// SPDX-License-Identifier: GPL-2.0+
// Driver for Awinic AW2013 3-channel LED driver

#include <linux/i2c.h>
#include <linux/leds.h>
#include <linux/module.h>
#include <linux/regulator/consumer.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/regmap.h>

#define AW2013_MAX_LEDS 3

/* Reset and ID register */
#define AW2013_RSTR 0x00
#define AW2013_RSTR_RESET 0x55
#define AW2013_RSTR_CHIP_ID 0x33

/* Global control register */
#define AW2013_GCR 0x01
#define AW2013_GCR_ENABLE BIT(0)

/* LED channel enable register */
#define AW2013_LCTR 0x30
#define AW2013_LCTR_LE(x) BIT((x))

/* LED channel control registers */
#define AW2013_LCFG(x) (0x31 + (x))
#define AW2013_LCFG_IMAX_MASK (BIT(0) | BIT(1)) // Should be 0-3
#define AW2013_LCFG_MD BIT(4)
#define AW2013_LCFG_FI BIT(5)
#define AW2013_LCFG_FO BIT(6)

/* LED channel PWM registers */
#define AW2013_REG_PWM(x) (0x34 + (x))

/* LED channel timing registers */
#define AW2013_LEDT0(x) (0x37 + (x) * 3)
#define AW2013_LEDT0_T1(x) ((x) << 4) // Should be 0-7
#define AW2013_LEDT0_T2(x) (x) // Should be 0-5

#define AW2013_LEDT1(x) (0x38 + (x) * 3)
#define AW2013_LEDT1_T3(x) ((x) << 4) // Should be 0-7
#define AW2013_LEDT1_T4(x) (x) // Should be 0-7

#define AW2013_LEDT2(x) (0x39 + (x) * 3)
#define AW2013_LEDT2_T0(x) ((x) << 4) // Should be 0-8
#define AW2013_LEDT2_REPEAT(x) (x) // Should be 0-15

#define AW2013_REG_MAX 0x77

#define AW2013_TIME_STEP 130 /* ms */

struct aw2013;

struct aw2013_led {
        struct aw2013 *chip;
        struct led_classdev cdev;
        u32 num;
        unsigned int imax;
};

struct aw2013 {
        struct mutex mutex; /* held when writing to registers */
        struct regulator_bulk_data regulators[2];
        struct i2c_client *client;
        struct aw2013_led leds[AW2013_MAX_LEDS];
        struct regmap *regmap;
        int num_leds;
        bool enabled;
};

static int aw2013_chip_init(struct aw2013 *chip)
{
        int i, ret;

        ret = regmap_write(chip->regmap, AW2013_GCR, AW2013_GCR_ENABLE);
        if (ret) {
                dev_err(&chip->client->dev, "Failed to enable the chip: %d\n",
                        ret);
                return ret;
        }

        for (i = 0; i < chip->num_leds; i++) {
                ret = regmap_update_bits(chip->regmap,
                                         AW2013_LCFG(chip->leds[i].num),
                                         AW2013_LCFG_IMAX_MASK,
                                         chip->leds[i].imax);
                if (ret) {
                        dev_err(&chip->client->dev,
                                "Failed to set maximum current for led %d: %d\n",
                                chip->leds[i].num, ret);
                        return ret;
                }
        }

        return ret;
}

static void aw2013_chip_disable(struct aw2013 *chip)
{
        int ret;

        if (!chip->enabled)
                return;

        regmap_write(chip->regmap, AW2013_GCR, 0);

        ret = regulator_bulk_disable(ARRAY_SIZE(chip->regulators),
                                     chip->regulators);
        if (ret) {
                dev_err(&chip->client->dev,
                        "Failed to disable regulators: %d\n", ret);
                return;
        }

        chip->enabled = false;
}

static int aw2013_chip_enable(struct aw2013 *chip)
{
        int ret;

        if (chip->enabled)
                return 0;

        ret = regulator_bulk_enable(ARRAY_SIZE(chip->regulators),
                                    chip->regulators);
        if (ret) {
                dev_err(&chip->client->dev,
                        "Failed to enable regulators: %d\n", ret);
                return ret;
        }
        chip->enabled = true;

        ret = aw2013_chip_init(chip);
        if (ret)
                aw2013_chip_disable(chip);

        return ret;
}

static bool aw2013_chip_in_use(struct aw2013 *chip)
{
        int i;

