1/*
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.%06d ", 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		if (iio_buffer_enabled(indio_dev))
158			return -EBUSY;
159
160		switch (chan->type) {
161		case IIO_MAGN: /* in 0.1 uT / LSB */
162			ret = mag3110_read(data, buffer);
163			if (ret < 0)
164				return ret;
165			*val = sign_extend32(
166				be16_to_cpu(buffer[chan->scan_index]), 15);
167			return IIO_VAL_INT;
168		case IIO_TEMP: /* in 1 C / LSB */
169			mutex_lock(&data->lock);
170			ret = mag3110_request(data);
171			if (ret < 0) {
172				mutex_unlock(&data->lock);
173				return ret;
174			}
175			ret = i2c_smbus_read_byte_data(data->client,
176				MAG3110_DIE_TEMP);
177			mutex_unlock(&data->lock);
178			if (ret < 0)
179				return ret;
180			*val = sign_extend32(ret, 7);
181			return IIO_VAL_INT;
182		default:
183			return -EINVAL;
184		}
185	case IIO_CHAN_INFO_SCALE:
186		switch (chan->type) {
187		case IIO_MAGN:
188			*val = 0;
189			*val2 = 1000;
190			return IIO_VAL_INT_PLUS_MICRO;
191		case IIO_TEMP:
192			*val = 1000;
193			return IIO_VAL_INT;
194		default:
195			return -EINVAL;
196		}
197	case IIO_CHAN_INFO_SAMP_FREQ:
198		i = data->ctrl_reg1 >> MAG3110_CTRL_DR_SHIFT;
199		*val = mag3110_samp_freq[i][0];
200		*val2 = mag3110_samp_freq[i][1];
201		return IIO_VAL_INT_PLUS_MICRO;
202	case IIO_CHAN_INFO_CALIBBIAS:
203		ret = i2c_smbus_read_word_swapped(data->client,
204			MAG3110_OFF_X +	2 * chan->scan_index);
205		if (ret < 0)
206			return ret;
207		*val = sign_extend32(ret >> 1, 14);
208		return IIO_VAL_INT;
209	}
210	return -EINVAL;
211}
212
213static int mag3110_write_raw(struct iio_dev *indio_dev,
214			     struct iio_chan_spec const *chan,
215			     int val, int val2, long mask)
216{
217	struct mag3110_data *data = iio_priv(indio_dev);
218	int rate;
219
220	if (iio_buffer_enabled(indio_dev))
221		return -EBUSY;
222
223	switch (mask) {
224	case IIO_CHAN_INFO_SAMP_FREQ:
225		rate = mag3110_get_samp_freq_index(data, val, val2);
226		if (rate < 0)
227			return -EINVAL;
228
229		data->ctrl_reg1 &= ~MAG3110_CTRL_DR_MASK;
230		data->ctrl_reg1 |= rate << MAG3110_CTRL_DR_SHIFT;
231		return i2c_smbus_write_byte_data(data->client,
232			MAG3110_CTRL_REG1, data->ctrl_reg1);
233	case IIO_CHAN_INFO_CALIBBIAS:
234		if (val < -10000 || val > 10000)
235			return -EINVAL;
236		return i2c_smbus_write_word_swapped(data->client,
237			MAG3110_OFF_X + 2 * chan->scan_index, val << 1);
238	default:
239		return -EINVAL;
240	}
241}
242
243static irqreturn_t mag3110_trigger_handler(int irq, void *p)
244{
245	struct iio_poll_func *pf = p;
246	struct iio_dev *indio_dev = pf->indio_dev;
247	struct mag3110_data *data = iio_priv(indio_dev);
248	u8 buffer[16]; /* 3 16-bit channels + 1 byte temp + padding + ts */
249	int ret;
250
251	ret = mag3110_read(data, (__be16 *) buffer);
252	if (ret < 0)
253		goto done;
254
255	if (test_bit(3, indio_dev->active_scan_mask)) {
256		ret = i2c_smbus_read_byte_data(data->client,
257			MAG3110_DIE_TEMP);
258		if (ret < 0)
259			goto done;
260		buffer[6] = ret;
261	}
262
263	iio_push_to_buffers_with_timestamp(indio_dev, buffer,
264		iio_get_time_ns());
265
266done:
267	iio_trigger_notify_done(indio_dev->trig);
268	return IRQ_HANDLED;
269}
270
271#define MAG3110_CHANNEL(axis, idx) { \
272	.type = IIO_MAGN, \
273	.modified = 1, \
274	.channel2 = IIO_MOD_##axis, \
275	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
276		BIT(IIO_CHAN_INFO_CALIBBIAS), \
277	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
278		BIT(IIO_CHAN_INFO_SCALE), \
279	.scan_index = idx, \
280	.scan_type = { \
281		.sign = 's', \
282		.realbits = 16, \
283		.storagebits = 16, \
284		.endianness = IIO_BE, \
285	}, \
286}
287
288static const struct iio_chan_spec mag3110_channels[] = {
289	MAG3110_CHANNEL(X, 0),
290	MAG3110_CHANNEL(Y, 1),
291	MAG3110_CHANNEL(Z, 2),
292	{
293		.type = IIO_TEMP,
294		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
