// SPDX-License-Identifier: GPL-2.0-only
/*
 * max8660.c  --  Voltage regulation for the Maxim 8660/8661
 *
 * based on max1586.c and wm8400-regulator.c
 *
 * Copyright (C) 2009 Wolfram Sang, Pengutronix e.K.
 *
 * Some info:
 *
 * Datasheet: http://datasheets.maxim-ic.com/en/ds/MAX8660-MAX8661.pdf
 *
 * This chip is a bit nasty because it is a write-only device. Thus, the driver
 * uses shadow registers to keep track of its values. The main problem appears
 * to be the initialization: When Linux boots up, we cannot know if the chip is
 * in the default state or not, so we would have to pass such information in
 * platform_data. As this adds a bit of complexity to the driver, this is left
 * out for now until it is really needed.
 *
 * [A|S|M]DTV1 registers are currently not used, but [A|S|M]DTV2.
 *
 * If the driver is feature complete, it might be worth to check if one set of
 * functions for V3-V7 is sufficient. For maximum flexibility during
 * development, they are separated for now.
 */

#include <linux/module.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/platform_device.h>
#include <linux/regulator/driver.h>
#include <linux/slab.h>
#include <linux/regulator/max8660.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/regulator/of_regulator.h>

#define MAX8660_DCDC_MIN_UV      725000
#define MAX8660_DCDC_MAX_UV     1800000
#define MAX8660_DCDC_STEP         25000
#define MAX8660_DCDC_MAX_SEL    0x2b

#define MAX8660_LDO5_MIN_UV     1700000
#define MAX8660_LDO5_MAX_UV     2000000
#define MAX8660_LDO5_STEP         25000
#define MAX8660_LDO5_MAX_SEL    0x0c

#define MAX8660_LDO67_MIN_UV    1800000
#define MAX8660_LDO67_MAX_UV    3300000
#define MAX8660_LDO67_STEP       100000
#define MAX8660_LDO67_MAX_SEL   0x0f

enum {
        MAX8660_OVER1,
        MAX8660_OVER2,
        MAX8660_VCC1,
        MAX8660_ADTV1,
        MAX8660_ADTV2,
        MAX8660_SDTV1,
        MAX8660_SDTV2,
        MAX8660_MDTV1,
        MAX8660_MDTV2,
        MAX8660_L12VCR,
        MAX8660_FPWM,
        MAX8660_N_REGS, /* not a real register */
};

struct max8660 {
        struct i2c_client *client;
        u8 shadow_regs[MAX8660_N_REGS];         /* as chip is write only */
};

static int max8660_write(struct max8660 *max8660, u8 reg, u8 mask, u8 val)
{
        static const u8 max8660_addresses[MAX8660_N_REGS] = {
         0x10, 0x12, 0x20, 0x23, 0x24, 0x29, 0x2a, 0x32, 0x33, 0x39, 0x80
        };

        int ret;
        u8 reg_val = (max8660->shadow_regs[reg] & mask) | val;

        dev_vdbg(&max8660->client->dev, "Writing reg %02x with %02x\n",
                        max8660_addresses[reg], reg_val);

        ret = i2c_smbus_write_byte_data(max8660->client,
                        max8660_addresses[reg], reg_val);
        if (ret == 0)
                max8660->shadow_regs[reg] = reg_val;

        return ret;
}


/*
 * DCDC functions
 */

static int max8660_dcdc_is_enabled(struct regulator_dev *rdev)
{
        struct max8660 *max8660 = rdev_get_drvdata(rdev);
        u8 val = max8660->shadow_regs[MAX8660_OVER1];
        u8 mask = (rdev_get_id(rdev) == MAX8660_V3) ? 1 : 4;

        return !!(val & mask);
}

static int max8660_dcdc_enable(struct regulator_dev *rdev)
{
        struct max8660 *max8660 = rdev_get_drvdata(rdev);
        u8 bit = (rdev_get_id(rdev) == MAX8660_V3) ? 1 : 4;

        return max8660_write(max8660, MAX8660_OVER1, 0xff, bit);
}

static int max8660_dcdc_disable(struct regulator_dev *rdev)
{
        struct max8660 *max8660 = rdev_get_drvdata(rdev);
        u8 mask = (rdev_get_id(rdev) == MAX8660_V3) ? ~1 : ~4;

        return max8660_write(max8660, MAX8660_OVER1, mask, 0);
}

static int max8660_dcdc_get_voltage_sel(struct regulator_dev *rdev)
{
        struct max8660 *max8660 = rdev_get_drvdata(rdev);
        u8 reg = (rdev_get_id(rdev) == MAX8660_V3) ? MAX8660_ADTV2 : MAX8660_SDTV2;
        u8 selector = max8660->shadow_regs[reg];

        return selector;
}

static int max8660_dcdc_set_voltage_sel(struct regulator_dev *rdev,
                                        unsigned int selector)
{
        struct max8660 *max8660 = rdev_get_drvdata(rdev);
        u8 reg, bits;
        int ret;

        reg = (rdev_get_id(rdev) == MAX8660_V3) ? MAX8660_ADTV2 : MAX8660_SDTV2;
        ret = max8660_write(max8660, reg, 0, selector);
        if (ret)
                return ret;

