// SPDX-License-Identifier: GPL-2.0-only
/*
 * Sensortek STK8BA50 3-Axis Accelerometer
 *
 * Copyright (c) 2015, Intel Corporation.
 *
 * STK8BA50 7-bit I2C address: 0x18.
 */

#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/types.h>
#include <linux/iio/buffer.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/trigger.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/iio/trigger_consumer.h>

#define STK8BA50_REG_XOUT                       0x02
#define STK8BA50_REG_YOUT                       0x04
#define STK8BA50_REG_ZOUT                       0x06
#define STK8BA50_REG_RANGE                      0x0F
#define STK8BA50_REG_BWSEL                      0x10
#define STK8BA50_REG_POWMODE                    0x11
#define STK8BA50_REG_SWRST                      0x14
#define STK8BA50_REG_INTEN2                     0x17
#define STK8BA50_REG_INTMAP2                    0x1A

#define STK8BA50_MODE_NORMAL                    0
#define STK8BA50_MODE_SUSPEND                   1
#define STK8BA50_MODE_POWERBIT                  BIT(7)
#define STK8BA50_DATA_SHIFT                     6
#define STK8BA50_RESET_CMD                      0xB6
#define STK8BA50_SR_1792HZ_IDX                  7
#define STK8BA50_DREADY_INT_MASK                0x10
#define STK8BA50_DREADY_INT_MAP                 0x81
#define STK8BA50_ALL_CHANNEL_MASK               7
#define STK8BA50_ALL_CHANNEL_SIZE               6

#define STK8BA50_DRIVER_NAME                    "stk8ba50"

#define STK8BA50_SCALE_AVAIL                    "0.0384 0.0767 0.1534 0.3069"

/*
 * The accelerometer has four measurement ranges:
 * +/-2g; +/-4g; +/-8g; +/-16g
 *
 * Acceleration values are 10-bit, 2's complement.
 * Scales are calculated as following:
 *
 * scale1 = (2 + 2) * 9.81 / (2^10 - 1)   = 0.0384
 * scale2 = (4 + 4) * 9.81 / (2^10 - 1)   = 0.0767
 * etc.
 *
 * Scales are stored in this format:
 * { <register value>, <scale value> }
 *
 * Locally, the range is stored as a table index.
 */
static const struct {
        u8 reg_val;
        u32 scale_val;
} stk8ba50_scale_table[] = {
        {3, 38400}, {5, 76700}, {8, 153400}, {12, 306900}
};

/* Sample rates are stored as { <register value>, <Hz value> } */
static const struct {
        u8 reg_val;
        u16 samp_freq;
} stk8ba50_samp_freq_table[] = {
        {0x08, 14},  {0x09, 25},  {0x0A, 56},  {0x0B, 112},
        {0x0C, 224}, {0x0D, 448}, {0x0E, 896}, {0x0F, 1792}
};

/* Used to map scan mask bits to their corresponding channel register. */
static const int stk8ba50_channel_table[] = {
        STK8BA50_REG_XOUT,
        STK8BA50_REG_YOUT,
        STK8BA50_REG_ZOUT
};

struct stk8ba50_data {
        struct i2c_client *client;
        struct mutex lock;
        int range;
        u8 sample_rate_idx;
        struct iio_trigger *dready_trig;
        bool dready_trigger_on;
        /* Ensure timestamp is naturally aligned */
        struct {
                s16 chans[3];
                aligned_s64 timetamp;
        } scan;
};

#define STK8BA50_ACCEL_CHANNEL(index, reg, axis) {                      \
        .type = IIO_ACCEL,                                              \
        .address = reg,                                                 \
        .modified = 1,                                                  \
        .channel2 = IIO_MOD_##axis,                                     \
        .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),                   \
        .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),           \
                                    BIT(IIO_CHAN_INFO_SAMP_FREQ),       \
        .scan_index = index,                                            \
        .scan_type = {                                                  \
                .sign = 's',                                            \
                .realbits = 10,                                         \
                .storagebits = 16,                                      \
                .shift = STK8BA50_DATA_SHIFT,                           \
                .endianness = IIO_CPU,                                  \
        },                                                              \
}

static const struct iio_chan_spec stk8ba50_channels[] = {
        STK8BA50_ACCEL_CHANNEL(0, STK8BA50_REG_XOUT, X),
        STK8BA50_ACCEL_CHANNEL(1, STK8BA50_REG_YOUT, Y),
        STK8BA50_ACCEL_CHANNEL(2, STK8BA50_REG_ZOUT, Z),
        IIO_CHAN_SOFT_TIMESTAMP(3),
};

