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Peter Meerwald39631b52013-10-21 21:53:00 +01001/*
2 * mag3110.c - Support for Freescale MAG3110 magnetometer sensor
3 *
4 * Copyright (c) 2013 Peter Meerwald <pmeerw@pmeerw.net>
5 *
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.
9 *
10 * (7-bit I2C slave address 0x0e)
11 *
12 * TODO: irq, user offset, oversampling, continuous mode
13 */
14
15#include <linux/module.h>
16#include <linux/i2c.h>
17#include <linux/iio/iio.h>
18#include <linux/iio/sysfs.h>
19#include <linux/iio/trigger_consumer.h>
20#include <linux/iio/buffer.h>
21#include <linux/iio/triggered_buffer.h>
22#include <linux/delay.h>
23
24#define MAG3110_STATUS 0x00
25#define MAG3110_OUT_X 0x01 /* MSB first */
26#define MAG3110_OUT_Y 0x03
27#define MAG3110_OUT_Z 0x05
28#define MAG3110_WHO_AM_I 0x07
29#define MAG3110_OFF_X 0x09 /* MSB first */
30#define MAG3110_OFF_Y 0x0b
31#define MAG3110_OFF_Z 0x0d
32#define MAG3110_DIE_TEMP 0x0f
33#define MAG3110_CTRL_REG1 0x10
34#define MAG3110_CTRL_REG2 0x11
35
36#define MAG3110_STATUS_DRDY (BIT(2) | BIT(1) | BIT(0))
37
38#define MAG3110_CTRL_DR_MASK (BIT(7) | BIT(6) | BIT(5))
39#define MAG3110_CTRL_DR_SHIFT 5
40#define MAG3110_CTRL_DR_DEFAULT 0
41
42#define MAG3110_CTRL_TM BIT(1) /* trigger single measurement */
43#define MAG3110_CTRL_AC BIT(0) /* continuous measurements */
44
45#define MAG3110_CTRL_AUTO_MRST_EN BIT(7) /* magnetic auto-reset */
46#define MAG3110_CTRL_RAW BIT(5) /* measurements not user-offset corrected */
47
48#define MAG3110_DEVICE_ID 0xc4
49
50/* Each client has this additional data */
51struct mag3110_data {
52 struct i2c_client *client;
53 struct mutex lock;
54 u8 ctrl_reg1;
55};
56
57static int mag3110_request(struct mag3110_data *data)
58{
59 int ret, tries = 150;
60
61 /* trigger measurement */
62 ret = i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
63 data->ctrl_reg1 | MAG3110_CTRL_TM);
64 if (ret < 0)
65 return ret;
66
67 while (tries-- > 0) {
68 ret = i2c_smbus_read_byte_data(data->client, MAG3110_STATUS);
69 if (ret < 0)
70 return ret;
71 /* wait for data ready */
72 if ((ret & MAG3110_STATUS_DRDY) == MAG3110_STATUS_DRDY)
73 break;
74 msleep(20);
75 }
76
77 if (tries < 0) {
78 dev_err(&data->client->dev, "data not ready\n");
79 return -EIO;
80 }
81
82 return 0;
83}
84
85static int mag3110_read(struct mag3110_data *data, __be16 buf[3])
86{
87 int ret;
88
89 mutex_lock(&data->lock);
90 ret = mag3110_request(data);
91 if (ret < 0) {
92 mutex_unlock(&data->lock);
93 return ret;
94 }
95 ret = i2c_smbus_read_i2c_block_data(data->client,
96 MAG3110_OUT_X, 3 * sizeof(__be16), (u8 *) buf);
97 mutex_unlock(&data->lock);
98
99 return ret;
100}
101
102static ssize_t mag3110_show_int_plus_micros(char *buf,
103 const int (*vals)[2], int n)
104{
105 size_t len = 0;
106
107 while (n-- > 0)
108 len += scnprintf(buf + len, PAGE_SIZE - len,
109 "%d.%d ", vals[n][0], vals[n][1]);
110
111 /* replace trailing space by newline */
112 buf[len - 1] = '\n';
113
114 return len;
115}
116
117static int mag3110_get_int_plus_micros_index(const int (*vals)[2], int n,
118 int val, int val2)
119{
120 while (n-- > 0)
121 if (val == vals[n][0] && val2 == vals[n][1])
122 return n;
123
124 return -EINVAL;
125}
126
127static const int mag3110_samp_freq[8][2] = {
128 {80, 0}, {40, 0}, {20, 0}, {10, 0}, {5, 0}, {2, 500000},
129 {1, 250000}, {0, 625000}
130};
131
132static ssize_t mag3110_show_samp_freq_avail(struct device *dev,
133 struct device_attribute *attr, char *buf)
134{
135 return mag3110_show_int_plus_micros(buf, mag3110_samp_freq, 8);
136}
137
138static IIO_DEV_ATTR_SAMP_FREQ_AVAIL(mag3110_show_samp_freq_avail);
139
