// SPDX-License-Identifier: GPL-2.0
/*
 * Driver for older Chrome OS EC accelerometer
 *
 * Copyright 2017 Google, Inc
 *
 * This driver uses the memory mapper cros-ec interface to communicate
 * with the Chrome OS EC about accelerometer data or older commands.
 * Accelerometer access is presented through iio sysfs.
 */

#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/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_device.h>

#define DRV_NAME        "cros-ec-accel-legacy"

#define CROS_EC_SENSOR_LEGACY_NUM 2
/*
 * Sensor scale hard coded at 10 bits per g, computed as:
 * g / (2^10 - 1) = 0.009586168; with g = 9.80665 m.s^-2
 */
#define ACCEL_LEGACY_NSCALE 9586168

/*
 * Sensor frequency is hard-coded to 10Hz.
 */
static const int cros_ec_legacy_sample_freq[] = { 10, 0 };

static int cros_ec_accel_legacy_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;
        u8 sensor_num;

        /*
         * Read all sensor data through a command.
         * Save sensor_num, it is assumed to stay.
         */
        sensor_num = st->param.info.sensor_num;
        st->param.cmd = MOTIONSENSE_CMD_DUMP;
        st->param.dump.max_sensor_count = CROS_EC_SENSOR_LEGACY_NUM;
        ret = cros_ec_motion_send_host_cmd(st,
                        sizeof(st->resp->dump) + CROS_EC_SENSOR_LEGACY_NUM *
                        sizeof(struct ec_response_motion_sensor_data));
        st->param.info.sensor_num = sensor_num;
        if (ret != 0) {
                dev_warn(&indio_dev->dev, "Unable to read sensor data\n");
                return ret;
        }

        for_each_set_bit(i, &scan_mask, iio_get_masklength(indio_dev)) {
                *data = st->resp->dump.sensor[sensor_num].data[i] *
                        st->sign[i];
                data++;
        }

        return 0;
}

static int cros_ec_accel_legacy_read(struct iio_dev *indio_dev,
                                     struct iio_chan_spec const *chan,
                                     int *val, int *val2, long mask)
{
        struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
        s16 data = 0;
        int ret;
        int idx = chan->scan_index;

        mutex_lock(&st->cmd_lock);

        switch (mask) {
        case IIO_CHAN_INFO_RAW:
                ret = st->read_ec_sensors_data(indio_dev, 1 << idx, &data);
                if (ret < 0)
                        break;
                ret = IIO_VAL_INT;
                *val = data;
                break;
        case IIO_CHAN_INFO_SCALE:
                WARN_ON(st->type != MOTIONSENSE_TYPE_ACCEL);
                *val = 0;
                *val2 = ACCEL_LEGACY_NSCALE;
                ret = IIO_VAL_INT_PLUS_NANO;
                break;
        case IIO_CHAN_INFO_CALIBBIAS:
                /* Calibration not supported. */
                *val = 0;
                ret = IIO_VAL_INT;
                break;
        case IIO_CHAN_INFO_SAMP_FREQ:
                *val = cros_ec_legacy_sample_freq[0];
                *val2 = cros_ec_legacy_sample_freq[1];
                ret = IIO_VAL_INT_PLUS_MICRO;
                break;
        default:
                ret = cros_ec_sensors_core_read(st, chan, val, val2,
                                mask);
                break;
        }
        mutex_unlock(&st->cmd_lock);

        return ret;
}

static int cros_ec_accel_legacy_write(struct iio_dev *indio_dev,
                                      struct iio_chan_spec const *chan,
                                      int val, int val2, long mask)
{
        /*
         * Do nothing but don't return an error code to allow calibration
         * script to work.
         */
        if (mask == IIO_CHAN_INFO_CALIBBIAS)
                return 0;

        return -EINVAL;
}

/**
 * cros_ec_accel_legacy_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 or IIO_AVAIL_LIST
 */
static int cros_ec_accel_legacy_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:
                *length = ARRAY_SIZE(cros_ec_legacy_sample_freq);
                *vals = cros_ec_legacy_sample_freq;
                *type = IIO_VAL_INT_PLUS_MICRO;
                return IIO_AVAIL_LIST;
        }

        return -EINVAL;
}

static const struct iio_info cros_ec_accel_legacy_info = {
        .read_raw = &cros_ec_accel_legacy_read,
        .write_raw = &cros_ec_accel_legacy_write,
        .read_avail = &cros_ec_accel_legacy_read_avail,
};

