// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright 2015-16 Golden Delicious Computers
 *
 * Author: Nikolaus Schaller <hns@goldelico.com>
 *
 * LED driver for the IS31FL319{0,1,3,6,9} to drive 1, 3, 6 or 9 light
 * effect LEDs.
 */

#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/leds.h>
#include <linux/module.h>
#include <linux/property.h>
#include <linux/regmap.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/gpio/consumer.h>

/* register numbers */
#define IS31FL319X_SHUTDOWN             0x00

/* registers for 3190, 3191 and 3193 */
#define IS31FL3190_BREATHING            0x01
#define IS31FL3190_LEDMODE              0x02
#define IS31FL3190_CURRENT              0x03
#define IS31FL3190_PWM(channel)         (0x04 + channel)
#define IS31FL3190_DATA_UPDATE          0x07
#define IS31FL3190_T0(channel)          (0x0a + channel)
#define IS31FL3190_T1T2(channel)        (0x10 + channel)
#define IS31FL3190_T3T4(channel)        (0x16 + channel)
#define IS31FL3190_TIME_UPDATE          0x1c
#define IS31FL3190_LEDCONTROL           0x1d
#define IS31FL3190_RESET                0x2f

#define IS31FL3190_CURRENT_uA_MIN       5000
#define IS31FL3190_CURRENT_uA_DEFAULT   42000
#define IS31FL3190_CURRENT_uA_MAX       42000
#define IS31FL3190_CURRENT_SHIFT        2
#define IS31FL3190_CURRENT_MASK         GENMASK(4, 2)
#define IS31FL3190_CURRENT_5_mA         0x02
#define IS31FL3190_CURRENT_10_mA        0x01
#define IS31FL3190_CURRENT_17dot5_mA    0x04
#define IS31FL3190_CURRENT_30_mA        0x03
#define IS31FL3190_CURRENT_42_mA        0x00

/* registers for 3196 and 3199 */
#define IS31FL3196_CTRL1                0x01
#define IS31FL3196_CTRL2                0x02
#define IS31FL3196_CONFIG1              0x03
#define IS31FL3196_CONFIG2              0x04
#define IS31FL3196_RAMP_MODE            0x05
#define IS31FL3196_BREATH_MARK          0x06
#define IS31FL3196_PWM(channel)         (0x07 + channel)
#define IS31FL3196_DATA_UPDATE          0x10
#define IS31FL3196_T0(channel)          (0x11 + channel)
#define IS31FL3196_T123_1               0x1a
#define IS31FL3196_T123_2               0x1b
#define IS31FL3196_T123_3               0x1c
#define IS31FL3196_T4(channel)          (0x1d + channel)
#define IS31FL3196_TIME_UPDATE          0x26
#define IS31FL3196_RESET                0xff

#define IS31FL3196_REG_CNT              (IS31FL3196_RESET + 1)

#define IS31FL319X_MAX_LEDS             9

/* CS (Current Setting) in CONFIG2 register */
#define IS31FL3196_CONFIG2_CS_SHIFT     4
#define IS31FL3196_CONFIG2_CS_MASK      GENMASK(2, 0)
#define IS31FL3196_CONFIG2_CS_STEP_REF  12

#define IS31FL3196_CURRENT_uA_MIN       5000
#define IS31FL3196_CURRENT_uA_MAX       40000
#define IS31FL3196_CURRENT_uA_STEP      5000
#define IS31FL3196_CURRENT_uA_DEFAULT   20000

/* Audio gain in CONFIG2 register */
#define IS31FL3196_AUDIO_GAIN_DB_MAX    ((u32)21)
#define IS31FL3196_AUDIO_GAIN_DB_STEP   3

