// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * max8952.c - Voltage and current regulation for the Maxim 8952
 *
 * Copyright (C) 2010 Samsung Electronics
 * MyungJoo Ham <myungjoo.ham@samsung.com>
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/i2c.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/max8952.h>
#include <linux/gpio/consumer.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/regulator/of_regulator.h>
#include <linux/slab.h>

/* Registers */
enum {
        MAX8952_REG_MODE0,
        MAX8952_REG_MODE1,
        MAX8952_REG_MODE2,
        MAX8952_REG_MODE3,
        MAX8952_REG_CONTROL,
        MAX8952_REG_SYNC,
        MAX8952_REG_RAMP,
        MAX8952_REG_CHIP_ID1,
        MAX8952_REG_CHIP_ID2,
};

struct max8952_data {
        struct i2c_client       *client;
        struct max8952_platform_data *pdata;
        struct gpio_desc *vid0_gpiod;
        struct gpio_desc *vid1_gpiod;
        bool vid0;
        bool vid1;
};

static int max8952_read_reg(struct max8952_data *max8952, u8 reg)
{
        int ret = i2c_smbus_read_byte_data(max8952->client, reg);

        if (ret > 0)
                ret &= 0xff;

        return ret;
}

static int max8952_write_reg(struct max8952_data *max8952,
                u8 reg, u8 value)
{
        return i2c_smbus_write_byte_data(max8952->client, reg, value);
}

static int max8952_list_voltage(struct regulator_dev *rdev,
                unsigned int selector)
{
        struct max8952_data *max8952 = rdev_get_drvdata(rdev);

        if (rdev_get_id(rdev) != 0)
                return -EINVAL;

        return (max8952->pdata->dvs_mode[selector] * 10 + 770) * 1000;
}

static int max8952_get_voltage_sel(struct regulator_dev *rdev)
{
        struct max8952_data *max8952 = rdev_get_drvdata(rdev);
        u8 vid = 0;

        if (max8952->vid0)
                vid += 1;
        if (max8952->vid1)
                vid += 2;

        return vid;
}

static int max8952_set_voltage_sel(struct regulator_dev *rdev,
                                   unsigned selector)
{
        struct max8952_data *max8952 = rdev_get_drvdata(rdev);

        if (!max8952->vid0_gpiod || !max8952->vid1_gpiod) {
                /* DVS not supported */
                return -EPERM;
        }

        max8952->vid0 = selector & 0x1;
        max8952->vid1 = (selector >> 1) & 0x1;
        gpiod_set_value(max8952->vid0_gpiod, max8952->vid0);
        gpiod_set_value(max8952->vid1_gpiod, max8952->vid1);

        return 0;
}

static const struct regulator_ops max8952_ops = {
        .list_voltage           = max8952_list_voltage,
        .get_voltage_sel        = max8952_get_voltage_sel,
        .set_voltage_sel        = max8952_set_voltage_sel,
};

static const struct regulator_desc regulator = {
        .name           = "MAX8952_VOUT",
        .id             = 0,
        .n_voltages     = MAX8952_NUM_DVS_MODE,
        .ops            = &max8952_ops,
        .type           = REGULATOR_VOLTAGE,
        .owner          = THIS_MODULE,
};

#ifdef CONFIG_OF
static const struct of_device_id max8952_dt_match[] = {
        { .compatible = "maxim,max8952" },
        {},
};
MODULE_DEVICE_TABLE(of, max8952_dt_match);

static struct max8952_platform_data *max8952_parse_dt(struct device *dev)
{
        struct max8952_platform_data *pd;
        struct device_node *np = dev->of_node;
        int ret;
        int i;

        pd = devm_kzalloc(dev, sizeof(*pd), GFP_KERNEL);
        if (!pd)
                return NULL;

        if (of_property_read_u32(np, "max8952,default-mode", &pd->default_mode))
                dev_warn(dev, "Default mode not specified, assuming 0\n");

