summaryrefslogtreecommitdiffstats
path: root/drivers/iio/magnetometer/mag3110.c
blob: f66955fb3509e261f3a0d0cf7028f6178b3cb1a2 (plain)
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
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
/*
 * mag3110.c - Support for Freescale MAG3110 magnetometer sensor
 *
 * Copyright (c) 2013 Peter Meerwald <pmeerw@pmeerw.net>
 *
 * This file is subject to the terms and conditions of version 2 of
 * the GNU General Public License.  See the file COPYING in the main
 * directory of this archive for more details.
 *
 * (7-bit I2C slave address 0x0e)
 *
 * TODO: irq, user offset, oversampling, continuous mode
 */

#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/buffer.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/delay.h>

#define MAG3110_STATUS 0x00
#define MAG3110_OUT_X 0x01 /* MSB first */
#define MAG3110_OUT_Y 0x03
#define MAG3110_OUT_Z 0x05
#define MAG3110_WHO_AM_I 0x07
#define MAG3110_OFF_X 0x09 /* MSB first */
#define MAG3110_OFF_Y 0x0b
#define MAG3110_OFF_Z 0x0d
#define MAG3110_DIE_TEMP 0x0f
#define MAG3110_CTRL_REG1 0x10
#define MAG3110_CTRL_REG2 0x11

#define MAG3110_STATUS_DRDY (BIT(2) | BIT(1) | BIT(0))

#define MAG3110_CTRL_DR_MASK (BIT(7) | BIT(6) | BIT(5))
#define MAG3110_CTRL_DR_SHIFT 5
#define MAG3110_CTRL_DR_DEFAULT 0

#define MAG3110_CTRL_TM BIT(1) /* trigger single measurement */
#define MAG3110_CTRL_AC BIT(0) /* continuous measurements */

#define MAG3110_CTRL_AUTO_MRST_EN BIT(7) /* magnetic auto-reset */
#define MAG3110_CTRL_RAW BIT(5) /* measurements not user-offset corrected */

#define MAG3110_DEVICE_ID 0xc4

/* Each client has this additional data */
struct mag3110_data {
	struct i2c_client *client;
	struct mutex lock;
	u8 ctrl_reg1;
};

static int mag3110_request(struct mag3110_data *data)
{
	int ret, tries = 150;

	/* trigger measurement */
	ret = i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
		data->ctrl_reg1 | MAG3110_CTRL_TM);
	if (ret < 0)
		return ret;

	while (tries-- > 0) {
		ret = i2c_smbus_read_byte_data(data->client, MAG3110_STATUS);
		if (ret < 0)
			return ret;
		/* wait for data ready */
		if ((ret & MAG3110_STATUS_DRDY) == MAG3110_STATUS_DRDY)
			break;
		msleep(20);
	}

	if (tries < 0) {
		dev_err(&data->client->dev, "data not ready\n");
		return -EIO;
	}

	return 0;
}

static int mag3110_read(struct mag3110_data *data, __be16 buf[3])
{
	int ret;

	mutex_lock(&data->lock);
	ret = mag3110_request(data);
	if (ret < 0) {
		mutex_unlock(&data->lock);
		return ret;
	}
	ret = i2c_smbus_read_i2c_block_data(data->client,
		MAG3110_OUT_X, 3 * sizeof(__be16), (u8 *) buf);
	mutex_unlock(&data->lock);

	return ret;
}

static ssize_t mag3110_show_int_plus_micros(char *buf,
	const int (*vals)[2], int n)
{
	size_t len = 0;

	while (n-- > 0)
		len += scnprintf(buf + len, PAGE_SIZE - len,
			"%d.%06d ", vals[n][0], vals[n][1]);

	/* replace trailing space by newline */
	buf[len - 1] = '\n';

	return len;
}

static int mag3110_get_int_plus_micros_index(const int (*vals)[2], int n,
					int val, int val2)
{
	while (n-- > 0)
		if (val == vals[n][0] && val2 == vals[n][1])
			return n;

	return -EINVAL;
}

static const int mag3110_samp_freq[8][2] = {
	{80, 0}, {40, 0}, {20, 0}, {10, 0}, {5, 0}, {2, 500000},
	{1, 250000}, {0, 625000}
};

static ssize_t mag3110_show_samp_freq_avail(struct device *dev,
				struct device_attribute *attr, char *buf)
{
	return mag3110_show_int_plus_micros(buf, mag3110_samp_freq, 8);
}