/*
 * regmap is used as a cache of chip's register space,
 * to avoid reading back brightness values from chip,
 * which is known to hang.
 */
struct is31fl319x_chip {
        const struct is31fl319x_chipdef *cdef;
        struct i2c_client               *client;
        struct gpio_desc                *shutdown_gpio;
        struct regmap                   *regmap;
        struct mutex                    lock;
        u32                             audio_gain_db;

        struct is31fl319x_led {
                struct is31fl319x_chip  *chip;
                struct led_classdev     cdev;
                u32                     max_microamp;
                bool                    configured;
        } leds[IS31FL319X_MAX_LEDS];
};

struct is31fl319x_chipdef {
        int num_leds;
        u8 reset_reg;
        const struct regmap_config *is31fl319x_regmap_config;
        int (*brightness_set)(struct led_classdev *cdev, enum led_brightness brightness);
        u32 current_default;
        u32 current_min;
        u32 current_max;
        bool is_3196or3199;
};

static bool is31fl319x_readable_reg(struct device *dev, unsigned int reg)
{
        /* we have no readable registers */
        return false;
}

static bool is31fl3190_volatile_reg(struct device *dev, unsigned int reg)
{
        /* volatile registers are not cached */
        switch (reg) {
        case IS31FL3190_DATA_UPDATE:
        case IS31FL3190_TIME_UPDATE:
        case IS31FL3190_RESET:
                return true; /* always write-through */
        default:
                return false;
        }
}

static const struct reg_default is31fl3190_reg_defaults[] = {
        { IS31FL3190_LEDMODE, 0x00 },
        { IS31FL3190_CURRENT, 0x00 },
        { IS31FL3190_PWM(0), 0x00 },
        { IS31FL3190_PWM(1), 0x00 },
        { IS31FL3190_PWM(2), 0x00 },
};

static const struct regmap_config is31fl3190_regmap_config = {
        .reg_bits = 8,
        .val_bits = 8,
        .max_register = IS31FL3190_RESET,
        .cache_type = REGCACHE_FLAT,
        .readable_reg = is31fl319x_readable_reg,
        .volatile_reg = is31fl3190_volatile_reg,
        .reg_defaults = is31fl3190_reg_defaults,
        .num_reg_defaults = ARRAY_SIZE(is31fl3190_reg_defaults),
};

static bool is31fl3196_volatile_reg(struct device *dev, unsigned int reg)
{
        /* volatile registers are not cached */
        switch (reg) {
        case IS31FL3196_DATA_UPDATE:
        case IS31FL3196_TIME_UPDATE:
        case IS31FL3196_RESET:
                return true; /* always write-through */
        default:
                return false;
        }
}

static const struct reg_default is31fl3196_reg_defaults[] = {
        { IS31FL3196_CONFIG1, 0x00 },
        { IS31FL3196_CONFIG2, 0x00 },
        { IS31FL3196_PWM(0), 0x00 },
        { IS31FL3196_PWM(1), 0x00 },
        { IS31FL3196_PWM(2), 0x00 },
        { IS31FL3196_PWM(3), 0x00 },
        { IS31FL3196_PWM(4), 0x00 },
        { IS31FL3196_PWM(5), 0x00 },
        { IS31FL3196_PWM(6), 0x00 },
        { IS31FL3196_PWM(7), 0x00 },
        { IS31FL3196_PWM(8), 0x00 },
};

static const struct regmap_config is31fl3196_regmap_config = {
        .reg_bits = 8,
        .val_bits = 8,
        .max_register = IS31FL3196_REG_CNT,
        .cache_type = REGCACHE_FLAT,
        .readable_reg = is31fl319x_readable_reg,
        .volatile_reg = is31fl3196_volatile_reg,
        .reg_defaults = is31fl3196_reg_defaults,
        .num_reg_defaults = ARRAY_SIZE(is31fl3196_reg_defaults),
};

static int is31fl3190_brightness_set(struct led_classdev *cdev,
                                     enum led_brightness brightness)
{
        struct is31fl319x_led *led = container_of(cdev, struct is31fl319x_led, cdev);
        struct is31fl319x_chip *is31 = led->chip;
        int chan = led - is31->leds;
        int ret;
        int i;
        u8 ctrl = 0;

        dev_dbg(&is31->client->dev, "channel %d: %d\n", chan, brightness);

        mutex_lock(&is31->lock);