140static int mag3110_get_samp_freq_index(struct mag3110_data *data,
141 int val, int val2)
142{
143 return mag3110_get_int_plus_micros_index(mag3110_samp_freq, 8, val,
144 val2);
145}
146
147static int mag3110_read_raw(struct iio_dev *indio_dev,
148 struct iio_chan_spec const *chan,
149 int *val, int *val2, long mask)
150{
151 struct mag3110_data *data = iio_priv(indio_dev);
152 __be16 buffer[3];
153 int i, ret;
154
155 switch (mask) {
156 case IIO_CHAN_INFO_RAW:
157 switch (chan->type) {
158 case IIO_MAGN: /* in 0.1 uT / LSB */
159 ret = mag3110_read(data, buffer);
160 if (ret < 0)
161 return ret;
162 *val = sign_extend32(
163 be16_to_cpu(buffer[chan->scan_index]), 15);
164 return IIO_VAL_INT;
165 case IIO_TEMP: /* in 1 C / LSB */
166 mutex_lock(&data->lock);
167 ret = mag3110_request(data);
168 if (ret < 0) {
169 mutex_unlock(&data->lock);
170 return ret;
171 }
172 ret = i2c_smbus_read_byte_data(data->client,
173 MAG3110_DIE_TEMP);
174 mutex_unlock(&data->lock);
175 if (ret < 0)
176 return ret;
177 *val = sign_extend32(ret, 7);
178 return IIO_VAL_INT;
179 default:
180 return -EINVAL;
181 }
182 case IIO_CHAN_INFO_SCALE:
183 *val = 0;
184 *val2 = 1000;
185 return IIO_VAL_INT_PLUS_MICRO;
186 case IIO_CHAN_INFO_SAMP_FREQ:
187 i = data->ctrl_reg1 >> MAG3110_CTRL_DR_SHIFT;
188 *val = mag3110_samp_freq[i][0];
189 *val2 = mag3110_samp_freq[i][1];
190 return IIO_VAL_INT_PLUS_MICRO;
191 }
192 return -EINVAL;
193}
194
195static int mag3110_write_raw(struct iio_dev *indio_dev,
196 struct iio_chan_spec const *chan,
197 int val, int val2, long mask)
198{
199 struct mag3110_data *data = iio_priv(indio_dev);
200 int rate;
201
202 switch (mask) {
203 case IIO_CHAN_INFO_SAMP_FREQ:
204 rate = mag3110_get_samp_freq_index(data, val, val2);
205 if (rate < 0)
206 return -EINVAL;
207
208 data->ctrl_reg1 &= ~MAG3110_CTRL_DR_MASK;
209 data->ctrl_reg1 |= rate << MAG3110_CTRL_DR_SHIFT;
210 return i2c_smbus_write_byte_data(data->client,
211 MAG3110_CTRL_REG1, data->ctrl_reg1);
212 default:
213 return -EINVAL;
214 }
215}
216
217static irqreturn_t mag3110_trigger_handler(int irq, void *p)
218{
219 struct iio_poll_func *pf = p;
220 struct iio_dev *indio_dev = pf->indio_dev;
221 struct mag3110_data *data = iio_priv(indio_dev);
222 u8 buffer[16]; /* 3 16-bit channels + 1 byte temp + padding + ts */
223 int ret;
224
225 ret = mag3110_read(data, (__be16 *) buffer);
226 if (ret < 0)
227 goto done;
228
229 if (test_bit(3, indio_dev->active_scan_mask)) {
230 ret = i2c_smbus_read_byte_data(data->client,
231 MAG3110_DIE_TEMP);
232 if (ret < 0)
233 goto done;
234 buffer[6] = ret;
235 }
236
237 iio_push_to_buffers_with_timestamp(indio_dev, buffer,
238 iio_get_time_ns());
239
240done:
241 iio_trigger_notify_done(indio_dev->trig);
242 return IRQ_HANDLED;
243}
244
245#define MAG3110_CHANNEL(axis, idx) { \
246 .type = IIO_MAGN, \
247 .modified = 1, \
248 .channel2 = IIO_MOD_##axis, \
249 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
250 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
251 BIT(IIO_CHAN_INFO_SCALE), \
252 .scan_index = idx, \
Peter Meerwald911bdc62013-10-29 00:59:00 +0000253 .scan_type = { \
254 .sign = 's', \
255 .realbits = 16, \
256 .storagebits = 16, \
257 .endianness = IIO_BE, \
258 }, \
Peter Meerwald39631b52013-10-21 21:53:00 +0100259}
260
261static const struct iio_chan_spec mag3110_channels[] = {
262 MAG3110_CHANNEL(X, 0),
263 MAG3110_CHANNEL(Y, 1),
264 MAG3110_CHANNEL(Z, 2),
265 {
266 .type = IIO_TEMP,
267 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
268 .scan_index = 3,
Jonathan Camerone56879792013-12-11 18:45:00 +0000269 .scan_type = {
270 .sign = 's',
271 .realbits = 8,
272 .storagebits = 8,
273 },
