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 
mpl3115_request(struct mpl3115_data * data)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 
mpl3115_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)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 	__be32 tmp = 0;
78 	int ret;
79 
80 	switch (mask) {
81 	case IIO_CHAN_INFO_RAW:
82 		ret = iio_device_claim_direct_mode(indio_dev);
83 		if (ret)
84 			return ret;
85 
86 		switch (chan->type) {
87 		case IIO_PRESSURE: /* in 0.25 pascal / LSB */
88 			mutex_lock(&data->lock);
89 			ret = mpl3115_request(data);
90 			if (ret < 0) {
91 				mutex_unlock(&data->lock);
92 				break;
93 			}
94 			ret = i2c_smbus_read_i2c_block_data(data->client,
95 				MPL3115_OUT_PRESS, 3, (u8 *) &tmp);
96 			mutex_unlock(&data->lock);
97 			if (ret < 0)
98 				break;
99 			*val = be32_to_cpu(tmp) >> 12;
100 			ret = IIO_VAL_INT;
101 			break;
102 		case IIO_TEMP: /* in 0.0625 celsius / LSB */
103 			mutex_lock(&data->lock);
104 			ret = mpl3115_request(data);
105 			if (ret < 0) {
106 				mutex_unlock(&data->lock);
107 				break;
108 			}
109 			ret = i2c_smbus_read_i2c_block_data(data->client,
110 				MPL3115_OUT_TEMP, 2, (u8 *) &tmp);
111 			mutex_unlock(&data->lock);
112 			if (ret < 0)
113 				break;
114 			*val = sign_extend32(be32_to_cpu(tmp) >> 20, 11);
115 			ret = IIO_VAL_INT;
116 			break;
117 		default:
118 			ret = -EINVAL;
119 			break;
120 		}
121 
122 		iio_device_release_direct_mode(indio_dev);
123 		return ret;
124 
125 	case IIO_CHAN_INFO_SCALE:
126 		switch (chan->type) {
127 		case IIO_PRESSURE:
128 			*val = 0;
129 			*val2 = 250; /* want kilopascal */
130 			return IIO_VAL_INT_PLUS_MICRO;
131 		case IIO_TEMP:
132 			*val = 0;
133 			*val2 = 62500;
134 			return IIO_VAL_INT_PLUS_MICRO;
135 		default:
136 			return -EINVAL;
137 		}
138 	}
139 	return -EINVAL;
140 }
141 
mpl3115_trigger_handler(int irq,void * p)142 static irqreturn_t mpl3115_trigger_handler(int irq, void *p)
143 {
144 	struct iio_poll_func *pf = p;
145 	struct iio_dev *indio_dev = pf->indio_dev;
146 	struct mpl3115_data *data = iio_priv(indio_dev);
147 	/*
148 	 * 32-bit channel + 16-bit channel + padding + ts
149 	 * Note that it is possible for only one of the first 2
150 	 * channels to be enabled. If that happens, the first element
151 	 * of the buffer may be either 16 or 32-bits.  As such we cannot
152 	 * use a simple structure definition to express this data layout.
153 	 */
154 	u8 buffer[16] __aligned(8);
155 	int ret, pos = 0;
156 
157 	mutex_lock(&data->lock);
158 	ret = mpl3115_request(data);
159 	if (ret < 0) {
160 		mutex_unlock(&data->lock);
161 		goto done;
162 	}
163 
164 	memset(buffer, 0, sizeof(buffer));
165 	if (test_bit(0, indio_dev->active_scan_mask)) {
166 		ret = i2c_smbus_read_i2c_block_data(data->client,
167 			MPL3115_OUT_PRESS, 3, &buffer[pos]);
168 		if (ret < 0) {
169 			mutex_unlock(&data->lock);
170 			goto done;
171 		}
172 		pos += 4;
173 	}
174 
175 	if (test_bit(1, indio_dev->active_scan_mask)) {
176 		ret = i2c_smbus_read_i2c_block_data(data->client,
177 			MPL3115_OUT_TEMP, 2, &buffer[pos]);
178 		if (ret < 0) {
179 			mutex_unlock(&data->lock);
180 			goto done;
181 		}
182 	}
183 	mutex_unlock(&data->lock);
184 
185 	iio_push_to_buffers_with_timestamp(indio_dev, buffer,
186 		iio_get_time_ns(indio_dev));
187 
188 done:
189 	iio_trigger_notify_done(indio_dev->trig);
190 	return IRQ_HANDLED;
191 }
192 
193 static const struct iio_chan_spec mpl3115_channels[] = {
194 	{
195 		.type = IIO_PRESSURE,
196 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