        /* update PWM register */
        ret = regmap_write(is31->regmap, IS31FL3190_PWM(chan), brightness);
        if (ret < 0)
                goto out;

        /* read current brightness of all PWM channels */
        for (i = 0; i < is31->cdef->num_leds; i++) {
                unsigned int pwm_value;
                bool on;

                /*
                 * since neither cdev nor the chip can provide
                 * the current setting, we read from the regmap cache
                 */

                ret = regmap_read(is31->regmap, IS31FL3190_PWM(i), &pwm_value);
                on = ret >= 0 && pwm_value > LED_OFF;

                ctrl |= on << i;
        }

        if (ctrl > 0) {
                dev_dbg(&is31->client->dev, "power up %02x\n", ctrl);
                regmap_write(is31->regmap, IS31FL3190_LEDCONTROL, ctrl);
                /* update PWMs */
                regmap_write(is31->regmap, IS31FL3190_DATA_UPDATE, 0x00);
                /* enable chip from shut down and enable all channels */
                ret = regmap_write(is31->regmap, IS31FL319X_SHUTDOWN, 0x20);
        } else {
                dev_dbg(&is31->client->dev, "power down\n");
                /* shut down (no need to clear LEDCONTROL) */
                ret = regmap_write(is31->regmap, IS31FL319X_SHUTDOWN, 0x01);
        }

out:
        mutex_unlock(&is31->lock);

        return ret;
}

static int is31fl3196_brightness_set(struct led_classdev *cdev,
                                     enum led_brightness brightness)
{
        struct is31fl319x_led *led = container_of(cdev, struct is31fl319x_led, cdev);
        struct is31fl319x_chip *is31 = led->chip;
        int chan = led - is31->leds;
        int ret;
        int i;
        u8 ctrl1 = 0, ctrl2 = 0;

        dev_dbg(&is31->client->dev, "channel %d: %d\n", chan, brightness);

        mutex_lock(&is31->lock);

        /* update PWM register */
        ret = regmap_write(is31->regmap, IS31FL3196_PWM(chan), brightness);
        if (ret < 0)
                goto out;

        /* read current brightness of all PWM channels */
        for (i = 0; i < is31->cdef->num_leds; i++) {
                unsigned int pwm_value;
                bool on;

                /*
                 * since neither cdev nor the chip can provide
                 * the current setting, we read from the regmap cache
                 */

                ret = regmap_read(is31->regmap, IS31FL3196_PWM(i), &pwm_value);
                on = ret >= 0 && pwm_value > LED_OFF;

                if (i < 3)
                        ctrl1 |= on << i;       /* 0..2 => bit 0..2 */
                else if (i < 6)
                        ctrl1 |= on << (i + 1); /* 3..5 => bit 4..6 */
                else
                        ctrl2 |= on << (i - 6); /* 6..8 => bit 0..2 */
        }

        if (ctrl1 > 0 || ctrl2 > 0) {
                dev_dbg(&is31->client->dev, "power up %02x %02x\n",
                        ctrl1, ctrl2);
                regmap_write(is31->regmap, IS31FL3196_CTRL1, ctrl1);
                regmap_write(is31->regmap, IS31FL3196_CTRL2, ctrl2);
                /* update PWMs */
                regmap_write(is31->regmap, IS31FL3196_DATA_UPDATE, 0x00);
                /* enable chip from shut down */
                ret = regmap_write(is31->regmap, IS31FL319X_SHUTDOWN, 0x01);
        } else {
                dev_dbg(&is31->client->dev, "power down\n");
                /* shut down (no need to clear CTRL1/2) */
                ret = regmap_write(is31->regmap, IS31FL319X_SHUTDOWN, 0x00);
        }

