xref: /openbmc/linux/drivers/iio/pressure/mpl3115.c (revision 9b93eb47) 
1 /*
2  * mpl3115.c - Support for Freescale MPL3115A2 pressure/temperature 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 0x60)
11  *
12  * TODO: FIFO buffer, altimeter mode, oversampling, continuous mode,
13  * interrupts, user offset correction, raw mode
14  */
15 
16 #include <linux/module.h>
17 #include <linux/i2c.h>
18 #include <linux/iio/iio.h>
19 #include <linux/iio/sysfs.h>
20 #include <linux/iio/trigger_consumer.h>
21 #include <linux/iio/buffer.h>
22 #include <linux/iio/triggered_buffer.h>
23 #include <linux/delay.h>
24 
25 #define MPL3115_STATUS 0x00
26 #define MPL3115_OUT_PRESS 0x01 /* MSB first, 20 bit */
27 #define MPL3115_OUT_TEMP 0x04 /* MSB first, 12 bit */
28 #define MPL3115_WHO_AM_I 0x0c
29 #define MPL3115_CTRL_REG1 0x26
30 
31 #define MPL3115_DEVICE_ID 0xc4
32 
33 #define MPL3115_STATUS_PRESS_RDY BIT(2)
34 #define MPL3115_STATUS_TEMP_RDY BIT(1)
35 
36 #define MPL3115_CTRL_RESET BIT(2) /* software reset */
37 #define MPL3115_CTRL_OST BIT(1) /* initiate measurement */
38 #define MPL3115_CTRL_ACTIVE BIT(0) /* continuous measurement */
39 #define MPL3115_CTRL_OS_258MS (BIT(5) | BIT(4)) /* 64x oversampling */
40 
41 struct mpl3115_data {
42 	struct i2c_client *client;
43 	struct mutex lock;
44 	u8 ctrl_reg1;
45 };
46 
47 static int mpl3115_request(struct mpl3115_data *data)
48 {
49 	int ret, tries = 15;
50 
51 	/* trigger measurement */
52 	ret = i2c_smbus_write_byte_data(data->client, MPL3115_CTRL_REG1,
53 		data->ctrl_reg1 | MPL3115_CTRL_OST);
54 	if (ret < 0)
55 		return ret;
56 
57 	while (tries-- > 0) {
58 		ret = i2c_smbus_read_byte_data(data->client, MPL3115_CTRL_REG1);
59 		if (ret < 0)
60 			return ret;
61 		/* wait for data ready, i.e. OST cleared */
62 		if (!(ret & MPL3115_CTRL_OST))
63 			break;
64 		msleep(20);
65 	}
66 
67 	if (tries < 0) {
68 		dev_err(&data->client->dev, "data not ready\n");
69 		return -EIO;
70 	}
71 
72 	return 0;
73 }
74 
75 static int mpl3115_read_raw(struct iio_dev *indio_dev,
76 			    struct iio_chan_spec const *chan,
77 			    int *val, int *val2, long mask)
78 {
79 	struct mpl3115_data *data = iio_priv(indio_dev);
80 	__be32 tmp = 0;
81 	int ret;
82 
83 	switch (mask) {
84 	case IIO_CHAN_INFO_RAW:
85 		ret = iio_device_claim_direct_mode(indio_dev);
86 		if (ret)
87 			return ret;
88 
89 		switch (chan->type) {
90 		case IIO_PRESSURE: /* in 0.25 pascal / LSB */
91 			mutex_lock(&data->lock);
92 			ret = mpl3115_request(data);
93 			if (ret < 0) {
94 				mutex_unlock(&data->lock);
95 				break;
96 			}
97 			ret = i2c_smbus_read_i2c_block_data(data->client,
98 				MPL3115_OUT_PRESS, 3, (u8 *) &tmp);
99 			mutex_unlock(&data->lock);
100 			if (ret < 0)
101 				break;
102 			*val = be32_to_cpu(tmp) >> 12;
103 			ret = IIO_VAL_INT;
104 			break;
105 		case IIO_TEMP: /* in 0.0625 celsius / LSB */
106 			mutex_lock(&data->lock);
107 			ret = mpl3115_request(data);
108 			if (ret < 0) {
109 				mutex_unlock(&data->lock);
110 				break;
111 			}
112 			ret = i2c_smbus_read_i2c_block_data(data->client,
