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.%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 
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 		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 
195 static 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 
217 static 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 
240 done:
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, \
253 	.scan_type = { \
254 		.sign = 's', \
255 		.realbits = 16, \
256 		.storagebits = 16, \
257 		.endianness = IIO_BE, \
258 	}, \
259 }
260 
261 static 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,
269 		.scan_type = IIO_ST('s', 8, 8, 0),
270 	},
271 	IIO_CHAN_SOFT_TIMESTAMP(4),
272 };
273 
274 static struct attribute *mag3110_attributes[] = {
275 	&iio_dev_attr_sampling_frequency_available.dev_attr.attr,
276 	NULL
277 };
278 
279 static const struct attribute_group mag3110_group = {
280 	.attrs = mag3110_attributes,
281 };
282 
283 static const struct iio_info mag3110_info = {
284 	.attrs = &mag3110_group,
285 	.read_raw = &mag3110_read_raw,
286 	.write_raw = &mag3110_write_raw,
287 	.driver_module = THIS_MODULE,
288 };
289 
290 static const unsigned long mag3110_scan_masks[] = {0x7, 0xf, 0};
291 
292 static int mag3110_probe(struct i2c_client *client,
293 			 const struct i2c_device_id *id)
294 {
295 	struct mag3110_data *data;
296 	struct iio_dev *indio_dev;
297 	int ret;
298 
299 	ret = i2c_smbus_read_byte_data(client, MAG3110_WHO_AM_I);
300 	if (ret < 0)
301 		return ret;
302 	if (ret != MAG3110_DEVICE_ID)
303 		return -ENODEV;
304 
305 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
306 	if (!indio_dev)
307 		return -ENOMEM;
308 
309 	data = iio_priv(indio_dev);
310 	data->client = client;
311 	mutex_init(&data->lock);
312 
313 	i2c_set_clientdata(client, indio_dev);
314 	indio_dev->info = &mag3110_info;
315 	indio_dev->name = id->name;
316 	indio_dev->dev.parent = &client->dev;
317 	indio_dev->modes = INDIO_DIRECT_MODE;
318 	indio_dev->channels = mag3110_channels;
319 	indio_dev->num_channels = ARRAY_SIZE(mag3110_channels);
320 	indio_dev->available_scan_masks = mag3110_scan_masks;
321 
322 	data->ctrl_reg1 = MAG3110_CTRL_DR_DEFAULT;
323 	ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG1,
324 		data->ctrl_reg1);
325 	if (ret < 0)
326 		return ret;
327 
328 	ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG2,
329 		MAG3110_CTRL_AUTO_MRST_EN | MAG3110_CTRL_RAW);
330 	if (ret < 0)
331 		return ret;
332 
333 	ret = iio_triggered_buffer_setup(indio_dev, NULL,
334 		mag3110_trigger_handler, NULL);
335 	if (ret < 0)
336 		return ret;
337 
338 	ret = iio_device_register(indio_dev);
339 	if (ret < 0)
340 		goto buffer_cleanup;
341 	return 0;
342 
343 buffer_cleanup:
344 	iio_triggered_buffer_cleanup(indio_dev);
345 	return ret;
346 }
347 
348 static int mag3110_standby(struct mag3110_data *data)
349 {
350 	return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
351 		data->ctrl_reg1 & ~MAG3110_CTRL_AC);
352 }
353 
354 static int mag3110_remove(struct i2c_client *client)
355 {
356 	struct iio_dev *indio_dev = i2c_get_clientdata(client);
357 
358 	iio_device_unregister(indio_dev);
359 	iio_triggered_buffer_cleanup(indio_dev);
360 	mag3110_standby(iio_priv(indio_dev));
361 
362 	return 0;
363 }
364 
365 #ifdef CONFIG_PM_SLEEP
366 static int mag3110_suspend(struct device *dev)
367 {
368 	return mag3110_standby(iio_priv(i2c_get_clientdata(
369 		to_i2c_client(dev))));
370 }
371 
372 static int mag3110_resume(struct device *dev)
373 {
374 	struct mag3110_data *data = iio_priv(i2c_get_clientdata(
375 		to_i2c_client(dev)));
376 
377 	return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
378 		data->ctrl_reg1);
379 }
380 
381 static SIMPLE_DEV_PM_OPS(mag3110_pm_ops, mag3110_suspend, mag3110_resume);
382 #define MAG3110_PM_OPS (&mag3110_pm_ops)
383 #else
384 #define MAG3110_PM_OPS NULL
385 #endif
386 
387 static const struct i2c_device_id mag3110_id[] = {
388 	{ "mag3110", 0 },
389 	{ }
390 };
391 MODULE_DEVICE_TABLE(i2c, mag3110_id);
392 
393 static struct i2c_driver mag3110_driver = {
394 	.driver = {
395 		.name	= "mag3110",
396 		.pm	= MAG3110_PM_OPS,
397 	},
398 	.probe = mag3110_probe,
399 	.remove = mag3110_remove,
400 	.id_table = mag3110_id,
401 };
402 module_i2c_driver(mag3110_driver);
403 
404 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
405 MODULE_DESCRIPTION("Freescale MAG3110 magnetometer driver");
406 MODULE_LICENSE("GPL");
407