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Thomas Gleixner36edc932019-05-29 16:57:44 -07001// SPDX-License-Identifier: GPL-2.0-only
Peter Meerwald3017d902014-02-05 16:58:00 +00002/*
Akinobu Mitac984b9c2016-01-16 01:00:03 +09003 * mpl115.c - Support for Freescale MPL115A pressure/temperature sensor
Peter Meerwald3017d902014-02-05 16:58:00 +00004 *
5 * Copyright (c) 2014 Peter Meerwald <pmeerw@pmeerw.net>
6 *
Peter Meerwald3017d902014-02-05 16:58:00 +00007 * TODO: shutdown pin
Peter Meerwald3017d902014-02-05 16:58:00 +00008 */
9
10#include <linux/module.h>
Peter Meerwald3017d902014-02-05 16:58:00 +000011#include <linux/iio/iio.h>
12#include <linux/delay.h>
13
Akinobu Mitac984b9c2016-01-16 01:00:03 +090014#include "mpl115.h"
15
Peter Meerwald3017d902014-02-05 16:58:00 +000016#define MPL115_PADC 0x00 /* pressure ADC output value, MSB first, 10 bit */
17#define MPL115_TADC 0x02 /* temperature ADC output value, MSB first, 10 bit */
18#define MPL115_A0 0x04 /* 12 bit integer, 3 bit fraction */
19#define MPL115_B1 0x06 /* 2 bit integer, 13 bit fraction */
20#define MPL115_B2 0x08 /* 1 bit integer, 14 bit fraction */
21#define MPL115_C12 0x0a /* 0 bit integer, 13 bit fraction */
22#define MPL115_CONVERT 0x12 /* convert temperature and pressure */
23
24struct mpl115_data {
Akinobu Mitac984b9c2016-01-16 01:00:03 +090025 struct device *dev;
Peter Meerwald3017d902014-02-05 16:58:00 +000026 struct mutex lock;
27 s16 a0;
28 s16 b1, b2;
29 s16 c12;
Akinobu Mitac984b9c2016-01-16 01:00:03 +090030 const struct mpl115_ops *ops;
Peter Meerwald3017d902014-02-05 16:58:00 +000031};
32
33static int mpl115_request(struct mpl115_data *data)
34{
Akinobu Mitac984b9c2016-01-16 01:00:03 +090035 int ret = data->ops->write(data->dev, MPL115_CONVERT, 0);
36
Peter Meerwald3017d902014-02-05 16:58:00 +000037 if (ret < 0)
38 return ret;
39
40 usleep_range(3000, 4000);
41
42 return 0;
43}
44
45static int mpl115_comp_pressure(struct mpl115_data *data, int *val, int *val2)
46{
47 int ret;
48 u16 padc, tadc;
49 int a1, y1, pcomp;
50 unsigned kpa;
51
52 mutex_lock(&data->lock);
53 ret = mpl115_request(data);
54 if (ret < 0)
55 goto done;
56
Akinobu Mitac984b9c2016-01-16 01:00:03 +090057 ret = data->ops->read(data->dev, MPL115_PADC);
Peter Meerwald3017d902014-02-05 16:58:00 +000058 if (ret < 0)
59 goto done;
60 padc = ret >> 6;
61
Akinobu Mitac984b9c2016-01-16 01:00:03 +090062 ret = data->ops->read(data->dev, MPL115_TADC);
Peter Meerwald3017d902014-02-05 16:58:00 +000063 if (ret < 0)
64 goto done;
65 tadc = ret >> 6;
66
67 /* see Freescale AN3785 */
68 a1 = data->b1 + ((data->c12 * tadc) >> 11);
69 y1 = (data->a0 << 10) + a1 * padc;
70
71 /* compensated pressure with 4 fractional bits */
72 pcomp = (y1 + ((data->b2 * (int) tadc) >> 1)) >> 9;
73
74 kpa = pcomp * (115 - 50) / 1023 + (50 << 4);
75 *val = kpa >> 4;
76 *val2 = (kpa & 15) * (1000000 >> 4);
77done:
78 mutex_unlock(&data->lock);
79 return ret;
80}
81
82static int mpl115_read_temp(struct mpl115_data *data)
83{
84 int ret;
85
86 mutex_lock(&data->lock);
87 ret = mpl115_request(data);
88 if (ret < 0)
89 goto done;
Akinobu Mitac984b9c2016-01-16 01:00:03 +090090 ret = data->ops->read(data->dev, MPL115_TADC);
Peter Meerwald3017d902014-02-05 16:58:00 +000091done:
92 mutex_unlock(&data->lock);
93 return ret;
94}
95
96static int mpl115_read_raw(struct iio_dev *indio_dev,
97 struct iio_chan_spec const *chan,
98 int *val, int *val2, long mask)
99{
100 struct mpl115_data *data = iio_priv(indio_dev);
101 int ret;
102
103 switch (mask) {
104 case IIO_CHAN_INFO_PROCESSED:
