// SPDX-License-Identifier: GPL-2.0
/*
 * cros_ec_sensors_core - Common function for Chrome OS EC sensor driver.
 *
 * Copyright (C) 2016 Google, Inc
 */

#include <linux/delay.h>
#include <linux/device.h>
#include <linux/iio/buffer.h>
#include <linux/iio/common/cros_ec_sensors_core.h>
#include <linux/iio/iio.h>
#include <linux/iio/kfifo_buf.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/trigger.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/platform_data/cros_ec_commands.h>
#include <linux/platform_data/cros_ec_proto.h>
#include <linux/platform_data/cros_ec_sensorhub.h>
#include <linux/platform_device.h>

/*
 * Hard coded to the first device to support sensor fifo.  The EC has a 2048
 * byte fifo and will trigger an interrupt when fifo is 2/3 full.
 */
#define CROS_EC_FIFO_SIZE (2048 * 2 / 3)

static char *cros_ec_loc[] = {
        [MOTIONSENSE_LOC_BASE] = "base",
        [MOTIONSENSE_LOC_LID] = "lid",
        [MOTIONSENSE_LOC_MAX] = "unknown",
};

static int cros_ec_get_host_cmd_version_mask(struct cros_ec_device *ec_dev,
                                             u16 cmd_offset, u16 cmd, u32 *mask)
{
        int ret;
        struct {
                struct cros_ec_command msg;
                union {
                        struct ec_params_get_cmd_versions params;
                        struct ec_response_get_cmd_versions resp;
                };
        } __packed buf = {
                .msg = {
                        .command = EC_CMD_GET_CMD_VERSIONS + cmd_offset,
                        .insize = sizeof(struct ec_response_get_cmd_versions),
                        .outsize = sizeof(struct ec_params_get_cmd_versions)
                        },
                .params = {.cmd = cmd}
        };

        ret = cros_ec_cmd_xfer_status(ec_dev, &buf.msg);
        if (ret >= 0)
                *mask = buf.resp.version_mask;
        return ret;
}

static void get_default_min_max_freq(enum motionsensor_type type,
                                     u32 *min_freq,
                                     u32 *max_freq,
                                     u32 *max_fifo_events)
{
        /*
         * We don't know fifo size, set to size previously used by older
         * hardware.
         */
        *max_fifo_events = CROS_EC_FIFO_SIZE;

        switch (type) {
        case MOTIONSENSE_TYPE_ACCEL:
                *min_freq = 12500;
                *max_freq = 100000;
                break;
        case MOTIONSENSE_TYPE_GYRO:
                *min_freq = 25000;
                *max_freq = 100000;
                break;
        case MOTIONSENSE_TYPE_MAG:
                *min_freq = 5000;
                *max_freq = 25000;
                break;
        case MOTIONSENSE_TYPE_PROX:
        case MOTIONSENSE_TYPE_LIGHT:
                *min_freq = 100;
                *max_freq = 50000;
                break;
        case MOTIONSENSE_TYPE_BARO:
                *min_freq = 250;
                *max_freq = 20000;
                break;
        case MOTIONSENSE_TYPE_ACTIVITY:
        default:
                *min_freq = 0;
                *max_freq = 0;
                break;
        }
}

static int cros_ec_sensor_set_ec_rate(struct cros_ec_sensors_core_state *st,
                                      int rate)
{
        int ret;

        if (rate > U16_MAX)
                rate = U16_MAX;

        mutex_lock(&st->cmd_lock);
        st->param.cmd = MOTIONSENSE_CMD_EC_RATE;
        st->param.ec_rate.data = rate;
        ret = cros_ec_motion_send_host_cmd(st, 0);
        mutex_unlock(&st->cmd_lock);
        return ret;
}

static ssize_t cros_ec_sensor_set_report_latency(struct device *dev,
                                                 struct device_attribute *attr,
                                                 const char *buf, size_t len)
{
        struct iio_dev *indio_dev = dev_to_iio_dev(dev);
        struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
        int integer, fract, ret;
        int latency;

        ret = iio_str_to_fixpoint(buf, 100000, &integer, &fract);
        if (ret)
                return ret;

