dev);
        unsigned int intensity;

        mutex_lock(&lcd->mutex);

        if (!backlight_is_blank(dev))
                intensity = acx565akm_get_actual_brightness(lcd);
        else
                intensity = 0;

        mutex_unlock(&lcd->mutex);

        return intensity;
}

static const struct backlight_ops acx565akm_bl_ops = {
        .get_brightness = acx565akm_bl_get_intensity,
        .update_status  = acx565akm_bl_update_status,
};

static int acx565akm_backlight_init(struct acx565akm_panel *lcd)
{
        struct backlight_properties props = {
                .power = BACKLIGHT_POWER_ON,
                .type = BACKLIGHT_RAW,
        };
        int ret;

        lcd->backlight = backlight_device_register(lcd->name, &lcd->spi->dev,
                                                   lcd, &acx565akm_bl_ops,
                                                   &props);
        if (IS_ERR(lcd->backlight)) {
                ret = PTR_ERR(lcd->backlight);
                lcd->backlight = NULL;
                return ret;
        }

        if (lcd->has_cabc) {
                ret = sysfs_create_group(&lcd->backlight->dev.kobj,
                                         &acx565akm_cabc_attr_group);
                if (ret < 0) {
                        dev_err(&lcd->spi->dev,
                                "%s failed to create sysfs files\n", __func__);
                        backlight_device_unregister(lcd->backlight);
                        return ret;
                }

                lcd->cabc_mode = acx565akm_get_hw_cabc_mode(lcd);
        }

        lcd->backlight->props.max_brightness = 255;
        lcd->backlight->props.brightness = acx565akm_get_actual_brightness(lcd);

        acx565akm_bl_update_status_locked(lcd->backlight);

        return 0;
}

static void acx565akm_backlight_cleanup(struct acx565akm_panel *lcd)
{
        if (lcd->has_cabc)
                sysfs_remove_group(&lcd->backlight->dev.kobj,
                                   &acx565akm_cabc_attr_group);

        backlight_device_unregister(lcd->backlight);
}

/* -----------------------------------------------------------------------------
 * DRM Bridge Operations
 */

static void acx565akm_set_sleep_mode(struct acx565akm_panel *lcd, int on)
{
        int cmd = on ? MIPI_DCS_ENTER_SLEEP_MODE : MIPI_DCS_EXIT_SLEEP_MODE;
        unsigned long wait;

        /*
         * We have to keep 120msec between sleep in/out commands.
         * (8.2.15, 8.2.16).
         */
        wait = lcd->hw_guard_end - jiffies;
        if ((long)wait > 0 && wait <= lcd->hw_guard_wait) {
                set_current_state(TASK_UNINTERRUPTIBLE);
                schedule_timeout(wait);
        }

        acx565akm_cmd(lcd, cmd);

        lcd->hw_guard_wait = msecs_to_jiffies(120);
        lcd->hw_guard_end = jiffies + lcd->hw_guard_wait;
}

static void acx565akm_set_display_state(struct acx565akm_panel *lcd,
                                        int enabled)
{
        int cmd = enabled ? MIPI_DCS_SET_DISPLAY_ON : MIPI_DCS_SET_DISPLAY_OFF;

        acx565akm_cmd(lcd, cmd);
}

static int acx565akm_power_on(struct acx565akm_panel *lcd)
{
        /*FIXME tweak me */
        msleep(50);

        gpiod_set_value(lcd->reset_gpio, 1);

        if (lcd->enabled) {
                dev_dbg(&lcd->spi->dev, "panel already enabled\n");
                return 0;
        }

        /*
         * We have to meet all the following delay requirements:
         * 1. tRW: reset pulse width 10usec (7.12.1)
         * 2. tRT: reset cancel time 5msec (7.12.1)
         * 3. Providing PCLK,HS,VS signals for 2 frames = ~50msec worst
         *    case (7.6.2)
         * 4. 120msec before the sleep out command (7.12.1)
         */
        msleep(120);

        acx565akm_set_sleep_mode(lcd, 0);
        lcd->enabled = true;

        /* 5msec between sleep out and the next command. (8.2.16) */
        usleep_range(5000, 10000);
        acx565akm_set_display_state(lcd, 1);
        acx565akm_set_cabc_mode(lcd, lcd->cabc_mode);

        return acx565akm_bl_update_status_locked(lcd->backlight);
}

static void acx565akm_power_off(struct acx565akm_panel *lcd)
{
        acx565akm_set_display_state(lcd, 0);
        acx565akm_set_sleep_mode(lcd, 1);
        lcd->enabled = false;
        /*
         * We have to provide PCLK,HS,VS signals for 2 frames (worst case
         * ~50msec) after sending the sleep in command and asserting the
         * reset signal. We probably could assert the reset w/o the delay
         * but we still delay to avoid possible artifacts. (7.6.1)
         */
        msleep(50);

        gpiod_set_value(lcd->reset_gpio, 0);

