xref: /linux/drivers/iio/adc/mcp320x.c (revision 0883c2c06fb5bcf5b9e008270827e63c09a88c1e) 
1 /*
2  * Copyright (C) 2013 Oskar Andero <oskar.andero@gmail.com>
3  * Copyright (C) 2014 Rose Technology
4  * 	   Allan Bendorff Jensen <abj@rosetechnology.dk>
5  *	   Soren Andersen <san@rosetechnology.dk>
6  *
7  * Driver for following ADC chips from Microchip Technology's:
8  * 10 Bit converter
9  * MCP3001
10  * MCP3002
11  * MCP3004
12  * MCP3008
13  * ------------
14  * 12 bit converter
15  * MCP3201
16  * MCP3202
17  * MCP3204
18  * MCP3208
19  * ------------
20  *
21  * Datasheet can be found here:
22  * http://ww1.microchip.com/downloads/en/DeviceDoc/21293C.pdf  mcp3001
23  * http://ww1.microchip.com/downloads/en/DeviceDoc/21294E.pdf  mcp3002
24  * http://ww1.microchip.com/downloads/en/DeviceDoc/21295d.pdf  mcp3004/08
25  * http://ww1.microchip.com/downloads/en/DeviceDoc/21290D.pdf  mcp3201
26  * http://ww1.microchip.com/downloads/en/DeviceDoc/21034D.pdf  mcp3202
27  * http://ww1.microchip.com/downloads/en/DeviceDoc/21298c.pdf  mcp3204/08
28  * http://ww1.microchip.com/downloads/en/DeviceDoc/21700E.pdf  mcp3301
29  *
30  * This program is free software; you can redistribute it and/or modify
31  * it under the terms of the GNU General Public License version 2 as
32  * published by the Free Software Foundation.
33  */
34 
35 #include <linux/err.h>
36 #include <linux/delay.h>
37 #include <linux/spi/spi.h>
38 #include <linux/module.h>
39 #include <linux/iio/iio.h>
40 #include <linux/regulator/consumer.h>
41 
42 enum {
43 	mcp3001,
44 	mcp3002,
45 	mcp3004,
46 	mcp3008,
47 	mcp3201,
48 	mcp3202,
49 	mcp3204,
50 	mcp3208,
51 	mcp3301,
52 };
53 
54 struct mcp320x_chip_info {
55 	const struct iio_chan_spec *channels;
56 	unsigned int num_channels;
57 	unsigned int resolution;
58 };
59 
60 struct mcp320x {
61 	struct spi_device *spi;
62 	struct spi_message msg;
63 	struct spi_transfer transfer[2];
64 
65 	struct regulator *reg;
66 	struct mutex lock;
67 	const struct mcp320x_chip_info *chip_info;
68 
69 	u8 tx_buf ____cacheline_aligned;
70 	u8 rx_buf[2];
71 };
72 
73 static int mcp320x_channel_to_tx_data(int device_index,
74 			const unsigned int channel, bool differential)
75 {
76 	int start_bit = 1;
77 
78 	switch (device_index) {
79 	case mcp3001:
80 	case mcp3201:
81 	case mcp3301:
82 		return 0;
83 	case mcp3002:
84 	case mcp3202:
85 		return ((start_bit << 4) | (!differential << 3) |
86 							(channel << 2));
87 	case mcp3004:
88 	case mcp3204:
89 	case mcp3008:
90 	case mcp3208:
91 		return ((start_bit << 6) | (!differential << 5) |
92 							(channel << 2));
93 	default:
94 		return -EINVAL;
95 	}
96 }
97 
98 static int mcp320x_adc_conversion(struct mcp320x *adc, u8 channel,
99 				  bool differential, int device_index)
100 {
101 	int ret;
102 
103 	adc->rx_buf[0] = 0;
104 	adc->rx_buf[1] = 0;
105 	adc->tx_buf = mcp320x_channel_to_tx_data(device_index,
106 						channel, differential);
107 
108 	if (device_index != mcp3001 && device_index != mcp3201 && device_index != mcp3301) {
109 		ret = spi_sync(adc->spi, &adc->msg);
110 		if (ret < 0)
111 			return ret;
112 	} else {
113 		ret = spi_read(adc->spi, &adc->rx_buf, sizeof(adc->rx_buf));
