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>
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 = (1 << IIO_CHAN_INFO_SCALE_SHARED),
127 .address = AD7746_REG_VT_DATA_HIGH << 8 |
128 AD7746_VTSETUP_VTMD_EXT_VIN,
134 .extend_name = "supply",
135 .info_mask = (1 << IIO_CHAN_INFO_SCALE_SHARED),
136 .address = AD7746_REG_VT_DATA_HIGH << 8 |
137 AD7746_VTSETUP_VTMD_VDD_MON,
143 .processed_val = IIO_PROCESSED,
144 .address = AD7746_REG_VT_DATA_HIGH << 8 |
145 AD7746_VTSETUP_VTMD_INT_TEMP,
151 .processed_val = IIO_PROCESSED,
152 .address = AD7746_REG_VT_DATA_HIGH << 8 |
153 AD7746_VTSETUP_VTMD_EXT_TEMP,
156 .type = IIO_CAPACITANCE,
159 .info_mask = (1 << IIO_CHAN_INFO_CALIBSCALE_SEPARATE) |
160 (1 << IIO_CHAN_INFO_CALIBBIAS_SHARED) |
161 (1 << IIO_CHAN_INFO_OFFSET_SEPARATE) |
162 (1 << IIO_CHAN_INFO_SCALE_SHARED),
163 .address = AD7746_REG_CAP_DATA_HIGH << 8,
166 .type = IIO_CAPACITANCE,
171 .info_mask = (1 << IIO_CHAN_INFO_CALIBSCALE_SEPARATE) |
172 (1 << IIO_CHAN_INFO_CALIBBIAS_SHARED) |
173 (1 << IIO_CHAN_INFO_OFFSET_SEPARATE) |
174 (1 << IIO_CHAN_INFO_SCALE_SHARED),
175 .address = AD7746_REG_CAP_DATA_HIGH << 8 |
176 AD7746_CAPSETUP_CAPDIFF
179 .type = IIO_CAPACITANCE,
182 .info_mask = (1 << IIO_CHAN_INFO_CALIBSCALE_SEPARATE) |
183 (1 << IIO_CHAN_INFO_CALIBBIAS_SHARED) |
184 (1 << IIO_CHAN_INFO_OFFSET_SEPARATE) |
185 (1 << IIO_CHAN_INFO_SCALE_SHARED),
186 .address = AD7746_REG_CAP_DATA_HIGH << 8 |
187 AD7746_CAPSETUP_CIN2,
190 .type = IIO_CAPACITANCE,
195 .info_mask = (1 << IIO_CHAN_INFO_CALIBSCALE_SEPARATE) |
196 (1 << IIO_CHAN_INFO_CALIBBIAS_SHARED) |
197 (1 << IIO_CHAN_INFO_OFFSET_SEPARATE) |
198 (1 << IIO_CHAN_INFO_SCALE_SHARED),
199 .address = AD7746_REG_CAP_DATA_HIGH << 8 |
200 AD7746_CAPSETUP_CAPDIFF | AD7746_CAPSETUP_CIN2,
204 /* Values are Update Rate (Hz), Conversion Time (ms) + 1*/
205 static const unsigned char ad7746_vt_filter_rate_table[][2] = {
206 {50, 20 + 1}, {31, 32 + 1}, {16, 62 + 1}, {8, 122 + 1},
209 static const unsigned char ad7746_cap_filter_rate_table[][2] = {
210 {91, 11 + 1}, {84, 12 + 1}, {50, 20 + 1}, {26, 38 + 1},
211 {16, 62 + 1}, {13, 77 + 1}, {11, 92 + 1}, {9, 110 + 1},
214 static int ad7746_select_channel(struct iio_dev *indio_dev,
215 struct iio_chan_spec const *chan)
217 struct ad7746_chip_info *chip = iio_priv(indio_dev);
219 u8 vt_setup, cap_setup;
221 switch (chan->type) {
222 case IIO_CAPACITANCE:
223 cap_setup = (chan->address & 0xFF) | AD7746_CAPSETUP_CAPEN;
224 vt_setup = chip->vt_setup & ~AD7746_VTSETUP_VTEN;
225 delay = ad7746_cap_filter_rate_table[(chip->config >> 3) &
228 if (chip->capdac_set != chan->channel) {
229 ret = i2c_smbus_write_byte_data(chip->client,
231 chip->capdac[chan->channel][0]);
234 ret = i2c_smbus_write_byte_data(chip->client,
236 chip->capdac[chan->channel][1]);
240 chip->capdac_set = chan->channel;
245 vt_setup = (chan->address & 0xFF) | AD7746_VTSETUP_VTEN;
246 cap_setup = chip->cap_setup & ~AD7746_CAPSETUP_CAPEN;
247 delay = ad7746_cap_filter_rate_table[(chip->config >> 6) &
