root/drivers/regulator/mp8859.c
// SPDX-License-Identifier: GPL-2.0
//
// Copyright (c) 2019 five technologies GmbH
// Author: Markus Reichl <m.reichl@fivetechno.de>

#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/of.h>
#include <linux/regulator/driver.h>
#include <linux/regmap.h>


#define VOL_MIN_IDX                     0x00
#define VOL_MAX_IDX                     0x7ff

/* Register definitions */
#define MP8859_VOUT_L_REG               0    //3 lo Bits
#define MP8859_VOUT_H_REG               1    //8 hi Bits
#define MP8859_VOUT_GO_REG              2
#define MP8859_IOUT_LIM_REG             3
#define MP8859_CTL1_REG                 4
#define MP8859_CTL2_REG                 5
#define MP8859_RESERVED1_REG            6
#define MP8859_RESERVED2_REG            7
#define MP8859_RESERVED3_REG            8
#define MP8859_STATUS_REG               9
#define MP8859_INTERRUPT_REG            0x0A
#define MP8859_MASK_REG                 0x0B
#define MP8859_ID1_REG                  0x0C
#define MP8859_MFR_ID_REG               0x27
#define MP8859_DEV_ID_REG               0x28
#define MP8859_IC_REV_REG               0x29

#define MP8859_MAX_REG                  0x29

#define MP8859_GO_BIT                   0x01

#define MP8859_IOUT_LIM_MASK            0x7f

#define MP8859_ENABLE_MASK              0x80
#define MP8859_DISCHG_EN_MASK           0x10
#define MP8859_MODE_MASK                0x08

#define MP8859_PG_MASK                  0x80
#define MP8859_OTP_MASK                 0x40
#define MP8859_OTW_MASK                 0x20
#define MP8859_CC_CV_MASK               0x10

static int mp8859_set_voltage_sel(struct regulator_dev *rdev, unsigned int sel)
{
        int ret;

        ret = regmap_write(rdev->regmap, MP8859_VOUT_L_REG, sel & 0x7);

        if (ret)
                return ret;
        ret = regmap_write(rdev->regmap, MP8859_VOUT_H_REG, sel >> 3);

        if (ret)
                return ret;
        ret = regmap_update_bits(rdev->regmap, MP8859_VOUT_GO_REG,
                                        MP8859_GO_BIT, 1);
        return ret;
}

static int mp8859_get_voltage_sel(struct regulator_dev *rdev)
{
        unsigned int val_tmp;
        unsigned int val;
        int ret;

        ret = regmap_read(rdev->regmap, MP8859_VOUT_H_REG, &val_tmp);

        if (ret)
                return ret;
        val = val_tmp << 3;

        ret = regmap_read(rdev->regmap, MP8859_VOUT_L_REG, &val_tmp);

        if (ret)
                return ret;
        val |= val_tmp & 0x07;
        return val;
}

static int mp8859_set_voltage_time_sel(struct regulator_dev *rdev,
                                       unsigned int from, unsigned int to)
{
        int change;

        /* The voltage ramps at 1mV/uS, selectors are 10mV */
        if (from > to)
                change = from - to;
        else
                change = to - from;

        return change * 10 * 1000;
}

static unsigned int mp8859_get_mode(struct regulator_dev *rdev)
{
        unsigned int val;
        int ret;

        ret = regmap_read(rdev->regmap, MP8859_CTL1_REG, &val);
        if (ret != 0) {
                dev_err(&rdev->dev, "Failed to read mode: %d\n", ret);
                return 0;
        }

        if (val & MP8859_MODE_MASK)
                return REGULATOR_MODE_FAST;
        else
                return REGULATOR_MODE_NORMAL;
}

static int mp8859_set_mode(struct regulator_dev *rdev, unsigned int mode)
{
        unsigned int val;

        switch (mode) {
        case REGULATOR_MODE_FAST:
                val = MP8859_MODE_MASK;
                break;
        case REGULATOR_MODE_NORMAL:
                val = 0;
                break;
        default:
                return -EINVAL;
        }

        return regmap_update_bits(rdev->regmap, MP8859_CTL1_REG,
                                  MP8859_MODE_MASK, val);
}

static int mp8859_set_current_limit(struct regulator_dev *rdev,
                                    int min_uA, int max_uA)
{
        unsigned int cur_val, new_val;
        int ret, i;

        /* Steps of 50mA */
        new_val = max_uA / 50000;
        if (new_val > MP8859_IOUT_LIM_MASK)
                return -EINVAL;
        if (new_val == 0)
                return -EINVAL;

