1/*
2 * MS5611 pressure and temperature sensor driver (SPI bus)
3 *
4 * Copyright (c) Tomasz Duszynski <tduszyns@gmail.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 */
11
12#include <linux/delay.h>
13#include <linux/module.h>
14#include <linux/spi/spi.h>
15
16#include "ms5611.h"
17
18static int ms5611_spi_reset(struct device *dev)
19{
20	u8 cmd = MS5611_RESET;
21	struct ms5611_state *st = iio_priv(dev_to_iio_dev(dev));
22
23	return spi_write_then_read(st->client, &cmd, 1, NULL, 0);
24}
25
26static int ms5611_spi_read_prom_word(struct device *dev, int index, u16 *word)
27{
28	int ret;
29	struct ms5611_state *st = iio_priv(dev_to_iio_dev(dev));
30
31	ret = spi_w8r16be(st->client, MS5611_READ_PROM_WORD + (index << 1));
32	if (ret < 0)
33		return ret;
34
35	*word = ret;
36
37	return 0;
38}
39
40static int ms5611_spi_read_adc(struct device *dev, s32 *val)
41{
42	int ret;
43	u8 buf[3] = { MS5611_READ_ADC };
44	struct ms5611_state *st = iio_priv(dev_to_iio_dev(dev));
45
46	ret = spi_write_then_read(st->client, buf, 1, buf, 3);
47	if (ret < 0)
48		return ret;
49
50	*val = (buf[0] << 16) | (buf[1] << 8) | buf[2];
51
52	return 0;
53}
54
55static int ms5611_spi_read_adc_temp_and_pressure(struct device *dev,
56						 s32 *temp, s32 *pressure)
57{
58	u8 cmd;
59	int ret;
60	struct ms5611_state *st = iio_priv(dev_to_iio_dev(dev));
61
62	cmd = MS5611_START_TEMP_CONV;
63	ret = spi_write_then_read(st->client, &cmd, 1, NULL, 0);
64	if (ret < 0)
65		return ret;
66
67	usleep_range(MS5611_CONV_TIME_MIN, MS5611_CONV_TIME_MAX);
68
69	ret = ms5611_spi_read_adc(dev, temp);
70	if (ret < 0)
71		return ret;
72
73	cmd = MS5611_START_PRESSURE_CONV;
74	ret = spi_write_then_read(st->client, &cmd, 1, NULL, 0);
75	if (ret < 0)
76		return ret;
77
78	usleep_range(MS5611_CONV_TIME_MIN, MS5611_CONV_TIME_MAX);
79
80	return ms5611_spi_read_adc(dev, pressure);
81}
82
83static int ms5611_spi_probe(struct spi_device *spi)
84{
85	int ret;
86	struct ms5611_state *st;
87	struct iio_dev *indio_dev;
88
89	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
90	if (!indio_dev)
91		return -ENOMEM;
92
93	spi->mode = SPI_MODE_0;
94	spi->max_speed_hz = 20000000;
95	spi->bits_per_word = 8;
96	ret = spi_setup(spi);
97	if (ret < 0)
98		return ret;
99
100	st = iio_priv(indio_dev);
101	st->reset = ms5611_spi_reset;
102	st->read_prom_word = ms5611_spi_read_prom_word;
103	st->read_adc_temp_and_pressure = ms5611_spi_read_adc_temp_and_pressure;
104	st->client = spi;
105
106	return ms5611_probe(indio_dev, &spi->dev);
107}
108
109static const struct spi_device_id ms5611_id[] = {
110	{ "ms5611", 0 },
111	{ }
112};
113MODULE_DEVICE_TABLE(spi, ms5611_id);
114
115static struct spi_driver ms5611_driver = {
116	.driver = {
117		.name = "ms5611",
118		.owner = THIS_MODULE,
119	},
120	.id_table = ms5611_id,
121	.probe = ms5611_spi_probe,
122};
123module_spi_driver(ms5611_driver);
124
125MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
126MODULE_DESCRIPTION("MS5611 spi driver");
127MODULE_LICENSE("GPL v2");
128