253 lines
6.8 KiB
C
253 lines
6.8 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Driver for older Chrome OS EC accelerometer
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*
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* Copyright 2017 Google, Inc
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*
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* This driver uses the memory mapper cros-ec interface to communicate
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* with the Chrome OS EC about accelerometer data or older commands.
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* Accelerometer access is presented through iio sysfs.
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*/
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#include <linux/delay.h>
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#include <linux/device.h>
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#include <linux/iio/buffer.h>
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#include <linux/iio/common/cros_ec_sensors_core.h>
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#include <linux/iio/iio.h>
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#include <linux/iio/kfifo_buf.h>
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#include <linux/iio/trigger_consumer.h>
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#include <linux/iio/triggered_buffer.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/platform_data/cros_ec_commands.h>
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#include <linux/platform_data/cros_ec_proto.h>
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#include <linux/platform_device.h>
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#define DRV_NAME "cros-ec-accel-legacy"
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#define CROS_EC_SENSOR_LEGACY_NUM 2
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/*
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* Sensor scale hard coded at 10 bits per g, computed as:
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* g / (2^10 - 1) = 0.009586168; with g = 9.80665 m.s^-2
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*/
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#define ACCEL_LEGACY_NSCALE 9586168
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/*
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* Sensor frequency is hard-coded to 10Hz.
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*/
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static const int cros_ec_legacy_sample_freq[] = { 10, 0 };
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static int cros_ec_accel_legacy_read_cmd(struct iio_dev *indio_dev,
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unsigned long scan_mask, s16 *data)
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{
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struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
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int ret;
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unsigned int i;
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u8 sensor_num;
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/*
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* Read all sensor data through a command.
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* Save sensor_num, it is assumed to stay.
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*/
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sensor_num = st->param.info.sensor_num;
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st->param.cmd = MOTIONSENSE_CMD_DUMP;
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st->param.dump.max_sensor_count = CROS_EC_SENSOR_LEGACY_NUM;
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ret = cros_ec_motion_send_host_cmd(st,
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sizeof(st->resp->dump) + CROS_EC_SENSOR_LEGACY_NUM *
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sizeof(struct ec_response_motion_sensor_data));
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st->param.info.sensor_num = sensor_num;
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if (ret != 0) {
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dev_warn(&indio_dev->dev, "Unable to read sensor data\n");
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return ret;
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}
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for_each_set_bit(i, &scan_mask, indio_dev->masklength) {
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*data = st->resp->dump.sensor[sensor_num].data[i] *
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st->sign[i];
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data++;
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}
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return 0;
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}
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static int cros_ec_accel_legacy_read(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan,
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int *val, int *val2, long mask)
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{
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struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
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s16 data = 0;
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int ret;
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int idx = chan->scan_index;
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mutex_lock(&st->cmd_lock);
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switch (mask) {
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case IIO_CHAN_INFO_RAW:
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ret = st->read_ec_sensors_data(indio_dev, 1 << idx, &data);
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if (ret < 0)
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break;
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ret = IIO_VAL_INT;
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*val = data;
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break;
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case IIO_CHAN_INFO_SCALE:
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WARN_ON(st->type != MOTIONSENSE_TYPE_ACCEL);
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*val = 0;
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*val2 = ACCEL_LEGACY_NSCALE;
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ret = IIO_VAL_INT_PLUS_NANO;
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break;
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case IIO_CHAN_INFO_CALIBBIAS:
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/* Calibration not supported. */
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*val = 0;
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ret = IIO_VAL_INT;
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break;
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case IIO_CHAN_INFO_SAMP_FREQ:
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*val = cros_ec_legacy_sample_freq[0];
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*val2 = cros_ec_legacy_sample_freq[1];
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ret = IIO_VAL_INT_PLUS_MICRO;
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break;
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default:
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ret = cros_ec_sensors_core_read(st, chan, val, val2,
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mask);
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break;
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}
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mutex_unlock(&st->cmd_lock);
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return ret;
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}
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static int cros_ec_accel_legacy_write(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan,
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int val, int val2, long mask)
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{
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/*
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* Do nothing but don't return an error code to allow calibration
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* script to work.
