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 #include <linux/of_device.h>
16
17 #include "ms5611.h"
18
ms5611_spi_reset(struct ms5611_state * st)19 static int ms5611_spi_reset(struct ms5611_state *st)
20 {
21 u8 cmd = MS5611_RESET;
22
23 return spi_write_then_read(st->client, &cmd, 1, NULL, 0);
24 }
25
ms5611_spi_read_prom_word(struct ms5611_state * st,int index,u16 * word)26 static int ms5611_spi_read_prom_word(struct ms5611_state *st, int index,
27 u16 *word)
28 {
29 int ret;
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
ms5611_spi_read_adc(struct ms5611_state * st,s32 * val)40 static int ms5611_spi_read_adc(struct ms5611_state *st, s32 *val)
41 {
42 int ret;
43 u8 buf[3] = { MS5611_READ_ADC };
44
45 ret = spi_write_then_read(st->client, buf, 1, buf, 3);
46 if (ret < 0)
47 return ret;
48
49 *val = (buf[0] << 16) | (buf[1] << 8) | buf[2];
50
51 return 0;
52 }
53
ms5611_spi_read_adc_temp_and_pressure(struct ms5611_state * st,s32 * temp,s32 * pressure)54 static int ms5611_spi_read_adc_temp_and_pressure(struct ms5611_state *st,
55 s32 *temp, s32 *pressure)
56 {
57 int ret;
58 const struct ms5611_osr *osr = st->temp_osr;
59
60 /*
61 * Warning: &osr->cmd MUST be aligned on a word boundary since used as
62 * 2nd argument (void*) of spi_write_then_read.
63 */
64 ret = spi_write_then_read(st->client, &osr->cmd, 1, NULL, 0);
65 if (ret < 0)
66 return ret;
67
68 usleep_range(osr->conv_usec, osr->conv_usec + (osr->conv_usec / 10UL));
69 ret = ms5611_spi_read_adc(st, temp);
70 if (ret < 0)
71 return ret;
72
73 osr = st->pressure_osr;
74 ret = spi_write_then_read(st->client, &osr->cmd, 1, NULL, 0);
75 if (ret < 0)
76 return ret;
77
78 usleep_range(osr->conv_usec, osr->conv_usec + (osr->conv_usec / 10UL));
79 return ms5611_spi_read_adc(st, pressure);
80 }
81
ms5611_spi_probe(struct spi_device * spi)82 static int ms5611_spi_probe(struct spi_device *spi)
83 {
84 int ret;
85 struct ms5611_state *st;
86 struct iio_dev *indio_dev;
87
88 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
89 if (!indio_dev)
90 return -ENOMEM;
91
92 spi_set_drvdata(spi, indio_dev);
93
94 spi->mode = SPI_MODE_0;
95 spi->max_speed_hz = min(spi->max_speed_hz, 20000000U);
96 spi->bits_per_word = 8;
97 ret = spi_setup(spi);
98 if (ret < 0)
99 return ret;
100
101 st = iio_priv(indio_dev);
102 st->reset = ms5611_spi_reset;
103 st->read_prom_word = ms5611_spi_read_prom_word;
104 st->read_adc_temp_and_pressure = ms5611_spi_read_adc_temp_and_pressure;
105 st->client = spi;
106
107 return ms5611_probe(indio_dev, &spi->dev, spi_get_device_id(spi)->name,
108 spi_get_device_id(spi)->driver_data);
109 }
110
ms5611_spi_remove(struct spi_device * spi)111 static int ms5611_spi_remove(struct spi_device *spi)
112 {
113 return ms5611_remove(spi_get_drvdata(spi));
114 }
115
116 #if defined(CONFIG_OF)
117 static const struct of_device_id ms5611_spi_matches[] = {
118 { .compatible = "meas,ms5611" },
119 { .compatible = "ms5611" },
120 { .compatible = "meas,ms5607" },
121 { .compatible = "ms5607" },
122 { }
123 };
124 MODULE_DEVICE_TABLE(of, ms5611_spi_matches);
125 #endif
126
127 static const struct spi_device_id ms5611_id[] = {
128 { "ms5611", MS5611 },
129 { "ms5607", MS5607 },
130 { }
131 };
132 MODULE_DEVICE_TABLE(spi, ms5611_id);
133
134 static struct spi_driver ms5611_driver = {
135 .driver = {
136 .name = "ms5611",
137 .of_match_table = of_match_ptr(ms5611_spi_matches)
138 },
139 .id_table = ms5611_id,
140 .probe = ms5611_spi_probe,
141 .remove = ms5611_spi_remove,
142 };
143 module_spi_driver(ms5611_driver);
144
145 MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
146 MODULE_DESCRIPTION("MS5611 spi driver");
147 MODULE_LICENSE("GPL v2");
148