xref: /openbmc/linux/drivers/iio/pressure/mpl3115.c (revision 6a87e0f0) 
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * mpl3115.c - Support for Freescale MPL3115A2 pressure/temperature sensor
4  *
5  * Copyright (c) 2013 Peter Meerwald <pmeerw@pmeerw.net>
6  *
7  * (7-bit I2C slave address 0x60)
8  *
9  * TODO: FIFO buffer, altimeter mode, oversampling, continuous mode,
10  * interrupts, user offset correction, raw mode
11  */
12 
13 #include <linux/module.h>
14 #include <linux/i2c.h>
15 #include <linux/iio/iio.h>
16 #include <linux/iio/sysfs.h>
17 #include <linux/iio/trigger_consumer.h>
18 #include <linux/iio/buffer.h>
19 #include <linux/iio/triggered_buffer.h>
20 #include <linux/delay.h>
21 
22 #define MPL3115_STATUS 0x00
23 #define MPL3115_OUT_PRESS 0x01 /* MSB first, 20 bit */
24 #define MPL3115_OUT_TEMP 0x04 /* MSB first, 12 bit */
25 #define MPL3115_WHO_AM_I 0x0c
26 #define MPL3115_CTRL_REG1 0x26
27 
28 #define MPL3115_DEVICE_ID 0xc4
29 
30 #define MPL3115_STATUS_PRESS_RDY BIT(2)
31 #define MPL3115_STATUS_TEMP_RDY BIT(1)
32 
33 #define MPL3115_CTRL_RESET BIT(2) /* software reset */
34 #define MPL3115_CTRL_OST BIT(1) /* initiate measurement */
35 #define MPL3115_CTRL_ACTIVE BIT(0) /* continuous measurement */
36 #define MPL3115_CTRL_OS_258MS (BIT(5) | BIT(4)) /* 64x oversampling */
37 
38 struct mpl3115_data {
39 	struct i2c_client *client;
40 	struct mutex lock;
41 	u8 ctrl_reg1;
42 };
43 
44 static int mpl3115_request(struct mpl3115_data *data)
45 {
46 	int ret, tries = 15;
47 
48 	/* trigger measurement */
49 	ret = i2c_smbus_write_byte_data(data->client, MPL3115_CTRL_REG1,
50 		data->ctrl_reg1 | MPL3115_CTRL_OST);
51 	if (ret < 0)
52 		return ret;
53 
54 	while (tries-- > 0) {
55 		ret = i2c_smbus_read_byte_data(data->client, MPL3115_CTRL_REG1);
56 		if (ret < 0)
57 			return ret;
58 		/* wait for data ready, i.e. OST cleared */
59 		if (!(ret & MPL3115_CTRL_OST))
60 			break;
61 		msleep(20);
62 	}
63 
64 	if (tries < 0) {
65 		dev_err(&data->client->dev, "data not ready\n");
66 		return -EIO;
67 	}
68 
69 	return 0;
70 }
71 
72 static int mpl3115_read_raw(struct iio_dev *indio_dev,
73 			    struct iio_chan_spec const *chan,
74 			    int *val, int *val2, long mask)
75 {
76 	struct mpl3115_data *data = iio_priv(indio_dev);
77 	int ret;
78 
79 	switch (mask) {
80 	case IIO_CHAN_INFO_RAW:
81 		ret = iio_device_claim_direct_mode(indio_dev);
82 		if (ret)
83 			return ret;
84 
85 		switch (chan->type) {
86 		case IIO_PRESSURE: { /* in 0.25 pascal / LSB */
87 			__be32 tmp = 0;
88 
89 			mutex_lock(&data->lock);
90 			ret = mpl3115_request(data);
91 			if (ret < 0) {
92 				mutex_unlock(&data->lock);
93 				break;
94 			}
95 			ret = i2c_smbus_read_i2c_block_data(data->client,
96 				MPL3115_OUT_PRESS, 3, (u8 *) &tmp);
97 			mutex_unlock(&data->lock);
98 			if (ret < 0)
99 				break;
100 			*val = be32_to_cpu(tmp) >> chan->scan_type.shift;
101 			ret = IIO_VAL_INT;
102 			break;
103 		}
104 		case IIO_TEMP: { /* in 0.0625 celsius / LSB */
105 			__be16 tmp;
106 
107 			mutex_lock(&data->lock);
108 			ret = mpl3115_request(data);
109 			if (ret < 0) {
110 				mutex_unlock(&data->lock);
111 				break;
112 			}
113 			ret = i2c_smbus_read_i2c_block_data(data->client,