254 if (chip->cap_setup != cap_setup) {
255 ret = i2c_smbus_write_byte_data(chip->client,
256 AD7746_REG_CAP_SETUP,
261 chip->cap_setup = cap_setup;
264 if (chip->vt_setup != vt_setup) {
265 ret = i2c_smbus_write_byte_data(chip->client,
271 chip->vt_setup = vt_setup;
277 static inline ssize_t ad7746_start_calib(struct device *dev,
278 struct device_attribute *attr,
283 struct iio_dev *indio_dev = dev_get_drvdata(dev);
284 struct ad7746_chip_info *chip = iio_priv(indio_dev);
286 int ret, timeout = 10;
288 ret = strtobool(buf, &doit);
295 mutex_lock(&indio_dev->mlock);
296 regval |= chip->config;
297 ret = i2c_smbus_write_byte_data(chip->client, AD7746_REG_CFG, regval);
299 mutex_unlock(&indio_dev->mlock);
305 ret = i2c_smbus_read_byte_data(chip->client, AD7746_REG_CFG);
307 mutex_unlock(&indio_dev->mlock);
310 } while ((ret == regval) && timeout--);
312 mutex_unlock(&indio_dev->mlock);
317 static ssize_t ad7746_start_offset_calib(struct device *dev,
318 struct device_attribute *attr,
322 struct iio_dev *indio_dev = dev_get_drvdata(dev);
323 int ret = ad7746_select_channel(indio_dev,
324 &ad7746_channels[to_iio_dev_attr(attr)->address]);
328 return ad7746_start_calib(dev, attr, buf, len,
329 AD7746_CONF_MODE_OFFS_CAL);
332 static ssize_t ad7746_start_gain_calib(struct device *dev,
333 struct device_attribute *attr,
337 struct iio_dev *indio_dev = dev_get_drvdata(dev);
338 int ret = ad7746_select_channel(indio_dev,
339 &ad7746_channels[to_iio_dev_attr(attr)->address]);
343 return ad7746_start_calib(dev, attr, buf, len,
344 AD7746_CONF_MODE_GAIN_CAL);
347 static IIO_DEVICE_ATTR(in_capacitance0_calibbias_calibration,
348 S_IWUSR, NULL, ad7746_start_offset_calib, CIN1);
349 static IIO_DEVICE_ATTR(in_capacitance1_calibbias_calibration,
350 S_IWUSR, NULL, ad7746_start_offset_calib, CIN2);
351 static IIO_DEVICE_ATTR(in_capacitance0_calibscale_calibration,
352 S_IWUSR, NULL, ad7746_start_gain_calib, CIN1);
353 static IIO_DEVICE_ATTR(in_capacitance1_calibscale_calibration,
354 S_IWUSR, NULL, ad7746_start_gain_calib, CIN2);
355 static IIO_DEVICE_ATTR(in_voltage0_calibscale_calibration,
356 S_IWUSR, NULL, ad7746_start_gain_calib, VIN);
358 static ssize_t ad7746_show_cap_filter_rate_setup(struct device *dev,
359 struct device_attribute *attr,
362 struct iio_dev *indio_dev = dev_get_drvdata(dev);
363 struct ad7746_chip_info *chip = iio_priv(indio_dev);
365 return sprintf(buf, "%d\n", ad7746_cap_filter_rate_table[
366 (chip->config >> 3) & 0x7][0]);
369 static ssize_t ad7746_store_cap_filter_rate_setup(struct device *dev,
370 struct device_attribute *attr,
374 struct iio_dev *indio_dev = dev_get_drvdata(dev);
375 struct ad7746_chip_info *chip = iio_priv(indio_dev);
379 ret = kstrtou8(buf, 10, &data);
383 for (i = 0; i < ARRAY_SIZE(ad7746_cap_filter_rate_table); i++)
384 if (data >= ad7746_cap_filter_rate_table[i][0])
387 if (i >= ARRAY_SIZE(ad7746_cap_filter_rate_table))
388 i = ARRAY_SIZE(ad7746_cap_filter_rate_table) - 1;
