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// 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/mfd/cros_ec.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
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, indio_dev->masklength) {
*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;
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;
}
static const struct iio_info cros_ec_accel_legacy_info = {
.read_raw = &cros_ec_accel_legacy_read,
.write_raw = &cros_ec_accel_legacy_write,
};
/*
* 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), \
.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 cros_ec_dev *ec = dev_get_drvdata(dev->parent);
struct iio_dev *indio_dev;
struct cros_ec_sensors_core_state *state;
int ret;
if (!ec || !ec->ec_dev) {
dev_warn(&pdev->dev, "No EC device found.\n");
return -EINVAL;
}
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);
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 (state->loc == MOTIONSENSE_LOC_LID) {
state->sign[CROS_EC_SENSOR_X] = -1;
state->sign[CROS_EC_SENSOR_Z] = -1;
}
ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
cros_ec_sensors_capture, NULL);
if (ret)
return ret;
return devm_iio_device_register(dev, indio_dev);
}
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);
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