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Commit | Line | Data |
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07914c84 | 1 | /* |
2816ac64 | 2 | * mcp3422.c - driver for the Microchip mcp3422/3/4/6/7/8 chip family |
07914c84 AC |
3 | * |
4 | * Copyright (C) 2013, Angelo Compagnucci | |
5 | * Author: Angelo Compagnucci <angelo.compagnucci@gmail.com> | |
6 | * | |
7 | * Datasheet: http://ww1.microchip.com/downloads/en/devicedoc/22088b.pdf | |
2816ac64 | 8 | * http://ww1.microchip.com/downloads/en/DeviceDoc/22226a.pdf |
07914c84 AC |
9 | * |
10 | * This driver exports the value of analog input voltage to sysfs, the | |
11 | * voltage unit is nV. | |
12 | * | |
13 | * This program is free software; you can redistribute it and/or modify | |
14 | * it under the terms of the GNU General Public License as published by | |
15 | * the Free Software Foundation; either version 2 of the License, or | |
16 | * (at your option) any later version. | |
17 | */ | |
18 | ||
19 | #include <linux/err.h> | |
20 | #include <linux/i2c.h> | |
21 | #include <linux/module.h> | |
22 | #include <linux/delay.h> | |
23 | #include <linux/sysfs.h> | |
de36d817 | 24 | #include <linux/of.h> |
07914c84 AC |
25 | |
26 | #include <linux/iio/iio.h> | |
27 | #include <linux/iio/sysfs.h> | |
28 | ||
29 | /* Masks */ | |
30 | #define MCP3422_CHANNEL_MASK 0x60 | |
31 | #define MCP3422_PGA_MASK 0x03 | |
32 | #define MCP3422_SRATE_MASK 0x0C | |
33 | #define MCP3422_SRATE_240 0x0 | |
34 | #define MCP3422_SRATE_60 0x1 | |
35 | #define MCP3422_SRATE_15 0x2 | |
36 | #define MCP3422_SRATE_3 0x3 | |
37 | #define MCP3422_PGA_1 0 | |
38 | #define MCP3422_PGA_2 1 | |
39 | #define MCP3422_PGA_4 2 | |
40 | #define MCP3422_PGA_8 3 | |
41 | #define MCP3422_CONT_SAMPLING 0x10 | |
42 | ||
43 | #define MCP3422_CHANNEL(config) (((config) & MCP3422_CHANNEL_MASK) >> 5) | |
44 | #define MCP3422_PGA(config) ((config) & MCP3422_PGA_MASK) | |
45 | #define MCP3422_SAMPLE_RATE(config) (((config) & MCP3422_SRATE_MASK) >> 2) | |
46 | ||
47 | #define MCP3422_CHANNEL_VALUE(value) (((value) << 5) & MCP3422_CHANNEL_MASK) | |
48 | #define MCP3422_PGA_VALUE(value) ((value) & MCP3422_PGA_MASK) | |
49 | #define MCP3422_SAMPLE_RATE_VALUE(value) ((value << 2) & MCP3422_SRATE_MASK) | |
50 | ||
51 | #define MCP3422_CHAN(_index) \ | |
52 | { \ | |
53 | .type = IIO_VOLTAGE, \ | |
54 | .indexed = 1, \ | |
55 | .channel = _index, \ | |
56 | .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) \ | |
57 | | BIT(IIO_CHAN_INFO_SCALE), \ | |
58 | .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ), \ | |
59 | } | |
60 | ||
07914c84 | 61 | static const int mcp3422_scales[4][4] = { |
9e128ced AC |
62 | { 1000000, 500000, 250000, 125000 }, |
63 | { 250000 , 125000, 62500 , 31250 }, | |
64 | { 62500 , 31250 , 15625 , 7812 }, | |
65 | { 15625 , 7812 , 3906 , 1953 } }; | |