114 		if (ret < 0)
115 			return ret;
116 	}
117 
118 	switch (device_index) {
119 	case mcp3001:
120 		return (adc->rx_buf[0] << 5 | adc->rx_buf[1] >> 3);
121 	case mcp3002:
122 	case mcp3004:
123 	case mcp3008:
124 		return (adc->rx_buf[0] << 2 | adc->rx_buf[1] >> 6);
125 	case mcp3201:
126 		return (adc->rx_buf[0] << 7 | adc->rx_buf[1] >> 1);
127 	case mcp3202:
128 	case mcp3204:
129 	case mcp3208:
130 		return (adc->rx_buf[0] << 4 | adc->rx_buf[1] >> 4);
131 	case mcp3301:
132 		return sign_extend32((adc->rx_buf[0] & 0x1f) << 8 | adc->rx_buf[1], 12);
133 	default:
134 		return -EINVAL;
135 	}
136 }
137 
138 static int mcp320x_read_raw(struct iio_dev *indio_dev,
139 			    struct iio_chan_spec const *channel, int *val,
140 			    int *val2, long mask)
141 {
142 	struct mcp320x *adc = iio_priv(indio_dev);
143 	int ret = -EINVAL;
144 	int device_index = 0;
145 
146 	mutex_lock(&adc->lock);
147 
148 	device_index = spi_get_device_id(adc->spi)->driver_data;
149 
150 	switch (mask) {
151 	case IIO_CHAN_INFO_RAW:
152 		ret = mcp320x_adc_conversion(adc, channel->address,
153 			channel->differential, device_index);
154 
155 		if (ret < 0)
156 			goto out;
157 
158 		*val = ret;
159 		ret = IIO_VAL_INT;
160 		break;
161 
162 	case IIO_CHAN_INFO_SCALE:
163 		ret = regulator_get_voltage(adc->reg);
164 		if (ret < 0)
165 			goto out;
166 
167 		/* convert regulator output voltage to mV */
168 		*val = ret / 1000;
169 		*val2 = adc->chip_info->resolution;
170 		ret = IIO_VAL_FRACTIONAL_LOG2;
171 		break;
172 	}
173 
174 out:
175 	mutex_unlock(&adc->lock);
176 
177 	return ret;
178 }
179 
180 #define MCP320X_VOLTAGE_CHANNEL(num)				\
181 	{							\
182 		.type = IIO_VOLTAGE,				\
183 		.indexed = 1,					\
184 		.channel = (num),				\
185 		.address = (num),				\
186 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
187 		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
188 	}
189 
190 #define MCP320X_VOLTAGE_CHANNEL_DIFF(chan1, chan2)		\
191 	{							\
192 		.type = IIO_VOLTAGE,				\
193 		.indexed = 1,					\
194 		.channel = (chan1),				\
195 		.channel2 = (chan2),				\
196 		.address = (chan1),				\
197 		.differential = 1,				\
198 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
199 		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
200 	}
201 
202 static const struct iio_chan_spec mcp3201_channels[] = {
203 	MCP320X_VOLTAGE_CHANNEL_DIFF(0, 1),
204 };
205 
206 static const struct iio_chan_spec mcp3202_channels[] = {
207 	MCP320X_VOLTAGE_CHANNEL(0),
208 	MCP320X_VOLTAGE_CHANNEL(1),
209 	MCP320X_VOLTAGE_CHANNEL_DIFF(0, 1),
210 	MCP320X_VOLTAGE_CHANNEL_DIFF(1, 0),
211 };
212 
213 static const struct iio_chan_spec mcp3204_channels[] = {
214 	MCP320X_VOLTAGE_CHANNEL(0),
215 	MCP320X_VOLTAGE_CHANNEL(1),
216 	MCP320X_VOLTAGE_CHANNEL(2),
217 	MCP320X_VOLTAGE_CHANNEL(3),
218 	MCP320X_VOLTAGE_CHANNEL_DIFF(0, 1),
219 	MCP320X_VOLTAGE_CHANNEL_DIFF(1, 0),
220 	MCP320X_VOLTAGE_CHANNEL_DIFF(2, 3),
221 	MCP320X_VOLTAGE_CHANNEL_DIFF(3, 2),
222 };
223 
224 static const struct iio_chan_spec mcp3208_channels[] = {
225 	MCP320X_VOLTAGE_CHANNEL(0),
226 	MCP320X_VOLTAGE_CHANNEL(1),
227 	MCP320X_VOLTAGE_CHANNEL(2),
228 	MCP320X_VOLTAGE_CHANNEL(3),