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*/
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if (mask == IIO_CHAN_INFO_CALIBBIAS)
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return 0;
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return -EINVAL;
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}
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/**
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* cros_ec_accel_legacy_read_avail() - get available values
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* @indio_dev: pointer to state information for device
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* @chan: channel specification structure table
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* @vals: list of available values
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* @type: type of data returned
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* @length: number of data returned in the array
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* @mask: specifies which values to be requested
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*
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* Return: an error code or IIO_AVAIL_LIST
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*/
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static int cros_ec_accel_legacy_read_avail(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan,
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const int **vals,
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int *type,
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int *length,
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long mask)
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{
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switch (mask) {
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case IIO_CHAN_INFO_SAMP_FREQ:
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*length = ARRAY_SIZE(cros_ec_legacy_sample_freq);
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*vals = cros_ec_legacy_sample_freq;
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*type = IIO_VAL_INT_PLUS_MICRO;
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return IIO_AVAIL_LIST;
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}
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return -EINVAL;
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}
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static const struct iio_info cros_ec_accel_legacy_info = {
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.read_raw = &cros_ec_accel_legacy_read,
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.write_raw = &cros_ec_accel_legacy_write,
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.read_avail = &cros_ec_accel_legacy_read_avail,
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};
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/*
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* Present the channel using HTML5 standard:
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* need to invert X and Y and invert some lid axis.
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*/
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#define CROS_EC_ACCEL_ROTATE_AXIS(_axis) \
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((_axis) == CROS_EC_SENSOR_Z ? CROS_EC_SENSOR_Z : \
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((_axis) == CROS_EC_SENSOR_X ? CROS_EC_SENSOR_Y : \
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CROS_EC_SENSOR_X))
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#define CROS_EC_ACCEL_LEGACY_CHAN(_axis) \
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{ \
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.type = IIO_ACCEL, \
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.channel2 = IIO_MOD_X + (_axis), \
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.modified = 1, \
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.info_mask_separate = \
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BIT(IIO_CHAN_INFO_RAW) | \
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BIT(IIO_CHAN_INFO_CALIBBIAS), \
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.info_mask_shared_by_all = \
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BIT(IIO_CHAN_INFO_SCALE) | \
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BIT(IIO_CHAN_INFO_SAMP_FREQ), \
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.info_mask_shared_by_all_available = \
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BIT(IIO_CHAN_INFO_SAMP_FREQ), \
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.ext_info = cros_ec_sensors_ext_info, \
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.scan_type = { \
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.sign = 's', \
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.realbits = CROS_EC_SENSOR_BITS, \
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.storagebits = CROS_EC_SENSOR_BITS, \
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}, \
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.scan_index = CROS_EC_ACCEL_ROTATE_AXIS(_axis), \
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} \
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static const struct iio_chan_spec cros_ec_accel_legacy_channels[] = {
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CROS_EC_ACCEL_LEGACY_CHAN(CROS_EC_SENSOR_X),
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CROS_EC_ACCEL_LEGACY_CHAN(CROS_EC_SENSOR_Y),
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CROS_EC_ACCEL_LEGACY_CHAN(CROS_EC_SENSOR_Z),
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IIO_CHAN_SOFT_TIMESTAMP(CROS_EC_SENSOR_MAX_AXIS)
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};
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static int cros_ec_accel_legacy_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct iio_dev *indio_dev;
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struct cros_ec_sensors_core_state *state;
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int ret;
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indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*state));
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if (!indio_dev)
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return -ENOMEM;
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ret = cros_ec_sensors_core_init(pdev, indio_dev, true,
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cros_ec_sensors_capture, NULL);
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if (ret)
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return ret;
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indio_dev->info = &cros_ec_accel_legacy_info;
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state = iio_priv(indio_dev);
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if (state->ec->cmd_readmem != NULL)
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state->read_ec_sensors_data = cros_ec_sensors_read_lpc;
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else
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state->read_ec_sensors_data = cros_ec_accel_legacy_read_cmd;
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indio_dev->channels = cros_ec_accel_legacy_channels;
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indio_dev->num_channels = ARRAY_SIZE(cros_ec_accel_legacy_channels);
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/* The lid sensor needs to be presented inverted. */
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if (state->loc == MOTIONSENSE_LOC_LID) {
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state->sign[CROS_EC_SENSOR_X] = -1;
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state->sign[CROS_EC_SENSOR_Z] = -1;
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}
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return devm_iio_device_register(dev, indio_dev);
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}
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static struct platform_driver cros_ec_accel_platform_driver = {
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.driver = {
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.name = DRV_NAME,
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},
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.probe = cros_ec_accel_legacy_probe,
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};
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module_platform_driver(cros_ec_accel_platform_driver);
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MODULE_DESCRIPTION("ChromeOS EC legacy accelerometer driver");
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MODULE_AUTHOR("Gwendal Grignou <gwendal@chromium.org>");
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MODULE_LICENSE("GPL v2");
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MODULE_ALIAS("platform:" DRV_NAME);
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