07914c84 AC |
66 | |
67 | /* Constant msleep times for data acquisitions */ | |
68 | static const int mcp3422_read_times[4] = { | |
69 | [MCP3422_SRATE_240] = 1000 / 240, | |
70 | [MCP3422_SRATE_60] = 1000 / 60, | |
71 | [MCP3422_SRATE_15] = 1000 / 15, | |
72 | [MCP3422_SRATE_3] = 1000 / 3 }; | |
73 | ||
74 | /* sample rates to integer conversion table */ | |
75 | static const int mcp3422_sample_rates[4] = { | |
76 | [MCP3422_SRATE_240] = 240, | |
77 | [MCP3422_SRATE_60] = 60, | |
78 | [MCP3422_SRATE_15] = 15, | |
79 | [MCP3422_SRATE_3] = 3 }; | |
80 | ||
81 | /* sample rates to sign extension table */ | |
82 | static const int mcp3422_sign_extend[4] = { | |
a5a3e431 PM |
83 | [MCP3422_SRATE_240] = 11, |
84 | [MCP3422_SRATE_60] = 13, | |
85 | [MCP3422_SRATE_15] = 15, | |
86 | [MCP3422_SRATE_3] = 17 }; | |
07914c84 AC |
87 | |
88 | /* Client data (each client gets its own) */ | |
89 | struct mcp3422 { | |
90 | struct i2c_client *i2c; | |
2816ac64 | 91 | u8 id; |
07914c84 AC |
92 | u8 config; |
93 | u8 pga[4]; | |
94 | struct mutex lock; | |
95 | }; | |
96 | ||
97 | static int mcp3422_update_config(struct mcp3422 *adc, u8 newconfig) | |
98 | { | |
99 | int ret; | |
100 | ||
101 | mutex_lock(&adc->lock); | |
102 | ||
103 | ret = i2c_master_send(adc->i2c, &newconfig, 1); | |
104 | if (ret > 0) { | |
105 | adc->config = newconfig; | |
106 | ret = 0; | |
107 | } | |
108 | ||
109 | mutex_unlock(&adc->lock); | |
110 | ||
111 | return ret; | |
112 | } | |
113 | ||
114 | static int mcp3422_read(struct mcp3422 *adc, int *value, u8 *config) | |
115 | { | |
116 | int ret = 0; | |
117 | u8 sample_rate = MCP3422_SAMPLE_RATE(adc->config); | |
118 | u8 buf[4] = {0, 0, 0, 0}; | |
119 | u32 temp; | |
120 | ||
121 | if (sample_rate == MCP3422_SRATE_3) { | |
122 | ret = i2c_master_recv(adc->i2c, buf, 4); | |
123 | temp = buf[0] << 16 | buf[1] << 8 | buf[2]; | |
124 | *config = buf[3]; | |
125 | } else { | |
126 | ret = i2c_master_recv(adc->i2c, buf, 3); | |
127 | temp = buf[0] << 8 | buf[1]; | |
128 | *config = buf[2]; | |
129 | } | |
130 | ||
131 | *value = sign_extend32(temp, mcp3422_sign_extend[sample_rate]); | |
132 | ||
133 | return ret; | |
134 | } | |
135 | ||
136 | static int mcp3422_read_channel(struct mcp3422 *adc, | |
137 | struct iio_chan_spec const *channel, int *value) | |
138 | { | |
139 | int ret; | |
140 | u8 config; | |
141 | u8 req_channel = channel->channel; | |
142 | ||
143 | if (req_channel != MCP3422_CHANNEL(adc->config)) { | |
144 | config = adc->config; | |
145 | config &= ~MCP3422_CHANNEL_MASK; | |
146 | config |= MCP3422_CHANNEL_VALUE(req_channel); | |
147 | config &= ~MCP3422_PGA_MASK; | |
148 | config |= MCP3422_PGA_VALUE(adc->pga[req_channel]); | |
149 | ret = mcp3422_update_config(adc, config); | |
150 | if (ret < 0) | |
151 | return ret; | |
152 | msleep(mcp3422_read_times[MCP3422_SAMPLE_RATE(adc->config)]); | |