229 	MCP320X_VOLTAGE_CHANNEL(4),
230 	MCP320X_VOLTAGE_CHANNEL(5),
231 	MCP320X_VOLTAGE_CHANNEL(6),
232 	MCP320X_VOLTAGE_CHANNEL(7),
233 	MCP320X_VOLTAGE_CHANNEL_DIFF(0, 1),
234 	MCP320X_VOLTAGE_CHANNEL_DIFF(1, 0),
235 	MCP320X_VOLTAGE_CHANNEL_DIFF(2, 3),
236 	MCP320X_VOLTAGE_CHANNEL_DIFF(3, 2),
237 	MCP320X_VOLTAGE_CHANNEL_DIFF(4, 5),
238 	MCP320X_VOLTAGE_CHANNEL_DIFF(5, 4),
239 	MCP320X_VOLTAGE_CHANNEL_DIFF(6, 7),
240 	MCP320X_VOLTAGE_CHANNEL_DIFF(7, 6),
241 };
242 
243 static const struct iio_info mcp320x_info = {
244 	.read_raw = mcp320x_read_raw,
245 	.driver_module = THIS_MODULE,
246 };
247 
248 static const struct mcp320x_chip_info mcp320x_chip_infos[] = {
249 	[mcp3001] = {
250 		.channels = mcp3201_channels,
251 		.num_channels = ARRAY_SIZE(mcp3201_channels),
252 		.resolution = 10
253 	},
254 	[mcp3002] = {
255 		.channels = mcp3202_channels,
256 		.num_channels = ARRAY_SIZE(mcp3202_channels),
257 		.resolution = 10
258 	},
259 	[mcp3004] = {
260 		.channels = mcp3204_channels,
261 		.num_channels = ARRAY_SIZE(mcp3204_channels),
262 		.resolution = 10
263 	},
264 	[mcp3008] = {
265 		.channels = mcp3208_channels,
266 		.num_channels = ARRAY_SIZE(mcp3208_channels),
267 		.resolution = 10
268 	},
269 	[mcp3201] = {
270 		.channels = mcp3201_channels,
271 		.num_channels = ARRAY_SIZE(mcp3201_channels),
272 		.resolution = 12
273 	},
274 	[mcp3202] = {
275 		.channels = mcp3202_channels,
276 		.num_channels = ARRAY_SIZE(mcp3202_channels),
277 		.resolution = 12
278 	},
279 	[mcp3204] = {
280 		.channels = mcp3204_channels,
281 		.num_channels = ARRAY_SIZE(mcp3204_channels),
282 		.resolution = 12
283 	},
284 	[mcp3208] = {
285 		.channels = mcp3208_channels,
286 		.num_channels = ARRAY_SIZE(mcp3208_channels),
287 		.resolution = 12
288 	},
289 	[mcp3301] = {
290 		.channels = mcp3201_channels,
291 		.num_channels = ARRAY_SIZE(mcp3201_channels),
292 		.resolution = 13
293 	},
294 };
295 
296 static int mcp320x_probe(struct spi_device *spi)
297 {
298 	struct iio_dev *indio_dev;
299 	struct mcp320x *adc;
300 	const struct mcp320x_chip_info *chip_info;
301 	int ret;
302 
303 	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
304 	if (!indio_dev)
305 		return -ENOMEM;
306 
307 	adc = iio_priv(indio_dev);
308 	adc->spi = spi;
309 
310 	indio_dev->dev.parent = &spi->dev;
311 	indio_dev->name = spi_get_device_id(spi)->name;
312 	indio_dev->modes = INDIO_DIRECT_MODE;
313 	indio_dev->info = &mcp320x_info;
314 
315 	chip_info = &mcp320x_chip_infos[spi_get_device_id(spi)->driver_data];
316 	indio_dev->channels = chip_info->channels;
317 	indio_dev->num_channels = chip_info->num_channels;
318 
319 	adc->chip_info = chip_info;
320 
321 	adc->transfer[0].tx_buf = &adc->tx_buf;
322 	adc->transfer[0].len = sizeof(adc->tx_buf);
323 	adc->transfer[1].rx_buf = adc->rx_buf;
324 	adc->transfer[1].len = sizeof(adc->rx_buf);
325 
326 	spi_message_init_with_transfers(&adc->msg, adc->transfer,
327 					ARRAY_SIZE(adc->transfer));
328 
329 	adc->reg = devm_regulator_get(&spi->dev, "vref");
330 	if (IS_ERR(adc->reg))
331 		return PTR_ERR(adc->reg);
332 
333 	ret = regulator_enable(adc->reg);
334 	if (ret < 0)
335 		return ret;
336 
