mm, page_alloc: set alloc_flags only once in slowpath
[linux/fpc-iii.git] / drivers / iio / pressure / mpl115.c
blob73f2f0c46e6252b0446fcaa8d4d88d4725d06e61
1 /*
2 * mpl115.c - Support for Freescale MPL115A pressure/temperature sensor
4 * Copyright (c) 2014 Peter Meerwald <pmeerw@pmeerw.net>
6 * This file is subject to the terms and conditions of version 2 of
7 * the GNU General Public License. See the file COPYING in the main
8 * directory of this archive for more details.
10 * TODO: shutdown pin
14 #include <linux/module.h>
15 #include <linux/iio/iio.h>
16 #include <linux/delay.h>
18 #include "mpl115.h"
20 #define MPL115_PADC 0x00 /* pressure ADC output value, MSB first, 10 bit */
21 #define MPL115_TADC 0x02 /* temperature ADC output value, MSB first, 10 bit */
22 #define MPL115_A0 0x04 /* 12 bit integer, 3 bit fraction */
23 #define MPL115_B1 0x06 /* 2 bit integer, 13 bit fraction */
24 #define MPL115_B2 0x08 /* 1 bit integer, 14 bit fraction */
25 #define MPL115_C12 0x0a /* 0 bit integer, 13 bit fraction */
26 #define MPL115_CONVERT 0x12 /* convert temperature and pressure */
28 struct mpl115_data {
29 struct device *dev;
30 struct mutex lock;
31 s16 a0;
32 s16 b1, b2;
33 s16 c12;
34 const struct mpl115_ops *ops;
37 static int mpl115_request(struct mpl115_data *data)
39 int ret = data->ops->write(data->dev, MPL115_CONVERT, 0);
41 if (ret < 0)
42 return ret;
44 usleep_range(3000, 4000);
46 return 0;
49 static int mpl115_comp_pressure(struct mpl115_data *data, int *val, int *val2)
51 int ret;
52 u16 padc, tadc;
53 int a1, y1, pcomp;
54 unsigned kpa;
56 mutex_lock(&data->lock);
57 ret = mpl115_request(data);
58 if (ret < 0)
59 goto done;
61 ret = data->ops->read(data->dev, MPL115_PADC);
62 if (ret < 0)
63 goto done;
64 padc = ret >> 6;
66 ret = data->ops->read(data->dev, MPL115_TADC);
67 if (ret < 0)
68 goto done;
69 tadc = ret >> 6;
71 /* see Freescale AN3785 */
72 a1 = data->b1 + ((data->c12 * tadc) >> 11);
73 y1 = (data->a0 << 10) + a1 * padc;
75 /* compensated pressure with 4 fractional bits */
76 pcomp = (y1 + ((data->b2 * (int) tadc) >> 1)) >> 9;
78 kpa = pcomp * (115 - 50) / 1023 + (50 << 4);
79 *val = kpa >> 4;
80 *val2 = (kpa & 15) * (1000000 >> 4);
81 done:
82 mutex_unlock(&data->lock);
83 return ret;
86 static int mpl115_read_temp(struct mpl115_data *data)
88 int ret;
90 mutex_lock(&data->lock);
91 ret = mpl115_request(data);
92 if (ret < 0)
93 goto done;
94 ret = data->ops->read(data->dev, MPL115_TADC);
95 done:
96 mutex_unlock(&data->lock);
97 return ret;
100 static int mpl115_read_raw(struct iio_dev *indio_dev,
101 struct iio_chan_spec const *chan,
102 int *val, int *val2, long mask)
104 struct mpl115_data *data = iio_priv(indio_dev);
105 int ret;
107 switch (mask) {
108 case IIO_CHAN_INFO_PROCESSED:
109 ret = mpl115_comp_pressure(data, val, val2);
110 if (ret < 0)
111 return ret;
112 return IIO_VAL_INT_PLUS_MICRO;
113 case IIO_CHAN_INFO_RAW:
114 /* temperature -5.35 C / LSB, 472 LSB is 25 C */
115 ret = mpl115_read_temp(data);
116 if (ret < 0)
117 return ret;
118 *val = ret >> 6;
119 return IIO_VAL_INT;
120 case IIO_CHAN_INFO_OFFSET:
121 *val = -605;
122 *val2 = 750000;
123 return IIO_VAL_INT_PLUS_MICRO;
124 case IIO_CHAN_INFO_SCALE:
125 *val = -186;
126 *val2 = 915888;
127 return IIO_VAL_INT_PLUS_MICRO;
129 return -EINVAL;
132 static const struct iio_chan_spec mpl115_channels[] = {
134 .type = IIO_PRESSURE,
135 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
138 .type = IIO_TEMP,
139 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
140 BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_SCALE),
144 static const struct iio_info mpl115_info = {
145 .read_raw = &mpl115_read_raw,
146 .driver_module = THIS_MODULE,
149 int mpl115_probe(struct device *dev, const char *name,
150 const struct mpl115_ops *ops)
152 struct mpl115_data *data;
153 struct iio_dev *indio_dev;
154 int ret;
156 indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
157 if (!indio_dev)
158 return -ENOMEM;
160 data = iio_priv(indio_dev);
161 data->dev = dev;
162 data->ops = ops;
163 mutex_init(&data->lock);
165 indio_dev->info = &mpl115_info;
166 indio_dev->name = name;
167 indio_dev->dev.parent = dev;
168 indio_dev->modes = INDIO_DIRECT_MODE;
169 indio_dev->channels = mpl115_channels;
170 indio_dev->num_channels = ARRAY_SIZE(mpl115_channels);
172 ret = data->ops->init(data->dev);
173 if (ret)
174 return ret;
176 ret = data->ops->read(data->dev, MPL115_A0);
177 if (ret < 0)
178 return ret;
179 data->a0 = ret;
180 ret = data->ops->read(data->dev, MPL115_B1);
181 if (ret < 0)
182 return ret;
183 data->b1 = ret;
184 ret = data->ops->read(data->dev, MPL115_B2);
185 if (ret < 0)
186 return ret;
187 data->b2 = ret;
188 ret = data->ops->read(data->dev, MPL115_C12);
189 if (ret < 0)
190 return ret;
191 data->c12 = ret;
193 return devm_iio_device_register(dev, indio_dev);
195 EXPORT_SYMBOL_GPL(mpl115_probe);
197 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
198 MODULE_DESCRIPTION("Freescale MPL115 pressure/temperature driver");
199 MODULE_LICENSE("GPL");