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 */
51 struct mag3110_data {
52 	struct i2c_client *client;
53 	struct mutex lock;
54 	u8 ctrl_reg1;
55 };
56 
57 static 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 
85 static 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 
102 static 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 
117 static 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 
127 static 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 
132 static 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 
138 static IIO_DEV_ATTR_SAMP_FREQ_AVAIL(mag3110_show_samp_freq_avail);
139 
140 static 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 
147 static 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 	}
203 	return -EINVAL;
204 }
205 
206 static int mag3110_write_raw(struct iio_dev *indio_dev,
207 			     struct iio_chan_spec const *chan,
208 			     int val, int val2, long mask)
209 {
210 	struct mag3110_data *data = iio_priv(indio_dev);
211 	int rate;
212 
213 	if (iio_buffer_enabled(indio_dev))
214 		return -EBUSY;
215 
216 	switch (mask) {
217 	case IIO_CHAN_INFO_SAMP_FREQ:
218 		rate = mag3110_get_samp_freq_index(data, val, val2);
219 		if (rate < 0)
220 			return -EINVAL;
221 
222 		data->ctrl_reg1 &= ~MAG3110_CTRL_DR_MASK;
223 		data->ctrl_reg1 |= rate << MAG3110_CTRL_DR_SHIFT;
224 		return i2c_smbus_write_byte_data(data->client,
225 			MAG3110_CTRL_REG1, data->ctrl_reg1);
226 	default:
227 		return -EINVAL;
228 	}
229 }
230 
231 static irqreturn_t mag3110_trigger_handler(int irq, void *p)
232 {
233 	struct iio_poll_func *pf = p;
234 	struct iio_dev *indio_dev = pf->indio_dev;
235 	struct mag3110_data *data = iio_priv(indio_dev);
236 	u8 buffer[16]; /* 3 16-bit channels + 1 byte temp + padding + ts */
237 	int ret;
238 
239 	ret = mag3110_read(data, (__be16 *) buffer);
240 	if (ret < 0)
241 		goto done;
242 
243 	if (test_bit(3, indio_dev->active_scan_mask)) {
244 		ret = i2c_smbus_read_byte_data(data->client,
245 			MAG3110_DIE_TEMP);
246 		if (ret < 0)
247 			goto done;
248 		buffer[6] = ret;
249 	}
250 
251 	iio_push_to_buffers_with_timestamp(indio_dev, buffer,
252 		iio_get_time_ns());
253 
254 done:
255 	iio_trigger_notify_done(indio_dev->trig);
256 	return IRQ_HANDLED;
257 }
258 
259 #define MAG3110_CHANNEL(axis, idx) { \
260 	.type = IIO_MAGN, \
261 	.modified = 1, \
262 	.channel2 = IIO_MOD_##axis, \
263 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
264 	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
265 		BIT(IIO_CHAN_INFO_SCALE), \
266 	.scan_index = idx, \
267 	.scan_type = { \
268 		.sign = 's', \
269 		.realbits = 16, \
270 		.storagebits = 16, \
271 		.endianness = IIO_BE, \
272 	}, \
273 }
274 
275 static const struct iio_chan_spec mag3110_channels[] = {
276 	MAG3110_CHANNEL(X, 0),
277 	MAG3110_CHANNEL(Y, 1),
278 	MAG3110_CHANNEL(Z, 2),
279 	{
280 		.type = IIO_TEMP,
281 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
282 			BIT(IIO_CHAN_INFO_SCALE),
283 		.scan_index = 3,
284 		.scan_type = {
285 			.sign = 's',
286 			.realbits = 8,
287 			.storagebits = 8,
288 			},
289 	},
290 	IIO_CHAN_SOFT_TIMESTAMP(4),
291 };
292 
293 static struct attribute *mag3110_attributes[] = {
294 	&iio_dev_attr_sampling_frequency_available.dev_attr.attr,
295 	NULL
296 };
297 
298 static const struct attribute_group mag3110_group = {
299 	.attrs = mag3110_attributes,
300 };
301 
302 static const struct iio_info mag3110_info = {
