// SPDX-License-Identifier: GPL-2.0-only
/*
 * Support for Vishay VCNL3020 proximity sensor on i2c bus.
 * Based on Vishay VCNL4000 driver code.
 */

#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/err.h>
#include <linux/delay.h>
#include <linux/regmap.h>
#include <linux/interrupt.h>

#include <linux/iio/iio.h>
#include <linux/iio/events.h>

#define VCNL3020_PROD_ID        0x21

#define VCNL_COMMAND            0x80 /* Command register */
#define VCNL_PROD_REV           0x81 /* Product ID and Revision ID */
#define VCNL_PROXIMITY_RATE     0x82 /* Rate of Proximity Measurement */
#define VCNL_LED_CURRENT        0x83 /* IR LED current for proximity mode */
#define VCNL_PS_RESULT_HI       0x87 /* Proximity result register, MSB */
#define VCNL_PS_RESULT_LO       0x88 /* Proximity result register, LSB */
#define VCNL_PS_ICR             0x89 /* Interrupt Control Register */
#define VCNL_PS_LO_THR_HI       0x8a /* High byte of low threshold value */
#define VCNL_PS_LO_THR_LO       0x8b /* Low byte of low threshold value */
#define VCNL_PS_HI_THR_HI       0x8c /* High byte of high threshold value */
#define VCNL_PS_HI_THR_LO       0x8d /* Low byte of high threshold value */
#define VCNL_ISR                0x8e /* Interrupt Status Register */
#define VCNL_PS_MOD_ADJ         0x8f /* Proximity Modulator Timing Adjustment */

/* Bit masks for COMMAND register */
#define VCNL_PS_RDY             BIT(5) /* proximity data ready? */
#define VCNL_PS_OD              BIT(3) /* start on-demand proximity
                                        * measurement
                                        */

/* Enables periodic proximity measurement */
#define VCNL_PS_EN              BIT(1)

/* Enables state machine and LP oscillator for self timed  measurements */
#define VCNL_PS_SELFTIMED_EN    BIT(0)

/* Bit masks for ICR */

/* Enable interrupts on low or high thresholds */
#define  VCNL_ICR_THRES_EN      BIT(1)

/* Bit masks for ISR */
#define VCNL_INT_TH_HI          BIT(0)  /* High threshold hit */
#define VCNL_INT_TH_LOW         BIT(1)  /* Low threshold hit */

#define VCNL_ON_DEMAND_TIMEOUT_US       100000
#define VCNL_POLL_US                    20000

static const int vcnl3020_prox_sampling_frequency[][2] = {
        {1, 950000},
        {3, 906250},
        {7, 812500},
        {16, 625000},
        {31, 250000},
        {62, 500000},
        {125, 0},
        {250, 0},
};

/**
 * struct vcnl3020_data - vcnl3020 specific data.
 * @regmap:     device register map.
 * @dev:        vcnl3020 device.
 * @rev:        revision id.
 * @lock:       lock for protecting access to device hardware registers.
 * @buf:        __be16 buffer.
 */
struct vcnl3020_data {
        struct regmap *regmap;
        struct device *dev;
        u8 rev;
        struct mutex lock;
        __be16 buf;
};

/**
 * struct vcnl3020_property - vcnl3020 property.
 * @name:       property name.
 * @reg:        i2c register offset.
 * @conversion_func:    conversion function.
 */
struct vcnl3020_property {
        const char *name;
        u32 reg;
        u32 (*conversion_func)(u32 *val);
};

static u32 microamp_to_reg(u32 *val)
{
        /*
         * An example of conversion from uA to reg val:
         * 200000 uA == 200 mA == 20
         */
        return *val /= 10000;
};

static const struct vcnl3020_property vcnl3020_led_current_property = {
        .name = "vishay,led-current-microamp",
        .reg = VCNL_LED_CURRENT,
        .conversion_func = microamp_to_reg,
};

static int vcnl3020_get_and_apply_property(struct vcnl3020_data *data,
                                           const struct vcnl3020_property *prop)
{
        int rc;
        u32 val;

        rc = device_property_read_u32(data->dev, prop->name, &val);
        if (rc)
                return 0;

        if (prop->conversion_func)
                prop->conversion_func(&val);