static IIO_CONST_ATTR(in_accel_scale_available, STK8BA50_SCALE_AVAIL);

static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("14 25 56 112 224 448 896 1792");

static struct attribute *stk8ba50_attributes[] = {
        &iio_const_attr_in_accel_scale_available.dev_attr.attr,
        &iio_const_attr_sampling_frequency_available.dev_attr.attr,
        NULL,
};

static const struct attribute_group stk8ba50_attribute_group = {
        .attrs = stk8ba50_attributes
};

static int stk8ba50_read_accel(struct stk8ba50_data *data, u8 reg)
{
        int ret;
        struct i2c_client *client = data->client;

        ret = i2c_smbus_read_word_data(client, reg);
        if (ret < 0) {
                dev_err(&client->dev, "register read failed\n");
                return ret;
        }

        return ret;
}

static int stk8ba50_data_rdy_trigger_set_state(struct iio_trigger *trig,
                                               bool state)
{
        struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
        struct stk8ba50_data *data = iio_priv(indio_dev);
        int ret;

        if (state)
                ret = i2c_smbus_write_byte_data(data->client,
                        STK8BA50_REG_INTEN2, STK8BA50_DREADY_INT_MASK);
        else
                ret = i2c_smbus_write_byte_data(data->client,
                        STK8BA50_REG_INTEN2, 0x00);

        if (ret < 0)
                dev_err(&data->client->dev, "failed to set trigger state\n");
        else
                data->dready_trigger_on = state;

        return ret;
}

static const struct iio_trigger_ops stk8ba50_trigger_ops = {
        .set_trigger_state = stk8ba50_data_rdy_trigger_set_state,
};

static int stk8ba50_set_power(struct stk8ba50_data *data, bool mode)
{
        int ret;
        u8 masked_reg;
        struct i2c_client *client = data->client;

        ret = i2c_smbus_read_byte_data(client, STK8BA50_REG_POWMODE);
        if (ret < 0)
                goto exit_err;

        if (mode)
                masked_reg = ret | STK8BA50_MODE_POWERBIT;
        else
                masked_reg = ret & (~STK8BA50_MODE_POWERBIT);

        ret = i2c_smbus_write_byte_data(client, STK8BA50_REG_POWMODE,
                                        masked_reg);
        if (ret < 0)
                goto exit_err;

        return ret;

exit_err:
        dev_err(&client->dev, "failed to change sensor mode\n");
        return ret;
}

static int stk8ba50_read_raw(struct iio_dev *indio_dev,
                             struct iio_chan_spec const *chan,
                             int *val, int *val2, long mask)
{
        struct stk8ba50_data *data = iio_priv(indio_dev);
        int ret;

        switch (mask) {
        case IIO_CHAN_INFO_RAW:
                if (iio_buffer_enabled(indio_dev))
                        return -EBUSY;
                mutex_lock(&data->lock);
                ret = stk8ba50_set_power(data, STK8BA50_MODE_NORMAL);
                if (ret < 0) {
                        mutex_unlock(&data->lock);
                        return -EINVAL;
                }
                ret = stk8ba50_read_accel(data, chan->address);
                if (ret < 0) {
                        stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
                        mutex_unlock(&data->lock);
                        return -EINVAL;
                }
                *val = sign_extend32(ret >> chan->scan_type.shift,
                                     chan->scan_type.realbits - 1);
                stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
                mutex_unlock(&data->lock);
                return IIO_VAL_INT;
        case IIO_CHAN_INFO_SCALE:
                *val = 0;
                *val2 = stk8ba50_scale_table[data->range].scale_val;
                return IIO_VAL_INT_PLUS_MICRO;
        case IIO_CHAN_INFO_SAMP_FREQ:
                *val = stk8ba50_samp_freq_table
                                [data->sample_rate_idx].samp_freq;
                *val2 = 0;
                return IIO_VAL_INT;
        }

        return -EINVAL;
}

static int stk8ba50_write_raw(struct iio_dev *indio_dev,
                              struct iio_chan_spec const *chan,
                              int val, int val2, long mask)
{
        int ret;
        int i;
        int index = -1;
        struct stk8ba50_data *data = iio_priv(indio_dev);

        switch (mask) {
        case IIO_CHAN_INFO_SCALE:
                if (val != 0)
                        return -EINVAL;

                for (i = 0; i < ARRAY_SIZE(stk8ba50_scale_table); i++)
                        if (val2 == stk8ba50_scale_table[i].scale_val) {
                                index = i;
                                break;
                        }
                if (index < 0)
                        return -EINVAL;