        /* EC rate is in ms. */
        latency = integer * 1000 + fract / 1000;
        ret = cros_ec_sensor_set_ec_rate(st, latency);
        if (ret < 0)
                return ret;

        return len;
}

static ssize_t cros_ec_sensor_get_report_latency(struct device *dev,
                                                 struct device_attribute *attr,
                                                 char *buf)
{
        struct iio_dev *indio_dev = dev_to_iio_dev(dev);
        struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
        int latency, ret;

        mutex_lock(&st->cmd_lock);
        st->param.cmd = MOTIONSENSE_CMD_EC_RATE;
        st->param.ec_rate.data = EC_MOTION_SENSE_NO_VALUE;

        ret = cros_ec_motion_send_host_cmd(st, 0);
        latency = st->resp->ec_rate.ret;
        mutex_unlock(&st->cmd_lock);
        if (ret < 0)
                return ret;

        return sprintf(buf, "%d.%06u\n",
                       latency / 1000,
                       (latency % 1000) * 1000);
}

static IIO_DEVICE_ATTR(hwfifo_timeout, 0644,
                       cros_ec_sensor_get_report_latency,
                       cros_ec_sensor_set_report_latency, 0);

static ssize_t hwfifo_watermark_max_show(struct device *dev,
                                         struct device_attribute *attr,
                                         char *buf)
{
        struct iio_dev *indio_dev = dev_to_iio_dev(dev);
        struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);

        return sprintf(buf, "%d\n", st->fifo_max_event_count);
}

static IIO_DEVICE_ATTR_RO(hwfifo_watermark_max, 0);

static const struct attribute *cros_ec_sensor_fifo_attributes[] = {
        &iio_dev_attr_hwfifo_timeout.dev_attr.attr,
        &iio_dev_attr_hwfifo_watermark_max.dev_attr.attr,
        NULL,
};

int cros_ec_sensors_push_data(struct iio_dev *indio_dev,
                              s16 *data,
                              s64 timestamp)
{
        struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
        s16 *out;
        s64 delta;
        unsigned int i;

        /*
         * Ignore samples if the buffer is not set: it is needed if the ODR is
         * set but the buffer is not enabled yet.
         */
        if (!iio_buffer_enabled(indio_dev))
                return 0;

        out = (s16 *)st->samples;
        for_each_set_bit(i,
                         indio_dev->active_scan_mask,
                         indio_dev->masklength) {
                *out = data[i];
                out++;
        }

        if (iio_device_get_clock(indio_dev) != CLOCK_BOOTTIME)
                delta = iio_get_time_ns(indio_dev) - cros_ec_get_time_ns();
        else
                delta = 0;

        iio_push_to_buffers_with_timestamp(indio_dev, st->samples,
                                           timestamp + delta);

        return 0;
}
EXPORT_SYMBOL_GPL(cros_ec_sensors_push_data);

static void cros_ec_sensors_core_clean(void *arg)
{
        struct platform_device *pdev = (struct platform_device *)arg;
        struct cros_ec_sensorhub *sensor_hub =
                dev_get_drvdata(pdev->dev.parent);
        struct iio_dev *indio_dev = platform_get_drvdata(pdev);
        struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
        u8 sensor_num = st->param.info.sensor_num;

        cros_ec_sensorhub_unregister_push_data(sensor_hub, sensor_num);
}

/**
 * cros_ec_sensors_core_init() - basic initialization of the core structure
 * @pdev:               platform device created for the sensors
 * @indio_dev:          iio device structure of the device
 * @physical_device:    true if the device refers to a physical device
 * @trigger_capture:    function pointer to call buffer is triggered,
 *    for backward compatibility.
 * @push_data:          function to call when cros_ec_sensorhub receives
 *    a sample for that sensor.
 *
 * Return: 0 on success, -errno on failure.
 */
int cros_ec_sensors_core_init(struct platform_device *pdev,
                              struct iio_dev *indio_dev,
                              bool physical_device,
                              cros_ec_sensors_capture_t trigger_capture,
                              cros_ec_sensorhub_push_data_cb_t push_data)
{
        struct device *dev = &pdev->dev;
        struct cros_ec_sensors_core_state *state = iio_priv(indio_dev);
        struct cros_ec_sensorhub *sensor_hub = dev_get_drvdata(dev->parent);
        struct cros_ec_dev *ec = sensor_hub->ec;
        struct cros_ec_sensor_platform *sensor_platform = dev_get_platdata(dev);
        u32 ver_mask, temp;
        int frequencies[ARRAY_SIZE(state->frequencies) / 2] = { 0 };
        int ret, i;

