2 * mcp3422.c - driver for the Microchip mcp3422/3/4 chip family
4 * Copyright (C) 2013, Angelo Compagnucci
5 * Author: Angelo Compagnucci <angelo.compagnucci@gmail.com>
7 * Datasheet: http://ww1.microchip.com/downloads/en/devicedoc/22088b.pdf
9 * This driver exports the value of analog input voltage to sysfs, the
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; either version 2 of the License, or
15 * (at your option) any later version.
18 #include <linux/err.h>
19 #include <linux/i2c.h>
20 #include <linux/module.h>
21 #include <linux/delay.h>
22 #include <linux/sysfs.h>
24 #include <linux/iio/iio.h>
25 #include <linux/iio/sysfs.h>
28 #define MCP3422_CHANNEL_MASK 0x60
29 #define MCP3422_PGA_MASK 0x03
30 #define MCP3422_SRATE_MASK 0x0C
31 #define MCP3422_SRATE_240 0x0
32 #define MCP3422_SRATE_60 0x1
33 #define MCP3422_SRATE_15 0x2
34 #define MCP3422_SRATE_3 0x3
35 #define MCP3422_PGA_1 0
36 #define MCP3422_PGA_2 1
37 #define MCP3422_PGA_4 2
38 #define MCP3422_PGA_8 3
39 #define MCP3422_CONT_SAMPLING 0x10
41 #define MCP3422_CHANNEL(config) (((config) & MCP3422_CHANNEL_MASK) >> 5)
42 #define MCP3422_PGA(config) ((config) & MCP3422_PGA_MASK)
43 #define MCP3422_SAMPLE_RATE(config) (((config) & MCP3422_SRATE_MASK) >> 2)
45 #define MCP3422_CHANNEL_VALUE(value) (((value) << 5) & MCP3422_CHANNEL_MASK)
46 #define MCP3422_PGA_VALUE(value) ((value) & MCP3422_PGA_MASK)
47 #define MCP3422_SAMPLE_RATE_VALUE(value) ((value << 2) & MCP3422_SRATE_MASK)
49 #define MCP3422_CHAN(_index) \
51 .type = IIO_VOLTAGE, \
54 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) \
55 | BIT(IIO_CHAN_INFO_SCALE), \
56 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
59 /* LSB is in nV to eliminate floating point */
60 static const u32 rates_to_lsb[] = {1000000, 250000, 62500, 15625};
63 * scales calculated as:
64 * rates_to_lsb[sample_rate] / (1 << pga);
68 static const int mcp3422_scales[4][4] = {
69 { 1000000, 250000, 62500, 15625 },
70 { 500000 , 125000, 31250, 7812 },
71 { 250000 , 62500 , 15625, 3906 },
72 { 125000 , 31250 , 7812 , 1953 } };
74 /* Constant msleep times for data acquisitions */
75 static const int mcp3422_read_times[4] = {
76 [MCP3422_SRATE_240] = 1000 / 240,
77 [MCP3422_SRATE_60] = 1000 / 60,
78 [MCP3422_SRATE_15] = 1000 / 15,
79 [MCP3422_SRATE_3] = 1000 / 3 };
81 /* sample rates to integer conversion table */
82 static const int mcp3422_sample_rates[4] = {
83 [MCP3422_SRATE_240] = 240,
84 [MCP3422_SRATE_60] = 60,
85 [MCP3422_SRATE_15] = 15,
86 [MCP3422_SRATE_3] = 3 };
88 /* sample rates to sign extension table */
89 static const int mcp3422_sign_extend[4] = {
90 [MCP3422_SRATE_240] = 12,
91 [MCP3422_SRATE_60] = 14,
92 [MCP3422_SRATE_15] = 16,
93 [MCP3422_SRATE_3] = 18 };
95 /* Client data (each client gets its own) */
97 struct i2c_client *i2c;
103 static int mcp3422_update_config(struct mcp3422 *adc, u8 newconfig)
107 mutex_lock(&adc->lock);
109 ret = i2c_master_send(adc->i2c, &newconfig, 1);