113 				MPL3115_OUT_TEMP, 2, (u8 *) &tmp);
114 			mutex_unlock(&data->lock);
115 			if (ret < 0)
116 				break;
117 			*val = sign_extend32(be32_to_cpu(tmp) >> 20, 11);
118 			ret = IIO_VAL_INT;
119 			break;
120 		default:
121 			ret = -EINVAL;
122 			break;
123 		}
124 
125 		iio_device_release_direct_mode(indio_dev);
126 		return ret;
127 
128 	case IIO_CHAN_INFO_SCALE:
129 		switch (chan->type) {
130 		case IIO_PRESSURE:
131 			*val = 0;
132 			*val2 = 250; /* want kilopascal */
133 			return IIO_VAL_INT_PLUS_MICRO;
134 		case IIO_TEMP:
135 			*val = 0;
136 			*val2 = 62500;
137 			return IIO_VAL_INT_PLUS_MICRO;
138 		default:
139 			return -EINVAL;
140 		}
141 	}
142 	return -EINVAL;
143 }
144 
145 static irqreturn_t mpl3115_trigger_handler(int irq, void *p)
146 {
147 	struct iio_poll_func *pf = p;
148 	struct iio_dev *indio_dev = pf->indio_dev;
149 	struct mpl3115_data *data = iio_priv(indio_dev);
150 	u8 buffer[16]; /* 32-bit channel + 16-bit channel + padding + ts */
151 	int ret, pos = 0;
152 
153 	mutex_lock(&data->lock);
154 	ret = mpl3115_request(data);
155 	if (ret < 0) {
156 		mutex_unlock(&data->lock);
157 		goto done;
158 	}
159 
160 	memset(buffer, 0, sizeof(buffer));
161 	if (test_bit(0, indio_dev->active_scan_mask)) {
162 		ret = i2c_smbus_read_i2c_block_data(data->client,
163 			MPL3115_OUT_PRESS, 3, &buffer[pos]);
164 		if (ret < 0) {
165 			mutex_unlock(&data->lock);
166 			goto done;
167 		}
168 		pos += 4;
169 	}
170 
171 	if (test_bit(1, indio_dev->active_scan_mask)) {
172 		ret = i2c_smbus_read_i2c_block_data(data->client,
173 			MPL3115_OUT_TEMP, 2, &buffer[pos]);
174 		if (ret < 0) {
175 			mutex_unlock(&data->lock);
176 			goto done;
177 		}
178 	}
179 	mutex_unlock(&data->lock);
180 
181 	iio_push_to_buffers_with_timestamp(indio_dev, buffer,
182 		iio_get_time_ns(indio_dev));
183 
184 done:
185 	iio_trigger_notify_done(indio_dev->trig);
186 	return IRQ_HANDLED;
187 }
188 
189 static const struct iio_chan_spec mpl3115_channels[] = {
190 	{
191 		.type = IIO_PRESSURE,
192 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
193 		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
194 		.scan_index = 0,
195 		.scan_type = {
196 			.sign = 'u',
197 			.realbits = 20,
198 			.storagebits = 32,
199 			.shift = 12,
200 			.endianness = IIO_BE,
201 		}
202 	},
203 	{
204 		.type = IIO_TEMP,
205 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
206 		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
207 		.scan_index = 1,
208 		.scan_type = {
209 			.sign = 's',
210 			.realbits = 12,
211 			.storagebits = 16,
212 			.shift = 4,
213 			.endianness = IIO_BE,
214 		}
215 	},
216 	IIO_CHAN_SOFT_TIMESTAMP(2),
217 };
218 
219 static const struct iio_info mpl3115_info = {
220 	.read_raw = &mpl3115_read_raw,
221 };
222 
223 static int mpl3115_probe(struct i2c_client *client,
224 			 const struct i2c_device_id *id)
225 {
226 	struct mpl3115_data *data;
227 	struct iio_dev *indio_dev;
228 	int ret;
229 
230 	ret = i2c_smbus_read_byte_data(client, MPL3115_WHO_AM_I);
231 	if (ret < 0)
232 		return ret;
233 	if (ret != MPL3115_DEVICE_ID)
