2 * AD7746 capacitive sensor driver supporting AD7745, AD7746 and AD7747
4 * Copyright 2011 Analog Devices Inc.
6 * Licensed under the GPL-2.
9 #include <linux/interrupt.h>
10 #include <linux/device.h>
11 #include <linux/kernel.h>
12 #include <linux/slab.h>
13 #include <linux/sysfs.h>
14 #include <linux/i2c.h>
15 #include <linux/delay.h>
16 #include <linux/module.h>
17 #include <linux/stat.h>
19 #include <linux/iio/iio.h>
20 #include <linux/iio/sysfs.h>
25 * AD7746 Register Definition
28 #define AD7746_REG_STATUS 0
29 #define AD7746_REG_CAP_DATA_HIGH 1
30 #define AD7746_REG_CAP_DATA_MID 2
31 #define AD7746_REG_CAP_DATA_LOW 3
32 #define AD7746_REG_VT_DATA_HIGH 4
33 #define AD7746_REG_VT_DATA_MID 5
34 #define AD7746_REG_VT_DATA_LOW 6
35 #define AD7746_REG_CAP_SETUP 7
36 #define AD7746_REG_VT_SETUP 8
37 #define AD7746_REG_EXC_SETUP 9
38 #define AD7746_REG_CFG 10
39 #define AD7746_REG_CAPDACA 11
40 #define AD7746_REG_CAPDACB 12
41 #define AD7746_REG_CAP_OFFH 13
42 #define AD7746_REG_CAP_OFFL 14
43 #define AD7746_REG_CAP_GAINH 15
44 #define AD7746_REG_CAP_GAINL 16
45 #define AD7746_REG_VOLT_GAINH 17
46 #define AD7746_REG_VOLT_GAINL 18
48 /* Status Register Bit Designations (AD7746_REG_STATUS) */
49 #define AD7746_STATUS_EXCERR (1 << 3)
50 #define AD7746_STATUS_RDY (1 << 2)
51 #define AD7746_STATUS_RDYVT (1 << 1)
52 #define AD7746_STATUS_RDYCAP (1 << 0)
54 /* Capacitive Channel Setup Register Bit Designations (AD7746_REG_CAP_SETUP) */
55 #define AD7746_CAPSETUP_CAPEN (1 << 7)
56 #define AD7746_CAPSETUP_CIN2 (1 << 6) /* AD7746 only */
57 #define AD7746_CAPSETUP_CAPDIFF (1 << 5)
58 #define AD7746_CAPSETUP_CACHOP (1 << 0)
60 /* Voltage/Temperature Setup Register Bit Designations (AD7746_REG_VT_SETUP) */
61 #define AD7746_VTSETUP_VTEN (1 << 7)
62 #define AD7746_VTSETUP_VTMD_INT_TEMP (0 << 5)
63 #define AD7746_VTSETUP_VTMD_EXT_TEMP (1 << 5)
64 #define AD7746_VTSETUP_VTMD_VDD_MON (2 << 5)
65 #define AD7746_VTSETUP_VTMD_EXT_VIN (3 << 5)
66 #define AD7746_VTSETUP_EXTREF (1 << 4)
67 #define AD7746_VTSETUP_VTSHORT (1 << 1)
68 #define AD7746_VTSETUP_VTCHOP (1 << 0)
70 /* Excitation Setup Register Bit Designations (AD7746_REG_EXC_SETUP) */
71 #define AD7746_EXCSETUP_CLKCTRL (1 << 7)
72 #define AD7746_EXCSETUP_EXCON (1 << 6)
73 #define AD7746_EXCSETUP_EXCB (1 << 5)
74 #define AD7746_EXCSETUP_NEXCB (1 << 4)
75 #define AD7746_EXCSETUP_EXCA (1 << 3)
76 #define AD7746_EXCSETUP_NEXCA (1 << 2)
77 #define AD7746_EXCSETUP_EXCLVL(x) (((x) & 0x3) << 0)
79 /* Config Register Bit Designations (AD7746_REG_CFG) */
80 #define AD7746_CONF_VTFS(x) ((x) << 6)
81 #define AD7746_CONF_CAPFS(x) ((x) << 3)
82 #define AD7746_CONF_MODE_IDLE (0 << 0)
83 #define AD7746_CONF_MODE_CONT_CONV (1 << 0)
84 #define AD7746_CONF_MODE_SINGLE_CONV (2 << 0)
85 #define AD7746_CONF_MODE_PWRDN (3 << 0)
86 #define AD7746_CONF_MODE_OFFS_CAL (5 << 0)
87 #define AD7746_CONF_MODE_GAIN_CAL (6 << 0)
89 /* CAPDAC Register Bit Designations (AD7746_REG_CAPDACx) */