153 | } | |
154 | ||
155 | return mcp3422_read(adc, value, &config); | |
156 | } | |
157 | ||
158 | static int mcp3422_read_raw(struct iio_dev *iio, | |
159 | struct iio_chan_spec const *channel, int *val1, | |
160 | int *val2, long mask) | |
161 | { | |
162 | struct mcp3422 *adc = iio_priv(iio); | |
163 | int err; | |
164 | ||
165 | u8 sample_rate = MCP3422_SAMPLE_RATE(adc->config); | |
166 | u8 pga = MCP3422_PGA(adc->config); | |
167 | ||
168 | switch (mask) { | |
169 | case IIO_CHAN_INFO_RAW: | |
170 | err = mcp3422_read_channel(adc, channel, val1); | |
171 | if (err < 0) | |
172 | return -EINVAL; | |
173 | return IIO_VAL_INT; | |
174 | ||
175 | case IIO_CHAN_INFO_SCALE: | |
176 | ||
177 | *val1 = 0; | |
178 | *val2 = mcp3422_scales[sample_rate][pga]; | |
179 | return IIO_VAL_INT_PLUS_NANO; | |
180 | ||
181 | case IIO_CHAN_INFO_SAMP_FREQ: | |
182 | *val1 = mcp3422_sample_rates[MCP3422_SAMPLE_RATE(adc->config)]; | |
183 | return IIO_VAL_INT; | |
184 | ||
185 | default: | |
186 | break; | |
187 | } | |
188 | ||
189 | return -EINVAL; | |
190 | } | |
191 | ||
192 | static int mcp3422_write_raw(struct iio_dev *iio, | |
193 | struct iio_chan_spec const *channel, int val1, | |
194 | int val2, long mask) | |
195 | { | |
196 | struct mcp3422 *adc = iio_priv(iio); | |
197 | u8 temp; | |
198 | u8 config = adc->config; | |
199 | u8 req_channel = channel->channel; | |
200 | u8 sample_rate = MCP3422_SAMPLE_RATE(config); | |
201 | u8 i; | |
202 | ||
203 | switch (mask) { | |
204 | case IIO_CHAN_INFO_SCALE: | |
205 | if (val1 != 0) | |
206 | return -EINVAL; | |
207 | ||
208 | for (i = 0; i < ARRAY_SIZE(mcp3422_scales[0]); i++) { | |
209 | if (val2 == mcp3422_scales[sample_rate][i]) { | |
210 | adc->pga[req_channel] = i; | |
211 | ||
212 | config &= ~MCP3422_CHANNEL_MASK; | |
213 | config |= MCP3422_CHANNEL_VALUE(req_channel); | |
214 | config &= ~MCP3422_PGA_MASK; | |
215 | config |= MCP3422_PGA_VALUE(adc->pga[req_channel]); | |
216 | ||
217 | return mcp3422_update_config(adc, config); | |
218 | } | |
219 | } | |
220 | return -EINVAL; | |
221 | ||
222 | case IIO_CHAN_INFO_SAMP_FREQ: | |
223 | switch (val1) { | |
224 | case 240: | |
225 | temp = MCP3422_SRATE_240; | |
226 | break; | |
227 | case 60: | |
228 | temp = MCP3422_SRATE_60; | |
229 | break; | |
230 | case 15: | |
231 | temp = MCP3422_SRATE_15; | |
232 | break; | |
233 | case 3: | |
2816ac64 AC |
234 | if (adc->id > 4) |
235 | return -EINVAL; | |
07914c84 AC |
236 | temp = MCP3422_SRATE_3; |
237 | break; | |
238 | default: | |
239 | return -EINVAL; | |
240 | } | |
241 | ||
242 | config &= ~MCP3422_CHANNEL_MASK; | |
243 | config |= MCP3422_CHANNEL_VALUE(req_channel); | |
244 | config &= ~MCP3422_SRATE_MASK; | |
245 | config |= MCP3422_SAMPLE_RATE_VALUE(temp); | |
246 | ||
247 | return mcp3422_update_config(adc, config); | |
