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// SPDX-License-Identifier: GPL-2.0-only
/*
* ltc2497.c - Driver for Analog Devices/Linear Technology LTC2497 ADC
*
* Copyright (C) 2017 Analog Devices Inc.
*
* Datasheet: http://cds.linear.com/docs/en/datasheet/2497fd.pdf
*/
#include <linux/i2c.h>
#include <linux/iio/iio.h>
#include <linux/iio/driver.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include "ltc2497.h"
struct ltc2497_driverdata {
/* this must be the first member */
struct ltc2497core_driverdata common_ddata;
struct i2c_client *client;
/*
* DMA (thus cache coherency maintenance) requires the
* transfer buffers to live in their own cache lines.
*/
__be32 buf ____cacheline_aligned;
};
static int ltc2497_result_and_measure(struct ltc2497core_driverdata *ddata,
u8 address, int *val)
{
struct ltc2497_driverdata *st =
container_of(ddata, struct ltc2497_driverdata, common_ddata);
int ret;
if (val) {
ret = i2c_master_recv(st->client, (char *)&st->buf, 3);
if (ret < 0) {
dev_err(&st->client->dev, "i2c_master_recv failed\n");
return ret;
}
*val = (be32_to_cpu(st->buf) >> 14) - (1 << 17);
/*
* The part started a new conversion at the end of the above i2c
* transfer, so if the address didn't change since the last call
* everything is fine and we can return early.
* If not (which should only happen when some sort of bulk
* conversion is implemented) we have to program the new
* address. Note that this probably fails as the conversion that
* was triggered above is like not complete yet and the two
* operations have to be done in a single transfer.
*/
if (ddata->addr_prev == address)
return 0;
}
ret = i2c_smbus_write_byte(st->client,
LTC2497_ENABLE | address);
if (ret)
dev_err(&st->client->dev, "i2c transfer failed: %pe\n",
ERR_PTR(ret));
return ret;
}
static int ltc2497_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct iio_dev *indio_dev;
struct ltc2497_driverdata *st;
struct device *dev = &client->dev;
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
I2C_FUNC_SMBUS_WRITE_BYTE))
return -EOPNOTSUPP;
indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
if (!indio_dev)
return -ENOMEM;
st = iio_priv(indio_dev);
i2c_set_clientdata(client, indio_dev);
st->client = client;
st->common_ddata.result_and_measure = ltc2497_result_and_measure;
return ltc2497core_probe(dev, indio_dev);
}
static int ltc2497_remove(struct i2c_client *client)
{
struct iio_dev *indio_dev = i2c_get_clientdata(client);
ltc2497core_remove(indio_dev);
return 0;
}
static const struct i2c_device_id ltc2497_id[] = {
{ "ltc2497", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, ltc2497_id);
static const struct of_device_id ltc2497_of_match[] = {
{ .compatible = "lltc,ltc2497", },
{},
};
MODULE_DEVICE_TABLE(of, ltc2497_of_match);
static struct i2c_driver ltc2497_driver = {
.driver = {
.name = "ltc2497",
.of_match_table = ltc2497_of_match,
},
.probe = ltc2497_probe,
.remove = ltc2497_remove,
.id_table = ltc2497_id,
};
module_i2c_driver(ltc2497_driver);
MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
MODULE_DESCRIPTION("Linear Technology LTC2497 ADC driver");
MODULE_LICENSE("GPL v2");
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