90 #define AD7746_CAPDAC_DACEN (1 << 7)
91 #define AD7746_CAPDAC_DACP(x) ((x) & 0x7F)
94 * struct ad7746_chip_info - chip specifc information
97 struct ad7746_chip_info {
98 struct i2c_client *client;
100 * Capacitive channel digital filter setup;
101 * conversion time/update rate setup per channel
121 static const struct iio_chan_spec ad7746_channels[] = {
126 .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |
127 IIO_CHAN_INFO_SCALE_SHARED_BIT,
128 .address = AD7746_REG_VT_DATA_HIGH << 8 |
129 AD7746_VTSETUP_VTMD_EXT_VIN,
135 .extend_name = "supply",
136 .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |
137 IIO_CHAN_INFO_SCALE_SHARED_BIT,
138 .address = AD7746_REG_VT_DATA_HIGH << 8 |
139 AD7746_VTSETUP_VTMD_VDD_MON,
145 .info_mask = IIO_CHAN_INFO_PROCESSED_SEPARATE_BIT,
146 .address = AD7746_REG_VT_DATA_HIGH << 8 |
147 AD7746_VTSETUP_VTMD_INT_TEMP,
153 .info_mask = IIO_CHAN_INFO_PROCESSED_SEPARATE_BIT,
154 .address = AD7746_REG_VT_DATA_HIGH << 8 |
155 AD7746_VTSETUP_VTMD_EXT_TEMP,
158 .type = IIO_CAPACITANCE,
161 .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |
162 IIO_CHAN_INFO_CALIBSCALE_SEPARATE_BIT |
163 IIO_CHAN_INFO_CALIBBIAS_SHARED_BIT |
164 IIO_CHAN_INFO_OFFSET_SEPARATE_BIT |
165 IIO_CHAN_INFO_SCALE_SHARED_BIT,
166 .address = AD7746_REG_CAP_DATA_HIGH << 8,
169 .type = IIO_CAPACITANCE,
174 .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |
175 IIO_CHAN_INFO_CALIBSCALE_SEPARATE_BIT |
176 IIO_CHAN_INFO_CALIBBIAS_SHARED_BIT |
177 IIO_CHAN_INFO_OFFSET_SEPARATE_BIT |
178 IIO_CHAN_INFO_SCALE_SHARED_BIT,
179 .address = AD7746_REG_CAP_DATA_HIGH << 8 |
180 AD7746_CAPSETUP_CAPDIFF
183 .type = IIO_CAPACITANCE,
186 .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |
187 IIO_CHAN_INFO_CALIBSCALE_SEPARATE_BIT |
188 IIO_CHAN_INFO_CALIBBIAS_SHARED_BIT |
189 IIO_CHAN_INFO_OFFSET_SEPARATE_BIT |
190 IIO_CHAN_INFO_SCALE_SHARED_BIT,
191 .address = AD7746_REG_CAP_DATA_HIGH << 8 |
192 AD7746_CAPSETUP_CIN2,
195 .type = IIO_CAPACITANCE,
200 .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |
201 IIO_CHAN_INFO_CALIBSCALE_SEPARATE_BIT |
202 IIO_CHAN_INFO_CALIBBIAS_SHARED_BIT |
203 IIO_CHAN_INFO_OFFSET_SEPARATE_BIT |
204 IIO_CHAN_INFO_SCALE_SHARED_BIT,
205 .address = AD7746_REG_CAP_DATA_HIGH << 8 |
206 AD7746_CAPSETUP_CAPDIFF | AD7746_CAPSETUP_CIN2,
210 /* Values are Update Rate (Hz), Conversion Time (ms) + 1*/
211 static const unsigned char ad7746_vt_filter_rate_table[][2] = {
212 {50, 20 + 1}, {31, 32 + 1}, {16, 62 + 1}, {8, 122 + 1},
215 static const unsigned char ad7746_cap_filter_rate_table[][2] = {
216 {91, 11 + 1}, {84, 12 + 1}, {50, 20 + 1}, {26, 38 + 1},
217 {16, 62 + 1}, {13, 77 + 1}, {11, 92 + 1}, {9, 110 + 1},
220 static int ad7746_select_channel(struct iio_dev *indio_dev,
221 struct iio_chan_spec const *chan)
223 struct ad7746_chip_info *chip = iio_priv(indio_dev);
225 u8 vt_setup, cap_setup;
227 switch (chan->type) {
228 case IIO_CAPACITANCE:
229 cap_setup = (chan->address & 0xFF) | AD7746_CAPSETUP_CAPEN;
230 vt_setup = chip->vt_setup & ~AD7746_VTSETUP_VTEN;
231 delay = ad7746_cap_filter_rate_table[(chip->config >> 3) &
234 if (chip->capdac_set != chan->channel) {
235 ret = i2c_smbus_write_byte_data(chip->client,
237 chip->capdac[chan->channel][0]);
240 ret = i2c_smbus_write_byte_data(chip->client,
242 chip->capdac[chan->channel][1]);
246 chip->capdac_set = chan->channel;
251 vt_setup = (chan->address & 0xFF) | AD7746_VTSETUP_VTEN;
252 cap_setup = chip->cap_setup & ~AD7746_CAPSETUP_CAPEN;
253 delay = ad7746_cap_filter_rate_table[(chip->config >> 6) &
260 if (chip->cap_setup != cap_setup) {
261 ret = i2c_smbus_write_byte_data(chip->client,
262 AD7746_REG_CAP_SETUP,
267 chip->cap_setup = cap_setup;
270 if (chip->vt_setup != vt_setup) {
271 ret = i2c_smbus_write_byte_data(chip->client,
277 chip->vt_setup = vt_setup;
283 static inline ssize_t ad7746_start_calib(struct device *dev,
284 struct device_attribute *attr,
289 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
290 struct ad7746_chip_info *chip = iio_priv(indio_dev);
292 int ret, timeout = 10;
294 ret = strtobool(buf, &doit);
301 mutex_lock(&indio_dev->mlock);
302 regval |= chip->config;
303 ret = i2c_smbus_write_byte_data(chip->client, AD7746_REG_CFG, regval);
305 mutex_unlock(&indio_dev->mlock);
311 ret = i2c_smbus_read_byte_data(chip->client, AD7746_REG_CFG);
313 mutex_unlock(&indio_dev->mlock);
316 } while ((ret == regval) && timeout--);
318 mutex_unlock(&indio_dev->mlock);
323 static ssize_t ad7746_start_offset_calib(struct device *dev,
324 struct device_attribute *attr,
328 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
329 int ret = ad7746_select_channel(indio_dev,
330 &ad7746_channels[to_iio_dev_attr(attr)->address]);
334 return ad7746_start_calib(dev, attr, buf, len,
335 AD7746_CONF_MODE_OFFS_CAL);
338 static ssize_t ad7746_start_gain_calib(struct device *dev,
339 struct device_attribute *attr,
343 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
344 int ret = ad7746_select_channel(indio_dev,
345 &ad7746_channels[to_iio_dev_attr(attr)->address]);
349 return ad7746_start_calib(dev, attr, buf, len,
350 AD7746_CONF_MODE_GAIN_CAL);
353 static IIO_DEVICE_ATTR(in_capacitance0_calibbias_calibration,
354 S_IWUSR, NULL, ad7746_start_offset_calib, CIN1);
355 static IIO_DEVICE_ATTR(in_capacitance1_calibbias_calibration,
356 S_IWUSR, NULL, ad7746_start_offset_calib, CIN2);
357 static IIO_DEVICE_ATTR(in_capacitance0_calibscale_calibration,
358 S_IWUSR, NULL, ad7746_start_gain_calib, CIN1);
359 static IIO_DEVICE_ATTR(in_capacitance1_calibscale_calibration,
360 S_IWUSR, NULL, ad7746_start_gain_calib, CIN2);
361 static IIO_DEVICE_ATTR(in_voltage0_calibscale_calibration,
362 S_IWUSR, NULL, ad7746_start_gain_calib, VIN);
364 static ssize_t ad7746_show_cap_filter_rate_setup(struct device *dev,
365 struct device_attribute *attr,
368 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