234 		return -ENODEV;
235 
236 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
237 	if (!indio_dev)
238 		return -ENOMEM;
239 
240 	data = iio_priv(indio_dev);
241 	data->client = client;
242 	mutex_init(&data->lock);
243 
244 	i2c_set_clientdata(client, indio_dev);
245 	indio_dev->info = &mpl3115_info;
246 	indio_dev->name = id->name;
247 	indio_dev->dev.parent = &client->dev;
248 	indio_dev->modes = INDIO_DIRECT_MODE;
249 	indio_dev->channels = mpl3115_channels;
250 	indio_dev->num_channels = ARRAY_SIZE(mpl3115_channels);
251 
252 	/* software reset, I2C transfer is aborted (fails) */
253 	i2c_smbus_write_byte_data(client, MPL3115_CTRL_REG1,
254 		MPL3115_CTRL_RESET);
255 	msleep(50);
256 
257 	data->ctrl_reg1 = MPL3115_CTRL_OS_258MS;
258 	ret = i2c_smbus_write_byte_data(client, MPL3115_CTRL_REG1,
259 		data->ctrl_reg1);
260 	if (ret < 0)
261 		return ret;
262 
263 	ret = iio_triggered_buffer_setup(indio_dev, NULL,
264 		mpl3115_trigger_handler, NULL);
265 	if (ret < 0)
266 		return ret;
267 
268 	ret = iio_device_register(indio_dev);
269 	if (ret < 0)
270 		goto buffer_cleanup;
271 	return 0;
272 
273 buffer_cleanup:
274 	iio_triggered_buffer_cleanup(indio_dev);
275 	return ret;
276 }
277 
278 static int mpl3115_standby(struct mpl3115_data *data)
279 {
280 	return i2c_smbus_write_byte_data(data->client, MPL3115_CTRL_REG1,
281 		data->ctrl_reg1 & ~MPL3115_CTRL_ACTIVE);
282 }
283 
284 static int mpl3115_remove(struct i2c_client *client)
285 {
286 	struct iio_dev *indio_dev = i2c_get_clientdata(client);
287 
288 	iio_device_unregister(indio_dev);
289 	iio_triggered_buffer_cleanup(indio_dev);
290 	mpl3115_standby(iio_priv(indio_dev));
291 
292 	return 0;
293 }
294 
295 #ifdef CONFIG_PM_SLEEP
296 static int mpl3115_suspend(struct device *dev)
297 {
298 	return mpl3115_standby(iio_priv(i2c_get_clientdata(
299 		to_i2c_client(dev))));
300 }
301 
302 static int mpl3115_resume(struct device *dev)
303 {
304 	struct mpl3115_data *data = iio_priv(i2c_get_clientdata(
305 		to_i2c_client(dev)));
306 
307 	return i2c_smbus_write_byte_data(data->client, MPL3115_CTRL_REG1,
308 		data->ctrl_reg1);
309 }
310 
311 static SIMPLE_DEV_PM_OPS(mpl3115_pm_ops, mpl3115_suspend, mpl3115_resume);
312 #define MPL3115_PM_OPS (&mpl3115_pm_ops)
313 #else
314 #define MPL3115_PM_OPS NULL
315 #endif
316 
317 static const struct i2c_device_id mpl3115_id[] = {
318 	{ "mpl3115", 0 },
319 	{ }
320 };
321 MODULE_DEVICE_TABLE(i2c, mpl3115_id);
322 
323 static const struct of_device_id mpl3115_of_match[] = {
324 	{ .compatible = "fsl,mpl3115" },
325 	{ }
326 };
327 MODULE_DEVICE_TABLE(of, mpl3115_of_match);
328 
329 static struct i2c_driver mpl3115_driver = {
330 	.driver = {
331 		.name	= "mpl3115",
332 		.of_match_table = mpl3115_of_match,
333 		.pm	= MPL3115_PM_OPS,
334 	},
335 	.probe = mpl3115_probe,
336 	.remove = mpl3115_remove,
337 	.id_table = mpl3115_id,
338 };
339 module_i2c_driver(mpl3115_driver);
340 
341 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
342 MODULE_DESCRIPTION("Freescale MPL3115 pressure/temperature driver");
343 MODULE_LICENSE("GPL");
344