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/*
* Freescale MPL115A1 pressure/temperature sensor
*
* Copyright (c) 2016 Akinobu Mita <akinobu.mita@gmail.com>
*
* This file is subject to the terms and conditions of version 2 of
* the GNU General Public License. See the file COPYING in the main
* directory of this archive for more details.
*
* Datasheet: http://www.nxp.com/files/sensors/doc/data_sheet/MPL115A1.pdf
*/
#include <linux/module.h>
#include <linux/spi/spi.h>
#include "mpl115.h"
#define MPL115_SPI_WRITE(address) ((address) << 1)
#define MPL115_SPI_READ(address) (0x80 | (address) << 1)
struct mpl115_spi_buf {
u8 tx[4];
u8 rx[4];
};
static int mpl115_spi_init(struct device *dev)
{
struct spi_device *spi = to_spi_device(dev);
struct mpl115_spi_buf *buf;
buf = devm_kzalloc(dev, sizeof(*buf), GFP_KERNEL);
if (!buf)
return -ENOMEM;
spi_set_drvdata(spi, buf);
return 0;
}
static int mpl115_spi_read(struct device *dev, u8 address)
{
struct spi_device *spi = to_spi_device(dev);
struct mpl115_spi_buf *buf = spi_get_drvdata(spi);
struct spi_transfer xfer = {
.tx_buf = buf->tx,
.rx_buf = buf->rx,
.len = 4,
};
int ret;
buf->tx[0] = MPL115_SPI_READ(address);
buf->tx[2] = MPL115_SPI_READ(address + 1);
ret = spi_sync_transfer(spi, &xfer, 1);
if (ret)
return ret;
return (buf->rx[1] << 8) | buf->rx[3];
}
static int mpl115_spi_write(struct device *dev, u8 address, u8 value)
{
struct spi_device *spi = to_spi_device(dev);
struct mpl115_spi_buf *buf = spi_get_drvdata(spi);
struct spi_transfer xfer = {
.tx_buf = buf->tx,
.len = 2,
};
buf->tx[0] = MPL115_SPI_WRITE(address);
buf->tx[1] = value;
return spi_sync_transfer(spi, &xfer, 1);
}
static const struct mpl115_ops mpl115_spi_ops = {
.init = mpl115_spi_init,
.read = mpl115_spi_read,
.write = mpl115_spi_write,
};
static int mpl115_spi_probe(struct spi_device *spi)
{
const struct spi_device_id *id = spi_get_device_id(spi);
return mpl115_probe(&spi->dev, id->name, &mpl115_spi_ops);
}
static const struct spi_device_id mpl115_spi_ids[] = {
{ "mpl115", 0 },
{}
};
MODULE_DEVICE_TABLE(spi, mpl115_spi_ids);
static struct spi_driver mpl115_spi_driver = {
.driver = {
.name = "mpl115",
},
.probe = mpl115_spi_probe,
.id_table = mpl115_spi_ids,
};
module_spi_driver(mpl115_spi_driver);
MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");
MODULE_DESCRIPTION("Freescale MPL115A1 pressure/temperature driver");
MODULE_LICENSE("GPL");
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