369 struct ad7746_chip_info *chip = iio_priv(indio_dev);
371 return sprintf(buf, "%d\n", ad7746_cap_filter_rate_table[
372 (chip->config >> 3) & 0x7][0]);
375 static ssize_t ad7746_store_cap_filter_rate_setup(struct device *dev,
376 struct device_attribute *attr,
380 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
381 struct ad7746_chip_info *chip = iio_priv(indio_dev);
385 ret = kstrtou8(buf, 10, &data);
389 for (i = 0; i < ARRAY_SIZE(ad7746_cap_filter_rate_table); i++)
390 if (data >= ad7746_cap_filter_rate_table[i][0])
393 if (i >= ARRAY_SIZE(ad7746_cap_filter_rate_table))
394 i = ARRAY_SIZE(ad7746_cap_filter_rate_table) - 1;
396 mutex_lock(&indio_dev->mlock);
397 chip->config &= ~AD7746_CONF_CAPFS(0x7);
398 chip->config |= AD7746_CONF_CAPFS(i);
399 mutex_unlock(&indio_dev->mlock);
404 static ssize_t ad7746_show_vt_filter_rate_setup(struct device *dev,
405 struct device_attribute *attr,
408 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
409 struct ad7746_chip_info *chip = iio_priv(indio_dev);
411 return sprintf(buf, "%d\n", ad7746_vt_filter_rate_table[
412 (chip->config >> 6) & 0x3][0]);
415 static ssize_t ad7746_store_vt_filter_rate_setup(struct device *dev,
416 struct device_attribute *attr,
420 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
421 struct ad7746_chip_info *chip = iio_priv(indio_dev);
425 ret = kstrtou8(buf, 10, &data);
429 for (i = 0; i < ARRAY_SIZE(ad7746_vt_filter_rate_table); i++)
430 if (data >= ad7746_vt_filter_rate_table[i][0])
433 if (i >= ARRAY_SIZE(ad7746_vt_filter_rate_table))
434 i = ARRAY_SIZE(ad7746_vt_filter_rate_table) - 1;
436 mutex_lock(&indio_dev->mlock);
437 chip->config &= ~AD7746_CONF_VTFS(0x3);
438 chip->config |= AD7746_CONF_VTFS(i);
439 mutex_unlock(&indio_dev->mlock);
444 static IIO_DEVICE_ATTR(in_capacitance_sampling_frequency,
445 S_IRUGO | S_IWUSR, ad7746_show_cap_filter_rate_setup,
446 ad7746_store_cap_filter_rate_setup, 0);
448 static IIO_DEVICE_ATTR(in_voltage_sampling_frequency,
449 S_IRUGO | S_IWUSR, ad7746_show_vt_filter_rate_setup,
450 ad7746_store_vt_filter_rate_setup, 0);
452 static IIO_CONST_ATTR(in_voltage_sampling_frequency_available, "50 31 16 8");
453 static IIO_CONST_ATTR(in_capacitance_sampling_frequency_available,
454 "91 84 50 26 16 13 11 9");
456 static struct attribute *ad7746_attributes[] = {
457 &iio_dev_attr_in_capacitance_sampling_frequency.dev_attr.attr,
458 &iio_dev_attr_in_voltage_sampling_frequency.dev_attr.attr,
459 &iio_dev_attr_in_capacitance0_calibbias_calibration.dev_attr.attr,
460 &iio_dev_attr_in_capacitance0_calibscale_calibration.dev_attr.attr,
461 &iio_dev_attr_in_capacitance1_calibscale_calibration.dev_attr.attr,
462 &iio_dev_attr_in_capacitance1_calibbias_calibration.dev_attr.attr,
463 &iio_dev_attr_in_voltage0_calibscale_calibration.dev_attr.attr,
464 &iio_const_attr_in_voltage_sampling_frequency_available.dev_attr.attr,
465 &iio_const_attr_in_capacitance_sampling_frequency_available.
