1// SPDX-License-Identifier: GPL-2.0
2/*
3 * MS5611 pressure and temperature sensor driver (SPI bus)
4 *
5 * Copyright (c) Tomasz Duszynski <tduszyns@gmail.com>
6 *
7 */
8
9#include <linux/delay.h>
10#include <linux/module.h>
11#include <linux/spi/spi.h>
12#include <linux/mod_devicetable.h>
13
14#include <asm/unaligned.h>
15
16#include "ms5611.h"
17
18static int ms5611_spi_reset(struct ms5611_state *st)
19{
20	u8 cmd = MS5611_RESET;
21
22	return spi_write_then_read(st->client, &cmd, 1, NULL, 0);
23}
24
25static int ms5611_spi_read_prom_word(struct ms5611_state *st, int index,
26				     u16 *word)
27{
28	int ret;
29
30	ret = spi_w8r16be(st->client, MS5611_READ_PROM_WORD + (index << 1));
31	if (ret < 0)
32		return ret;
33
34	*word = ret;
35
36	return 0;
37}
38
39static int ms5611_spi_read_adc(struct ms5611_state *st, s32 *val)
40{
41	int ret;
42	u8 buf[3] = { MS5611_READ_ADC };
43
44	ret = spi_write_then_read(st->client, buf, 1, buf, 3);
45	if (ret < 0)
46		return ret;
47
48	*val = get_unaligned_be24(&buf[0]);
49
50	return 0;
51}
52
53static int ms5611_spi_read_adc_temp_and_pressure(struct ms5611_state *st,
54						 s32 *temp, s32 *pressure)
55{
56	int ret;
57	const struct ms5611_osr *osr = st->temp_osr;
58
59	/*
60	 * Warning: &osr->cmd MUST be aligned on a word boundary since used as
61	 * 2nd argument (void*) of spi_write_then_read.
62	 */
63	ret = spi_write_then_read(st->client, &osr->cmd, 1, NULL, 0);
64	if (ret < 0)
65		return ret;
66
67	usleep_range(osr->conv_usec, osr->conv_usec + (osr->conv_usec / 10UL));
68	ret = ms5611_spi_read_adc(st, temp);
69	if (ret < 0)
70		return ret;
71
72	osr = st->pressure_osr;
73	ret = spi_write_then_read(st->client, &osr->cmd, 1, NULL, 0);
74	if (ret < 0)
75		return ret;
76
77	usleep_range(osr->conv_usec, osr->conv_usec + (osr->conv_usec / 10UL));
78	return ms5611_spi_read_adc(st, pressure);
79}
80
81static int ms5611_spi_probe(struct spi_device *spi)
82{
83	int ret;
84	struct ms5611_state *st;
85	struct iio_dev *indio_dev;
86
87	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
88	if (!indio_dev)
89		return -ENOMEM;
90
91	spi_set_drvdata(spi, indio_dev);
92
93	spi->mode = SPI_MODE_0;
94	spi->max_speed_hz = min(spi->max_speed_hz, 20000000U);
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, spi_get_device_id(spi)->name,
107			    spi_get_device_id(spi)->driver_data);
108}
109
110static const struct of_device_id ms5611_spi_matches[] = {
111	{ .compatible = "meas,ms5611" },
112	{ .compatible = "meas,ms5607" },
113	{ }
114};
115MODULE_DEVICE_TABLE(of, ms5611_spi_matches);
116
117static const struct spi_device_id ms5611_id[] = {
118	{ "ms5611", MS5611 },
119	{ "ms5607", MS5607 },
120	{ }
121};
122MODULE_DEVICE_TABLE(spi, ms5611_id);
123
124static struct spi_driver ms5611_driver = {
125	.driver = {
126		.name = "ms5611",
127		.of_match_table = ms5611_spi_matches
128	},
129	.id_table = ms5611_id,
130	.probe = ms5611_spi_probe,
131};
132module_spi_driver(ms5611_driver);
133
134MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
135MODULE_DESCRIPTION("MS5611 spi driver");
136MODULE_LICENSE("GPL v2");
137MODULE_IMPORT_NS(IIO_MS5611);
138