        rc = regmap_write(data->regmap, prop->reg, val);
        if (rc) {
                dev_err(data->dev, "Error (%d) setting property (%s)\n",
                        rc, prop->name);
        }

        return rc;
}

static int vcnl3020_init(struct vcnl3020_data *data)
{
        int rc;
        unsigned int reg;

        rc = regmap_read(data->regmap, VCNL_PROD_REV, &reg);
        if (rc) {
                dev_err(data->dev,
                        "Error (%d) reading product revision\n", rc);
                return rc;
        }

        if (reg != VCNL3020_PROD_ID) {
                dev_err(data->dev,
                        "Product id (%x) did not match vcnl3020 (%x)\n", reg,
                        VCNL3020_PROD_ID);
                return -ENODEV;
        }

        data->rev = reg;
        mutex_init(&data->lock);

        return vcnl3020_get_and_apply_property(data,
                                               &vcnl3020_led_current_property);
};

static bool vcnl3020_is_in_periodic_mode(struct vcnl3020_data *data)
{
        int rc;
        unsigned int cmd;

        rc = regmap_read(data->regmap, VCNL_COMMAND, &cmd);
        if (rc) {
                dev_err(data->dev,
                        "Error (%d) reading command register\n", rc);
                return false;
        }

        return !!(cmd & VCNL_PS_SELFTIMED_EN);
}

static int vcnl3020_measure_proximity(struct vcnl3020_data *data, int *val)
{
        int rc;
        unsigned int reg;

        mutex_lock(&data->lock);

        /* Protect against event capture. */
        if (vcnl3020_is_in_periodic_mode(data)) {
                rc = -EBUSY;
                goto err_unlock;
        }

        rc = regmap_write(data->regmap, VCNL_COMMAND, VCNL_PS_OD);
        if (rc)
                goto err_unlock;

        /* wait for data to become ready */
        rc = regmap_read_poll_timeout(data->regmap, VCNL_COMMAND, reg,
                                      reg & VCNL_PS_RDY, VCNL_POLL_US,
                                      VCNL_ON_DEMAND_TIMEOUT_US);
        if (rc) {
                dev_err(data->dev,
                        "Error (%d) reading vcnl3020 command register\n", rc);
                goto err_unlock;
        }

        /* high & low result bytes read */
        rc = regmap_bulk_read(data->regmap, VCNL_PS_RESULT_HI, &data->buf,
                              sizeof(data->buf));
        if (rc)
                goto err_unlock;

        *val = be16_to_cpu(data->buf);

err_unlock:
        mutex_unlock(&data->lock);

        return rc;
}

static int vcnl3020_read_proxy_samp_freq(struct vcnl3020_data *data, int *val,
                                         int *val2)
{
        int rc;
        unsigned int prox_rate;

        rc = regmap_read(data->regmap, VCNL_PROXIMITY_RATE, &prox_rate);
        if (rc)
                return rc;

        if (prox_rate >= ARRAY_SIZE(vcnl3020_prox_sampling_frequency))
                return -EINVAL;

        *val = vcnl3020_prox_sampling_frequency[prox_rate][0];
        *val2 = vcnl3020_prox_sampling_frequency[prox_rate][1];

        return 0;
}

static int vcnl3020_write_proxy_samp_freq(struct vcnl3020_data *data, int val,
                                          int val2)
{
        unsigned int i;
        int index = -1;
        int rc;

        mutex_lock(&data->lock);

        /* Protect against event capture. */
        if (vcnl3020_is_in_periodic_mode(data)) {
                rc = -EBUSY;
                goto err_unlock;
        }

        for (i = 0; i < ARRAY_SIZE(vcnl3020_prox_sampling_frequency); i++) {
                if (val == vcnl3020_prox_sampling_frequency[i][0] &&
                    val2 == vcnl3020_prox_sampling_frequency[i][1]) {
                        index = i;
                        break;
                }
        }

        if (index < 0) {
                rc = -EINVAL;
                goto err_unlock;
        }

        rc = regmap_write(data->regmap, VCNL_PROXIMITY_RATE, index);
        if (rc)
                dev_err(data->dev,
                        "Error (%d) writing proximity rate register\n", rc);

err_unlock:
        mutex_unlock(&data->lock);

        return rc;
}

static bool vcnl3020_is_thr_enabled(struct vcnl3020_data *data)
{
        int rc;
        unsigned int icr;