        /*
         * If the regulator is limiting then ramp gradually as per
         * datasheet, otherwise just set the value directly.
         */
        ret = regmap_read(rdev->regmap, MP8859_STATUS_REG, &cur_val);
        if (ret != 0)
                return ret;
        if (!(cur_val & MP8859_CC_CV_MASK)) {
                return regmap_update_bits(rdev->regmap, MP8859_IOUT_LIM_REG,
                                          MP8859_IOUT_LIM_MASK, new_val);
        }

        ret = regmap_read(rdev->regmap, MP8859_IOUT_LIM_REG, &cur_val);
        if (ret != 0)
                return ret;

        if (cur_val >= new_val) {
                for (i = cur_val; i >= new_val; i--) {
                        ret = regmap_update_bits(rdev->regmap,
                                                 MP8859_IOUT_LIM_REG,
                                                 MP8859_IOUT_LIM_MASK,
                                                 cur_val - i);
                        if (ret != 0)
                                return ret;
                }
        } else {
                for (i = cur_val; i <= new_val; i++) {
                        ret = regmap_update_bits(rdev->regmap,
                                                 MP8859_IOUT_LIM_REG,
                                                 MP8859_IOUT_LIM_MASK,
                                                 cur_val + i);
                        if (ret != 0)
                                return ret;
                }
        }

        return 0;
}

static int mp8859_get_status(struct regulator_dev *rdev)
{
        unsigned int val;
        int ret;

        /* Output status is only meaingful when enabled */
        ret = regmap_read(rdev->regmap, MP8859_CTL1_REG, &val);
        if (ret != 0)
                return ret;
        if (!(val & MP8859_ENABLE_MASK))
                return REGULATOR_STATUS_UNDEFINED;

        ret = regmap_read(rdev->regmap, MP8859_STATUS_REG, &val);
        if (ret != 0)
                return ret;

        if (val & MP8859_PG_MASK)
                return REGULATOR_STATUS_ON;
        else
                return REGULATOR_STATUS_ERROR;
}

static int mp8859_get_error_flags(struct regulator_dev *rdev,
                                  unsigned int *flags)
{
        unsigned int status, enabled;
        int ret;

        *flags = 0;

        /* Output status is only meaingful when enabled */
        ret = regmap_read(rdev->regmap, MP8859_CTL1_REG, &enabled);
        if (ret != 0)
                return ret;
        enabled &= MP8859_ENABLE_MASK;

        ret = regmap_read(rdev->regmap, MP8859_STATUS_REG, &status);
        if (ret != 0)
                return ret;

        if (enabled && !(status & MP8859_PG_MASK))
                status |= REGULATOR_ERROR_FAIL;
        if (status & MP8859_OTP_MASK)
                status |= REGULATOR_ERROR_OVER_TEMP;
        if (status & MP8859_OTW_MASK)
                status |= REGULATOR_ERROR_OVER_TEMP_WARN;
        if (status & MP8859_CC_CV_MASK)
                status |= REGULATOR_ERROR_OVER_CURRENT;

        return 0;
}

static const struct linear_range mp8859_dcdc_ranges[] = {
        REGULATOR_LINEAR_RANGE(0, VOL_MIN_IDX, VOL_MAX_IDX, 10000),
};

static bool mp8859_readable(struct device *dev, unsigned int reg)
{
        switch (reg) {
        case MP8859_VOUT_L_REG:
        case MP8859_VOUT_H_REG:
        case MP8859_VOUT_GO_REG:
        case MP8859_IOUT_LIM_REG:
        case MP8859_CTL1_REG:
        case MP8859_CTL2_REG:
        case MP8859_STATUS_REG:
        case MP8859_INTERRUPT_REG:
        case MP8859_MASK_REG:
        case MP8859_ID1_REG:
        case MP8859_MFR_ID_REG:
        case MP8859_DEV_ID_REG:
        case MP8859_IC_REV_REG:
                return true;
        default:
                return false;
        }
}

static bool mp8859_volatile(struct device *dev, unsigned int reg)
{
        switch (reg) {
        case MP8859_VOUT_GO_REG:
        case MP8859_STATUS_REG:
        case MP8859_INTERRUPT_REG:
                return true;
        default:
                return false;
        }
}

static const struct regmap_config mp8859_regmap = {
        .reg_bits = 8,
        .val_bits = 8,
        .max_register = MP8859_MAX_REG,
        .cache_type = REGCACHE_MAPLE,
        .readable_reg = mp8859_readable,
        .volatile_reg = mp8859_volatile,
};