        platform_set_drvdata(pdev, indio_dev);

        state->ec = ec->ec_dev;
        state->msg = devm_kzalloc(&pdev->dev,
                                max((u16)sizeof(struct ec_params_motion_sense),
                                state->ec->max_response), GFP_KERNEL);
        if (!state->msg)
                return -ENOMEM;

        state->resp = (struct ec_response_motion_sense *)state->msg->data;

        mutex_init(&state->cmd_lock);

        ret = cros_ec_get_host_cmd_version_mask(state->ec,
                                                ec->cmd_offset,
                                                EC_CMD_MOTION_SENSE_CMD,
                                                &ver_mask);
        if (ret < 0)
                return ret;

        /* Set up the host command structure. */
        state->msg->version = fls(ver_mask) - 1;
        state->msg->command = EC_CMD_MOTION_SENSE_CMD + ec->cmd_offset;
        state->msg->outsize = sizeof(struct ec_params_motion_sense);

        indio_dev->name = pdev->name;

        if (physical_device) {
                state->param.cmd = MOTIONSENSE_CMD_INFO;
                state->param.info.sensor_num = sensor_platform->sensor_num;
                ret = cros_ec_motion_send_host_cmd(state, 0);
                if (ret) {
                        dev_warn(dev, "Can not access sensor info\n");
                        return ret;
                }
                state->type = state->resp->info.type;
                state->loc = state->resp->info.location;

                /* Set sign vector, only used for backward compatibility. */
                memset(state->sign, 1, CROS_EC_SENSOR_MAX_AXIS);

                for (i = CROS_EC_SENSOR_X; i < CROS_EC_SENSOR_MAX_AXIS; i++)
                        state->calib[i].scale = MOTION_SENSE_DEFAULT_SCALE;

                /* 0 is a correct value used to stop the device */
                if (state->msg->version < 3) {
                        get_default_min_max_freq(state->resp->info.type,
                                                 &frequencies[1],
                                                 &frequencies[2],
                                                 &state->fifo_max_event_count);
                } else {
                        if (state->resp->info_3.max_frequency == 0) {
                                get_default_min_max_freq(state->resp->info.type,
                                                         &frequencies[1],
                                                         &frequencies[2],
                                                         &temp);
                        } else {
                                frequencies[1] = state->resp->info_3.min_frequency;
                                frequencies[2] = state->resp->info_3.max_frequency;
                        }
                        state->fifo_max_event_count = state->resp->info_3.fifo_max_event_count;
                }
                for (i = 0; i < ARRAY_SIZE(frequencies); i++) {
                        state->frequencies[2 * i] = frequencies[i] / 1000;
                        state->frequencies[2 * i + 1] =
                                (frequencies[i] % 1000) * 1000;
                }

                if (cros_ec_check_features(ec, EC_FEATURE_MOTION_SENSE_FIFO)) {
                        /*
                         * Create a software buffer, feed by the EC FIFO.
                         * We can not use trigger here, as events are generated
                         * as soon as sample_frequency is set.
                         */
                        ret = devm_iio_kfifo_buffer_setup_ext(dev, indio_dev,
                                                              INDIO_BUFFER_SOFTWARE, NULL,
                                                              cros_ec_sensor_fifo_attributes);
                        if (ret)
                                return ret;

                        ret = cros_ec_sensorhub_register_push_data(
                                        sensor_hub, sensor_platform->sensor_num,
                                        indio_dev, push_data);
                        if (ret)
                                return ret;

                        ret = devm_add_action_or_reset(
                                        dev, cros_ec_sensors_core_clean, pdev);
                        if (ret)
                                return ret;