248 | ||
249 | default: | |
250 | break; | |
251 | } | |
252 | ||
253 | return -EINVAL; | |
254 | } | |
255 | ||
256 | static int mcp3422_write_raw_get_fmt(struct iio_dev *indio_dev, | |
257 | struct iio_chan_spec const *chan, long mask) | |
258 | { | |
259 | switch (mask) { | |
260 | case IIO_CHAN_INFO_SCALE: | |
261 | return IIO_VAL_INT_PLUS_NANO; | |
262 | case IIO_CHAN_INFO_SAMP_FREQ: | |
263 | return IIO_VAL_INT_PLUS_MICRO; | |
264 | default: | |
265 | return -EINVAL; | |
266 | } | |
267 | } | |
268 | ||
2816ac64 AC |
269 | static ssize_t mcp3422_show_samp_freqs(struct device *dev, |
270 | struct device_attribute *attr, char *buf) | |
271 | { | |
272 | struct mcp3422 *adc = iio_priv(dev_to_iio_dev(dev)); | |
273 | ||
274 | if (adc->id > 4) | |
275 | return sprintf(buf, "240 60 15\n"); | |
276 | ||
277 | return sprintf(buf, "240 60 15 3\n"); | |
278 | } | |
279 | ||
07914c84 AC |
280 | static ssize_t mcp3422_show_scales(struct device *dev, |
281 | struct device_attribute *attr, char *buf) | |
282 | { | |
283 | struct mcp3422 *adc = iio_priv(dev_to_iio_dev(dev)); | |
284 | u8 sample_rate = MCP3422_SAMPLE_RATE(adc->config); | |
285 | ||
286 | return sprintf(buf, "0.%09u 0.%09u 0.%09u 0.%09u\n", | |
287 | mcp3422_scales[sample_rate][0], | |
288 | mcp3422_scales[sample_rate][1], | |
289 | mcp3422_scales[sample_rate][2], | |
290 | mcp3422_scales[sample_rate][3]); | |
291 | } | |
292 | ||
2816ac64 AC |
293 | static IIO_DEVICE_ATTR(sampling_frequency_available, S_IRUGO, |
294 | mcp3422_show_samp_freqs, NULL, 0); | |
07914c84 AC |
295 | static IIO_DEVICE_ATTR(in_voltage_scale_available, S_IRUGO, |
296 | mcp3422_show_scales, NULL, 0); | |
297 | ||
298 | static struct attribute *mcp3422_attributes[] = { | |
2816ac64 | 299 | &iio_dev_attr_sampling_frequency_available.dev_attr.attr, |
07914c84 AC |
300 | &iio_dev_attr_in_voltage_scale_available.dev_attr.attr, |
301 | NULL, | |
302 | }; | |
303 | ||
304 | static const struct attribute_group mcp3422_attribute_group = { | |
305 | .attrs = mcp3422_attributes, | |
306 | }; | |
307 | ||
308 | static const struct iio_chan_spec mcp3422_channels[] = { | |
309 | MCP3422_CHAN(0), | |
310 | MCP3422_CHAN(1), | |
311 | }; | |
312 | ||
313 | static const struct iio_chan_spec mcp3424_channels[] = { | |
314 | MCP3422_CHAN(0), | |
315 | MCP3422_CHAN(1), | |
316 | MCP3422_CHAN(2), | |
317 | MCP3422_CHAN(3), | |
318 | }; | |
319 | ||
320 | static const struct iio_info mcp3422_info = { | |
321 | .read_raw = mcp3422_read_raw, | |
322 | .write_raw = mcp3422_write_raw, | |
323 | .write_raw_get_fmt = mcp3422_write_raw_get_fmt, | |
324 | .attrs = &mcp3422_attribute_group, | |
325 | .driver_module = THIS_MODULE, | |
326 | }; | |
327 | ||
328 | static int mcp3422_probe(struct i2c_client *client, | |
329 | const struct i2c_device_id *id) | |
330 | { | |
331 | struct iio_dev *indio_dev; | |