/*
 * Present the channel using HTML5 standard:
 * need to invert X and Y and invert some lid axis.
 */
#define CROS_EC_ACCEL_ROTATE_AXIS(_axis)                                \
        ((_axis) == CROS_EC_SENSOR_Z ? CROS_EC_SENSOR_Z :               \
         ((_axis) == CROS_EC_SENSOR_X ? CROS_EC_SENSOR_Y :              \
          CROS_EC_SENSOR_X))

#define CROS_EC_ACCEL_LEGACY_CHAN(_axis)                                \
        {                                                               \
                .type = IIO_ACCEL,                                      \
                .channel2 = IIO_MOD_X + (_axis),                        \
                .modified = 1,                                          \
                .info_mask_separate =                                   \
                        BIT(IIO_CHAN_INFO_RAW) |                        \
                        BIT(IIO_CHAN_INFO_CALIBBIAS),                   \
                .info_mask_shared_by_all =                              \
                        BIT(IIO_CHAN_INFO_SCALE) |                      \
                        BIT(IIO_CHAN_INFO_SAMP_FREQ),                   \
                .info_mask_shared_by_all_available =                    \
                        BIT(IIO_CHAN_INFO_SAMP_FREQ),                   \
                .ext_info = cros_ec_sensors_ext_info,                   \
                .scan_type = {                                          \
                        .sign = 's',                                    \
                        .realbits = CROS_EC_SENSOR_BITS,                \
                        .storagebits = CROS_EC_SENSOR_BITS,             \
                },                                                      \
                .scan_index = CROS_EC_ACCEL_ROTATE_AXIS(_axis),         \
        }                                                               \

static const struct iio_chan_spec cros_ec_accel_legacy_channels[] = {
                CROS_EC_ACCEL_LEGACY_CHAN(CROS_EC_SENSOR_X),
                CROS_EC_ACCEL_LEGACY_CHAN(CROS_EC_SENSOR_Y),
                CROS_EC_ACCEL_LEGACY_CHAN(CROS_EC_SENSOR_Z),
                IIO_CHAN_SOFT_TIMESTAMP(CROS_EC_SENSOR_MAX_AXIS)
};

static int cros_ec_accel_legacy_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct iio_dev *indio_dev;
        struct cros_ec_sensors_core_state *state;
        int ret;

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

        ret = cros_ec_sensors_core_init(pdev, indio_dev, true,
                                        cros_ec_sensors_capture);
        if (ret)
                return ret;

        indio_dev->info = &cros_ec_accel_legacy_info;
        state = iio_priv(indio_dev);

        if (state->ec->cmd_readmem != NULL)
                state->read_ec_sensors_data = cros_ec_sensors_read_lpc;
        else
                state->read_ec_sensors_data = cros_ec_accel_legacy_read_cmd;

        indio_dev->channels = cros_ec_accel_legacy_channels;
        indio_dev->num_channels = ARRAY_SIZE(cros_ec_accel_legacy_channels);
        /* The lid sensor needs to be presented inverted. */
        if (!strcmp(indio_dev->label, "accel-display")) {
                state->sign[CROS_EC_SENSOR_X] = -1;
                state->sign[CROS_EC_SENSOR_Z] = -1;
        }

        return cros_ec_sensors_core_register(dev, indio_dev, NULL);
}

static struct platform_driver cros_ec_accel_platform_driver = {
        .driver = {
                .name   = DRV_NAME,
        },
        .probe          = cros_ec_accel_legacy_probe,
};
module_platform_driver(cros_ec_accel_platform_driver);

MODULE_DESCRIPTION("ChromeOS EC legacy accelerometer driver");
MODULE_AUTHOR("Gwendal Grignou <gwendal@chromium.org>");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:" DRV_NAME);