static IIO_DEV_ATTR_SAMP_FREQ_AVAIL(mag3110_show_samp_freq_avail);

static int mag3110_get_samp_freq_index(struct mag3110_data *data,
	int val, int val2)
{
	return mag3110_get_int_plus_micros_index(mag3110_samp_freq, 8, val,
		val2);
}

static int mag3110_read_raw(struct iio_dev *indio_dev,
			    struct iio_chan_spec const *chan,
			    int *val, int *val2, long mask)
{
	struct mag3110_data *data = iio_priv(indio_dev);
	__be16 buffer[3];
	int i, ret;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		if (iio_buffer_enabled(indio_dev))
			return -EBUSY;

		switch (chan->type) {
		case IIO_MAGN: /* in 0.1 uT / LSB */
			ret = mag3110_read(data, buffer);
			if (ret < 0)
				return ret;
			*val = sign_extend32(
				be16_to_cpu(buffer[chan->scan_index]), 15);
			return IIO_VAL_INT;
		case IIO_TEMP: /* in 1 C / LSB */
			mutex_lock(&data->lock);
			ret = mag3110_request(data);
			if (ret < 0) {
				mutex_unlock(&data->lock);
				return ret;
			}
			ret = i2c_smbus_read_byte_data(data->client,
				MAG3110_DIE_TEMP);
			mutex_unlock(&data->lock);
			if (ret < 0)
				return ret;
			*val = sign_extend32(ret, 7);
			return IIO_VAL_INT;
		default:
			return -EINVAL;
		}
	case IIO_CHAN_INFO_SCALE:
		*val = 0;
		*val2 = 1000;
		return IIO_VAL_INT_PLUS_MICRO;
	case IIO_CHAN_INFO_SAMP_FREQ:
		i = data->ctrl_reg1 >> MAG3110_CTRL_DR_SHIFT;
		*val = mag3110_samp_freq[i][0];
		*val2 = mag3110_samp_freq[i][1];
		return IIO_VAL_INT_PLUS_MICRO;
	}
	return -EINVAL;
}

static int mag3110_write_raw(struct iio_dev *indio_dev,
			     struct iio_chan_spec const *chan,
			     int val, int val2, long mask)
{
	struct mag3110_data *data = iio_priv(indio_dev);
	int rate;

	if (iio_buffer_enabled(indio_dev))
		return -EBUSY;

	switch (mask) {
	case IIO_CHAN_INFO_SAMP_FREQ:
		rate = mag3110_get_samp_freq_index(data, val, val2);
		if (rate < 0)
			return -EINVAL;

		data->ctrl_reg1 &= ~MAG3110_CTRL_DR_MASK;
		data->ctrl_reg1 |= rate << MAG3110_CTRL_DR_SHIFT;
		return i2c_smbus_write_byte_data(data->client,
			MAG3110_CTRL_REG1, data->ctrl_reg1);
	default:
		return -EINVAL;
	}
}

static irqreturn_t mag3110_trigger_handler(int irq, void *p)
{
	struct iio_poll_func *pf = p;
	struct iio_dev *indio_dev = pf->indio_dev;
	struct mag3110_data *data = iio_priv(indio_dev);
	u8 buffer[16]; /* 3 16-bit channels + 1 byte temp + padding + ts */
	int ret;

	ret = mag3110_read(data, (__be16 *) buffer);
	if (ret < 0)
		goto done;

	if (test_bit(3, indio_dev->active_scan_mask)) {
		ret = i2c_smbus_read_byte_data(data->client,
			MAG3110_DIE_TEMP);
		if (ret < 0)
			goto done;
		buffer[6] = ret;
	}

	iio_push_to_buffers_with_timestamp(indio_dev, buffer,
		iio_get_time_ns());

done:
	iio_trigger_notify_done(indio_dev->trig);
	return IRQ_HANDLED;
}

#define MAG3110_CHANNEL(axis, idx) { \
	.type = IIO_MAGN, \
	.modified = 1, \
	.channel2 = IIO_MOD_##axis, \
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
		BIT(IIO_CHAN_INFO_SCALE), \
	.scan_index = idx, \
	.scan_type = { \
		.sign = 's', \
		.realbits = 16, \
		.storagebits = 16, \
		.endianness = IIO_BE, \
	}, \
}