out:
        mutex_unlock(&is31->lock);

        return ret;
}

static const struct is31fl319x_chipdef is31fl3190_cdef = {
        .num_leds = 1,
        .reset_reg = IS31FL3190_RESET,
        .is31fl319x_regmap_config = &is31fl3190_regmap_config,
        .brightness_set = is31fl3190_brightness_set,
        .current_default = IS31FL3190_CURRENT_uA_DEFAULT,
        .current_min = IS31FL3190_CURRENT_uA_MIN,
        .current_max = IS31FL3190_CURRENT_uA_MAX,
        .is_3196or3199 = false,
};

static const struct is31fl319x_chipdef is31fl3193_cdef = {
        .num_leds = 3,
        .reset_reg = IS31FL3190_RESET,
        .is31fl319x_regmap_config = &is31fl3190_regmap_config,
        .brightness_set = is31fl3190_brightness_set,
        .current_default = IS31FL3190_CURRENT_uA_DEFAULT,
        .current_min = IS31FL3190_CURRENT_uA_MIN,
        .current_max = IS31FL3190_CURRENT_uA_MAX,
        .is_3196or3199 = false,
};

static const struct is31fl319x_chipdef is31fl3196_cdef = {
        .num_leds = 6,
        .reset_reg = IS31FL3196_RESET,
        .is31fl319x_regmap_config = &is31fl3196_regmap_config,
        .brightness_set = is31fl3196_brightness_set,
        .current_default = IS31FL3196_CURRENT_uA_DEFAULT,
        .current_min = IS31FL3196_CURRENT_uA_MIN,
        .current_max = IS31FL3196_CURRENT_uA_MAX,
        .is_3196or3199 = true,
};

static const struct is31fl319x_chipdef is31fl3199_cdef = {
        .num_leds = 9,
        .reset_reg = IS31FL3196_RESET,
        .is31fl319x_regmap_config = &is31fl3196_regmap_config,
        .brightness_set = is31fl3196_brightness_set,
        .current_default = IS31FL3196_CURRENT_uA_DEFAULT,
        .current_min = IS31FL3196_CURRENT_uA_MIN,
        .current_max = IS31FL3196_CURRENT_uA_MAX,
        .is_3196or3199 = true,
};

static const struct of_device_id of_is31fl319x_match[] = {
        { .compatible = "issi,is31fl3190", .data = &is31fl3190_cdef, },
        { .compatible = "issi,is31fl3191", .data = &is31fl3190_cdef, },
        { .compatible = "issi,is31fl3193", .data = &is31fl3193_cdef, },
        { .compatible = "issi,is31fl3196", .data = &is31fl3196_cdef, },
        { .compatible = "issi,is31fl3199", .data = &is31fl3199_cdef, },
        { .compatible = "si-en,sn3190",    .data = &is31fl3190_cdef, },
        { .compatible = "si-en,sn3191",    .data = &is31fl3190_cdef, },
        { .compatible = "si-en,sn3193",    .data = &is31fl3193_cdef, },
        { .compatible = "si-en,sn3196",    .data = &is31fl3196_cdef, },
        { .compatible = "si-en,sn3199",    .data = &is31fl3199_cdef, },
        { }
};
MODULE_DEVICE_TABLE(of, of_is31fl319x_match);

static int is31fl319x_parse_child_fw(const struct device *dev,
                                     const struct fwnode_handle *child,
                                     struct is31fl319x_led *led,
                                     struct is31fl319x_chip *is31)
{
        struct led_classdev *cdev = &led->cdev;
        int ret;

        if (fwnode_property_read_string(child, "label", &cdev->name))
                cdev->name = fwnode_get_name(child);

        ret = fwnode_property_read_string(child, "linux,default-trigger", &cdev->default_trigger);
        if (ret < 0 && ret != -EINVAL) /* is optional */
                return ret;

