// SPDX-License-Identifier: GPL-2.0-only
/*
 * axp288_adc.c - X-Powers AXP288 PMIC ADC Driver
 *
 * Copyright (C) 2014 Intel Corporation
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 */

#include <linux/dmi.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/regmap.h>
#include <linux/mfd/axp20x.h>
#include <linux/platform_device.h>

#include <linux/iio/iio.h>
#include <linux/iio/machine.h>
#include <linux/iio/driver.h>

/*
 * This mask enables all ADCs except for the battery temp-sensor (TS), that is
 * left as-is to avoid breaking charging on devices without a temp-sensor.
 */
#define AXP288_ADC_EN_MASK                              0xF0
#define AXP288_ADC_TS_ENABLE                            0x01

#define AXP288_ADC_TS_BIAS_MASK                         GENMASK(5, 4)
#define AXP288_ADC_TS_BIAS_20UA                         (0 << 4)
#define AXP288_ADC_TS_BIAS_40UA                         (1 << 4)
#define AXP288_ADC_TS_BIAS_60UA                         (2 << 4)
#define AXP288_ADC_TS_BIAS_80UA                         (3 << 4)
#define AXP288_ADC_TS_CURRENT_ON_OFF_MASK               GENMASK(1, 0)
#define AXP288_ADC_TS_CURRENT_OFF                       (0 << 0)
#define AXP288_ADC_TS_CURRENT_ON_WHEN_CHARGING          (1 << 0)
#define AXP288_ADC_TS_CURRENT_ON_ONDEMAND               (2 << 0)
#define AXP288_ADC_TS_CURRENT_ON                        (3 << 0)

enum axp288_adc_id {
        AXP288_ADC_TS,
        AXP288_ADC_PMIC,
        AXP288_ADC_GP,
        AXP288_ADC_BATT_CHRG_I,
        AXP288_ADC_BATT_DISCHRG_I,
        AXP288_ADC_BATT_V,
        AXP288_ADC_NR_CHAN,
};

struct axp288_adc_info {
        int irq;
        struct regmap *regmap;
        /* lock to protect against multiple access to the device */
        struct mutex lock;
        bool ts_enabled;
};

static const struct iio_chan_spec axp288_adc_channels[] = {
        {
                .indexed = 1,
                .type = IIO_TEMP,
                .channel = 0,
                .address = AXP288_TS_ADC_H,
                .datasheet_name = "TS_PIN",
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
        }, {
                .indexed = 1,
                .type = IIO_TEMP,
                .channel = 1,
                .address = AXP288_PMIC_ADC_H,
                .datasheet_name = "PMIC_TEMP",
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
        }, {
                .indexed = 1,
                .type = IIO_TEMP,
                .channel = 2,
                .address = AXP288_GP_ADC_H,
                .datasheet_name = "GPADC",
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
        }, {
                .indexed = 1,
                .type = IIO_CURRENT,
                .channel = 3,
                .address = AXP20X_BATT_CHRG_I_H,
                .datasheet_name = "BATT_CHG_I",
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
        }, {
                .indexed = 1,
                .type = IIO_CURRENT,
                .channel = 4,
                .address = AXP20X_BATT_DISCHRG_I_H,
                .datasheet_name = "BATT_DISCHRG_I",
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
        }, {
                .indexed = 1,
                .type = IIO_VOLTAGE,
                .channel = 5,
                .address = AXP20X_BATT_V_H,
                .datasheet_name = "BATT_V",
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
        },
};

/* for consumer drivers */
static const struct iio_map axp288_adc_default_maps[] = {
        IIO_MAP("TS_PIN", "axp288-batt", "axp288-batt-temp"),
        IIO_MAP("PMIC_TEMP", "axp288-pmic", "axp288-pmic-temp"),
        IIO_MAP("GPADC", "axp288-gpadc", "axp288-system-temp"),
        IIO_MAP("BATT_CHG_I", "axp288-chrg", "axp288-chrg-curr"),
        IIO_MAP("BATT_DISCHRG_I", "axp288-chrg", "axp288-chrg-d-curr"),
        IIO_MAP("BATT_V", "axp288-batt", "axp288-batt-volt"),
        { }
};

static int axp288_adc_read_channel(int *val, unsigned long address,
                                struct regmap *regmap)
{
        u8 buf[2];

        if (regmap_bulk_read(regmap, address, buf, 2))
                return -EIO;
        *val = (buf[0] << 4) + ((buf[1] >> 4) & 0x0F);

        return IIO_VAL_INT;
}

/*
 * The current-source used for the battery temp-sensor (TS) is shared
 * with the GPADC. For proper fuel-gauge and charger operation the TS
 * current-source needs to be permanently on. But to read the GPADC we
 * need to temporary switch the TS current-source to ondemand, so that
 * the GPADC can use it, otherwise we will always read an all 0 value.
 */
static int axp288_adc_set_ts(struct axp288_adc_info *info,
                             unsigned int mode, unsigned long address)
{
        int ret;

        /* No need to switch the current-source if the TS pin is disabled */
        if (!info->ts_enabled)
                return 0;

        /* Channels other than GPADC do not need the current source */
        if (address != AXP288_GP_ADC_H)
                return 0;

        ret = regmap_update_bits(info->regmap, AXP288_ADC_TS_PIN_CTRL,
                                 AXP288_ADC_TS_CURRENT_ON_OFF_MASK, mode);
        if (ret)
                return ret;

