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// SPDX-License-Identifier: GPL-2.0-only
/*
* ltc2496.c - Driver for Analog Devices/Linear Technology LTC2496 ADC
*
* Based on ltc2497.c which has
* Copyright (C) 2017 Analog Devices Inc.
*
* Licensed under the GPL-2.
*
* Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/2496fc.pdf
*/
#include <linux/spi/spi.h>
#include <linux/iio/iio.h>
#include <linux/iio/driver.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include "ltc2497.h"
struct ltc2496_driverdata {
/* this must be the first member */
struct ltc2497core_driverdata common_ddata;
struct spi_device *spi;
/*
* DMA (thus cache coherency maintenance) requires the
* transfer buffers to live in their own cache lines.
*/
unsigned char rxbuf[3] ____cacheline_aligned;
unsigned char txbuf[3];
};
static int ltc2496_result_and_measure(struct ltc2497core_driverdata *ddata,
u8 address, int *val)
{
struct ltc2496_driverdata *st =
container_of(ddata, struct ltc2496_driverdata, common_ddata);
struct spi_transfer t = {
.tx_buf = st->txbuf,
.rx_buf = st->rxbuf,
.len = sizeof(st->txbuf),
};
int ret;
st->txbuf[0] = LTC2497_ENABLE | address;
ret = spi_sync_transfer(st->spi, &t, 1);
if (ret < 0) {
dev_err(&st->spi->dev, "spi_sync_transfer failed: %pe\n",
ERR_PTR(ret));
return ret;
}
if (val)
*val = ((st->rxbuf[0] & 0x3f) << 12 |
st->rxbuf[1] << 4 | st->rxbuf[2] >> 4) -
(1 << 17);
return 0;
}
static int ltc2496_probe(struct spi_device *spi)
{
struct iio_dev *indio_dev;
struct ltc2496_driverdata *st;
struct device *dev = &spi->dev;
indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
if (!indio_dev)
return -ENOMEM;
st = iio_priv(indio_dev);
spi_set_drvdata(spi, indio_dev);
st->spi = spi;
st->common_ddata.result_and_measure = ltc2496_result_and_measure;
return ltc2497core_probe(dev, indio_dev);
}
static void ltc2496_remove(struct spi_device *spi)
{
struct iio_dev *indio_dev = spi_get_drvdata(spi);
ltc2497core_remove(indio_dev);
}
static const struct of_device_id ltc2496_of_match[] = {
{ .compatible = "lltc,ltc2496", },
{},
};
MODULE_DEVICE_TABLE(of, ltc2496_of_match);
static struct spi_driver ltc2496_driver = {
.driver = {
.name = "ltc2496",
.of_match_table = ltc2496_of_match,
},
.probe = ltc2496_probe,
.remove = ltc2496_remove,
};
module_spi_driver(ltc2496_driver);
MODULE_AUTHOR("Uwe Kleine-König <u.kleine-könig@pengutronix.de>");
MODULE_DESCRIPTION("Linear Technology LTC2496 ADC driver");
MODULE_LICENSE("GPL v2");
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