        rc = regmap_read(data->regmap, VCNL_PS_ICR, &icr);
        if (rc) {
                dev_err(data->dev,
                        "Error (%d) reading ICR register\n", rc);
                return false;
        }

        return !!(icr & VCNL_ICR_THRES_EN);
}

static int vcnl3020_read_event(struct iio_dev *indio_dev,
                               const struct iio_chan_spec *chan,
                               enum iio_event_type type,
                               enum iio_event_direction dir,
                               enum iio_event_info info,
                               int *val, int *val2)
{
        int rc;
        struct vcnl3020_data *data = iio_priv(indio_dev);

        switch (info) {
        case IIO_EV_INFO_VALUE:
                switch (dir) {
                case IIO_EV_DIR_RISING:
                        rc = regmap_bulk_read(data->regmap, VCNL_PS_HI_THR_HI,
                                              &data->buf, sizeof(data->buf));
                        if (rc < 0)
                                return rc;
                        *val = be16_to_cpu(data->buf);
                        return IIO_VAL_INT;
                case IIO_EV_DIR_FALLING:
                        rc = regmap_bulk_read(data->regmap, VCNL_PS_LO_THR_HI,
                                              &data->buf, sizeof(data->buf));
                        if (rc < 0)
                                return rc;
                        *val = be16_to_cpu(data->buf);
                        return IIO_VAL_INT;
                default:
                        return -EINVAL;
                }
        default:
                return -EINVAL;
        }
}

static int vcnl3020_write_event(struct iio_dev *indio_dev,
                                const struct iio_chan_spec *chan,
                                enum iio_event_type type,
                                enum iio_event_direction dir,
                                enum iio_event_info info,
                                int val, int val2)
{
        int rc;
        struct vcnl3020_data *data = iio_priv(indio_dev);

        mutex_lock(&data->lock);

        switch (info) {
        case IIO_EV_INFO_VALUE:
                switch (dir) {
                case IIO_EV_DIR_RISING:
                        /* 16 bit word/ low * high */
                        data->buf = cpu_to_be16(val);
                        rc = regmap_bulk_write(data->regmap, VCNL_PS_HI_THR_HI,
                                               &data->buf, sizeof(data->buf));
                        if (rc < 0)
                                goto err_unlock;
                        rc = IIO_VAL_INT;
                        goto err_unlock;
                case IIO_EV_DIR_FALLING:
                        data->buf = cpu_to_be16(val);
                        rc = regmap_bulk_write(data->regmap, VCNL_PS_LO_THR_HI,
                                               &data->buf, sizeof(data->buf));
                        if (rc < 0)
                                goto err_unlock;
                        rc = IIO_VAL_INT;
                        goto err_unlock;
                default:
                        rc = -EINVAL;
                        goto err_unlock;
                }
        default:
                rc = -EINVAL;
                goto err_unlock;
        }
err_unlock:
        mutex_unlock(&data->lock);

        return rc;
}

static int vcnl3020_enable_periodic(struct iio_dev *indio_dev,
                                    struct vcnl3020_data *data)
{
        int rc;
        int cmd;

        mutex_lock(&data->lock);

        /* Enable periodic measurement of proximity data. */
        cmd = VCNL_PS_EN | VCNL_PS_SELFTIMED_EN;

        rc = regmap_write(data->regmap, VCNL_COMMAND, cmd);
        if (rc) {
                dev_err(data->dev,
                        "Error (%d) writing command register\n", rc);
                goto err_unlock;
        }

        /*
         * Enable interrupts on threshold, for proximity data by
         * default.
         */
        rc = regmap_write(data->regmap, VCNL_PS_ICR, VCNL_ICR_THRES_EN);
        if (rc)
                dev_err(data->dev,
                        "Error (%d) reading ICR register\n", rc);

err_unlock:
        mutex_unlock(&data->lock);

        return rc;
}

static int vcnl3020_disable_periodic(struct iio_dev *indio_dev,
                                     struct vcnl3020_data *data)
{
        int rc;

        mutex_lock(&data->lock);

        rc = regmap_write(data->regmap, VCNL_COMMAND, 0);
        if (rc) {
                dev_err(data->dev,
                        "Error (%d) writing command register\n", rc);
                goto err_unlock;
        }

        rc = regmap_write(data->regmap, VCNL_PS_ICR, 0);
        if (rc) {
                dev_err(data->dev,
                        "Error (%d) writing ICR register\n", rc);
                goto err_unlock;
        }