        for (i = 0; i < chip->num_leds; i++)
                if (chip->leds[i].cdev.brightness)
                        return true;

        return false;
}

static int aw2013_brightness_set(struct led_classdev *cdev,
                                 enum led_brightness brightness)
{
        struct aw2013_led *led = container_of(cdev, struct aw2013_led, cdev);
        int ret, num;

        mutex_lock(&led->chip->mutex);

        if (aw2013_chip_in_use(led->chip)) {
                ret = aw2013_chip_enable(led->chip);
                if (ret)
                        goto error;
        }

        num = led->num;

        ret = regmap_write(led->chip->regmap, AW2013_REG_PWM(num), brightness);
        if (ret)
                goto error;

        if (brightness) {
                ret = regmap_update_bits(led->chip->regmap, AW2013_LCTR,
                                         AW2013_LCTR_LE(num), 0xFF);
        } else {
                ret = regmap_update_bits(led->chip->regmap, AW2013_LCTR,
                                         AW2013_LCTR_LE(num), 0);
                if (ret)
                        goto error;
                ret = regmap_update_bits(led->chip->regmap, AW2013_LCFG(num),
                                         AW2013_LCFG_MD, 0);
        }
        if (ret)
                goto error;

        if (!aw2013_chip_in_use(led->chip))
                aw2013_chip_disable(led->chip);

error:
        mutex_unlock(&led->chip->mutex);

        return ret;
}

static int aw2013_blink_set(struct led_classdev *cdev,
                            unsigned long *delay_on, unsigned long *delay_off)
{
        struct aw2013_led *led = container_of(cdev, struct aw2013_led, cdev);
        int ret, num = led->num;
        unsigned long off = 0, on = 0;

        /* If no blink specified, default to 1 Hz. */
        if (!*delay_off && !*delay_on) {
                *delay_off = 500;
                *delay_on = 500;
        }

        if (!led->cdev.brightness) {
                led->cdev.brightness = LED_FULL;
                ret = aw2013_brightness_set(&led->cdev, led->cdev.brightness);
                if (ret)
                        return ret;
        }

        /* Never on - just set to off */
        if (!*delay_on) {
                led->cdev.brightness = LED_OFF;
                return aw2013_brightness_set(&led->cdev, LED_OFF);
        }

        mutex_lock(&led->chip->mutex);

        /* Never off - brightness is already set, disable blinking */
        if (!*delay_off) {
                ret = regmap_update_bits(led->chip->regmap, AW2013_LCFG(num),
                                         AW2013_LCFG_MD, 0);
                goto out;
        }

        /* Convert into values the HW will understand. */
        off = min(5, ilog2((*delay_off - 1) / AW2013_TIME_STEP) + 1);
        on = min(7, ilog2((*delay_on - 1) / AW2013_TIME_STEP) + 1);

        *delay_off = BIT(off) * AW2013_TIME_STEP;
        *delay_on = BIT(on) * AW2013_TIME_STEP;

        /* Set timings */
        ret = regmap_write(led->chip->regmap,
                           AW2013_LEDT0(num), AW2013_LEDT0_T2(on));
        if (ret)
                goto out;
        ret = regmap_write(led->chip->regmap,
                           AW2013_LEDT1(num), AW2013_LEDT1_T4(off));
        if (ret)
                goto out;

        /* Finally, enable the LED */
        ret = regmap_update_bits(led->chip->regmap, AW2013_LCFG(num),
                                 AW2013_LCFG_MD, 0xFF);
        if (ret)
                goto out;

        ret = regmap_update_bits(led->chip->regmap, AW2013_LCTR,
                                 AW2013_LCTR_LE(num), 0xFF);

out:
        mutex_unlock(&led->chip->mutex);

        return ret;
}

static int aw2013_probe_dt(struct aw2013 *chip)
{
        struct device_node *np = dev_of_node(&chip->client->dev);
        int count, ret = 0, i = 0;
        struct aw2013_led *led;

        count = of_get_available_child_count(np);
        if (!count || count > AW2013_MAX_LEDS)
                return -EINVAL;

        regmap_write(chip->regmap, AW2013_RSTR, AW2013_RSTR_RESET);

        for_each_available_child_of_node_scoped(np, child) {
                struct led_init_data init_data = {};
                u32 source;
                u32 imax;