                        /* Timestamp coming from FIFO are in ns since boot. */
                        ret = iio_device_set_clock(indio_dev, CLOCK_BOOTTIME);
                        if (ret)
                                return ret;

                } else {
                        /*
                         * The only way to get samples in buffer is to set a
                         * software trigger (systrig, hrtimer).
                         */
                        ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
                                        NULL, trigger_capture, NULL);
                        if (ret)
                                return ret;
                }
        }

        return 0;
}
EXPORT_SYMBOL_GPL(cros_ec_sensors_core_init);

/**
 * cros_ec_motion_send_host_cmd() - send motion sense host command
 * @state:              pointer to state information for device
 * @opt_length: optional length to reduce the response size, useful on the data
 *              path. Otherwise, the maximal allowed response size is used
 *
 * When called, the sub-command is assumed to be set in param->cmd.
 *
 * Return: 0 on success, -errno on failure.
 */
int cros_ec_motion_send_host_cmd(struct cros_ec_sensors_core_state *state,
                                 u16 opt_length)
{
        int ret;

        if (opt_length)
                state->msg->insize = min(opt_length, state->ec->max_response);
        else
                state->msg->insize = state->ec->max_response;

        memcpy(state->msg->data, &state->param, sizeof(state->param));

        ret = cros_ec_cmd_xfer_status(state->ec, state->msg);
        if (ret < 0)
                return ret;

        if (ret &&
            state->resp != (struct ec_response_motion_sense *)state->msg->data)
                memcpy(state->resp, state->msg->data, ret);

        return 0;
}
EXPORT_SYMBOL_GPL(cros_ec_motion_send_host_cmd);

static ssize_t cros_ec_sensors_calibrate(struct iio_dev *indio_dev,
                uintptr_t private, const struct iio_chan_spec *chan,
                const char *buf, size_t len)
{
        struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
        int ret, i;
        bool calibrate;

        ret = strtobool(buf, &calibrate);
        if (ret < 0)
                return ret;
        if (!calibrate)
                return -EINVAL;

        mutex_lock(&st->cmd_lock);
        st->param.cmd = MOTIONSENSE_CMD_PERFORM_CALIB;
        ret = cros_ec_motion_send_host_cmd(st, 0);
        if (ret != 0) {
                dev_warn(&indio_dev->dev, "Unable to calibrate sensor\n");
        } else {
                /* Save values */
                for (i = CROS_EC_SENSOR_X; i < CROS_EC_SENSOR_MAX_AXIS; i++)
                        st->calib[i].offset = st->resp->perform_calib.offset[i];
        }
        mutex_unlock(&st->cmd_lock);

        return ret ? ret : len;
}

static ssize_t cros_ec_sensors_id(struct iio_dev *indio_dev,
                                  uintptr_t private,
                                  const struct iio_chan_spec *chan, char *buf)
{
        struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);

        return snprintf(buf, PAGE_SIZE, "%d\n", st->param.info.sensor_num);
}

static ssize_t cros_ec_sensors_loc(struct iio_dev *indio_dev,
                uintptr_t private, const struct iio_chan_spec *chan,
                char *buf)
{
        struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);

        return snprintf(buf, PAGE_SIZE, "%s\n", cros_ec_loc[st->loc]);
}

const struct iio_chan_spec_ext_info cros_ec_sensors_ext_info[] = {
        {
                .name = "calibrate",
                .shared = IIO_SHARED_BY_ALL,
                .write = cros_ec_sensors_calibrate
        },
        {
                .name = "id",
                .shared = IIO_SHARED_BY_ALL,
                .read = cros_ec_sensors_id
        },
        {
                .name = "location",
                .shared = IIO_SHARED_BY_ALL,
                .read = cros_ec_sensors_loc
        },
        { },
};
EXPORT_SYMBOL_GPL(cros_ec_sensors_ext_info);