        /* Select target voltage register and activate regulation */
        bits = (rdev_get_id(rdev) == MAX8660_V3) ? 0x03 : 0x30;
        return max8660_write(max8660, MAX8660_VCC1, 0xff, bits);
}

static struct regulator_ops max8660_dcdc_ops = {
        .is_enabled = max8660_dcdc_is_enabled,
        .list_voltage = regulator_list_voltage_linear,
        .map_voltage = regulator_map_voltage_linear,
        .set_voltage_sel = max8660_dcdc_set_voltage_sel,
        .get_voltage_sel = max8660_dcdc_get_voltage_sel,
};


/*
 * LDO5 functions
 */

static int max8660_ldo5_get_voltage_sel(struct regulator_dev *rdev)
{
        struct max8660 *max8660 = rdev_get_drvdata(rdev);

        u8 selector = max8660->shadow_regs[MAX8660_MDTV2];
        return selector;
}

static int max8660_ldo5_set_voltage_sel(struct regulator_dev *rdev,
                                        unsigned int selector)
{
        struct max8660 *max8660 = rdev_get_drvdata(rdev);
        int ret;

        ret = max8660_write(max8660, MAX8660_MDTV2, 0, selector);
        if (ret)
                return ret;

        /* Select target voltage register and activate regulation */
        return max8660_write(max8660, MAX8660_VCC1, 0xff, 0xc0);
}

static const struct regulator_ops max8660_ldo5_ops = {
        .list_voltage = regulator_list_voltage_linear,
        .map_voltage = regulator_map_voltage_linear,
        .set_voltage_sel = max8660_ldo5_set_voltage_sel,
        .get_voltage_sel = max8660_ldo5_get_voltage_sel,
};


/*
 * LDO67 functions
 */

static int max8660_ldo67_is_enabled(struct regulator_dev *rdev)
{
        struct max8660 *max8660 = rdev_get_drvdata(rdev);
        u8 val = max8660->shadow_regs[MAX8660_OVER2];
        u8 mask = (rdev_get_id(rdev) == MAX8660_V6) ? 2 : 4;

        return !!(val & mask);
}

static int max8660_ldo67_enable(struct regulator_dev *rdev)
{
        struct max8660 *max8660 = rdev_get_drvdata(rdev);
        u8 bit = (rdev_get_id(rdev) == MAX8660_V6) ? 2 : 4;

        return max8660_write(max8660, MAX8660_OVER2, 0xff, bit);
}

static int max8660_ldo67_disable(struct regulator_dev *rdev)
{
        struct max8660 *max8660 = rdev_get_drvdata(rdev);
        u8 mask = (rdev_get_id(rdev) == MAX8660_V6) ? ~2 : ~4;

        return max8660_write(max8660, MAX8660_OVER2, mask, 0);
}

static int max8660_ldo67_get_voltage_sel(struct regulator_dev *rdev)
{
        struct max8660 *max8660 = rdev_get_drvdata(rdev);
        u8 shift = (rdev_get_id(rdev) == MAX8660_V6) ? 0 : 4;
        u8 selector = (max8660->shadow_regs[MAX8660_L12VCR] >> shift) & 0xf;

        return selector;
}

static int max8660_ldo67_set_voltage_sel(struct regulator_dev *rdev,
                                         unsigned int selector)
{
        struct max8660 *max8660 = rdev_get_drvdata(rdev);

        if (rdev_get_id(rdev) == MAX8660_V6)
                return max8660_write(max8660, MAX8660_L12VCR, 0xf0, selector);
        else
                return max8660_write(max8660, MAX8660_L12VCR, 0x0f,
                                     selector << 4);
}

static const struct regulator_ops max8660_ldo67_ops = {
        .is_enabled = max8660_ldo67_is_enabled,
        .enable = max8660_ldo67_enable,
        .disable = max8660_ldo67_disable,
        .list_voltage = regulator_list_voltage_linear,
        .map_voltage = regulator_map_voltage_linear,
        .get_voltage_sel = max8660_ldo67_get_voltage_sel,
        .set_voltage_sel = max8660_ldo67_set_voltage_sel,
};