        /* When switching to the GPADC pin give things some time to settle */
        if (mode == AXP288_ADC_TS_CURRENT_ON_ONDEMAND)
                usleep_range(6000, 10000);

        return 0;
}

static int axp288_adc_read_raw(struct iio_dev *indio_dev,
                        struct iio_chan_spec const *chan,
                        int *val, int *val2, long mask)
{
        int ret;
        struct axp288_adc_info *info = iio_priv(indio_dev);

        mutex_lock(&info->lock);
        switch (mask) {
        case IIO_CHAN_INFO_RAW:
                if (axp288_adc_set_ts(info, AXP288_ADC_TS_CURRENT_ON_ONDEMAND,
                                        chan->address)) {
                        dev_err(&indio_dev->dev, "GPADC mode\n");
                        ret = -EINVAL;
                        break;
                }
                ret = axp288_adc_read_channel(val, chan->address, info->regmap);
                if (axp288_adc_set_ts(info, AXP288_ADC_TS_CURRENT_ON,
                                                chan->address))
                        dev_err(&indio_dev->dev, "TS pin restore\n");
                break;
        default:
                ret = -EINVAL;
        }
        mutex_unlock(&info->lock);

        return ret;
}

/*
 * We rely on the machine's firmware to correctly setup the TS pin bias current
 * at boot. This lists systems with broken fw where we need to set it ourselves.
 */
static const struct dmi_system_id axp288_adc_ts_bias_override[] = {
        {
                /* Lenovo Ideapad 100S (11 inch) */
                .matches = {
                  DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
                  DMI_MATCH(DMI_PRODUCT_VERSION, "Lenovo ideapad 100S-11IBY"),
                },
                .driver_data = (void *)(uintptr_t)AXP288_ADC_TS_BIAS_80UA,
        },
        {
                /* Nuvision Solo 10 Draw */
                .matches = {
                  DMI_MATCH(DMI_SYS_VENDOR, "TMAX"),
                  DMI_MATCH(DMI_PRODUCT_NAME, "TM101W610L"),
                },
                .driver_data = (void *)(uintptr_t)AXP288_ADC_TS_BIAS_80UA,
        },
        { }
};

static int axp288_adc_initialize(struct axp288_adc_info *info)
{
        const struct dmi_system_id *bias_override;
        int ret, adc_enable_val;

        bias_override = dmi_first_match(axp288_adc_ts_bias_override);
        if (bias_override) {
                ret = regmap_update_bits(info->regmap, AXP288_ADC_TS_PIN_CTRL,
                                         AXP288_ADC_TS_BIAS_MASK,
                                         (uintptr_t)bias_override->driver_data);
                if (ret)
                        return ret;
        }

        /*
         * Determine if the TS pin is enabled and set the TS current-source
         * accordingly.
         */
        ret = regmap_read(info->regmap, AXP20X_ADC_EN1, &adc_enable_val);
        if (ret)
                return ret;

        if (adc_enable_val & AXP288_ADC_TS_ENABLE) {
                info->ts_enabled = true;
                ret = regmap_update_bits(info->regmap, AXP288_ADC_TS_PIN_CTRL,
                                         AXP288_ADC_TS_CURRENT_ON_OFF_MASK,
                                         AXP288_ADC_TS_CURRENT_ON);
        } else {
                info->ts_enabled = false;
                ret = regmap_update_bits(info->regmap, AXP288_ADC_TS_PIN_CTRL,
                                         AXP288_ADC_TS_CURRENT_ON_OFF_MASK,
                                         AXP288_ADC_TS_CURRENT_OFF);
        }
        if (ret)
                return ret;

        /* Turn on the ADC for all channels except TS, leave TS as is */
        return regmap_set_bits(info->regmap, AXP20X_ADC_EN1,
                               AXP288_ADC_EN_MASK);
}

static const struct iio_info axp288_adc_iio_info = {
        .read_raw = &axp288_adc_read_raw,
};

static int axp288_adc_probe(struct platform_device *pdev)
{
        int ret;
        struct axp288_adc_info *info;
        struct iio_dev *indio_dev;
        struct axp20x_dev *axp20x = dev_get_drvdata(pdev->dev.parent);

        indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*info));
        if (!indio_dev)
                return -ENOMEM;

        info = iio_priv(indio_dev);
        info->irq = platform_get_irq(pdev, 0);
        if (info->irq < 0)
                return info->irq;

        info->regmap = axp20x->regmap;
        /*
         * Set ADC to enabled state at all time, including system suspend.
         * otherwise internal fuel gauge functionality may be affected.
         */
        ret = axp288_adc_initialize(info);
        if (ret) {
                dev_err(&pdev->dev, "unable to enable ADC device\n");
                return ret;
        }

        indio_dev->name = pdev->name;
        indio_dev->channels = axp288_adc_channels;
        indio_dev->num_channels = ARRAY_SIZE(axp288_adc_channels);
        indio_dev->info = &axp288_adc_iio_info;
        indio_dev->modes = INDIO_DIRECT_MODE;

        ret = devm_iio_map_array_register(&pdev->dev, indio_dev, axp288_adc_default_maps);
        if (ret < 0)
                return ret;

        mutex_init(&info->lock);

        return devm_iio_device_register(&pdev->dev, indio_dev);
}

static const struct platform_device_id axp288_adc_id_table[] = {
        { .name = "axp288_adc" },
        { }
};

static struct platform_driver axp288_adc_driver = {
        .probe = axp288_adc_probe,
        .id_table = axp288_adc_id_table,
        .driver = {
                .name = "axp288_adc",
        },
};

MODULE_DEVICE_TABLE(platform, axp288_adc_id_table);

module_platform_driver(axp288_adc_driver);

MODULE_AUTHOR("Jacob Pan <jacob.jun.pan@linux.intel.com>");
MODULE_DESCRIPTION("X-Powers AXP288 ADC Driver");
MODULE_LICENSE("GPL");