332 | struct mcp3422 *adc; | |
333 | int err; | |
334 | u8 config; | |
335 | ||
336 | if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) | |
337 | return -ENODEV; | |
338 | ||
339 | indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*adc)); | |
340 | if (!indio_dev) | |
341 | return -ENOMEM; | |
342 | ||
343 | adc = iio_priv(indio_dev); | |
344 | adc->i2c = client; | |
2816ac64 | 345 | adc->id = (u8)(id->driver_data); |
07914c84 AC |
346 | |
347 | mutex_init(&adc->lock); | |
348 | ||
349 | indio_dev->dev.parent = &client->dev; | |
350 | indio_dev->name = dev_name(&client->dev); | |
351 | indio_dev->modes = INDIO_DIRECT_MODE; | |
352 | indio_dev->info = &mcp3422_info; | |
353 | ||
2816ac64 | 354 | switch (adc->id) { |
07914c84 AC |
355 | case 2: |
356 | case 3: | |
2816ac64 AC |
357 | case 6: |
358 | case 7: | |
07914c84 AC |
359 | indio_dev->channels = mcp3422_channels; |
360 | indio_dev->num_channels = ARRAY_SIZE(mcp3422_channels); | |
361 | break; | |
362 | case 4: | |
2816ac64 | 363 | case 8: |
07914c84 AC |
364 | indio_dev->channels = mcp3424_channels; |
365 | indio_dev->num_channels = ARRAY_SIZE(mcp3424_channels); | |
366 | break; | |
367 | } | |
368 | ||
369 | /* meaningful default configuration */ | |
370 | config = (MCP3422_CONT_SAMPLING | |
371 | | MCP3422_CHANNEL_VALUE(1) | |
372 | | MCP3422_PGA_VALUE(MCP3422_PGA_1) | |
373 | | MCP3422_SAMPLE_RATE_VALUE(MCP3422_SRATE_240)); | |
374 | mcp3422_update_config(adc, config); | |
375 | ||
2842d4cc | 376 | err = devm_iio_device_register(&client->dev, indio_dev); |
07914c84 AC |
377 | if (err < 0) |
378 | return err; | |
379 | ||
380 | i2c_set_clientdata(client, indio_dev); | |
381 | ||
382 | return 0; | |
383 | } | |
384 | ||
07914c84 AC |
385 | static const struct i2c_device_id mcp3422_id[] = { |
386 | { "mcp3422", 2 }, | |
387 | { "mcp3423", 3 }, | |
388 | { "mcp3424", 4 }, | |
2816ac64 AC |
389 | { "mcp3426", 6 }, |
390 | { "mcp3427", 7 }, | |
391 | { "mcp3428", 8 }, | |
07914c84 AC |
392 | { } |
393 | }; | |
394 | MODULE_DEVICE_TABLE(i2c, mcp3422_id); | |
395 | ||
396 | #ifdef CONFIG_OF | |
397 | static const struct of_device_id mcp3422_of_match[] = { | |
398 | { .compatible = "mcp3422" }, | |
399 | { } | |
400 | }; | |
401 | MODULE_DEVICE_TABLE(of, mcp3422_of_match); | |
402 | #endif | |
403 | ||
404 | static struct i2c_driver mcp3422_driver = { | |
405 | .driver = { | |
406 | .name = "mcp3422", | |
07914c84 AC |
407 | .of_match_table = of_match_ptr(mcp3422_of_match), |
408 | }, | |
409 | .probe = mcp3422_probe, | |
07914c84 AC |
410 | .id_table = mcp3422_id, |
411 | }; | |
412 | module_i2c_driver(mcp3422_driver); | |
413 | ||
414 | MODULE_AUTHOR("Angelo Compagnucci <angelo.compagnucci@gmail.com>"); | |
2816ac64 | 415 | MODULE_DESCRIPTION("Microchip mcp3422/3/4/6/7/8 driver"); |
07914c84 | 416 | MODULE_LICENSE("GPL v2"); |