470 static const struct attribute_group ad7746_attribute_group = {
471 .attrs = ad7746_attributes,
474 static int ad7746_write_raw(struct iio_dev *indio_dev,
475 struct iio_chan_spec const *chan,
480 struct ad7746_chip_info *chip = iio_priv(indio_dev);
483 mutex_lock(&indio_dev->mlock);
486 case IIO_CHAN_INFO_CALIBSCALE:
492 val = (val2 * 1024) / 15625;
494 switch (chan->type) {
495 case IIO_CAPACITANCE:
496 reg = AD7746_REG_CAP_GAINH;
499 reg = AD7746_REG_VOLT_GAINH;
506 ret = i2c_smbus_write_word_data(chip->client, reg, swab16(val));
512 case IIO_CHAN_INFO_CALIBBIAS:
513 if ((val < 0) | (val > 0xFFFF)) {
517 ret = i2c_smbus_write_word_data(chip->client,
518 AD7746_REG_CAP_OFFH, swab16(val));
524 case IIO_CHAN_INFO_OFFSET:
525 if ((val < 0) | (val > 43008000)) { /* 21pF */
530 /* CAPDAC Scale = 21pF_typ / 127
531 * CIN Scale = 8.192pF / 2^24
532 * Offset Scale = CAPDAC Scale / CIN Scale = 338646
537 chip->capdac[chan->channel][chan->differential] = (val > 0 ?
538 AD7746_CAPDAC_DACP(val) | AD7746_CAPDAC_DACEN : 0);
540 ret = i2c_smbus_write_byte_data(chip->client,
542 chip->capdac[chan->channel][0]);
545 ret = i2c_smbus_write_byte_data(chip->client,
547 chip->capdac[chan->channel][1]);
551 chip->capdac_set = chan->channel;
560 mutex_unlock(&indio_dev->mlock);
564 static int ad7746_read_raw(struct iio_dev *indio_dev,
565 struct iio_chan_spec const *chan,
569 struct ad7746_chip_info *chip = iio_priv(indio_dev);
578 mutex_lock(&indio_dev->mlock);
581 case IIO_CHAN_INFO_RAW:
582 case IIO_CHAN_INFO_PROCESSED:
583 ret = ad7746_select_channel(indio_dev, chan);
588 regval = chip->config | AD7746_CONF_MODE_SINGLE_CONV;
589 ret = i2c_smbus_write_byte_data(chip->client, AD7746_REG_CFG,
595 /* Now read the actual register */
597 ret = i2c_smbus_read_i2c_block_data(chip->client,
598 chan->address >> 8, 3, &data.d8[1]);
603 *val = (be32_to_cpu(data.d32) & 0xFFFFFF) - 0x800000;
605 switch (chan->type) {
607 /* temperature in milli degrees Celsius
608 * T = ((*val / 2048) - 4096) * 1000
610 *val = (*val * 125) / 256;
613 if (chan->channel == 1) /* supply_raw*/
622 case IIO_CHAN_INFO_CALIBSCALE:
623 switch (chan->type) {
624 case IIO_CAPACITANCE:
625 reg = AD7746_REG_CAP_GAINH;
628 reg = AD7746_REG_VOLT_GAINH;
635 ret = i2c_smbus_read_word_data(chip->client, reg);
638 /* 1 + gain_val / 2^16 */
640 *val2 = (15625 * swab16(ret)) / 1024;
642 ret = IIO_VAL_INT_PLUS_MICRO;
644 case IIO_CHAN_INFO_CALIBBIAS:
645 ret = i2c_smbus_read_word_data(chip->client,
646 AD7746_REG_CAP_OFFH);
653 case IIO_CHAN_INFO_OFFSET:
654 *val = AD7746_CAPDAC_DACP(chip->capdac[chan->channel]
655 [chan->differential]) * 338646;
659 case IIO_CHAN_INFO_SCALE:
660 switch (chan->type) {