        ret = of_property_read_u32_array(np, "max8952,dvs-mode-microvolt",
                                        pd->dvs_mode, ARRAY_SIZE(pd->dvs_mode));
        if (ret) {
                dev_err(dev, "max8952,dvs-mode-microvolt property not specified");
                return NULL;
        }

        for (i = 0; i < ARRAY_SIZE(pd->dvs_mode); ++i) {
                if (pd->dvs_mode[i] < 770000 || pd->dvs_mode[i] > 1400000) {
                        dev_err(dev, "DVS voltage %d out of range\n", i);
                        return NULL;
                }
                pd->dvs_mode[i] = (pd->dvs_mode[i] - 770000) / 10000;
        }

        if (of_property_read_u32(np, "max8952,sync-freq", &pd->sync_freq))
                dev_warn(dev, "max8952,sync-freq property not specified, defaulting to 26MHz\n");

        if (of_property_read_u32(np, "max8952,ramp-speed", &pd->ramp_speed))
                dev_warn(dev, "max8952,ramp-speed property not specified, defaulting to 32mV/us\n");

        pd->reg_data = of_get_regulator_init_data(dev, np, &regulator);
        if (!pd->reg_data) {
                dev_err(dev, "Failed to parse regulator init data\n");
                return NULL;
        }

        return pd;
}
#else
static struct max8952_platform_data *max8952_parse_dt(struct device *dev)
{
        return NULL;
}
#endif

static int max8952_pmic_probe(struct i2c_client *client)
{
        struct i2c_adapter *adapter = client->adapter;
        struct max8952_platform_data *pdata = dev_get_platdata(&client->dev);
        struct regulator_config config = { };
        struct max8952_data *max8952;
        struct regulator_dev *rdev;
        struct gpio_desc *gpiod;
        enum gpiod_flags gflags;

        int ret = 0;

        if (client->dev.of_node)
                pdata = max8952_parse_dt(&client->dev);

        if (!pdata) {
                dev_err(&client->dev, "Require the platform data\n");
                return -EINVAL;
        }

        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
                return -EIO;

        max8952 = devm_kzalloc(&client->dev, sizeof(struct max8952_data),
                               GFP_KERNEL);
        if (!max8952)
                return -ENOMEM;

        max8952->client = client;
        max8952->pdata = pdata;

        config.dev = &client->dev;
        config.init_data = pdata->reg_data;
        config.driver_data = max8952;
        config.of_node = client->dev.of_node;

        if (pdata->reg_data->constraints.boot_on)
                gflags = GPIOD_OUT_HIGH;
        else
                gflags = GPIOD_OUT_LOW;
        gflags |= GPIOD_FLAGS_BIT_NONEXCLUSIVE;
        /*
         * Do not use devm* here: the regulator core takes over the
         * lifecycle management of the GPIO descriptor.
         */
        gpiod = gpiod_get_optional(&client->dev,
                                   "max8952,en",
                                   gflags);
        if (IS_ERR(gpiod))
                return PTR_ERR(gpiod);
        if (gpiod)
                config.ena_gpiod = gpiod;

        rdev = devm_regulator_register(&client->dev, &regulator, &config);
        if (IS_ERR(rdev)) {
                ret = PTR_ERR(rdev);
                dev_err(&client->dev, "regulator init failed (%d)\n", ret);
                return ret;
        }

        max8952->vid0 = pdata->default_mode & 0x1;
        max8952->vid1 = (pdata->default_mode >> 1) & 0x1;

        /* Fetch vid0 and vid1 GPIOs if available */
        gflags = max8952->vid0 ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
        max8952->vid0_gpiod = devm_gpiod_get_index_optional(&client->dev,
                                                            "max8952,vid",
                                                            0, gflags);
        if (IS_ERR(max8952->vid0_gpiod))
                return PTR_ERR(max8952->vid0_gpiod);
        gflags = max8952->vid1 ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
        max8952->vid1_gpiod = devm_gpiod_get_index_optional(&client->dev,
                                                            "max8952,vid",
                                                            1, gflags);
        if (IS_ERR(max8952->vid1_gpiod))
                return PTR_ERR(max8952->vid1_gpiod);