        /* Clear interrupt flag bit */
        rc = regmap_write(data->regmap, VCNL_ISR, 0);
        if (rc)
                dev_err(data->dev,
                        "Error (%d) writing ISR register\n", rc);

err_unlock:
        mutex_unlock(&data->lock);

        return rc;
}

static int vcnl3020_config_threshold(struct iio_dev *indio_dev, bool state)
{
        struct vcnl3020_data *data = iio_priv(indio_dev);

        if (state) {
                return vcnl3020_enable_periodic(indio_dev, data);
        } else {
                if (!vcnl3020_is_thr_enabled(data))
                        return 0;
                return vcnl3020_disable_periodic(indio_dev, data);
        }
}

static int vcnl3020_write_event_config(struct iio_dev *indio_dev,
                                       const struct iio_chan_spec *chan,
                                       enum iio_event_type type,
                                       enum iio_event_direction dir,
                                       bool state)
{
        switch (chan->type) {
        case IIO_PROXIMITY:
                return vcnl3020_config_threshold(indio_dev, state);
        default:
                return -EINVAL;
        }
}

static int vcnl3020_read_event_config(struct iio_dev *indio_dev,
                                      const struct iio_chan_spec *chan,
                                      enum iio_event_type type,
                                      enum iio_event_direction dir)
{
        struct vcnl3020_data *data = iio_priv(indio_dev);

        switch (chan->type) {
        case IIO_PROXIMITY:
                return vcnl3020_is_thr_enabled(data);
        default:
                return -EINVAL;
        }
}

static const struct iio_event_spec vcnl3020_event_spec[] = {
        {
                .type = IIO_EV_TYPE_THRESH,
                .dir = IIO_EV_DIR_RISING,
                .mask_separate = BIT(IIO_EV_INFO_VALUE),
        }, {
                .type = IIO_EV_TYPE_THRESH,
                .dir = IIO_EV_DIR_FALLING,
                .mask_separate = BIT(IIO_EV_INFO_VALUE),
        }, {
                .type = IIO_EV_TYPE_THRESH,
                .dir = IIO_EV_DIR_EITHER,
                .mask_separate = BIT(IIO_EV_INFO_ENABLE),
        },
};

static const struct iio_chan_spec vcnl3020_channels[] = {
        {
                .type = IIO_PROXIMITY,
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
                                      BIT(IIO_CHAN_INFO_SAMP_FREQ),
                .info_mask_separate_available = BIT(IIO_CHAN_INFO_SAMP_FREQ),
                .event_spec = vcnl3020_event_spec,
                .num_event_specs = ARRAY_SIZE(vcnl3020_event_spec),
        },
};

static int vcnl3020_read_raw(struct iio_dev *indio_dev,
                             struct iio_chan_spec const *chan, int *val,
                             int *val2, long mask)
{
        int rc;
        struct vcnl3020_data *data = iio_priv(indio_dev);

        switch (mask) {
        case IIO_CHAN_INFO_RAW:
                rc = vcnl3020_measure_proximity(data, val);
                if (rc)
                        return rc;
                return IIO_VAL_INT;
        case IIO_CHAN_INFO_SAMP_FREQ:
                rc = vcnl3020_read_proxy_samp_freq(data, val, val2);
                if (rc < 0)
                        return rc;
                return IIO_VAL_INT_PLUS_MICRO;
        default:
                return -EINVAL;
        }
}

static int vcnl3020_write_raw(struct iio_dev *indio_dev,
                              struct iio_chan_spec const *chan,
                              int val, int val2, long mask)
{
        struct vcnl3020_data *data = iio_priv(indio_dev);

        switch (mask) {
        case IIO_CHAN_INFO_SAMP_FREQ:
                return vcnl3020_write_proxy_samp_freq(data, val, val2);
        default:
                return -EINVAL;
        }
}