static const struct regulator_desc max8660_reg[] = {
        {
                .name = "V3(DCDC)",
                .id = MAX8660_V3,
                .ops = &max8660_dcdc_ops,
                .type = REGULATOR_VOLTAGE,
                .n_voltages = MAX8660_DCDC_MAX_SEL + 1,
                .owner = THIS_MODULE,
                .min_uV = MAX8660_DCDC_MIN_UV,
                .uV_step = MAX8660_DCDC_STEP,
        },
        {
                .name = "V4(DCDC)",
                .id = MAX8660_V4,
                .ops = &max8660_dcdc_ops,
                .type = REGULATOR_VOLTAGE,
                .n_voltages = MAX8660_DCDC_MAX_SEL + 1,
                .owner = THIS_MODULE,
                .min_uV = MAX8660_DCDC_MIN_UV,
                .uV_step = MAX8660_DCDC_STEP,
        },
        {
                .name = "V5(LDO)",
                .id = MAX8660_V5,
                .ops = &max8660_ldo5_ops,
                .type = REGULATOR_VOLTAGE,
                .n_voltages = MAX8660_LDO5_MAX_SEL + 1,
                .owner = THIS_MODULE,
                .min_uV = MAX8660_LDO5_MIN_UV,
                .uV_step = MAX8660_LDO5_STEP,
        },
        {
                .name = "V6(LDO)",
                .id = MAX8660_V6,
                .ops = &max8660_ldo67_ops,
                .type = REGULATOR_VOLTAGE,
                .n_voltages = MAX8660_LDO67_MAX_SEL + 1,
                .owner = THIS_MODULE,
                .min_uV = MAX8660_LDO67_MIN_UV,
                .uV_step = MAX8660_LDO67_STEP,
        },
        {
                .name = "V7(LDO)",
                .id = MAX8660_V7,
                .ops = &max8660_ldo67_ops,
                .type = REGULATOR_VOLTAGE,
                .n_voltages = MAX8660_LDO67_MAX_SEL + 1,
                .owner = THIS_MODULE,
                .min_uV = MAX8660_LDO67_MIN_UV,
                .uV_step = MAX8660_LDO67_STEP,
        },
};

enum {
        MAX8660 = 0,
        MAX8661 = 1,
};

#ifdef CONFIG_OF
static const struct of_device_id max8660_dt_ids[] = {
        { .compatible = "maxim,max8660", .data = (void *) MAX8660 },
        { .compatible = "maxim,max8661", .data = (void *) MAX8661 },
        { }
};
MODULE_DEVICE_TABLE(of, max8660_dt_ids);

static int max8660_pdata_from_dt(struct device *dev,
                                 struct device_node **of_node,
                                 struct max8660_platform_data *pdata)
{
        int matched, i;
        struct device_node *np;
        struct max8660_subdev_data *sub;
        struct of_regulator_match rmatch[ARRAY_SIZE(max8660_reg)] = { };

        np = of_get_child_by_name(dev->of_node, "regulators");
        if (!np) {
                dev_err(dev, "missing 'regulators' subnode in DT\n");
                return -EINVAL;
        }

        for (i = 0; i < ARRAY_SIZE(rmatch); i++)
                rmatch[i].name = max8660_reg[i].name;

        matched = of_regulator_match(dev, np, rmatch, ARRAY_SIZE(rmatch));
        of_node_put(np);
        if (matched <= 0)
                return matched;

        pdata->subdevs = devm_kcalloc(dev,
                                      matched,
                                      sizeof(struct max8660_subdev_data),
                                      GFP_KERNEL);
        if (!pdata->subdevs)
                return -ENOMEM;

        pdata->num_subdevs = matched;
        sub = pdata->subdevs;

        for (i = 0; i < matched; i++) {
                sub->id = i;
                sub->name = rmatch[i].name;
                sub->platform_data = rmatch[i].init_data;
                of_node[i] = rmatch[i].of_node;
                sub++;
        }

        return 0;
}
#else
static inline int max8660_pdata_from_dt(struct device *dev,
                                        struct device_node **of_node,
                                        struct max8660_platform_data *pdata)
{
        return 0;
}
#endif

static int max8660_probe(struct i2c_client *client)
{
        const struct i2c_device_id *i2c_id = i2c_client_get_device_id(client);
        struct device *dev = &client->dev;
        struct max8660_platform_data pdata_of, *pdata = dev_get_platdata(dev);
        struct regulator_config config = { };
        struct max8660 *max8660;
        int boot_on, i, id, ret = -EINVAL;
        struct device_node *of_node[MAX8660_V_END];
        unsigned long type;

