// SPDX-License-Identifier: GPL-2.0-only
/*
 * TI LP855x Backlight Driver
 *
 *                      Copyright (C) 2011 Texas Instruments
 */

#include <linux/acpi.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/backlight.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/of.h>
#include <linux/platform_data/lp855x.h>
#include <linux/pwm.h>
#include <linux/regulator/consumer.h>

/* LP8550/1/2/3/6 Registers */
#define LP855X_BRIGHTNESS_CTRL          0x00
#define LP855X_DEVICE_CTRL              0x01
#define LP855X_EEPROM_START             0xA0
#define LP855X_EEPROM_END               0xA7
#define LP8556_EPROM_START              0x98
#define LP8556_EPROM_END                0xAF

/* LP8555/7 Registers */
#define LP8557_BL_CMD                   0x00
#define LP8557_BL_MASK                  0x01
#define LP8557_BL_ON                    0x01
#define LP8557_BL_OFF                   0x00
#define LP8557_BRIGHTNESS_CTRL          0x04
#define LP8557_CONFIG                   0x10
#define LP8555_EPROM_START              0x10
#define LP8555_EPROM_END                0x7A
#define LP8557_EPROM_START              0x10
#define LP8557_EPROM_END                0x1E

#define DEFAULT_BL_NAME         "lcd-backlight"
#define MAX_BRIGHTNESS          255

enum lp855x_brightness_ctrl_mode {
        PWM_BASED = 1,
        REGISTER_BASED,
};

struct lp855x;

/*
 * struct lp855x_device_config
 * @pre_init_device: init device function call before updating the brightness
 * @reg_brightness: register address for brigthenss control
 * @reg_devicectrl: register address for device control
 * @post_init_device: late init device function call
 */
struct lp855x_device_config {
        int (*pre_init_device)(struct lp855x *);
        u8 reg_brightness;
        u8 reg_devicectrl;
        int (*post_init_device)(struct lp855x *);
};

struct lp855x {
        const char *chipname;
        enum lp855x_chip_id chip_id;
        enum lp855x_brightness_ctrl_mode mode;
        struct lp855x_device_config *cfg;
        struct i2c_client *client;
        struct backlight_device *bl;
        struct device *dev;
        struct lp855x_platform_data *pdata;
        struct pwm_device *pwm;
        bool needs_pwm_init;
        struct regulator *supply;       /* regulator for VDD input */
        struct regulator *enable;       /* regulator for EN/VDDIO input */
};

static int lp855x_write_byte(struct lp855x *lp, u8 reg, u8 data)
{
        return i2c_smbus_write_byte_data(lp->client, reg, data);
}

static int lp855x_update_bit(struct lp855x *lp, u8 reg, u8 mask, u8 data)
{
        int ret;
        u8 tmp;

        ret = i2c_smbus_read_byte_data(lp->client, reg);
        if (ret < 0) {
                dev_err(lp->dev, "failed to read 0x%.2x\n", reg);
                return ret;
        }

        tmp = (u8)ret;
        tmp &= ~mask;
        tmp |= data & mask;

        return lp855x_write_byte(lp, reg, tmp);
}

static bool lp855x_is_valid_rom_area(struct lp855x *lp, u8 addr)
{
        u8 start, end;

        switch (lp->chip_id) {
        case LP8550:
        case LP8551:
        case LP8552:
        case LP8553:
                start = LP855X_EEPROM_START;
                end = LP855X_EEPROM_END;
                break;
        case LP8556:
                start = LP8556_EPROM_START;
                end = LP8556_EPROM_END;
                break;
        case LP8555:
                start = LP8555_EPROM_START;
                end = LP8555_EPROM_END;
                break;
        case LP8557:
                start = LP8557_EPROM_START;
                end = LP8557_EPROM_END;
                break;
        default:
                return false;
        }

        return addr >= start && addr <= end;
}

static int lp8557_bl_off(struct lp855x *lp)
{
        /* BL_ON = 0 before updating EPROM settings */
        return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK,
                                LP8557_BL_OFF);
}

static int lp8557_bl_on(struct lp855x *lp)
{
        /* BL_ON = 1 after updating EPROM settings */
        return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK,
                                LP8557_BL_ON);
}

static struct lp855x_device_config lp855x_dev_cfg = {
        .reg_brightness = LP855X_BRIGHTNESS_CTRL,
        .reg_devicectrl = LP855X_DEVICE_CTRL,
};

static struct lp855x_device_config lp8557_dev_cfg = {
        .reg_brightness = LP8557_BRIGHTNESS_CTRL,
        .reg_devicectrl = LP8557_CONFIG,
        .pre_init_device = lp8557_bl_off,
        .post_init_device = lp8557_bl_on,
};