661 case IIO_CAPACITANCE:
676 ret = IIO_VAL_INT_PLUS_NANO;
682 mutex_unlock(&indio_dev->mlock);
686 static const struct iio_info ad7746_info = {
687 .attrs = &ad7746_attribute_group,
688 .read_raw = &ad7746_read_raw,
689 .write_raw = &ad7746_write_raw,
690 .driver_module = THIS_MODULE,
694 * device probe and remove
697 static int __devinit ad7746_probe(struct i2c_client *client,
698 const struct i2c_device_id *id)
700 struct ad7746_platform_data *pdata = client->dev.platform_data;
701 struct ad7746_chip_info *chip;
702 struct iio_dev *indio_dev;
704 unsigned char regval = 0;
706 indio_dev = iio_device_alloc(sizeof(*chip));
707 if (indio_dev == NULL) {
711 chip = iio_priv(indio_dev);
712 /* this is only used for device removal purposes */
713 i2c_set_clientdata(client, indio_dev);
715 chip->client = client;
716 chip->capdac_set = -1;
718 /* Establish that the iio_dev is a child of the i2c device */
719 indio_dev->name = id->name;
720 indio_dev->dev.parent = &client->dev;
721 indio_dev->info = &ad7746_info;
722 indio_dev->channels = ad7746_channels;
723 if (id->driver_data == 7746)
724 indio_dev->num_channels = ARRAY_SIZE(ad7746_channels);
726 indio_dev->num_channels = ARRAY_SIZE(ad7746_channels) - 2;
727 indio_dev->num_channels = ARRAY_SIZE(ad7746_channels);
728 indio_dev->modes = INDIO_DIRECT_MODE;
731 if (pdata->exca_en) {
732 if (pdata->exca_inv_en)
733 regval |= AD7746_EXCSETUP_NEXCA;
735 regval |= AD7746_EXCSETUP_EXCA;
738 if (pdata->excb_en) {
739 if (pdata->excb_inv_en)
740 regval |= AD7746_EXCSETUP_NEXCB;
742 regval |= AD7746_EXCSETUP_EXCB;
745 regval |= AD7746_EXCSETUP_EXCLVL(pdata->exclvl);
747 dev_warn(&client->dev, "No platform data? using default\n");
748 regval = AD7746_EXCSETUP_EXCA | AD7746_EXCSETUP_EXCB |
749 AD7746_EXCSETUP_EXCLVL(3);
752 ret = i2c_smbus_write_byte_data(chip->client,
753 AD7746_REG_EXC_SETUP, regval);
757 ret = iio_device_register(indio_dev);
761 dev_info(&client->dev, "%s capacitive sensor registered\n", id->name);
766 iio_device_free(indio_dev);
771 static int __devexit ad7746_remove(struct i2c_client *client)
773 struct iio_dev *indio_dev = i2c_get_clientdata(client);
775 iio_device_unregister(indio_dev);
776 iio_device_free(indio_dev);
781 static const struct i2c_device_id ad7746_id[] = {
788 MODULE_DEVICE_TABLE(i2c, ad7746_id);
790 static struct i2c_driver ad7746_driver = {
792 .name = KBUILD_MODNAME,
794 .probe = ad7746_probe,
795 .remove = __devexit_p(ad7746_remove),
796 .id_table = ad7746_id,
798 module_i2c_driver(ad7746_driver);
800 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
801 MODULE_DESCRIPTION("Analog Devices AD7746/5/7 capacitive sensor driver");
802 MODULE_LICENSE("GPL v2");