111 adc->config = newconfig;
115 mutex_unlock(&adc->lock);
120 static int mcp3422_read(struct mcp3422 *adc, int *value, u8 *config)
123 u8 sample_rate = MCP3422_SAMPLE_RATE(adc->config);
124 u8 buf[4] = {0, 0, 0, 0};
127 if (sample_rate == MCP3422_SRATE_3) {
128 ret = i2c_master_recv(adc->i2c, buf, 4);
129 temp = buf[0] << 16 | buf[1] << 8 | buf[2];
132 ret = i2c_master_recv(adc->i2c, buf, 3);
133 temp = buf[0] << 8 | buf[1];
137 *value = sign_extend32(temp, mcp3422_sign_extend[sample_rate]);
142 static int mcp3422_read_channel(struct mcp3422 *adc,
143 struct iio_chan_spec const *channel, int *value)
147 u8 req_channel = channel->channel;
149 if (req_channel != MCP3422_CHANNEL(adc->config)) {
150 config = adc->config;
151 config &= ~MCP3422_CHANNEL_MASK;
152 config |= MCP3422_CHANNEL_VALUE(req_channel);
153 config &= ~MCP3422_PGA_MASK;
154 config |= MCP3422_PGA_VALUE(adc->pga[req_channel]);
155 ret = mcp3422_update_config(adc, config);
158 msleep(mcp3422_read_times[MCP3422_SAMPLE_RATE(adc->config)]);
161 return mcp3422_read(adc, value, &config);
164 static int mcp3422_read_raw(struct iio_dev *iio,
165 struct iio_chan_spec const *channel, int *val1,
166 int *val2, long mask)
168 struct mcp3422 *adc = iio_priv(iio);
171 u8 sample_rate = MCP3422_SAMPLE_RATE(adc->config);
172 u8 pga = MCP3422_PGA(adc->config);
175 case IIO_CHAN_INFO_RAW:
176 err = mcp3422_read_channel(adc, channel, val1);
181 case IIO_CHAN_INFO_SCALE:
184 *val2 = mcp3422_scales[sample_rate][pga];
185 return IIO_VAL_INT_PLUS_NANO;
187 case IIO_CHAN_INFO_SAMP_FREQ:
188 *val1 = mcp3422_sample_rates[MCP3422_SAMPLE_RATE(adc->config)];
198 static int mcp3422_write_raw(struct iio_dev *iio,
199 struct iio_chan_spec const *channel, int val1,
202 struct mcp3422 *adc = iio_priv(iio);
204 u8 config = adc->config;
205 u8 req_channel = channel->channel;
206 u8 sample_rate = MCP3422_SAMPLE_RATE(config);
210 case IIO_CHAN_INFO_SCALE:
214 for (i = 0; i < ARRAY_SIZE(mcp3422_scales[0]); i++) {
215 if (val2 == mcp3422_scales[sample_rate][i]) {
216 adc->pga[req_channel] = i;
218 config &= ~MCP3422_CHANNEL_MASK;
219 config |= MCP3422_CHANNEL_VALUE(req_channel);
220 config &= ~MCP3422_PGA_MASK;
221 config |= MCP3422_PGA_VALUE(adc->pga[req_channel]);
223 return mcp3422_update_config(adc, config);
228 case IIO_CHAN_INFO_SAMP_FREQ:
231 temp = MCP3422_SRATE_240;
234 temp = MCP3422_SRATE_60;
237 temp = MCP3422_SRATE_15;
240 temp = MCP3422_SRATE_3;
246 config &= ~MCP3422_CHANNEL_MASK;
247 config |= MCP3422_CHANNEL_VALUE(req_channel);
248 config &= ~MCP3422_SRATE_MASK;
249 config |= MCP3422_SAMPLE_RATE_VALUE(temp);
251 return mcp3422_update_config(adc, config);
260 static int mcp3422_write_raw_get_fmt(struct iio_dev *indio_dev,
261 struct iio_chan_spec const *chan, long mask)
264 case IIO_CHAN_INFO_SCALE:
265 return IIO_VAL_INT_PLUS_NANO;
266 case IIO_CHAN_INFO_SAMP_FREQ:
267 return IIO_VAL_INT_PLUS_MICRO;
273 static ssize_t mcp3422_show_scales(struct device *dev,
274 struct device_attribute *attr, char *buf)