        /* FIXME need to tweak this delay */
        msleep(100);
}

static int acx565akm_disable(struct drm_panel *panel)
{
        struct acx565akm_panel *lcd = to_acx565akm_device(panel);

        mutex_lock(&lcd->mutex);
        acx565akm_power_off(lcd);
        mutex_unlock(&lcd->mutex);

        return 0;
}

static int acx565akm_enable(struct drm_panel *panel)
{
        struct acx565akm_panel *lcd = to_acx565akm_device(panel);

        mutex_lock(&lcd->mutex);
        acx565akm_power_on(lcd);
        mutex_unlock(&lcd->mutex);

        return 0;
}

static const struct drm_display_mode acx565akm_mode = {
        .clock = 24000,
        .hdisplay = 800,
        .hsync_start = 800 + 28,
        .hsync_end = 800 + 28 + 4,
        .htotal = 800 + 28 + 4 + 24,
        .vdisplay = 480,
        .vsync_start = 480 + 3,
        .vsync_end = 480 + 3 + 3,
        .vtotal = 480 + 3 + 3 + 4,
        .type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED,
        .flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
        .width_mm = 77,
        .height_mm = 46,
};

static int acx565akm_get_modes(struct drm_panel *panel,
                               struct drm_connector *connector)
{
        struct drm_display_mode *mode;

        mode = drm_mode_duplicate(connector->dev, &acx565akm_mode);
        if (!mode)
                return -ENOMEM;

        drm_mode_set_name(mode);
        drm_mode_probed_add(connector, mode);

        connector->display_info.width_mm = acx565akm_mode.width_mm;
        connector->display_info.height_mm = acx565akm_mode.height_mm;
        connector->display_info.bus_flags = DRM_BUS_FLAG_DE_HIGH
                                          | DRM_BUS_FLAG_SYNC_SAMPLE_POSEDGE
                                          | DRM_BUS_FLAG_PIXDATA_SAMPLE_NEGEDGE;

        return 1;
}

static const struct drm_panel_funcs acx565akm_funcs = {
        .disable = acx565akm_disable,
        .enable = acx565akm_enable,
        .get_modes = acx565akm_get_modes,
};

/* -----------------------------------------------------------------------------
 * Probe, Detect and Remove
 */

static int acx565akm_detect(struct acx565akm_panel *lcd)
{
        __be32 value;
        u32 status;
        int ret = 0;

        /*
         * After being taken out of reset the panel needs 5ms before the first
         * command can be sent.
         */
        gpiod_set_value(lcd->reset_gpio, 1);
        usleep_range(5000, 10000);

        acx565akm_read(lcd, MIPI_DCS_GET_DISPLAY_STATUS, (u8 *)&value, 4);
        status = __be32_to_cpu(value);
        lcd->enabled = (status & (1 << 17)) && (status & (1 << 10));

        dev_dbg(&lcd->spi->dev,
                "LCD panel %s by bootloader (status 0x%04x)\n",
                lcd->enabled ? "enabled" : "disabled ", status);

        acx565akm_read(lcd, MIPI_DCS_GET_DISPLAY_ID, lcd->display_id, 3);
        dev_dbg(&lcd->spi->dev, "MIPI display ID: %3phN\n", lcd->display_id);

        switch (lcd->display_id[0]) {
        case 0x10:
                lcd->model = MIPID_VER_ACX565AKM;
                lcd->name = "acx565akm";
                lcd->has_bc = 1;
                lcd->has_cabc = 1;
                break;
        case 0x29:
                lcd->model = MIPID_VER_L4F00311;
                lcd->name = "l4f00311";
                break;
        case 0x45:
                lcd->model = MIPID_VER_LPH8923;
                lcd->name = "lph8923";
                break;
        case 0x83:
                lcd->model = MIPID_VER_LS041Y3;
                lcd->name = "ls041y3";
                break;
        default:
                lcd->name = "unknown";
                dev_err(&lcd->spi->dev, "unknown display ID\n");
                ret = -ENODEV;
                goto done;
        }

        lcd->revision = lcd->display_id[1];

        dev_info(&lcd->spi->dev, "%s rev %02x panel detected\n",
                 lcd->name, lcd->revision);

done:
        if (!lcd->enabled)
                gpiod_set_value(lcd->reset_gpio, 0);

        return ret;
}

static int acx565akm_probe(struct spi_device *spi)
{
        struct acx565akm_panel *lcd;
        int ret;

        lcd = devm_drm_panel_alloc(&spi->dev, struct acx565akm_panel, panel,
                                   &acx565akm_funcs, DRM_MODE_CONNECTOR_DPI);
        if (IS_ERR(lcd))
                return PTR_ERR(lcd);

        spi_set_drvdata(spi, lcd);
        spi->mode = SPI_MODE_3;

        lcd->spi = spi;
        mutex_init(&lcd->mutex);

        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);
        }

        ret = acx565akm_detect(lcd);
        if (ret < 0) {
                dev_err(&spi->dev, "panel detection failed\n");
                return ret;
        }

        if (lcd->has_bc) {
                ret = acx565akm_backlight_init(lcd);
                if (ret < 0)
                        return ret;
        }

        drm_panel_add(&lcd->panel);

        return 0;
}

static void acx565akm_remove(struct spi_device *spi)
{
        struct acx565akm_panel *lcd = spi_get_drvdata(spi);

        drm_panel_remove(&lcd->panel);

        if (lcd->has_bc)
                acx565akm_backlight_cleanup(lcd);
}

static const struct of_device_id acx565akm_of_match[] = {
        { .compatible = "sony,acx565akm", },
        { /* sentinel */ },
};

MODULE_DEVICE_TABLE(of, acx565akm_of_match);

static const struct spi_device_id acx565akm_ids[] = {
        { "acx565akm", 0 },
        { /* sentinel */ }
};

MODULE_DEVICE_TABLE(spi, acx565akm_ids);

static struct spi_driver acx565akm_driver = {
        .probe          = acx565akm_probe,
        .remove         = acx565akm_remove,
        .id_table       = acx565akm_ids,
        .driver         = {
                .name   = "panel-sony-acx565akm",
                .of_match_table = acx565akm_of_match,
        },
};

module_spi_driver(acx565akm_driver);

MODULE_AUTHOR("Nokia Corporation");
MODULE_DESCRIPTION("Sony ACX565AKM LCD Panel Driver");
MODULE_LICENSE("GPL");