303 	.attrs = &mag3110_group,
304 	.read_raw = &mag3110_read_raw,
305 	.write_raw = &mag3110_write_raw,
306 	.driver_module = THIS_MODULE,
307 };
308 
309 static const unsigned long mag3110_scan_masks[] = {0x7, 0xf, 0};
310 
311 static int mag3110_probe(struct i2c_client *client,
312 			 const struct i2c_device_id *id)
313 {
314 	struct mag3110_data *data;
315 	struct iio_dev *indio_dev;
316 	int ret;
317 
318 	ret = i2c_smbus_read_byte_data(client, MAG3110_WHO_AM_I);
319 	if (ret < 0)
320 		return ret;
321 	if (ret != MAG3110_DEVICE_ID)
322 		return -ENODEV;
323 
324 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
325 	if (!indio_dev)
326 		return -ENOMEM;
327 
328 	data = iio_priv(indio_dev);
329 	data->client = client;
330 	mutex_init(&data->lock);
331 
332 	i2c_set_clientdata(client, indio_dev);
333 	indio_dev->info = &mag3110_info;
334 	indio_dev->name = id->name;
335 	indio_dev->dev.parent = &client->dev;
336 	indio_dev->modes = INDIO_DIRECT_MODE;
337 	indio_dev->channels = mag3110_channels;
338 	indio_dev->num_channels = ARRAY_SIZE(mag3110_channels);
339 	indio_dev->available_scan_masks = mag3110_scan_masks;
340 
341 	data->ctrl_reg1 = MAG3110_CTRL_DR_DEFAULT;
342 	ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG1,
343 		data->ctrl_reg1);
344 	if (ret < 0)
345 		return ret;
346 
347 	ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG2,
348 		MAG3110_CTRL_AUTO_MRST_EN | MAG3110_CTRL_RAW);
349 	if (ret < 0)
350 		return ret;
351 
352 	ret = iio_triggered_buffer_setup(indio_dev, NULL,
353 		mag3110_trigger_handler, NULL);
354 	if (ret < 0)
355 		return ret;
356 
357 	ret = iio_device_register(indio_dev);
358 	if (ret < 0)
359 		goto buffer_cleanup;
360 	return 0;
361 
362 buffer_cleanup:
363 	iio_triggered_buffer_cleanup(indio_dev);
364 	return ret;
365 }
366 
367 static int mag3110_standby(struct mag3110_data *data)
368 {
369 	return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
370 		data->ctrl_reg1 & ~MAG3110_CTRL_AC);
371 }
372 
373 static int mag3110_remove(struct i2c_client *client)
374 {
375 	struct iio_dev *indio_dev = i2c_get_clientdata(client);
376 
377 	iio_device_unregister(indio_dev);
378 	iio_triggered_buffer_cleanup(indio_dev);
379 	mag3110_standby(iio_priv(indio_dev));
380 
381 	return 0;
382 }
383 
384 #ifdef CONFIG_PM_SLEEP
385 static int mag3110_suspend(struct device *dev)
386 {
387 	return mag3110_standby(iio_priv(i2c_get_clientdata(
388 		to_i2c_client(dev))));
389 }
390 
391 static int mag3110_resume(struct device *dev)
392 {
393 	struct mag3110_data *data = iio_priv(i2c_get_clientdata(
394 		to_i2c_client(dev)));
395 
396 	return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
397 		data->ctrl_reg1);
398 }
399 
400 static SIMPLE_DEV_PM_OPS(mag3110_pm_ops, mag3110_suspend, mag3110_resume);
401 #define MAG3110_PM_OPS (&mag3110_pm_ops)
402 #else
403 #define MAG3110_PM_OPS NULL
404 #endif
405 
406 static const struct i2c_device_id mag3110_id[] = {
407 	{ "mag3110", 0 },
408 	{ }
409 };
410 MODULE_DEVICE_TABLE(i2c, mag3110_id);
411 
412 static struct i2c_driver mag3110_driver = {
413 	.driver = {
414 		.name	= "mag3110",
415 		.pm	= MAG3110_PM_OPS,
416 	},
417 	.probe = mag3110_probe,
418 	.remove = mag3110_remove,
419 	.id_table = mag3110_id,
420 };
421 module_i2c_driver(mag3110_driver);
422 
423 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
424 MODULE_DESCRIPTION("Freescale MAG3110 magnetometer driver");
425 MODULE_LICENSE("GPL");
426