Peter Meerwald39631b52013-10-21 21:53:00 +0100274 },
275 IIO_CHAN_SOFT_TIMESTAMP(4),
276};
277
278static struct attribute *mag3110_attributes[] = {
279 &iio_dev_attr_sampling_frequency_available.dev_attr.attr,
280 NULL
281};
282
283static const struct attribute_group mag3110_group = {
284 .attrs = mag3110_attributes,
285};
286
287static const struct iio_info mag3110_info = {
288 .attrs = &mag3110_group,
289 .read_raw = &mag3110_read_raw,
290 .write_raw = &mag3110_write_raw,
291 .driver_module = THIS_MODULE,
292};
293
294static const unsigned long mag3110_scan_masks[] = {0x7, 0xf, 0};
295
296static int mag3110_probe(struct i2c_client *client,
297 const struct i2c_device_id *id)
298{
299 struct mag3110_data *data;
300 struct iio_dev *indio_dev;
301 int ret;
302
303 ret = i2c_smbus_read_byte_data(client, MAG3110_WHO_AM_I);
304 if (ret < 0)
305 return ret;
306 if (ret != MAG3110_DEVICE_ID)
307 return -ENODEV;
308
309 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
310 if (!indio_dev)
311 return -ENOMEM;
312
313 data = iio_priv(indio_dev);
314 data->client = client;
315 mutex_init(&data->lock);
316
317 i2c_set_clientdata(client, indio_dev);
318 indio_dev->info = &mag3110_info;
319 indio_dev->name = id->name;
320 indio_dev->dev.parent = &client->dev;
321 indio_dev->modes = INDIO_DIRECT_MODE;
322 indio_dev->channels = mag3110_channels;
323 indio_dev->num_channels = ARRAY_SIZE(mag3110_channels);
324 indio_dev->available_scan_masks = mag3110_scan_masks;
325
326 data->ctrl_reg1 = MAG3110_CTRL_DR_DEFAULT;
327 ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG1,
328 data->ctrl_reg1);
329 if (ret < 0)
330 return ret;
331
332 ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG2,
333 MAG3110_CTRL_AUTO_MRST_EN | MAG3110_CTRL_RAW);
334 if (ret < 0)
335 return ret;
336
337 ret = iio_triggered_buffer_setup(indio_dev, NULL,
338 mag3110_trigger_handler, NULL);
339 if (ret < 0)
340 return ret;
341
342 ret = iio_device_register(indio_dev);
343 if (ret < 0)
344 goto buffer_cleanup;
345 return 0;
346
347buffer_cleanup:
348 iio_triggered_buffer_cleanup(indio_dev);
349 return ret;
350}
351
352static int mag3110_standby(struct mag3110_data *data)
353{
354 return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
355 data->ctrl_reg1 & ~MAG3110_CTRL_AC);
356}
357
358static int mag3110_remove(struct i2c_client *client)
359{
360 struct iio_dev *indio_dev = i2c_get_clientdata(client);
361
362 iio_device_unregister(indio_dev);
363 iio_triggered_buffer_cleanup(indio_dev);
364 mag3110_standby(iio_priv(indio_dev));
365
366 return 0;
367}
368
369#ifdef CONFIG_PM_SLEEP
370static int mag3110_suspend(struct device *dev)
371{
372 return mag3110_standby(iio_priv(i2c_get_clientdata(
373 to_i2c_client(dev))));
374}
375
376static int mag3110_resume(struct device *dev)
377{
378 struct mag3110_data *data = iio_priv(i2c_get_clientdata(
379 to_i2c_client(dev)));
380
381 return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
382 data->ctrl_reg1);
383}
384
385static SIMPLE_DEV_PM_OPS(mag3110_pm_ops, mag3110_suspend, mag3110_resume);
386#define MAG3110_PM_OPS (&mag3110_pm_ops)
387#else
388#define MAG3110_PM_OPS NULL
389#endif
390
391static const struct i2c_device_id mag3110_id[] = {
392 { "mag3110", 0 },
393 { }
394};
395MODULE_DEVICE_TABLE(i2c, mag3110_id);
396
397static struct i2c_driver mag3110_driver = {
398 .driver = {
399 .name = "mag3110",
400 .pm = MAG3110_PM_OPS,
401 },
402 .probe = mag3110_probe,
403 .remove = mag3110_remove,
404 .id_table = mag3110_id,
405};
406module_i2c_driver(mag3110_driver);
407
408MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
409MODULE_DESCRIPTION("Freescale MAG3110 magnetometer driver");
410MODULE_LICENSE("GPL");