        /* If either VID GPIO is missing just disable this */
        if (!max8952->vid0_gpiod || !max8952->vid1_gpiod) {
                dev_warn(&client->dev, "VID0/1 gpio invalid: "
                         "DVS not available.\n");
                max8952->vid0 = 0;
                max8952->vid1 = 0;
                /* Make sure if we have any descriptors they get set to low */
                if (max8952->vid0_gpiod)
                        gpiod_set_value(max8952->vid0_gpiod, 0);
                if (max8952->vid1_gpiod)
                        gpiod_set_value(max8952->vid1_gpiod, 0);

                /* Disable Pulldown of EN only */
                max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x60);

                dev_err(&client->dev, "DVS modes disabled because VID0 and VID1"
                                " do not have proper controls.\n");
        } else {
                /*
                 * Disable Pulldown on EN, VID0, VID1 to reduce
                 * leakage current of MAX8952 assuming that MAX8952
                 * is turned on (EN==1). Note that without having VID0/1
                 * properly connected, turning pulldown off can be
                 * problematic. Thus, turn this off only when they are
                 * controllable by GPIO.
                 */
                max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x0);
        }

        max8952_write_reg(max8952, MAX8952_REG_MODE0,
                        (max8952_read_reg(max8952,
                                          MAX8952_REG_MODE0) & 0xC0) |
                        (pdata->dvs_mode[0] & 0x3F));
        max8952_write_reg(max8952, MAX8952_REG_MODE1,
                        (max8952_read_reg(max8952,
                                          MAX8952_REG_MODE1) & 0xC0) |
                        (pdata->dvs_mode[1] & 0x3F));
        max8952_write_reg(max8952, MAX8952_REG_MODE2,
                        (max8952_read_reg(max8952,
                                          MAX8952_REG_MODE2) & 0xC0) |
                        (pdata->dvs_mode[2] & 0x3F));
        max8952_write_reg(max8952, MAX8952_REG_MODE3,
                        (max8952_read_reg(max8952,
                                          MAX8952_REG_MODE3) & 0xC0) |
                        (pdata->dvs_mode[3] & 0x3F));

        max8952_write_reg(max8952, MAX8952_REG_SYNC,
                        (max8952_read_reg(max8952, MAX8952_REG_SYNC) & 0x3F) |
                        ((pdata->sync_freq & 0x3) << 6));
        max8952_write_reg(max8952, MAX8952_REG_RAMP,
                        (max8952_read_reg(max8952, MAX8952_REG_RAMP) & 0x1F) |
                        ((pdata->ramp_speed & 0x7) << 5));

        i2c_set_clientdata(client, max8952);

        return 0;
}

static const struct i2c_device_id max8952_ids[] = {
        { "max8952" },
        { }
};
MODULE_DEVICE_TABLE(i2c, max8952_ids);

static struct i2c_driver max8952_pmic_driver = {
        .probe          = max8952_pmic_probe,
        .driver         = {
                .name   = "max8952",
                .probe_type = PROBE_PREFER_ASYNCHRONOUS,
                .of_match_table = of_match_ptr(max8952_dt_match),
        },
        .id_table       = max8952_ids,
};

static int __init max8952_pmic_init(void)
{
        return i2c_add_driver(&max8952_pmic_driver);
}
subsys_initcall(max8952_pmic_init);

static void __exit max8952_pmic_exit(void)
{
        i2c_del_driver(&max8952_pmic_driver);
}
module_exit(max8952_pmic_exit);

MODULE_DESCRIPTION("MAXIM 8952 voltage regulator driver");
MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
MODULE_LICENSE("GPL");