/*
 * Device specific configuration flow
 *
 *    a) pre_init_device(optional)
 *    b) update the brightness register
 *    c) update device control register
 *    d) update ROM area(optional)
 *    e) post_init_device(optional)
 *
 */
static int lp855x_configure(struct lp855x *lp)
{
        u8 val, addr;
        int i, ret;
        struct lp855x_platform_data *pd = lp->pdata;

        if (lp->cfg->pre_init_device) {
                ret = lp->cfg->pre_init_device(lp);
                if (ret) {
                        dev_err(lp->dev, "pre init device err: %d\n", ret);
                        goto err;
                }
        }

        val = pd->initial_brightness;
        ret = lp855x_write_byte(lp, lp->cfg->reg_brightness, val);
        if (ret)
                goto err;

        val = pd->device_control;
        ret = lp855x_write_byte(lp, lp->cfg->reg_devicectrl, val);
        if (ret)
                goto err;

        if (pd->size_program > 0) {
                for (i = 0; i < pd->size_program; i++) {
                        addr = pd->rom_data[i].addr;
                        val = pd->rom_data[i].val;
                        if (!lp855x_is_valid_rom_area(lp, addr))
                                continue;

                        ret = lp855x_write_byte(lp, addr, val);
                        if (ret)
                                goto err;
                }
        }

        if (lp->cfg->post_init_device) {
                ret = lp->cfg->post_init_device(lp);
                if (ret) {
                        dev_err(lp->dev, "post init device err: %d\n", ret);
                        goto err;
                }
        }

        return 0;

err:
        return ret;
}

static int lp855x_pwm_ctrl(struct lp855x *lp, int br, int max_br)
{
        struct pwm_state state;

        if (lp->needs_pwm_init) {
                pwm_init_state(lp->pwm, &state);
                /* Legacy platform data compatibility */
                if (lp->pdata->period_ns > 0)
                        state.period = lp->pdata->period_ns;
                lp->needs_pwm_init = false;
        } else {
                pwm_get_state(lp->pwm, &state);
        }

        state.duty_cycle = div_u64(br * state.period, max_br);
        state.enabled = state.duty_cycle;

        return pwm_apply_might_sleep(lp->pwm, &state);
}

static int lp855x_bl_update_status(struct backlight_device *bl)
{
        struct lp855x *lp = bl_get_data(bl);
        int brightness = bl->props.brightness;

        if (bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
                brightness = 0;

        if (lp->mode == PWM_BASED)
                return lp855x_pwm_ctrl(lp, brightness,
                                      bl->props.max_brightness);
        else if (lp->mode == REGISTER_BASED)
                return lp855x_write_byte(lp, lp->cfg->reg_brightness,
                                        (u8)brightness);
        return -EINVAL;
}

static const struct backlight_ops lp855x_bl_ops = {
        .options = BL_CORE_SUSPENDRESUME,
        .update_status = lp855x_bl_update_status,
};

static int lp855x_backlight_register(struct lp855x *lp)
{
        struct backlight_device *bl;
        struct backlight_properties props;
        struct lp855x_platform_data *pdata = lp->pdata;
        const char *name = pdata->name ? : DEFAULT_BL_NAME;

        memset(&props, 0, sizeof(props));
        props.type = BACKLIGHT_PLATFORM;
        props.max_brightness = MAX_BRIGHTNESS;

        if (pdata->initial_brightness > props.max_brightness)
                pdata->initial_brightness = props.max_brightness;

        props.brightness = pdata->initial_brightness;

        bl = devm_backlight_device_register(lp->dev, name, lp->dev, lp,
                                       &lp855x_bl_ops, &props);
        if (IS_ERR(bl))
                return PTR_ERR(bl);

        lp->bl = bl;

        return 0;
}

static ssize_t lp855x_get_chip_id(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        struct lp855x *lp = dev_get_drvdata(dev);

        return scnprintf(buf, PAGE_SIZE, "%s\n", lp->chipname);
}

static ssize_t lp855x_get_bl_ctl_mode(struct device *dev,
                                     struct device_attribute *attr, char *buf)
{
        struct lp855x *lp = dev_get_drvdata(dev);
        char *strmode = NULL;

        if (lp->mode == PWM_BASED)
                strmode = "pwm based";
        else if (lp->mode == REGISTER_BASED)
                strmode = "register based";

        return scnprintf(buf, PAGE_SIZE, "%s\n", strmode);
}

static DEVICE_ATTR(chip_id, S_IRUGO, lp855x_get_chip_id, NULL);
static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp855x_get_bl_ctl_mode, NULL);

static struct attribute *lp855x_attributes[] = {
        &dev_attr_chip_id.attr,
        &dev_attr_bl_ctl_mode.attr,
        NULL,
};

static const struct attribute_group lp855x_attr_group = {
        .attrs = lp855x_attributes,
};