114 				MPL3115_OUT_TEMP, 2, (u8 *) &tmp);
115 			mutex_unlock(&data->lock);
116 			if (ret < 0)
117 				break;
118 			*val = sign_extend32(be16_to_cpu(tmp) >> chan->scan_type.shift,
119 					     chan->scan_type.realbits - 1);
120 			ret = IIO_VAL_INT;
121 			break;
122 		}
123 		default:
124 			ret = -EINVAL;
125 			break;
126 		}
127 
128 		iio_device_release_direct_mode(indio_dev);
129 		return ret;
130 
131 	case IIO_CHAN_INFO_SCALE:
132 		switch (chan->type) {
133 		case IIO_PRESSURE:
134 			*val = 0;
135 			*val2 = 250; /* want kilopascal */
136 			return IIO_VAL_INT_PLUS_MICRO;
137 		case IIO_TEMP:
138 			*val = 0;
139 			*val2 = 62500;
140 			return IIO_VAL_INT_PLUS_MICRO;
141 		default:
142 			return -EINVAL;
143 		}
144 	}
145 	return -EINVAL;
146 }
147 
148 static irqreturn_t mpl3115_trigger_handler(int irq, void *p)
149 {
150 	struct iio_poll_func *pf = p;
151 	struct iio_dev *indio_dev = pf->indio_dev;
152 	struct mpl3115_data *data = iio_priv(indio_dev);
153 	/*
154 	 * 32-bit channel + 16-bit channel + padding + ts
155 	 * Note that it is possible for only one of the first 2
156 	 * channels to be enabled. If that happens, the first element
157 	 * of the buffer may be either 16 or 32-bits.  As such we cannot
158 	 * use a simple structure definition to express this data layout.
159 	 */
160 	u8 buffer[16] __aligned(8);
161 	int ret, pos = 0;
162 
163 	mutex_lock(&data->lock);
164 	ret = mpl3115_request(data);
165 	if (ret < 0) {
166 		mutex_unlock(&data->lock);
167 		goto done;
168 	}
169 
170 	memset(buffer, 0, sizeof(buffer));
171 	if (test_bit(0, indio_dev->active_scan_mask)) {
172 		ret = i2c_smbus_read_i2c_block_data(data->client,
173 			MPL3115_OUT_PRESS, 3, &buffer[pos]);
174 		if (ret < 0) {
175 			mutex_unlock(&data->lock);
176 			goto done;
177 		}
178 		pos += 4;
179 	}
180 
181 	if (test_bit(1, indio_dev->active_scan_mask)) {
182 		ret = i2c_smbus_read_i2c_block_data(data->client,
183 			MPL3115_OUT_TEMP, 2, &buffer[pos]);
184 		if (ret < 0) {
185 			mutex_unlock(&data->lock);
186 			goto done;
187 		}
188 	}
189 	mutex_unlock(&data->lock);
190 
191 	iio_push_to_buffers_with_timestamp(indio_dev, buffer,
192 		iio_get_time_ns(indio_dev));
193 
194 done:
195 	iio_trigger_notify_done(indio_dev->trig);
196 	return IRQ_HANDLED;
197 }
198 
199 static const struct iio_chan_spec mpl3115_channels[] = {
200 	{
201 		.type = IIO_PRESSURE,
202 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
203 		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
204 		.scan_index = 0,
205 		.scan_type = {
206 			.sign = 'u',
207 			.realbits = 20,
208 			.storagebits = 32,
209 			.shift = 12,
210 			.endianness = IIO_BE,
211 		}
212 	},
213 	{
214 		.type = IIO_TEMP,
215 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
216 		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
217 		.scan_index = 1,
218 		.scan_type = {
219 			.sign = 's',
220 			.realbits = 12,
221 			.storagebits = 16,
222 			.shift = 4,
223 			.endianness = IIO_BE,
224 		}
225 	},
226 	IIO_CHAN_SOFT_TIMESTAMP(2),
227 };
228 
229 static const struct iio_info mpl3115_info = {
230 	.read_raw = &mpl3115_read_raw,
231 };
232 
233 static int mpl3115_probe(struct i2c_client *client)