        led->max_microamp = is31->cdef->current_default;
        ret = fwnode_property_read_u32(child, "led-max-microamp", &led->max_microamp);
        if (!ret) {
                if (led->max_microamp < is31->cdef->current_min)
                        return -EINVAL; /* not supported */
                led->max_microamp = min(led->max_microamp,
                                        is31->cdef->current_max);
        }

        return 0;
}

static int is31fl319x_parse_fw(struct device *dev, struct is31fl319x_chip *is31)
{
        struct fwnode_handle *fwnode = dev_fwnode(dev);
        int count;
        int ret;

        is31->shutdown_gpio = devm_gpiod_get_optional(dev, "shutdown", GPIOD_OUT_HIGH);
        if (IS_ERR(is31->shutdown_gpio))
                return dev_err_probe(dev, PTR_ERR(is31->shutdown_gpio),
                                     "Failed to get shutdown gpio\n");

        is31->cdef = device_get_match_data(dev);

        count = 0;
        device_for_each_child_node_scoped(dev, child)
                count++;

        dev_dbg(dev, "probing with %d leds defined in DT\n", count);

        if (!count || count > is31->cdef->num_leds)
                return dev_err_probe(dev, -ENODEV,
                                     "Number of leds defined must be between 1 and %u\n",
                                     is31->cdef->num_leds);

        device_for_each_child_node_scoped(dev, child) {
                struct is31fl319x_led *led;
                u32 reg;

                ret = fwnode_property_read_u32(child, "reg", &reg);
                if (ret)
                        return dev_err_probe(dev, ret, "Failed to read led 'reg' property\n");

                if (reg < 1 || reg > is31->cdef->num_leds)
                        return dev_err_probe(dev, -EINVAL, "invalid led reg %u\n", reg);

                led = &is31->leds[reg - 1];

                if (led->configured)
                        return dev_err_probe(dev, -EINVAL, "led %u is already configured\n", reg);

                ret = is31fl319x_parse_child_fw(dev, child, led, is31);
                if (ret)
                        return dev_err_probe(dev, ret, "led %u DT parsing failed\n", reg);

                led->configured = true;
        }

        is31->audio_gain_db = 0;
        if (is31->cdef->is_3196or3199) {
                ret = fwnode_property_read_u32(fwnode, "audio-gain-db", &is31->audio_gain_db);
                if (!ret)
                        is31->audio_gain_db = min(is31->audio_gain_db,
                                                  IS31FL3196_AUDIO_GAIN_DB_MAX);
        }

        return 0;
}

static inline int is31fl3190_microamp_to_cs(struct device *dev, u32 microamp)
{
        switch (microamp) {
        case 5000:
                return IS31FL3190_CURRENT_5_mA;
        case 10000:
                return IS31FL3190_CURRENT_10_mA;
        case 17500:
                return IS31FL3190_CURRENT_17dot5_mA;
        case 30000:
                return IS31FL3190_CURRENT_30_mA;
        case 42000:
                return IS31FL3190_CURRENT_42_mA;
        default:
                dev_warn(dev, "Unsupported current value: %d, using 5000 µA!\n", microamp);
                return IS31FL3190_CURRENT_5_mA;
        }
}

static inline int is31fl3196_microamp_to_cs(struct device *dev, u32 microamp)
{
        /* round down to nearest supported value (range check done by caller) */
        u32 step = microamp / IS31FL3196_CURRENT_uA_STEP;

        return ((IS31FL3196_CONFIG2_CS_STEP_REF - step) &
                IS31FL3196_CONFIG2_CS_MASK) <<
                IS31FL3196_CONFIG2_CS_SHIFT; /* CS encoding */
}

static inline int is31fl3196_db_to_gain(u32 dezibel)
{
        /* round down to nearest supported value (range check done by caller) */
        return dezibel / IS31FL3196_AUDIO_GAIN_DB_STEP;
}

static int is31fl319x_probe(struct i2c_client *client)
{
        struct is31fl319x_chip *is31;
        struct device *dev = &client->dev;
        int err;
        int i = 0;
        u32 aggregated_led_microamp;