#ifdef CONFIG_OF
static int lp855x_parse_dt(struct lp855x *lp)
{
        struct device *dev = lp->dev;
        struct device_node *node = dev->of_node;
        struct lp855x_platform_data *pdata = lp->pdata;
        int rom_length;

        if (!node) {
                dev_err(dev, "no platform data\n");
                return -EINVAL;
        }

        of_property_read_string(node, "bl-name", &pdata->name);
        of_property_read_u8(node, "dev-ctrl", &pdata->device_control);
        of_property_read_u8(node, "init-brt", &pdata->initial_brightness);
        /* Deprecated, specify period in pwms property instead */
        of_property_read_u32(node, "pwm-period", &pdata->period_ns);

        /* Fill ROM platform data if defined */
        rom_length = of_get_child_count(node);
        if (rom_length > 0) {
                struct lp855x_rom_data *rom;
                struct device_node *child;
                int i = 0;

                rom = devm_kcalloc(dev, rom_length, sizeof(*rom), GFP_KERNEL);
                if (!rom)
                        return -ENOMEM;

                for_each_child_of_node(node, child) {
                        of_property_read_u8(child, "rom-addr", &rom[i].addr);
                        of_property_read_u8(child, "rom-val", &rom[i].val);
                        i++;
                }

                pdata->size_program = rom_length;
                pdata->rom_data = &rom[0];
        }

        return 0;
}
#else
static int lp855x_parse_dt(struct lp855x *lp)
{
        return -EINVAL;
}
#endif

static int lp855x_parse_acpi(struct lp855x *lp)
{
        int ret;

        /*
         * On ACPI the device has already been initialized by the firmware
         * and is in register mode, so we can read back the settings from
         * the registers.
         */
        ret = i2c_smbus_read_byte_data(lp->client, lp->cfg->reg_brightness);
        if (ret < 0)
                return ret;

        lp->pdata->initial_brightness = ret;

        ret = i2c_smbus_read_byte_data(lp->client, lp->cfg->reg_devicectrl);
        if (ret < 0)
                return ret;

        lp->pdata->device_control = ret;
        return 0;
}

static int lp855x_probe(struct i2c_client *cl)
{
        const struct i2c_device_id *id = i2c_client_get_device_id(cl);
        const struct acpi_device_id *acpi_id = NULL;
        struct device *dev = &cl->dev;
        struct lp855x *lp;
        int ret;

        if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
                return -EIO;

        lp = devm_kzalloc(dev, sizeof(struct lp855x), GFP_KERNEL);
        if (!lp)
                return -ENOMEM;

        lp->client = cl;
        lp->dev = dev;
        lp->pdata = dev_get_platdata(dev);

        if (id) {
                lp->chipname = id->name;
                lp->chip_id = id->driver_data;
        } else {
                acpi_id = acpi_match_device(dev->driver->acpi_match_table, dev);
                if (!acpi_id)
                        return -ENODEV;

                lp->chipname = acpi_id->id;
                lp->chip_id = acpi_id->driver_data;
        }

        switch (lp->chip_id) {
        case LP8550:
        case LP8551:
        case LP8552:
        case LP8553:
        case LP8556:
                lp->cfg = &lp855x_dev_cfg;
                break;
        case LP8555:
        case LP8557:
                lp->cfg = &lp8557_dev_cfg;
                break;
        default:
                return -EINVAL;
        }

        if (!lp->pdata) {
                lp->pdata = devm_kzalloc(dev, sizeof(*lp->pdata), GFP_KERNEL);
                if (!lp->pdata)
                        return -ENOMEM;

                if (id) {
                        ret = lp855x_parse_dt(lp);
                        if (ret < 0)
                                return ret;
                } else {
                        ret = lp855x_parse_acpi(lp);
                        if (ret < 0)
                                return ret;
                }
        }

        lp->supply = devm_regulator_get(dev, "power");
        if (IS_ERR(lp->supply)) {
                if (PTR_ERR(lp->supply) == -EPROBE_DEFER)
                        return -EPROBE_DEFER;
                lp->supply = NULL;
        }