234 {
235 	const struct i2c_device_id *id = i2c_client_get_device_id(client);
236 	struct mpl3115_data *data;
237 	struct iio_dev *indio_dev;
238 	int ret;
239 
240 	ret = i2c_smbus_read_byte_data(client, MPL3115_WHO_AM_I);
241 	if (ret < 0)
242 		return ret;
243 	if (ret != MPL3115_DEVICE_ID)
244 		return -ENODEV;
245 
246 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
247 	if (!indio_dev)
248 		return -ENOMEM;
249 
250 	data = iio_priv(indio_dev);
251 	data->client = client;
252 	mutex_init(&data->lock);
253 
254 	i2c_set_clientdata(client, indio_dev);
255 	indio_dev->info = &mpl3115_info;
256 	indio_dev->name = id->name;
257 	indio_dev->modes = INDIO_DIRECT_MODE;
258 	indio_dev->channels = mpl3115_channels;
259 	indio_dev->num_channels = ARRAY_SIZE(mpl3115_channels);
260 
261 	/* software reset, I2C transfer is aborted (fails) */
262 	i2c_smbus_write_byte_data(client, MPL3115_CTRL_REG1,
263 		MPL3115_CTRL_RESET);
264 	msleep(50);
265 
266 	data->ctrl_reg1 = MPL3115_CTRL_OS_258MS;
267 	ret = i2c_smbus_write_byte_data(client, MPL3115_CTRL_REG1,
268 		data->ctrl_reg1);
269 	if (ret < 0)
270 		return ret;
271 
272 	ret = iio_triggered_buffer_setup(indio_dev, NULL,
273 		mpl3115_trigger_handler, NULL);
274 	if (ret < 0)
275 		return ret;
276 
277 	ret = iio_device_register(indio_dev);
278 	if (ret < 0)
279 		goto buffer_cleanup;
280 	return 0;
281 
282 buffer_cleanup:
283 	iio_triggered_buffer_cleanup(indio_dev);
284 	return ret;
285 }
286 
287 static int mpl3115_standby(struct mpl3115_data *data)
288 {
289 	return i2c_smbus_write_byte_data(data->client, MPL3115_CTRL_REG1,
290 		data->ctrl_reg1 & ~MPL3115_CTRL_ACTIVE);
291 }
292 
293 static void mpl3115_remove(struct i2c_client *client)
294 {
295 	struct iio_dev *indio_dev = i2c_get_clientdata(client);
296 
297 	iio_device_unregister(indio_dev);
298 	iio_triggered_buffer_cleanup(indio_dev);
299 	mpl3115_standby(iio_priv(indio_dev));
300 }
301 
302 static int mpl3115_suspend(struct device *dev)
303 {
304 	return mpl3115_standby(iio_priv(i2c_get_clientdata(
305 		to_i2c_client(dev))));
306 }
307 
308 static int mpl3115_resume(struct device *dev)
309 {
310 	struct mpl3115_data *data = iio_priv(i2c_get_clientdata(
311 		to_i2c_client(dev)));
312 
313 	return i2c_smbus_write_byte_data(data->client, MPL3115_CTRL_REG1,
314 		data->ctrl_reg1);
315 }
316 
317 static DEFINE_SIMPLE_DEV_PM_OPS(mpl3115_pm_ops, mpl3115_suspend,
318 				mpl3115_resume);
319 
320 static const struct i2c_device_id mpl3115_id[] = {
321 	{ "mpl3115", 0 },
322 	{ }
323 };
324 MODULE_DEVICE_TABLE(i2c, mpl3115_id);
325 
326 static const struct of_device_id mpl3115_of_match[] = {
327 	{ .compatible = "fsl,mpl3115" },
328 	{ }
329 };
330 MODULE_DEVICE_TABLE(of, mpl3115_of_match);
331 
332 static struct i2c_driver mpl3115_driver = {
333 	.driver = {
334 		.name	= "mpl3115",
335 		.of_match_table = mpl3115_of_match,
336 		.pm	= pm_sleep_ptr(&mpl3115_pm_ops),
337 	},
338 	.probe = mpl3115_probe,
339 	.remove = mpl3115_remove,
340 	.id_table = mpl3115_id,
341 };
342 module_i2c_driver(mpl3115_driver);
343 
344 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
345 MODULE_DESCRIPTION("Freescale MPL3115 pressure/temperature driver");
346 MODULE_LICENSE("GPL");
347