/**
 * cros_ec_sensors_idx_to_reg - convert index into offset in shared memory
 * @st:         pointer to state information for device
 * @idx:        sensor index (should be element of enum sensor_index)
 *
 * Return:      address to read at
 */
static unsigned int cros_ec_sensors_idx_to_reg(
                                        struct cros_ec_sensors_core_state *st,
                                        unsigned int idx)
{
        /*
         * When using LPC interface, only space for 2 Accel and one Gyro.
         * First halfword of MOTIONSENSE_TYPE_ACCEL is used by angle.
         */
        if (st->type == MOTIONSENSE_TYPE_ACCEL)
                return EC_MEMMAP_ACC_DATA + sizeof(u16) *
                        (1 + idx + st->param.info.sensor_num *
                         CROS_EC_SENSOR_MAX_AXIS);

        return EC_MEMMAP_GYRO_DATA + sizeof(u16) * idx;
}

static int cros_ec_sensors_cmd_read_u8(struct cros_ec_device *ec,
                                       unsigned int offset, u8 *dest)
{
        return ec->cmd_readmem(ec, offset, 1, dest);
}

static int cros_ec_sensors_cmd_read_u16(struct cros_ec_device *ec,
                                         unsigned int offset, u16 *dest)
{
        __le16 tmp;
        int ret = ec->cmd_readmem(ec, offset, 2, &tmp);

        if (ret >= 0)
                *dest = le16_to_cpu(tmp);

        return ret;
}

/**
 * cros_ec_sensors_read_until_not_busy() - read until is not busy
 *
 * @st: pointer to state information for device
 *
 * Read from EC status byte until it reads not busy.
 * Return: 8-bit status if ok, -errno on failure.
 */
static int cros_ec_sensors_read_until_not_busy(
                                        struct cros_ec_sensors_core_state *st)
{
        struct cros_ec_device *ec = st->ec;
        u8 status;
        int ret, attempts = 0;

        ret = cros_ec_sensors_cmd_read_u8(ec, EC_MEMMAP_ACC_STATUS, &status);
        if (ret < 0)
                return ret;

        while (status & EC_MEMMAP_ACC_STATUS_BUSY_BIT) {
                /* Give up after enough attempts, return error. */
                if (attempts++ >= 50)
                        return -EIO;

                /* Small delay every so often. */
                if (attempts % 5 == 0)
                        msleep(25);

                ret = cros_ec_sensors_cmd_read_u8(ec, EC_MEMMAP_ACC_STATUS,
                                                  &status);
                if (ret < 0)
                        return ret;
        }

        return status;
}

/**
 * cros_ec_sensors_read_data_unsafe() - read acceleration data from EC shared memory
 * @indio_dev:  pointer to IIO device
 * @scan_mask:  bitmap of the sensor indices to scan
 * @data:       location to store data
 *
 * This is the unsafe function for reading the EC data. It does not guarantee
 * that the EC will not modify the data as it is being read in.
 *
 * Return: 0 on success, -errno on failure.
 */
static int cros_ec_sensors_read_data_unsafe(struct iio_dev *indio_dev,
                         unsigned long scan_mask, s16 *data)
{
        struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
        struct cros_ec_device *ec = st->ec;
        unsigned int i;
        int ret;

        /* Read all sensors enabled in scan_mask. Each value is 2 bytes. */
        for_each_set_bit(i, &scan_mask, indio_dev->masklength) {
                ret = cros_ec_sensors_cmd_read_u16(ec,
                                             cros_ec_sensors_idx_to_reg(st, i),
                                             data);
                if (ret < 0)
                        return ret;

                *data *= st->sign[i];
                data++;
        }

        return 0;
}

/**
 * cros_ec_sensors_read_lpc() - read acceleration data from EC shared memory.
 * @indio_dev: pointer to IIO device.
 * @scan_mask: bitmap of the sensor indices to scan.
 * @data: location to store data.
 *
 * Note: this is the safe function for reading the EC data. It guarantees
 * that the data sampled was not modified by the EC while being read.
 *
 * Return: 0 on success, -errno on failure.
 */
int cros_ec_sensors_read_lpc(struct iio_dev *indio_dev,
                             unsigned long scan_mask, s16 *data)
{
        struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
        struct cros_ec_device *ec = st->ec;
        u8 samp_id = 0xff, status = 0;
        int ret, attempts = 0;