static int vcnl3020_read_avail(struct iio_dev *indio_dev,
                               struct iio_chan_spec const *chan,
                               const int **vals, int *type, int *length,
                               long mask)
{
        switch (mask) {
        case IIO_CHAN_INFO_SAMP_FREQ:
                *vals = (int *)vcnl3020_prox_sampling_frequency;
                *type = IIO_VAL_INT_PLUS_MICRO;
                *length = 2 * ARRAY_SIZE(vcnl3020_prox_sampling_frequency);
                return IIO_AVAIL_LIST;
        default:
                return -EINVAL;
        }
}

static const struct iio_info vcnl3020_info = {
        .read_raw = vcnl3020_read_raw,
        .write_raw = vcnl3020_write_raw,
        .read_avail = vcnl3020_read_avail,
        .read_event_value = vcnl3020_read_event,
        .write_event_value = vcnl3020_write_event,
        .read_event_config = vcnl3020_read_event_config,
        .write_event_config = vcnl3020_write_event_config,
};

static const struct regmap_config vcnl3020_regmap_config = {
        .reg_bits       = 8,
        .val_bits       = 8,
        .max_register   = VCNL_PS_MOD_ADJ,
};

static irqreturn_t vcnl3020_handle_irq_thread(int irq, void *p)
{
        struct iio_dev *indio_dev = p;
        struct vcnl3020_data *data = iio_priv(indio_dev);
        unsigned int isr;
        int rc;

        rc = regmap_read(data->regmap, VCNL_ISR, &isr);
        if (rc) {
                dev_err(data->dev, "Error (%d) reading reg (0x%x)\n",
                        rc, VCNL_ISR);
                return IRQ_HANDLED;
        }

        if (!(isr & VCNL_ICR_THRES_EN))
                return IRQ_NONE;

        iio_push_event(indio_dev,
                       IIO_UNMOD_EVENT_CODE(IIO_PROXIMITY, 1,
                                            IIO_EV_TYPE_THRESH,
                                            IIO_EV_DIR_RISING),
                       iio_get_time_ns(indio_dev));

        rc = regmap_write(data->regmap, VCNL_ISR, isr & VCNL_ICR_THRES_EN);
        if (rc)
                dev_err(data->dev, "Error (%d) writing in reg (0x%x)\n",
                        rc, VCNL_ISR);

        return IRQ_HANDLED;
}

static int vcnl3020_probe(struct i2c_client *client)
{
        struct vcnl3020_data *data;
        struct iio_dev *indio_dev;
        struct regmap *regmap;
        int rc;

        regmap = devm_regmap_init_i2c(client, &vcnl3020_regmap_config);
        if (IS_ERR(regmap)) {
                dev_err(&client->dev, "regmap_init failed\n");
                return PTR_ERR(regmap);
        }

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

        data = iio_priv(indio_dev);
        i2c_set_clientdata(client, indio_dev);
        data->regmap = regmap;
        data->dev = &client->dev;

        rc = vcnl3020_init(data);
        if (rc)
                return rc;

        indio_dev->info = &vcnl3020_info;
        indio_dev->channels = vcnl3020_channels;
        indio_dev->num_channels = ARRAY_SIZE(vcnl3020_channels);
        indio_dev->name = "vcnl3020";
        indio_dev->modes = INDIO_DIRECT_MODE;

        if (client->irq) {
                rc = devm_request_threaded_irq(&client->dev, client->irq,
                                               NULL, vcnl3020_handle_irq_thread,
                                               IRQF_ONESHOT, indio_dev->name,
                                               indio_dev);
                if (rc) {
                        dev_err(&client->dev,
                                "Error (%d) irq request failed (%u)\n", rc,
                                client->irq);
                        return rc;
                }
        }

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

static const struct of_device_id vcnl3020_of_match[] = {
        {
                .compatible = "vishay,vcnl3020",
        },
        { }
};
MODULE_DEVICE_TABLE(of, vcnl3020_of_match);

static struct i2c_driver vcnl3020_driver = {
        .driver = {
                .name   = "vcnl3020",
                .of_match_table = vcnl3020_of_match,
        },
        .probe      = vcnl3020_probe,
};
module_i2c_driver(vcnl3020_driver);

MODULE_AUTHOR("Ivan Mikhaylov <i.mikhaylov@yadro.com>");
MODULE_DESCRIPTION("Vishay VCNL3020 proximity sensor driver");
MODULE_LICENSE("GPL");