1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Freescale MPL115A1 pressure/temperature sensor
  4 *
  5 * Copyright (c) 2016 Akinobu Mita <akinobu.mita@gmail.com>
  6 *
  7 * Datasheet: http://www.nxp.com/files/sensors/doc/data_sheet/MPL115A1.pdf
  8 */
  9
 10#include <linux/module.h>
 11#include <linux/spi/spi.h>
 12
 13#include "mpl115.h"
 14
 15#define MPL115_SPI_WRITE(address)	((address) << 1)
 16#define MPL115_SPI_READ(address)	(0x80 | (address) << 1)
 17
 18struct mpl115_spi_buf {
 19	u8 tx[4];
 20	u8 rx[4];
 21};
 22
 23static int mpl115_spi_init(struct device *dev)
 24{
 25	struct spi_device *spi = to_spi_device(dev);
 26	struct mpl115_spi_buf *buf;
 27
 28	buf = devm_kzalloc(dev, sizeof(*buf), GFP_KERNEL);
 29	if (!buf)
 30		return -ENOMEM;
 31
 32	spi_set_drvdata(spi, buf);
 33
 34	return 0;
 35}
 36
 37static int mpl115_spi_read(struct device *dev, u8 address)
 38{
 39	struct spi_device *spi = to_spi_device(dev);
 40	struct mpl115_spi_buf *buf = spi_get_drvdata(spi);
 41	struct spi_transfer xfer = {
 42		.tx_buf = buf->tx,
 43		.rx_buf = buf->rx,
 44		.len = 4,
 45	};
 46	int ret;
 47
 48	buf->tx[0] = MPL115_SPI_READ(address);
 49	buf->tx[2] = MPL115_SPI_READ(address + 1);
 50
 51	ret = spi_sync_transfer(spi, &xfer, 1);
 52	if (ret)
 53		return ret;
 54
 55	return (buf->rx[1] << 8) | buf->rx[3];
 56}
 57
 58static int mpl115_spi_write(struct device *dev, u8 address, u8 value)
 59{
 60	struct spi_device *spi = to_spi_device(dev);
 61	struct mpl115_spi_buf *buf = spi_get_drvdata(spi);
 62	struct spi_transfer xfer = {
 63		.tx_buf = buf->tx,
 64		.len = 2,
 65	};
 66
 67	buf->tx[0] = MPL115_SPI_WRITE(address);
 68	buf->tx[1] = value;
 69
 70	return spi_sync_transfer(spi, &xfer, 1);
 71}
 72
 73static const struct mpl115_ops mpl115_spi_ops = {
 74	.init = mpl115_spi_init,
 75	.read = mpl115_spi_read,
 76	.write = mpl115_spi_write,
 77};
 78
 79static int mpl115_spi_probe(struct spi_device *spi)
 80{
 81	const struct spi_device_id *id = spi_get_device_id(spi);
 82
 83	return mpl115_probe(&spi->dev, id->name, &mpl115_spi_ops);
 84}
 85
 86static const struct spi_device_id mpl115_spi_ids[] = {
 87	{ "mpl115", 0 },
 88	{}
 89};
 90MODULE_DEVICE_TABLE(spi, mpl115_spi_ids);
 91
 92static struct spi_driver mpl115_spi_driver = {
 93	.driver = {
 94		.name   = "mpl115",
 95		.pm = pm_ptr(&mpl115_dev_pm_ops),
 96	},
 97	.probe = mpl115_spi_probe,
 98	.id_table = mpl115_spi_ids,
 99};
100module_spi_driver(mpl115_spi_driver);
101
102MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");
103MODULE_DESCRIPTION("Freescale MPL115A1 pressure/temperature driver");
104MODULE_LICENSE("GPL");
105MODULE_IMPORT_NS("IIO_MPL115");