                ret = of_property_read_u32(child, "reg", &source);
                if (ret != 0 || source >= AW2013_MAX_LEDS) {
                        dev_err(&chip->client->dev,
                                "Couldn't read LED address: %d\n", ret);
                        count--;
                        continue;
                }

                led = &chip->leds[i];
                led->num = source;
                led->chip = chip;
                init_data.fwnode = of_fwnode_handle(child);

                if (!of_property_read_u32(child, "led-max-microamp", &imax)) {
                        led->imax = min_t(u32, imax / 5000, 3);
                } else {
                        led->imax = 1; // 5mA
                        dev_info(&chip->client->dev,
                                 "DT property led-max-microamp is missing\n");
                }

                led->cdev.brightness_set_blocking = aw2013_brightness_set;
                led->cdev.blink_set = aw2013_blink_set;

                ret = devm_led_classdev_register_ext(&chip->client->dev,
                                                     &led->cdev, &init_data);
                if (ret < 0)
                        return ret;

                i++;
        }

        if (!count)
                return -EINVAL;

        chip->num_leds = i;

        return 0;
}

static void aw2013_chip_disable_action(void *data)
{
        aw2013_chip_disable(data);
}

static const struct regmap_config aw2013_regmap_config = {
        .reg_bits = 8,
        .val_bits = 8,
        .max_register = AW2013_REG_MAX,
};

static int aw2013_probe(struct i2c_client *client)
{
        struct aw2013 *chip;
        int ret;
        unsigned int chipid;

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

        ret = devm_mutex_init(&client->dev, &chip->mutex);
        if (ret)
                return ret;

        mutex_lock(&chip->mutex);

        chip->client = client;
        i2c_set_clientdata(client, chip);

        chip->regmap = devm_regmap_init_i2c(client, &aw2013_regmap_config);
        if (IS_ERR(chip->regmap)) {
                ret = PTR_ERR(chip->regmap);
                dev_err(&client->dev, "Failed to allocate register map: %d\n",
                        ret);
                goto error;
        }

        chip->regulators[0].supply = "vcc";
        chip->regulators[1].supply = "vio";
        ret = devm_regulator_bulk_get(&client->dev,
                                      ARRAY_SIZE(chip->regulators),
                                      chip->regulators);
        if (ret < 0) {
                if (ret != -EPROBE_DEFER)
                        dev_err(&client->dev,
                                "Failed to request regulators: %d\n", ret);
                goto error;
        }

        ret = regulator_bulk_enable(ARRAY_SIZE(chip->regulators),
                                    chip->regulators);
        if (ret) {
                dev_err(&client->dev,
                        "Failed to enable regulators: %d\n", ret);
                goto error;
        }

        ret = regmap_read(chip->regmap, AW2013_RSTR, &chipid);
        if (ret) {
                dev_err(&client->dev, "Failed to read chip ID: %d\n",
                        ret);
                goto error_reg;
        }

        if (chipid != AW2013_RSTR_CHIP_ID) {
                dev_err(&client->dev, "Chip reported wrong ID: %x\n",
                        chipid);
                ret = -ENODEV;
                goto error_reg;
        }

        ret = devm_add_action(&client->dev, aw2013_chip_disable_action, chip);
        if (ret)
                goto error_reg;

        ret = aw2013_probe_dt(chip);
        if (ret < 0)
                goto error_reg;

        ret = regulator_bulk_disable(ARRAY_SIZE(chip->regulators),
                                     chip->regulators);
        if (ret) {
                dev_err(&client->dev,
                        "Failed to disable regulators: %d\n", ret);
                goto error;
        }

        mutex_unlock(&chip->mutex);

        return 0;

error_reg:
        regulator_bulk_disable(ARRAY_SIZE(chip->regulators),
                               chip->regulators);

error:
        mutex_unlock(&chip->mutex);
        return ret;
}

static const struct of_device_id aw2013_match_table[] = {
        { .compatible = "awinic,aw2013", },
        { /* sentinel */ },
};

MODULE_DEVICE_TABLE(of, aw2013_match_table);

static struct i2c_driver aw2013_driver = {
        .driver = {
                .name = "leds-aw2013",
                .of_match_table = aw2013_match_table,
        },
        .probe = aw2013_probe,
};

module_i2c_driver(aw2013_driver);

MODULE_AUTHOR("Nikita Travkin <nikitos.tr@gmail.com>");
MODULE_DESCRIPTION("AW2013 LED driver");
MODULE_LICENSE("GPL v2");