        lp->enable = devm_regulator_get_optional(dev, "enable");
        if (IS_ERR(lp->enable)) {
                ret = PTR_ERR(lp->enable);
                if (ret == -ENODEV)
                        lp->enable = NULL;
                else
                        return dev_err_probe(dev, ret, "getting enable regulator\n");
        }

        lp->pwm = devm_pwm_get(lp->dev, lp->chipname);
        if (IS_ERR(lp->pwm)) {
                ret = PTR_ERR(lp->pwm);
                if (ret == -ENODEV || ret == -EINVAL)
                        lp->pwm = NULL;
                else
                        return dev_err_probe(dev, ret, "getting PWM\n");

                lp->needs_pwm_init = false;
                lp->mode = REGISTER_BASED;
                dev_dbg(dev, "mode: register based\n");
        } else {
                lp->needs_pwm_init = true;
                lp->mode = PWM_BASED;
                dev_dbg(dev, "mode: PWM based\n");
        }

        if (lp->supply) {
                ret = regulator_enable(lp->supply);
                if (ret < 0) {
                        dev_err(dev, "failed to enable supply: %d\n", ret);
                        return ret;
                }
        }

        if (lp->enable) {
                ret = regulator_enable(lp->enable);
                if (ret < 0) {
                        dev_err(dev, "failed to enable vddio: %d\n", ret);
                        goto disable_supply;
                }

                /*
                 * LP8555 datasheet says t_RESPONSE (time between VDDIO and
                 * I2C) is 1ms.
                 */
                usleep_range(1000, 2000);
        }

        i2c_set_clientdata(cl, lp);

        ret = lp855x_configure(lp);
        if (ret) {
                dev_err(dev, "device config err: %d", ret);
                goto disable_vddio;
        }

        ret = lp855x_backlight_register(lp);
        if (ret) {
                dev_err(dev, "failed to register backlight. err: %d\n", ret);
                goto disable_vddio;
        }

        ret = sysfs_create_group(&dev->kobj, &lp855x_attr_group);
        if (ret) {
                dev_err(dev, "failed to register sysfs. err: %d\n", ret);
                goto disable_vddio;
        }

        backlight_update_status(lp->bl);

        return 0;

disable_vddio:
        if (lp->enable)
                regulator_disable(lp->enable);
disable_supply:
        if (lp->supply)
                regulator_disable(lp->supply);

        return ret;
}

static void lp855x_remove(struct i2c_client *cl)
{
        struct lp855x *lp = i2c_get_clientdata(cl);

        lp->bl->props.brightness = 0;
        backlight_update_status(lp->bl);
        if (lp->enable)
                regulator_disable(lp->enable);
        if (lp->supply)
                regulator_disable(lp->supply);
        sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group);
}

static const struct of_device_id lp855x_dt_ids[] __maybe_unused = {
        { .compatible = "ti,lp8550", },
        { .compatible = "ti,lp8551", },
        { .compatible = "ti,lp8552", },
        { .compatible = "ti,lp8553", },
        { .compatible = "ti,lp8555", },
        { .compatible = "ti,lp8556", },
        { .compatible = "ti,lp8557", },
        { }
};
MODULE_DEVICE_TABLE(of, lp855x_dt_ids);

static const struct i2c_device_id lp855x_ids[] = {
        {"lp8550", LP8550},
        {"lp8551", LP8551},
        {"lp8552", LP8552},
        {"lp8553", LP8553},
        {"lp8555", LP8555},
        {"lp8556", LP8556},
        {"lp8557", LP8557},
        { }
};
MODULE_DEVICE_TABLE(i2c, lp855x_ids);

#ifdef CONFIG_ACPI
static const struct acpi_device_id lp855x_acpi_match[] = {
        /* Xiaomi specific HID used for the LP8556 on the Mi Pad 2 */
        { "XMCC0001", LP8556 },
        { }
};
MODULE_DEVICE_TABLE(acpi, lp855x_acpi_match);
#endif

static struct i2c_driver lp855x_driver = {
        .driver = {
                   .name = "lp855x",
                   .of_match_table = of_match_ptr(lp855x_dt_ids),
                   .acpi_match_table = ACPI_PTR(lp855x_acpi_match),
                   },
        .probe = lp855x_probe,
        .remove = lp855x_remove,
        .id_table = lp855x_ids,
};

module_i2c_driver(lp855x_driver);

MODULE_DESCRIPTION("Texas Instruments LP855x Backlight driver");
MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>");
MODULE_LICENSE("GPL");