        if (dev->of_node && !pdata) {
                const struct of_device_id *id;

                id = of_match_device(of_match_ptr(max8660_dt_ids), dev);
                if (!id)
                        return -ENODEV;

                ret = max8660_pdata_from_dt(dev, of_node, &pdata_of);
                if (ret < 0)
                        return ret;

                pdata = &pdata_of;
                type = (unsigned long) id->data;
        } else {
                type = i2c_id->driver_data;
                memset(of_node, 0, sizeof(of_node));
        }

        if (pdata->num_subdevs > MAX8660_V_END) {
                dev_err(dev, "Too many regulators found!\n");
                return -EINVAL;
        }

        max8660 = devm_kzalloc(dev, sizeof(struct max8660), GFP_KERNEL);
        if (!max8660)
                return -ENOMEM;

        max8660->client = client;

        if (pdata->en34_is_high) {
                /* Simulate always on */
                max8660->shadow_regs[MAX8660_OVER1] = 5;
        } else {
                /* Otherwise devices can be toggled via software */
                max8660_dcdc_ops.enable = max8660_dcdc_enable;
                max8660_dcdc_ops.disable = max8660_dcdc_disable;
        }

        /*
         * First, set up shadow registers to prevent glitches. As some
         * registers are shared between regulators, everything must be properly
         * set up for all regulators in advance.
         */
        max8660->shadow_regs[MAX8660_ADTV1] =
                max8660->shadow_regs[MAX8660_ADTV2] =
                max8660->shadow_regs[MAX8660_SDTV1] =
                max8660->shadow_regs[MAX8660_SDTV2] = 0x1b;
        max8660->shadow_regs[MAX8660_MDTV1] =
                max8660->shadow_regs[MAX8660_MDTV2] = 0x04;

        for (i = 0; i < pdata->num_subdevs; i++) {

                if (!pdata->subdevs[i].platform_data)
                        boot_on = false;
                else
                        boot_on = pdata->subdevs[i].platform_data->constraints.boot_on;

                switch (pdata->subdevs[i].id) {
                case MAX8660_V3:
                        if (boot_on)
                                max8660->shadow_regs[MAX8660_OVER1] |= 1;
                        break;

                case MAX8660_V4:
                        if (boot_on)
                                max8660->shadow_regs[MAX8660_OVER1] |= 4;
                        break;

                case MAX8660_V5:
                        break;

                case MAX8660_V6:
                        if (boot_on)
                                max8660->shadow_regs[MAX8660_OVER2] |= 2;
                        break;

                case MAX8660_V7:
                        if (type == MAX8661) {
                                dev_err(dev, "Regulator not on this chip!\n");
                                return -EINVAL;
                        }

                        if (boot_on)
                                max8660->shadow_regs[MAX8660_OVER2] |= 4;
                        break;

                default:
                        dev_err(dev, "invalid regulator %s\n",
                                 pdata->subdevs[i].name);
                        return ret;
                }
        }

        /* Finally register devices */
        for (i = 0; i < pdata->num_subdevs; i++) {
                struct regulator_dev *rdev;

                id = pdata->subdevs[i].id;

                config.dev = dev;
                config.init_data = pdata->subdevs[i].platform_data;
                config.of_node = of_node[i];
                config.driver_data = max8660;

                rdev = devm_regulator_register(&client->dev,
                                                  &max8660_reg[id], &config);
                if (IS_ERR(rdev)) {
                        dev_err(&client->dev, "failed to register %s\n",
                                max8660_reg[id].name);
                        return PTR_ERR(rdev);
                }
        }

        i2c_set_clientdata(client, max8660);
        return 0;
}

static const struct i2c_device_id max8660_id[] = {
        { .name = "max8660", .driver_data = MAX8660 },
        { .name = "max8661", .driver_data = MAX8661 },
        { }
};
MODULE_DEVICE_TABLE(i2c, max8660_id);

static struct i2c_driver max8660_driver = {
        .probe = max8660_probe,
        .driver         = {
                .name   = "max8660",
                .probe_type = PROBE_PREFER_ASYNCHRONOUS,
        },
        .id_table       = max8660_id,
};

static int __init max8660_init(void)
{
        return i2c_add_driver(&max8660_driver);
}
subsys_initcall(max8660_init);

static void __exit max8660_exit(void)
{
        i2c_del_driver(&max8660_driver);
}
module_exit(max8660_exit);

/* Module information */
MODULE_DESCRIPTION("MAXIM 8660/8661 voltage regulator driver");
MODULE_AUTHOR("Wolfram Sang");
MODULE_LICENSE("GPL v2");