197 		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
198 		.scan_index = 0,
199 		.scan_type = {
200 			.sign = 'u',
201 			.realbits = 20,
202 			.storagebits = 32,
203 			.shift = 12,
204 			.endianness = IIO_BE,
205 		}
206 	},
207 	{
208 		.type = IIO_TEMP,
209 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
210 		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
211 		.scan_index = 1,
212 		.scan_type = {
213 			.sign = 's',
214 			.realbits = 12,
215 			.storagebits = 16,
216 			.shift = 4,
217 			.endianness = IIO_BE,
218 		}
219 	},
220 	IIO_CHAN_SOFT_TIMESTAMP(2),
221 };
222 
223 static const struct iio_info mpl3115_info = {
224 	.read_raw = &mpl3115_read_raw,
225 };
226 
mpl3115_probe(struct i2c_client * client,const struct i2c_device_id * id)227 static int mpl3115_probe(struct i2c_client *client,
228 			 const struct i2c_device_id *id)
229 {
230 	struct mpl3115_data *data;
231 	struct iio_dev *indio_dev;
232 	int ret;
233 
234 	ret = i2c_smbus_read_byte_data(client, MPL3115_WHO_AM_I);
235 	if (ret < 0)
236 		return ret;
237 	if (ret != MPL3115_DEVICE_ID)
238 		return -ENODEV;
239 
240 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
241 	if (!indio_dev)
242 		return -ENOMEM;
243 
244 	data = iio_priv(indio_dev);
245 	data->client = client;
246 	mutex_init(&data->lock);
247 
248 	i2c_set_clientdata(client, indio_dev);
249 	indio_dev->info = &mpl3115_info;
250 	indio_dev->name = id->name;
251 	indio_dev->modes = INDIO_DIRECT_MODE;
252 	indio_dev->channels = mpl3115_channels;
253 	indio_dev->num_channels = ARRAY_SIZE(mpl3115_channels);
254 
255 	/* software reset, I2C transfer is aborted (fails) */
256 	i2c_smbus_write_byte_data(client, MPL3115_CTRL_REG1,
257 		MPL3115_CTRL_RESET);
258 	msleep(50);
259 
260 	data->ctrl_reg1 = MPL3115_CTRL_OS_258MS;
261 	ret = i2c_smbus_write_byte_data(client, MPL3115_CTRL_REG1,
262 		data->ctrl_reg1);
263 	if (ret < 0)
264 		return ret;
265 
266 	ret = iio_triggered_buffer_setup(indio_dev, NULL,
267 		mpl3115_trigger_handler, NULL);
268 	if (ret < 0)
269 		return ret;
270 
271 	ret = iio_device_register(indio_dev);
272 	if (ret < 0)
273 		goto buffer_cleanup;
274 	return 0;
275 
276 buffer_cleanup:
277 	iio_triggered_buffer_cleanup(indio_dev);
278 	return ret;
279 }
280 
mpl3115_standby(struct mpl3115_data * data)281 static int mpl3115_standby(struct mpl3115_data *data)
282 {
283 	return i2c_smbus_write_byte_data(data->client, MPL3115_CTRL_REG1,
284 		data->ctrl_reg1 & ~MPL3115_CTRL_ACTIVE);
285 }
286 
mpl3115_remove(struct i2c_client * client)287 static int mpl3115_remove(struct i2c_client *client)
288 {
289 	struct iio_dev *indio_dev = i2c_get_clientdata(client);
290 
291 	iio_device_unregister(indio_dev);
292 	iio_triggered_buffer_cleanup(indio_dev);
293 	mpl3115_standby(iio_priv(indio_dev));
294 
295 	return 0;
296 }
297 
298 #ifdef CONFIG_PM_SLEEP
mpl3115_suspend(struct device * dev)299 static int mpl3115_suspend(struct device *dev)
300 {
301 	return mpl3115_standby(iio_priv(i2c_get_clientdata(
302 		to_i2c_client(dev))));
303 }
304 
mpl3115_resume(struct device * dev)305 static int mpl3115_resume(struct device *dev)
306 {
307 	struct mpl3115_data *data = iio_priv(i2c_get_clientdata(
308 		to_i2c_client(dev)));
309 
310 	return i2c_smbus_write_byte_data(data->client, MPL3115_CTRL_REG1,
311 		data->ctrl_reg1);
312 }
313 
314 static SIMPLE_DEV_PM_OPS(mpl3115_pm_ops, mpl3115_suspend, mpl3115_resume);
315 #define MPL3115_PM_OPS (&mpl3115_pm_ops)
316 #else
317 #define MPL3115_PM_OPS NULL
318 #endif
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	= 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