static const struct iio_chan_spec mag3110_channels[] = {
	MAG3110_CHANNEL(X, 0),
	MAG3110_CHANNEL(Y, 1),
	MAG3110_CHANNEL(Z, 2),
	{
		.type = IIO_TEMP,
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
		.scan_index = 3,
		.scan_type = {
			.sign = 's',
			.realbits = 8,
			.storagebits = 8,
			},
	},
	IIO_CHAN_SOFT_TIMESTAMP(4),
};

static struct attribute *mag3110_attributes[] = {
	&iio_dev_attr_sampling_frequency_available.dev_attr.attr,
	NULL
};

static const struct attribute_group mag3110_group = {
	.attrs = mag3110_attributes,
};

static const struct iio_info mag3110_info = {
	.attrs = &mag3110_group,
	.read_raw = &mag3110_read_raw,
	.write_raw = &mag3110_write_raw,
	.driver_module = THIS_MODULE,
};

static const unsigned long mag3110_scan_masks[] = {0x7, 0xf, 0};

static int mag3110_probe(struct i2c_client *client,
			 const struct i2c_device_id *id)
{
	struct mag3110_data *data;
	struct iio_dev *indio_dev;
	int ret;

	ret = i2c_smbus_read_byte_data(client, MAG3110_WHO_AM_I);
	if (ret < 0)
		return ret;
	if (ret != MAG3110_DEVICE_ID)
		return -ENODEV;

	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
	if (!indio_dev)
		return -ENOMEM;

	data = iio_priv(indio_dev);
	data->client = client;
	mutex_init(&data->lock);

	i2c_set_clientdata(client, indio_dev);
	indio_dev->info = &mag3110_info;
	indio_dev->name = id->name;
	indio_dev->dev.parent = &client->dev;
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->channels = mag3110_channels;
	indio_dev->num_channels = ARRAY_SIZE(mag3110_channels);
	indio_dev->available_scan_masks = mag3110_scan_masks;

	data->ctrl_reg1 = MAG3110_CTRL_DR_DEFAULT;
	ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG1,
		data->ctrl_reg1);
	if (ret < 0)
		return ret;

	ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG2,
		MAG3110_CTRL_AUTO_MRST_EN | MAG3110_CTRL_RAW);
	if (ret < 0)
		return ret;

	ret = iio_triggered_buffer_setup(indio_dev, NULL,
		mag3110_trigger_handler, NULL);
	if (ret < 0)
		return ret;

	ret = iio_device_register(indio_dev);
	if (ret < 0)
		goto buffer_cleanup;
	return 0;

buffer_cleanup:
	iio_triggered_buffer_cleanup(indio_dev);
	return ret;
}

static int mag3110_standby(struct mag3110_data *data)
{
	return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
		data->ctrl_reg1 & ~MAG3110_CTRL_AC);
}

static int mag3110_remove(struct i2c_client *client)
{
	struct iio_dev *indio_dev = i2c_get_clientdata(client);

	iio_device_unregister(indio_dev);
	iio_triggered_buffer_cleanup(indio_dev);
	mag3110_standby(iio_priv(indio_dev));

	return 0;
}

#ifdef CONFIG_PM_SLEEP
static int mag3110_suspend(struct device *dev)
{
	return mag3110_standby(iio_priv(i2c_get_clientdata(
		to_i2c_client(dev))));
}

static int mag3110_resume(struct device *dev)
{
	struct mag3110_data *data = iio_priv(i2c_get_clientdata(
		to_i2c_client(dev)));

	return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
		data->ctrl_reg1);
}

static SIMPLE_DEV_PM_OPS(mag3110_pm_ops, mag3110_suspend, mag3110_resume);
#define MAG3110_PM_OPS (&mag3110_pm_ops)
#else
#define MAG3110_PM_OPS NULL
#endif

static const struct i2c_device_id mag3110_id[] = {
	{ "mag3110", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, mag3110_id);

static struct i2c_driver mag3110_driver = {
	.driver = {
		.name	= "mag3110",
		.pm	= MAG3110_PM_OPS,
	},
	.probe = mag3110_probe,
	.remove = mag3110_remove,
	.id_table = mag3110_id,
};
module_i2c_driver(mag3110_driver);

MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
MODULE_DESCRIPTION("Freescale MAG3110 magnetometer driver");
MODULE_LICENSE("GPL");