105 ret = mpl115_comp_pressure(data, val, val2);
106 if (ret < 0)
107 return ret;
108 return IIO_VAL_INT_PLUS_MICRO;
109 case IIO_CHAN_INFO_RAW:
110 /* temperature -5.35 C / LSB, 472 LSB is 25 C */
111 ret = mpl115_read_temp(data);
112 if (ret < 0)
113 return ret;
114 *val = ret >> 6;
115 return IIO_VAL_INT;
116 case IIO_CHAN_INFO_OFFSET:
Akinobu Mita431386e2016-01-21 01:07:31 +0900117 *val = -605;
Peter Meerwald3017d902014-02-05 16:58:00 +0000118 *val2 = 750000;
119 return IIO_VAL_INT_PLUS_MICRO;
120 case IIO_CHAN_INFO_SCALE:
121 *val = -186;
122 *val2 = 915888;
123 return IIO_VAL_INT_PLUS_MICRO;
124 }
125 return -EINVAL;
126}
127
128static const struct iio_chan_spec mpl115_channels[] = {
129 {
130 .type = IIO_PRESSURE,
131 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
132 },
133 {
134 .type = IIO_TEMP,
135 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
Peter Rosin6a6e1d52017-02-01 21:40:57 +0100136 .info_mask_shared_by_type =
Peter Meerwald3017d902014-02-05 16:58:00 +0000137 BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_SCALE),
138 },
139};
140
141static const struct iio_info mpl115_info = {
142 .read_raw = &mpl115_read_raw,
Peter Meerwald3017d902014-02-05 16:58:00 +0000143};
144
Akinobu Mitac984b9c2016-01-16 01:00:03 +0900145int mpl115_probe(struct device *dev, const char *name,
146 const struct mpl115_ops *ops)
Peter Meerwald3017d902014-02-05 16:58:00 +0000147{
148 struct mpl115_data *data;
149 struct iio_dev *indio_dev;
150 int ret;
151
Akinobu Mitac984b9c2016-01-16 01:00:03 +0900152 indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
Peter Meerwald3017d902014-02-05 16:58:00 +0000153 if (!indio_dev)
154 return -ENOMEM;
155
156 data = iio_priv(indio_dev);
Akinobu Mitac984b9c2016-01-16 01:00:03 +0900157 data->dev = dev;
158 data->ops = ops;
Peter Meerwald3017d902014-02-05 16:58:00 +0000159 mutex_init(&data->lock);
160
Peter Meerwald3017d902014-02-05 16:58:00 +0000161 indio_dev->info = &mpl115_info;
Akinobu Mitac984b9c2016-01-16 01:00:03 +0900162 indio_dev->name = name;
163 indio_dev->dev.parent = dev;
Peter Meerwald3017d902014-02-05 16:58:00 +0000164 indio_dev->modes = INDIO_DIRECT_MODE;
165 indio_dev->channels = mpl115_channels;
166 indio_dev->num_channels = ARRAY_SIZE(mpl115_channels);
167
Akinobu Mitac984b9c2016-01-16 01:00:03 +0900168 ret = data->ops->init(data->dev);
169 if (ret)
170 return ret;
171
172 ret = data->ops->read(data->dev, MPL115_A0);
Peter Meerwald3017d902014-02-05 16:58:00 +0000173 if (ret < 0)
174 return ret;
175 data->a0 = ret;
Akinobu Mitac984b9c2016-01-16 01:00:03 +0900176 ret = data->ops->read(data->dev, MPL115_B1);
Peter Meerwald3017d902014-02-05 16:58:00 +0000177 if (ret < 0)
178 return ret;
179 data->b1 = ret;
Akinobu Mitac984b9c2016-01-16 01:00:03 +0900180 ret = data->ops->read(data->dev, MPL115_B2);
Peter Meerwald3017d902014-02-05 16:58:00 +0000181 if (ret < 0)
182 return ret;
183 data->b2 = ret;
Akinobu Mitac984b9c2016-01-16 01:00:03 +0900184 ret = data->ops->read(data->dev, MPL115_C12);
Peter Meerwald3017d902014-02-05 16:58:00 +0000185 if (ret < 0)
186 return ret;
187 data->c12 = ret;
188
Akinobu Mitac984b9c2016-01-16 01:00:03 +0900189 return devm_iio_device_register(dev, indio_dev);
Peter Meerwald3017d902014-02-05 16:58:00 +0000190}
Akinobu Mitac984b9c2016-01-16 01:00:03 +0900191EXPORT_SYMBOL_GPL(mpl115_probe);
Peter Meerwald3017d902014-02-05 16:58:00 +0000192
193MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
194MODULE_DESCRIPTION("Freescale MPL115 pressure/temperature driver");
195MODULE_LICENSE("GPL");