        if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
                return -EIO;

        is31 = devm_kzalloc(&client->dev, sizeof(*is31), GFP_KERNEL);
        if (!is31)
                return -ENOMEM;

        err = devm_mutex_init(dev, &is31->lock);
        if (err)
                return err;

        err = is31fl319x_parse_fw(&client->dev, is31);
        if (err)
                return err;

        if (is31->shutdown_gpio) {
                gpiod_direction_output(is31->shutdown_gpio, 0);
                mdelay(5);
                gpiod_direction_output(is31->shutdown_gpio, 1);
        }

        is31->client = client;
        is31->regmap = devm_regmap_init_i2c(client, is31->cdef->is31fl319x_regmap_config);
        if (IS_ERR(is31->regmap))
                return dev_err_probe(dev, PTR_ERR(is31->regmap), "failed to allocate register map\n");

        i2c_set_clientdata(client, is31);

        /* check for write-reply from chip (we can't read any registers) */
        err = regmap_write(is31->regmap, is31->cdef->reset_reg, 0x00);
        if (err < 0)
                return dev_err_probe(dev, err, "no response from chip write\n");

        /*
         * Kernel conventions require per-LED led-max-microamp property.
         * But the chip does not allow to limit individual LEDs.
         * So we take minimum from all subnodes for safety of hardware.
         */
        aggregated_led_microamp = is31->cdef->current_max;
        for (i = 0; i < is31->cdef->num_leds; i++)
                if (is31->leds[i].configured &&
                    is31->leds[i].max_microamp < aggregated_led_microamp)
                        aggregated_led_microamp = is31->leds[i].max_microamp;

        if (is31->cdef->is_3196or3199)
                regmap_write(is31->regmap, IS31FL3196_CONFIG2,
                             is31fl3196_microamp_to_cs(dev, aggregated_led_microamp) |
                             is31fl3196_db_to_gain(is31->audio_gain_db));
        else
                regmap_update_bits(is31->regmap, IS31FL3190_CURRENT, IS31FL3190_CURRENT_MASK,
                                   is31fl3190_microamp_to_cs(dev, aggregated_led_microamp) << IS31FL3190_CURRENT_SHIFT);

        for (i = 0; i < is31->cdef->num_leds; i++) {
                struct is31fl319x_led *led = &is31->leds[i];

                if (!led->configured)
                        continue;

                led->chip = is31;
                led->cdev.brightness_set_blocking = is31->cdef->brightness_set;

                err = devm_led_classdev_register(&client->dev, &led->cdev);
                if (err < 0)
                        return err;
        }

        return 0;
}

/*
 * i2c-core (and modalias) requires that id_table be properly filled,
 * even though it is not used for DeviceTree based instantiation.
 */
static const struct i2c_device_id is31fl319x_id[] = {
        { .name = "is31fl3190" },
        { .name = "is31fl3191" },
        { .name = "is31fl3193" },
        { .name = "is31fl3196" },
        { .name = "is31fl3199" },
        { .name = "sn3190" },
        { .name = "sn3191" },
        { .name = "sn3193" },
        { .name = "sn3196" },
        { .name = "sn3199" },
        { }
};
MODULE_DEVICE_TABLE(i2c, is31fl319x_id);

static struct i2c_driver is31fl319x_driver = {
        .driver   = {
                .name           = "leds-is31fl319x",
                .of_match_table = of_is31fl319x_match,
        },
        .probe = is31fl319x_probe,
        .id_table = is31fl319x_id,
};

module_i2c_driver(is31fl319x_driver);

MODULE_AUTHOR("H. Nikolaus Schaller <hns@goldelico.com>");
MODULE_AUTHOR("Andrey Utkin <andrey_utkin@fastmail.com>");
MODULE_DESCRIPTION("IS31FL319X LED driver");
MODULE_LICENSE("GPL v2");