337 	mutex_init(&adc->lock);
338 
339 	ret = iio_device_register(indio_dev);
340 	if (ret < 0)
341 		goto reg_disable;
342 
343 	return 0;
344 
345 reg_disable:
346 	regulator_disable(adc->reg);
347 
348 	return ret;
349 }
350 
351 static int mcp320x_remove(struct spi_device *spi)
352 {
353 	struct iio_dev *indio_dev = spi_get_drvdata(spi);
354 	struct mcp320x *adc = iio_priv(indio_dev);
355 
356 	iio_device_unregister(indio_dev);
357 	regulator_disable(adc->reg);
358 
359 	return 0;
360 }
361 
362 #if defined(CONFIG_OF)
363 static const struct of_device_id mcp320x_dt_ids[] = {
364 	/* NOTE: The use of compatibles with no vendor prefix is deprecated. */
365 	{
366 		.compatible = "mcp3001",
367 		.data = &mcp320x_chip_infos[mcp3001],
368 	}, {
369 		.compatible = "mcp3002",
370 		.data = &mcp320x_chip_infos[mcp3002],
371 	}, {
372 		.compatible = "mcp3004",
373 		.data = &mcp320x_chip_infos[mcp3004],
374 	}, {
375 		.compatible = "mcp3008",
376 		.data = &mcp320x_chip_infos[mcp3008],
377 	}, {
378 		.compatible = "mcp3201",
379 		.data = &mcp320x_chip_infos[mcp3201],
380 	}, {
381 		.compatible = "mcp3202",
382 		.data = &mcp320x_chip_infos[mcp3202],
383 	}, {
384 		.compatible = "mcp3204",
385 		.data = &mcp320x_chip_infos[mcp3204],
386 	}, {
387 		.compatible = "mcp3208",
388 		.data = &mcp320x_chip_infos[mcp3208],
389 	}, {
390 		.compatible = "mcp3301",
391 		.data = &mcp320x_chip_infos[mcp3301],
392 	}, {
393 		.compatible = "microchip,mcp3001",
394 		.data = &mcp320x_chip_infos[mcp3001],
395 	}, {
396 		.compatible = "microchip,mcp3002",
397 		.data = &mcp320x_chip_infos[mcp3002],
398 	}, {
399 		.compatible = "microchip,mcp3004",
400 		.data = &mcp320x_chip_infos[mcp3004],
401 	}, {
402 		.compatible = "microchip,mcp3008",
403 		.data = &mcp320x_chip_infos[mcp3008],
404 	}, {
405 		.compatible = "microchip,mcp3201",
406 		.data = &mcp320x_chip_infos[mcp3201],
407 	}, {
408 		.compatible = "microchip,mcp3202",
409 		.data = &mcp320x_chip_infos[mcp3202],
410 	}, {
411 		.compatible = "microchip,mcp3204",
412 		.data = &mcp320x_chip_infos[mcp3204],
413 	}, {
414 		.compatible = "microchip,mcp3208",
415 		.data = &mcp320x_chip_infos[mcp3208],
416 	}, {
417 		.compatible = "microchip,mcp3301",
418 		.data = &mcp320x_chip_infos[mcp3301],
419 	}, {
420 	}
421 };
422 MODULE_DEVICE_TABLE(of, mcp320x_dt_ids);
423 #endif
424 
425 static const struct spi_device_id mcp320x_id[] = {
426 	{ "mcp3001", mcp3001 },
427 	{ "mcp3002", mcp3002 },
428 	{ "mcp3004", mcp3004 },
429 	{ "mcp3008", mcp3008 },
430 	{ "mcp3201", mcp3201 },
431 	{ "mcp3202", mcp3202 },
432 	{ "mcp3204", mcp3204 },
433 	{ "mcp3208", mcp3208 },
434 	{ "mcp3301", mcp3301 },
435 	{ }
436 };
437 MODULE_DEVICE_TABLE(spi, mcp320x_id);
438 
439 static struct spi_driver mcp320x_driver = {
440 	.driver = {
441 		.name = "mcp320x",
442 		.of_match_table = of_match_ptr(mcp320x_dt_ids),
443 	},
444 	.probe = mcp320x_probe,
445 	.remove = mcp320x_remove,
446 	.id_table = mcp320x_id,
447 };
448 module_spi_driver(mcp320x_driver);
449 
450 MODULE_AUTHOR("Oskar Andero <oskar.andero@gmail.com>");
451 MODULE_DESCRIPTION("Microchip Technology MCP3x01/02/04/08");
452 MODULE_LICENSE("GPL v2");
453