        /*
         * Continually read all data from EC until the status byte after
         * all reads reflects that the EC is not busy and the sample id
         * matches the sample id from before all reads. This guarantees
         * that data read in was not modified by the EC while reading.
         */
        while ((status & (EC_MEMMAP_ACC_STATUS_BUSY_BIT |
                          EC_MEMMAP_ACC_STATUS_SAMPLE_ID_MASK)) != samp_id) {
                /* If we have tried to read too many times, return error. */
                if (attempts++ >= 5)
                        return -EIO;

                /* Read status byte until EC is not busy. */
                ret = cros_ec_sensors_read_until_not_busy(st);
                if (ret < 0)
                        return ret;

                /*
                 * Store the current sample id so that we can compare to the
                 * sample id after reading the data.
                 */
                samp_id = ret & EC_MEMMAP_ACC_STATUS_SAMPLE_ID_MASK;

                /* Read all EC data, format it, and store it into data. */
                ret = cros_ec_sensors_read_data_unsafe(indio_dev, scan_mask,
                                                       data);
                if (ret < 0)
                        return ret;

                /* Read status byte. */
                ret = cros_ec_sensors_cmd_read_u8(ec, EC_MEMMAP_ACC_STATUS,
                                                  &status);
                if (ret < 0)
                        return ret;
        }

        return 0;
}
EXPORT_SYMBOL_GPL(cros_ec_sensors_read_lpc);

/**
 * cros_ec_sensors_read_cmd() - retrieve data using the EC command protocol
 * @indio_dev:  pointer to IIO device
 * @scan_mask:  bitmap of the sensor indices to scan
 * @data:       location to store data
 *
 * Return: 0 on success, -errno on failure.
 */
int cros_ec_sensors_read_cmd(struct iio_dev *indio_dev,
                             unsigned long scan_mask, s16 *data)
{
        struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
        int ret;
        unsigned int i;

        /* Read all sensor data through a command. */
        st->param.cmd = MOTIONSENSE_CMD_DATA;
        ret = cros_ec_motion_send_host_cmd(st, sizeof(st->resp->data));
        if (ret != 0) {
                dev_warn(&indio_dev->dev, "Unable to read sensor data\n");
                return ret;
        }

        for_each_set_bit(i, &scan_mask, indio_dev->masklength) {
                *data = st->resp->data.data[i];
                data++;
        }

        return 0;
}
EXPORT_SYMBOL_GPL(cros_ec_sensors_read_cmd);

/**
 * cros_ec_sensors_capture() - the trigger handler function
 * @irq:        the interrupt number.
 * @p:          a pointer to the poll function.
 *
 * On a trigger event occurring, if the pollfunc is attached then this
 * handler is called as a threaded interrupt (and hence may sleep). It
 * is responsible for grabbing data from the device and pushing it into
 * the associated buffer.
 *
 * Return: IRQ_HANDLED
 */
irqreturn_t cros_ec_sensors_capture(int irq, void *p)
{
        struct iio_poll_func *pf = p;
        struct iio_dev *indio_dev = pf->indio_dev;
        struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
        int ret;

        mutex_lock(&st->cmd_lock);

        /* Clear capture data. */
        memset(st->samples, 0, indio_dev->scan_bytes);

        /* Read data based on which channels are enabled in scan mask. */
        ret = st->read_ec_sensors_data(indio_dev,
                                       *(indio_dev->active_scan_mask),
                                       (s16 *)st->samples);
        if (ret < 0)
                goto done;

        iio_push_to_buffers_with_timestamp(indio_dev, st->samples,
                                           iio_get_time_ns(indio_dev));

done:
        /*
         * Tell the core we are done with this trigger and ready for the
         * next one.
         */
        iio_trigger_notify_done(indio_dev->trig);

        mutex_unlock(&st->cmd_lock);

        return IRQ_HANDLED;
}
EXPORT_SYMBOL_GPL(cros_ec_sensors_capture);