                ret = i2c_smbus_write_byte_data(data->client,
                                STK8BA50_REG_RANGE,
                                stk8ba50_scale_table[index].reg_val);
                if (ret < 0)
                        dev_err(&data->client->dev,
                                        "failed to set measurement range\n");
                else
                        data->range = index;

                return ret;
        case IIO_CHAN_INFO_SAMP_FREQ:
                for (i = 0; i < ARRAY_SIZE(stk8ba50_samp_freq_table); i++)
                        if (val == stk8ba50_samp_freq_table[i].samp_freq) {
                                index = i;
                                break;
                        }
                if (index < 0)
                        return -EINVAL;

                ret = i2c_smbus_write_byte_data(data->client,
                                STK8BA50_REG_BWSEL,
                                stk8ba50_samp_freq_table[index].reg_val);
                if (ret < 0)
                        dev_err(&data->client->dev,
                                        "failed to set sampling rate\n");
                else
                        data->sample_rate_idx = index;

                return ret;
        }

        return -EINVAL;
}

static const struct iio_info stk8ba50_info = {
        .read_raw               = stk8ba50_read_raw,
        .write_raw              = stk8ba50_write_raw,
        .attrs                  = &stk8ba50_attribute_group,
};

static irqreturn_t stk8ba50_trigger_handler(int irq, void *p)
{
        struct iio_poll_func *pf = p;
        struct iio_dev *indio_dev = pf->indio_dev;
        struct stk8ba50_data *data = iio_priv(indio_dev);
        int bit, ret, i = 0;

        mutex_lock(&data->lock);
        /*
         * Do a bulk read if all channels are requested,
         * from 0x02 (XOUT1) to 0x07 (ZOUT2)
         */
        if (*(indio_dev->active_scan_mask) == STK8BA50_ALL_CHANNEL_MASK) {
                ret = i2c_smbus_read_i2c_block_data(data->client,
                                                    STK8BA50_REG_XOUT,
                                                    STK8BA50_ALL_CHANNEL_SIZE,
                                                    (u8 *)data->scan.chans);
                if (ret < STK8BA50_ALL_CHANNEL_SIZE) {
                        dev_err(&data->client->dev, "register read failed\n");
                        goto err;
                }
        } else {
                iio_for_each_active_channel(indio_dev, bit) {
                        ret = stk8ba50_read_accel(data,
                                                  stk8ba50_channel_table[bit]);
                        if (ret < 0)
                                goto err;

                        data->scan.chans[i++] = ret;
                }
        }
        iio_push_to_buffers_with_ts(indio_dev, &data->scan, sizeof(data->scan),
                                    pf->timestamp);
err:
        mutex_unlock(&data->lock);
        iio_trigger_notify_done(indio_dev->trig);

        return IRQ_HANDLED;
}

static irqreturn_t stk8ba50_data_rdy_trig_poll(int irq, void *private)
{
        struct iio_dev *indio_dev = private;
        struct stk8ba50_data *data = iio_priv(indio_dev);

        if (data->dready_trigger_on)
                iio_trigger_poll(data->dready_trig);

        return IRQ_HANDLED;
}

static int stk8ba50_buffer_preenable(struct iio_dev *indio_dev)
{
        struct stk8ba50_data *data = iio_priv(indio_dev);

        return stk8ba50_set_power(data, STK8BA50_MODE_NORMAL);
}

static int stk8ba50_buffer_postdisable(struct iio_dev *indio_dev)
{
        struct stk8ba50_data *data = iio_priv(indio_dev);

        return stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
}

static const struct iio_buffer_setup_ops stk8ba50_buffer_setup_ops = {
        .preenable   = stk8ba50_buffer_preenable,
        .postdisable = stk8ba50_buffer_postdisable,
};

static int stk8ba50_probe(struct i2c_client *client)
{
        int ret;
        struct iio_dev *indio_dev;
        struct stk8ba50_data *data;

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

        data = iio_priv(indio_dev);
        data->client = client;
        i2c_set_clientdata(client, indio_dev);
        mutex_init(&data->lock);

        indio_dev->info = &stk8ba50_info;
        indio_dev->name = STK8BA50_DRIVER_NAME;
        indio_dev->modes = INDIO_DIRECT_MODE;
        indio_dev->channels = stk8ba50_channels;
        indio_dev->num_channels = ARRAY_SIZE(stk8ba50_channels);

        /* Reset all registers on startup */
        ret = i2c_smbus_write_byte_data(client,
                        STK8BA50_REG_SWRST, STK8BA50_RESET_CMD);
        if (ret < 0) {
                dev_err(&client->dev, "failed to reset sensor\n");
                goto err_power_off;
        }

