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 
ms5611_spi_reset(struct ms5611_state * st)18 static 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 
ms5611_spi_read_prom_word(struct ms5611_state * st,int index,u16 * word)25 static 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 
ms5611_spi_read_adc(struct ms5611_state * st,s32 * val)39 static 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 
ms5611_spi_read_adc_temp_and_pressure(struct ms5611_state * st,s32 * temp,s32 * pressure)53 static 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 
ms5611_spi_probe(struct spi_device * spi)81 static 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 
110 static const struct of_device_id ms5611_spi_matches[] = {
111 	{ .compatible = "meas,ms5611" },
112 	{ .compatible = "meas,ms5607" },
113 	{ }
114 };
115 MODULE_DEVICE_TABLE(of, ms5611_spi_matches);
116 
117 static const struct spi_device_id ms5611_id[] = {
118 	{ "ms5611", MS5611 },
119 	{ "ms5607", MS5607 },
120 	{ }
121 };
122 MODULE_DEVICE_TABLE(spi, ms5611_id);
123 
124 static 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 };
132 module_spi_driver(ms5611_driver);
133 
134 MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
135 MODULE_DESCRIPTION("MS5611 spi driver");
136 MODULE_LICENSE("GPL v2");
137 MODULE_IMPORT_NS(IIO_MS5611);
138