276 struct mcp3422 *adc = iio_priv(dev_to_iio_dev(dev));
277 u8 sample_rate = MCP3422_SAMPLE_RATE(adc->config);
279 return sprintf(buf, "0.%09u 0.%09u 0.%09u 0.%09u\n",
280 mcp3422_scales[sample_rate][0],
281 mcp3422_scales[sample_rate][1],
282 mcp3422_scales[sample_rate][2],
283 mcp3422_scales[sample_rate][3]);
286 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("240 60 15 3");
287 static IIO_DEVICE_ATTR(in_voltage_scale_available, S_IRUGO,
288 mcp3422_show_scales, NULL, 0);
290 static struct attribute *mcp3422_attributes[] = {
291 &iio_const_attr_sampling_frequency_available.dev_attr.attr,
292 &iio_dev_attr_in_voltage_scale_available.dev_attr.attr,
296 static const struct attribute_group mcp3422_attribute_group = {
297 .attrs = mcp3422_attributes,
300 static const struct iio_chan_spec mcp3422_channels[] = {
305 static const struct iio_chan_spec mcp3424_channels[] = {
312 static const struct iio_info mcp3422_info = {
313 .read_raw = mcp3422_read_raw,
314 .write_raw = mcp3422_write_raw,
315 .write_raw_get_fmt = mcp3422_write_raw_get_fmt,
316 .attrs = &mcp3422_attribute_group,
317 .driver_module = THIS_MODULE,
320 static int mcp3422_probe(struct i2c_client *client,
321 const struct i2c_device_id *id)
323 struct iio_dev *indio_dev;
328 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
331 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*adc));
335 adc = iio_priv(indio_dev);
338 mutex_init(&adc->lock);
340 indio_dev->dev.parent = &client->dev;
341 indio_dev->name = dev_name(&client->dev);
342 indio_dev->modes = INDIO_DIRECT_MODE;
343 indio_dev->info = &mcp3422_info;
345 switch ((unsigned int)(id->driver_data)) {
348 indio_dev->channels = mcp3422_channels;
349 indio_dev->num_channels = ARRAY_SIZE(mcp3422_channels);
352 indio_dev->channels = mcp3424_channels;
353 indio_dev->num_channels = ARRAY_SIZE(mcp3424_channels);
357 /* meaningful default configuration */
358 config = (MCP3422_CONT_SAMPLING
359 | MCP3422_CHANNEL_VALUE(1)
360 | MCP3422_PGA_VALUE(MCP3422_PGA_1)
361 | MCP3422_SAMPLE_RATE_VALUE(MCP3422_SRATE_240));
362 mcp3422_update_config(adc, config);
364 err = iio_device_register(indio_dev);
368 i2c_set_clientdata(client, indio_dev);
373 static int mcp3422_remove(struct i2c_client *client)
375 iio_device_unregister(i2c_get_clientdata(client));
379 static const struct i2c_device_id mcp3422_id[] = {
385 MODULE_DEVICE_TABLE(i2c, mcp3422_id);
388 static const struct of_device_id mcp3422_of_match[] = {
389 { .compatible = "mcp3422" },
392 MODULE_DEVICE_TABLE(of, mcp3422_of_match);
395 static struct i2c_driver mcp3422_driver = {
398 .owner = THIS_MODULE,
399 .of_match_table = of_match_ptr(mcp3422_of_match),
401 .probe = mcp3422_probe,
402 .remove = mcp3422_remove,
403 .id_table = mcp3422_id,
405 module_i2c_driver(mcp3422_driver);
407 MODULE_AUTHOR("Angelo Compagnucci <angelo.compagnucci@gmail.com>");
408 MODULE_DESCRIPTION("Microchip mcp3422/3/4 driver");
409 MODULE_LICENSE("GPL v2");