static const struct regulator_ops mp8859_ops = {
        .set_voltage_sel = mp8859_set_voltage_sel,
        .get_voltage_sel = mp8859_get_voltage_sel,
        .list_voltage = regulator_list_voltage_linear_range,
        .set_voltage_time_sel = mp8859_set_voltage_time_sel,
        .enable = regulator_enable_regmap,
        .disable = regulator_disable_regmap,
        .is_enabled = regulator_is_enabled_regmap,
        .set_mode = mp8859_set_mode,
        .get_mode = mp8859_get_mode,
        .set_active_discharge = regulator_set_active_discharge_regmap,
        .set_current_limit = mp8859_set_current_limit,
        .get_status = mp8859_get_status,
        .get_error_flags = mp8859_get_error_flags,
};

static const struct regulator_desc mp8859_regulators[] = {
        {
                .id = 0,
                .type = REGULATOR_VOLTAGE,
                .name = "mp8859_dcdc",
                .supply_name = "vin",
                .of_match = of_match_ptr("mp8859_dcdc"),
                .n_voltages = VOL_MAX_IDX + 1,
                .linear_ranges = mp8859_dcdc_ranges,
                .n_linear_ranges = 1,
                .enable_reg = MP8859_CTL1_REG,
                .enable_mask = MP8859_ENABLE_MASK,
                .enable_val = MP8859_ENABLE_MASK,
                .active_discharge_reg = MP8859_CTL1_REG,
                .active_discharge_on = MP8859_DISCHG_EN_MASK,
                .active_discharge_mask = MP8859_DISCHG_EN_MASK,
                .ops = &mp8859_ops,
                .owner = THIS_MODULE,
        },
};

static int mp8859_i2c_probe(struct i2c_client *i2c)
{
        int ret;
        struct regulator_config config = {.dev = &i2c->dev};
        struct regmap *regmap = devm_regmap_init_i2c(i2c, &mp8859_regmap);
        struct regulator_dev *rdev;
        unsigned int val, rev;

        if (IS_ERR(regmap)) {
                ret = PTR_ERR(regmap);
                dev_err(&i2c->dev, "regmap init failed: %d\n", ret);
                return ret;
        }

        ret = regmap_read(regmap, MP8859_MFR_ID_REG, &val);
        if (ret != 0) {
                dev_err(&i2c->dev, "Failed to read manufacturer ID: %d\n", ret);
                return ret;
        }
        if (val != 0x9) {
                dev_err(&i2c->dev, "Manufacturer ID %x != 9\n", val);
                return -EINVAL;
        }

        ret = regmap_read(regmap, MP8859_DEV_ID_REG, &val);
        if (ret != 0) {
                dev_err(&i2c->dev, "Failed to read device ID: %d\n", ret);
                return ret;
        }
        if (val != 0x58) {
                dev_err(&i2c->dev, "Manufacturer ID %x != 0x58\n", val);
                return -EINVAL;
        }

        ret = regmap_read(regmap, MP8859_IC_REV_REG, &rev);
        if (ret != 0) {
                dev_err(&i2c->dev, "Failed to read device revision: %d\n", ret);
                return ret;
        }
        ret = regmap_read(regmap, MP8859_ID1_REG, &val);
        if (ret != 0) {
                dev_err(&i2c->dev, "Failed to read device ID1: %d\n", ret);
                return ret;
        }
        dev_info(&i2c->dev, "MP8859-%04d revision %d\n", val, rev);

        rdev = devm_regulator_register(&i2c->dev, &mp8859_regulators[0],
                                        &config);

        if (IS_ERR(rdev)) {
                ret = PTR_ERR(rdev);
                dev_err(&i2c->dev, "failed to register %s: %d\n",
                        mp8859_regulators[0].name, ret);
                return ret;
        }
        return 0;
}

static const struct of_device_id mp8859_dt_id[] __maybe_unused = {
        {.compatible =  "mps,mp8859"},
        {},
};
MODULE_DEVICE_TABLE(of, mp8859_dt_id);

static const struct i2c_device_id mp8859_i2c_id[] = {
        { "mp8859", },
        {  },
};
MODULE_DEVICE_TABLE(i2c, mp8859_i2c_id);

static struct i2c_driver mp8859_regulator_driver = {
        .driver = {
                .name = "mp8859",
                .probe_type = PROBE_PREFER_ASYNCHRONOUS,
                .of_match_table = of_match_ptr(mp8859_dt_id),
        },
        .probe = mp8859_i2c_probe,
        .id_table = mp8859_i2c_id,
};

module_i2c_driver(mp8859_regulator_driver);

MODULE_DESCRIPTION("Monolithic Power Systems MP8859 voltage regulator driver");
MODULE_AUTHOR("Markus Reichl <m.reichl@fivetechno.de>");
MODULE_LICENSE("GPL v2");