/**
 * cros_ec_sensors_core_read() - function to request a value from the sensor
 * @st:         pointer to state information for device
 * @chan:       channel specification structure table
 * @val:        will contain one element making up the returned value
 * @val2:       will contain another element making up the returned value
 * @mask:       specifies which values to be requested
 *
 * Return:      the type of value returned by the device
 */
int cros_ec_sensors_core_read(struct cros_ec_sensors_core_state *st,
                          struct iio_chan_spec const *chan,
                          int *val, int *val2, long mask)
{
        int ret, frequency;

        switch (mask) {
        case IIO_CHAN_INFO_SAMP_FREQ:
                st->param.cmd = MOTIONSENSE_CMD_SENSOR_ODR;
                st->param.sensor_odr.data =
                        EC_MOTION_SENSE_NO_VALUE;

                ret = cros_ec_motion_send_host_cmd(st, 0);
                if (ret)
                        break;

                frequency = st->resp->sensor_odr.ret;
                *val = frequency / 1000;
                *val2 = (frequency % 1000) * 1000;
                ret = IIO_VAL_INT_PLUS_MICRO;
                break;
        default:
                ret = -EINVAL;
                break;
        }

        return ret;
}
EXPORT_SYMBOL_GPL(cros_ec_sensors_core_read);

/**
 * cros_ec_sensors_core_read_avail() - get available values
 * @indio_dev:          pointer to state information for device
 * @chan:       channel specification structure table
 * @vals:       list of available values
 * @type:       type of data returned
 * @length:     number of data returned in the array
 * @mask:       specifies which values to be requested
 *
 * Return:      an error code, IIO_AVAIL_RANGE or IIO_AVAIL_LIST
 */
int cros_ec_sensors_core_read_avail(struct iio_dev *indio_dev,
                                    struct iio_chan_spec const *chan,
                                    const int **vals,
                                    int *type,
                                    int *length,
                                    long mask)
{
        struct cros_ec_sensors_core_state *state = iio_priv(indio_dev);

        switch (mask) {
        case IIO_CHAN_INFO_SAMP_FREQ:
                *length = ARRAY_SIZE(state->frequencies);
                *vals = (const int *)&state->frequencies;
                *type = IIO_VAL_INT_PLUS_MICRO;
                return IIO_AVAIL_LIST;
        }

        return -EINVAL;
}
EXPORT_SYMBOL_GPL(cros_ec_sensors_core_read_avail);

/**
 * cros_ec_sensors_core_write() - function to write a value to the sensor
 * @st:         pointer to state information for device
 * @chan:       channel specification structure table
 * @val:        first part of value to write
 * @val2:       second part of value to write
 * @mask:       specifies which values to write
 *
 * Return:      the type of value returned by the device
 */
int cros_ec_sensors_core_write(struct cros_ec_sensors_core_state *st,
                               struct iio_chan_spec const *chan,
                               int val, int val2, long mask)
{
        int ret, frequency;

        switch (mask) {
        case IIO_CHAN_INFO_SAMP_FREQ:
                frequency = val * 1000 + val2 / 1000;
                st->param.cmd = MOTIONSENSE_CMD_SENSOR_ODR;
                st->param.sensor_odr.data = frequency;

                /* Always roundup, so caller gets at least what it asks for. */
                st->param.sensor_odr.roundup = 1;

                ret = cros_ec_motion_send_host_cmd(st, 0);
                break;
        default:
                ret = -EINVAL;
                break;
        }
        return ret;
}
EXPORT_SYMBOL_GPL(cros_ec_sensors_core_write);

static int __maybe_unused cros_ec_sensors_resume(struct device *dev)
{
        struct platform_device *pdev = to_platform_device(dev);
        struct iio_dev *indio_dev = platform_get_drvdata(pdev);
        struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
        int ret = 0;

        if (st->range_updated) {
                mutex_lock(&st->cmd_lock);
                st->param.cmd = MOTIONSENSE_CMD_SENSOR_RANGE;
                st->param.sensor_range.data = st->curr_range;
                st->param.sensor_range.roundup = 1;
                ret = cros_ec_motion_send_host_cmd(st, 0);
                mutex_unlock(&st->cmd_lock);
        }
        return ret;
}

SIMPLE_DEV_PM_OPS(cros_ec_sensors_pm_ops, NULL, cros_ec_sensors_resume);
EXPORT_SYMBOL_GPL(cros_ec_sensors_pm_ops);

MODULE_DESCRIPTION("ChromeOS EC sensor hub core functions");
MODULE_LICENSE("GPL v2");