        /* The default range is +/-2g */
        data->range = 0;

        /* The default sampling rate is 1792 Hz (maximum) */
        data->sample_rate_idx = STK8BA50_SR_1792HZ_IDX;

        /* Set up interrupts */
        ret = i2c_smbus_write_byte_data(client,
                        STK8BA50_REG_INTEN2, STK8BA50_DREADY_INT_MASK);
        if (ret < 0) {
                dev_err(&client->dev, "failed to set up interrupts\n");
                goto err_power_off;
        }
        ret = i2c_smbus_write_byte_data(client,
                        STK8BA50_REG_INTMAP2, STK8BA50_DREADY_INT_MAP);
        if (ret < 0) {
                dev_err(&client->dev, "failed to set up interrupts\n");
                goto err_power_off;
        }

        if (client->irq > 0) {
                ret = devm_request_irq(&client->dev, client->irq,
                                       stk8ba50_data_rdy_trig_poll,
                                       IRQF_TRIGGER_RISING | IRQF_NO_THREAD,
                                       "stk8ba50_event", indio_dev);
                if (ret < 0) {
                        dev_err(&client->dev, "request irq %d failed\n",
                                client->irq);
                        goto err_power_off;
                }

                data->dready_trig = devm_iio_trigger_alloc(&client->dev,
                                                           "%s-dev%d",
                                                           indio_dev->name,
                                                           iio_device_id(indio_dev));
                if (!data->dready_trig) {
                        ret = -ENOMEM;
                        goto err_power_off;
                }

                data->dready_trig->ops = &stk8ba50_trigger_ops;
                iio_trigger_set_drvdata(data->dready_trig, indio_dev);
                ret = iio_trigger_register(data->dready_trig);
                if (ret) {
                        dev_err(&client->dev, "iio trigger register failed\n");
                        goto err_power_off;
                }
        }

        ret = iio_triggered_buffer_setup(indio_dev,
                                         iio_pollfunc_store_time,
                                         stk8ba50_trigger_handler,
                                         &stk8ba50_buffer_setup_ops);
        if (ret < 0) {
                dev_err(&client->dev, "iio triggered buffer setup failed\n");
                goto err_trigger_unregister;
        }

        ret = iio_device_register(indio_dev);
        if (ret < 0) {
                dev_err(&client->dev, "device_register failed\n");
                goto err_buffer_cleanup;
        }

        return ret;

err_buffer_cleanup:
        iio_triggered_buffer_cleanup(indio_dev);
err_trigger_unregister:
        if (data->dready_trig)
                iio_trigger_unregister(data->dready_trig);
err_power_off:
        stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
        return ret;
}

static void stk8ba50_remove(struct i2c_client *client)
{
        struct iio_dev *indio_dev = i2c_get_clientdata(client);
        struct stk8ba50_data *data = iio_priv(indio_dev);

        iio_device_unregister(indio_dev);
        iio_triggered_buffer_cleanup(indio_dev);

        if (data->dready_trig)
                iio_trigger_unregister(data->dready_trig);

        stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
}

static int stk8ba50_suspend(struct device *dev)
{
        struct stk8ba50_data *data;

        data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));

        return stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
}

static int stk8ba50_resume(struct device *dev)
{
        struct stk8ba50_data *data;

        data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));

        return stk8ba50_set_power(data, STK8BA50_MODE_NORMAL);
}

static DEFINE_SIMPLE_DEV_PM_OPS(stk8ba50_pm_ops, stk8ba50_suspend,
                                stk8ba50_resume);

static const struct i2c_device_id stk8ba50_i2c_id[] = {
        { "stk8ba50" },
        { }
};
MODULE_DEVICE_TABLE(i2c, stk8ba50_i2c_id);

static const struct acpi_device_id stk8ba50_acpi_id[] = {
        {"STK8BA50", 0},
        { }
};

MODULE_DEVICE_TABLE(acpi, stk8ba50_acpi_id);

static struct i2c_driver stk8ba50_driver = {
        .driver = {
                .name = "stk8ba50",
                .pm = pm_sleep_ptr(&stk8ba50_pm_ops),
                .acpi_match_table = stk8ba50_acpi_id,
        },
        .probe =        stk8ba50_probe,
        .remove =           stk8ba50_remove,
        .id_table =         stk8ba50_i2c_id,
};

module_i2c_driver(stk8ba50_driver);

MODULE_AUTHOR("Tiberiu Breana <tiberiu.a.breana@intel.com>");
MODULE_DESCRIPTION("STK8BA50 3-Axis Accelerometer driver");
MODULE_LICENSE("GPL v2");