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);
106