1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
|
/*
* MS5611 pressure and temperature sensor driver
*
* Copyright (c) Tomasz Duszynski <tduszyns@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Data sheet:
* http://www.meas-spec.com/downloads/MS5611-01BA03.pdf
*
*/
#include <linux/module.h>
#include <linux/iio/iio.h>
#include <linux/delay.h>
#include "ms5611.h"
static bool ms5611_prom_is_valid(u16 *prom, size_t len)
{
int i, j;
uint16_t crc = 0, crc_orig = prom[7] & 0x000F;
prom[7] &= 0xFF00;
for (i = 0; i < len * 2; i++) {
if (i % 2 == 1)
crc ^= prom[i >> 1] & 0x00FF;
else
crc ^= prom[i >> 1] >> 8;
for (j = 0; j < 8; j++) {
if (crc & 0x8000)
crc = (crc << 1) ^ 0x3000;
else
crc <<= 1;
}
}
crc = (crc >> 12) & 0x000F;
return crc_orig != 0x0000 && crc == crc_orig;
}
static int ms5611_read_prom(struct iio_dev *indio_dev)
{
int ret, i;
struct ms5611_state *st = iio_priv(indio_dev);
for (i = 0; i < MS5611_PROM_WORDS_NB; i++) {
ret = st->read_prom_word(&indio_dev->dev, i, &st->prom[i]);
if (ret < 0) {
dev_err(&indio_dev->dev,
"failed to read prom at %d\n", i);
return ret;
}
}
if (!ms5611_prom_is_valid(st->prom, MS5611_PROM_WORDS_NB)) {
dev_err(&indio_dev->dev, "PROM integrity check failed\n");
return -ENODEV;
}
return 0;
}
static int ms5611_read_temp_and_pressure(struct iio_dev *indio_dev,
s32 *temp, s32 *pressure)
{
int ret;
s32 t, p;
s64 off, sens, dt;
struct ms5611_state *st = iio_priv(indio_dev);
ret = st->read_adc_temp_and_pressure(&indio_dev->dev, &t, &p);
if (ret < 0) {
dev_err(&indio_dev->dev,
"failed to read temperature and pressure\n");
return ret;
}
dt = t - (st->prom[5] << 8);
off = ((s64)st->prom[2] << 16) + ((st->prom[4] * dt) >> 7);
sens = ((s64)st->prom[1] << 15) + ((st->prom[3] * dt) >> 8);
t = 2000 + ((st->prom[6] * dt) >> 23);
if (t < 2000) {
s64 off2, sens2, t2;
t2 = (dt * dt) >> 31;
off2 = (5 * (t - 2000) * (t - 2000)) >> 1;
sens2 = off2 >> 1;
if (t < -1500) {
s64 tmp = (t + 1500) * (t + 1500);
off2 += 7 * tmp;
sens2 += (11 * tmp) >> 1;
}
t -= t2;
off -= off2;
sens -= sens2;
}
*temp = t;
*pressure = (((p * sens) >> 21) - off) >> 15;
return 0;
}
static int ms5611_reset(struct iio_dev *indio_dev)
{
int ret;
struct ms5611_state *st = iio_priv(indio_dev);
ret = st->reset(&indio_dev->dev);
if (ret < 0) {
dev_err(&indio_dev->dev, "failed to reset device\n");
return ret;
}
usleep_range(3000, 4000);
return 0;
}
static int ms5611_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
int ret;
s32 temp, pressure;
struct ms5611_state *st = iio_priv(indio_dev);
switch (mask) {
case IIO_CHAN_INFO_PROCESSED:
mutex_lock(&st->lock);
ret = ms5611_read_temp_and_pressure(indio_dev,
&temp, &pressure);
mutex_unlock(&st->lock);
if (ret < 0)
return ret;
switch (chan->type) {
case IIO_TEMP:
*val = temp * 10;
return IIO_VAL_INT;
case IIO_PRESSURE:
*val = pressure / 1000;
*val2 = (pressure % 1000) * 1000;
return IIO_VAL_INT_PLUS_MICRO;
default:
return -EINVAL;
}
}
return -EINVAL;
}
static const struct iio_chan_spec ms5611_channels[] = {
{
.type = IIO_PRESSURE,
.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
BIT(IIO_CHAN_INFO_SCALE)
},
{
.type = IIO_TEMP,
.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
BIT(IIO_CHAN_INFO_SCALE)
}
};
static const struct iio_info ms5611_info = {
.read_raw = &ms5611_read_raw,
.driver_module = THIS_MODULE,
};
static int ms5611_init(struct iio_dev *indio_dev)
{
int ret;
ret = ms5611_reset(indio_dev);
if (ret < 0)
return ret;
return ms5611_read_prom(indio_dev);
}
int ms5611_probe(struct iio_dev *indio_dev, struct device *dev)
{
int ret;
struct ms5611_state *st = iio_priv(indio_dev);
mutex_init(&st->lock);
indio_dev->dev.parent = dev;
indio_dev->name = dev->driver->name;
indio_dev->info = &ms5611_info;
indio_dev->channels = ms5611_channels;
indio_dev->num_channels = ARRAY_SIZE(ms5611_channels);
indio_dev->modes = INDIO_DIRECT_MODE;
ret = ms5611_init(indio_dev);
if (ret < 0)
return ret;
return devm_iio_device_register(dev, indio_dev);
}
EXPORT_SYMBOL(ms5611_probe);
MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
MODULE_DESCRIPTION("MS5611 core driver");
MODULE_LICENSE("GPL v2");
|