295			BIT(IIO_CHAN_INFO_SCALE),
296		.scan_index = 3,
297		.scan_type = {
298			.sign = 's',
299			.realbits = 8,
300			.storagebits = 8,
301			},
302	},
303	IIO_CHAN_SOFT_TIMESTAMP(4),
304};
305
306static struct attribute *mag3110_attributes[] = {
307	&iio_dev_attr_sampling_frequency_available.dev_attr.attr,
308	NULL
309};
310
311static const struct attribute_group mag3110_group = {
312	.attrs = mag3110_attributes,
313};
314
315static const struct iio_info mag3110_info = {
316	.attrs = &mag3110_group,
317	.read_raw = &mag3110_read_raw,
318	.write_raw = &mag3110_write_raw,
319	.driver_module = THIS_MODULE,
320};
321
322static const unsigned long mag3110_scan_masks[] = {0x7, 0xf, 0};
323
324static int mag3110_standby(struct mag3110_data *data)
325{
326	return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
327		data->ctrl_reg1 & ~MAG3110_CTRL_AC);
328}
329
330static int mag3110_probe(struct i2c_client *client,
331			 const struct i2c_device_id *id)
332{
333	struct mag3110_data *data;
334	struct iio_dev *indio_dev;
335	int ret;
336
337	ret = i2c_smbus_read_byte_data(client, MAG3110_WHO_AM_I);
338	if (ret < 0)
339		return ret;
340	if (ret != MAG3110_DEVICE_ID)
341		return -ENODEV;
342
343	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
344	if (!indio_dev)
345		return -ENOMEM;
346
347	data = iio_priv(indio_dev);
348	data->client = client;
349	mutex_init(&data->lock);
350
351	i2c_set_clientdata(client, indio_dev);
352	indio_dev->info = &mag3110_info;
353	indio_dev->name = id->name;
354	indio_dev->dev.parent = &client->dev;
355	indio_dev->modes = INDIO_DIRECT_MODE;
356	indio_dev->channels = mag3110_channels;
357	indio_dev->num_channels = ARRAY_SIZE(mag3110_channels);
358	indio_dev->available_scan_masks = mag3110_scan_masks;
359
360	data->ctrl_reg1 = MAG3110_CTRL_DR_DEFAULT << MAG3110_CTRL_DR_SHIFT;
361	ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG1,
362		data->ctrl_reg1);
363	if (ret < 0)
364		return ret;
365
366	ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG2,
367		MAG3110_CTRL_AUTO_MRST_EN);
368	if (ret < 0)
369		goto standby_on_error;
370
371	ret = iio_triggered_buffer_setup(indio_dev, NULL,
372		mag3110_trigger_handler, NULL);
373	if (ret < 0)
374		goto standby_on_error;
375
376	ret = iio_device_register(indio_dev);
377	if (ret < 0)
378		goto buffer_cleanup;
379	return 0;
380
381buffer_cleanup:
382	iio_triggered_buffer_cleanup(indio_dev);
383standby_on_error:
384	mag3110_standby(iio_priv(indio_dev));
385	return ret;
386}
387
388static int mag3110_remove(struct i2c_client *client)
389{
390	struct iio_dev *indio_dev = i2c_get_clientdata(client);
391
392	iio_device_unregister(indio_dev);
393	iio_triggered_buffer_cleanup(indio_dev);
394	mag3110_standby(iio_priv(indio_dev));
395
396	return 0;
397}
398
399#ifdef CONFIG_PM_SLEEP
400static int mag3110_suspend(struct device *dev)
401{
402	return mag3110_standby(iio_priv(i2c_get_clientdata(
403		to_i2c_client(dev))));
404}
405
406static int mag3110_resume(struct device *dev)
407{
408	struct mag3110_data *data = iio_priv(i2c_get_clientdata(
409		to_i2c_client(dev)));
410
411	return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
412		data->ctrl_reg1);
413}
414
415static SIMPLE_DEV_PM_OPS(mag3110_pm_ops, mag3110_suspend, mag3110_resume);
416#define MAG3110_PM_OPS (&mag3110_pm_ops)
417#else
418#define MAG3110_PM_OPS NULL
419#endif
420
421static const struct i2c_device_id mag3110_id[] = {
422	{ "mag3110", 0 },
423	{ }
424};
425MODULE_DEVICE_TABLE(i2c, mag3110_id);
426
427static struct i2c_driver mag3110_driver = {
428	.driver = {
429		.name	= "mag3110",
430		.pm	= MAG3110_PM_OPS,
431	},
432	.probe = mag3110_probe,
433	.remove = mag3110_remove,
434	.id_table = mag3110_id,
435};
436module_i2c_driver(mag3110_driver);
437
438MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
439MODULE_DESCRIPTION("Freescale MAG3110 magnetometer driver");
440MODULE_LICENSE("GPL");
441