390 mutex_lock(&indio_dev->mlock);
391 chip->config &= ~AD7746_CONF_CAPFS(0x7);
392 chip->config |= AD7746_CONF_CAPFS(i);
393 mutex_unlock(&indio_dev->mlock);
398 static ssize_t ad7746_show_vt_filter_rate_setup(struct device *dev,
399 struct device_attribute *attr,
402 struct iio_dev *indio_dev = dev_get_drvdata(dev);
403 struct ad7746_chip_info *chip = iio_priv(indio_dev);
405 return sprintf(buf, "%d\n", ad7746_vt_filter_rate_table[
406 (chip->config >> 6) & 0x3][0]);
409 static ssize_t ad7746_store_vt_filter_rate_setup(struct device *dev,
410 struct device_attribute *attr,
414 struct iio_dev *indio_dev = dev_get_drvdata(dev);
415 struct ad7746_chip_info *chip = iio_priv(indio_dev);
419 ret = kstrtou8(buf, 10, &data);
423 for (i = 0; i < ARRAY_SIZE(ad7746_vt_filter_rate_table); i++)
424 if (data >= ad7746_vt_filter_rate_table[i][0])
427 if (i >= ARRAY_SIZE(ad7746_vt_filter_rate_table))
428 i = ARRAY_SIZE(ad7746_vt_filter_rate_table) - 1;
430 mutex_lock(&indio_dev->mlock);
431 chip->config &= ~AD7746_CONF_VTFS(0x3);
432 chip->config |= AD7746_CONF_VTFS(i);
433 mutex_unlock(&indio_dev->mlock);
438 static IIO_DEVICE_ATTR(in_capacitance_sampling_frequency,
439 S_IRUGO | S_IWUSR, ad7746_show_cap_filter_rate_setup,
440 ad7746_store_cap_filter_rate_setup, 0);
442 static IIO_DEVICE_ATTR(in_voltage_sampling_frequency,
443 S_IRUGO | S_IWUSR, ad7746_show_vt_filter_rate_setup,
444 ad7746_store_vt_filter_rate_setup, 0);
446 static IIO_CONST_ATTR(in_voltage_sampling_frequency_available, "50 31 16 8");
447 static IIO_CONST_ATTR(in_capacitance_sampling_frequency_available,
448 "91 84 50 26 16 13 11 9");
450 static struct attribute *ad7746_attributes[] = {
451 &iio_dev_attr_in_capacitance_sampling_frequency.dev_attr.attr,
452 &iio_dev_attr_in_voltage_sampling_frequency.dev_attr.attr,
453 &iio_dev_attr_in_capacitance0_calibbias_calibration.dev_attr.attr,
454 &iio_dev_attr_in_capacitance0_calibscale_calibration.dev_attr.attr,
455 &iio_dev_attr_in_capacitance1_calibscale_calibration.dev_attr.attr,
456 &iio_dev_attr_in_capacitance1_calibbias_calibration.dev_attr.attr,
457 &iio_dev_attr_in_voltage0_calibscale_calibration.dev_attr.attr,
458 &iio_const_attr_in_voltage_sampling_frequency_available.dev_attr.attr,
459 &iio_const_attr_in_capacitance_sampling_frequency_available.
464 static const struct attribute_group ad7746_attribute_group = {
465 .attrs = ad7746_attributes,
468 static int ad7746_write_raw(struct iio_dev *indio_dev,
469 struct iio_chan_spec const *chan,
474 struct ad7746_chip_info *chip = iio_priv(indio_dev);
477 mutex_lock(&indio_dev->mlock);
480 case (1 << IIO_CHAN_INFO_CALIBSCALE_SEPARATE):
486 val = (val2 * 1024) / 15625;
488 switch (chan->type) {
489 case IIO_CAPACITANCE:
490 reg = AD7746_REG_CAP_GAINH;
493 reg = AD7746_REG_VOLT_GAINH;
500 ret = i2c_smbus_write_word_data(chip->client, reg, swab16(val));
506 case (1 << IIO_CHAN_INFO_CALIBBIAS_SHARED):
507 if ((val < 0) | (val > 0xFFFF)) {
511 ret = i2c_smbus_write_word_data(chip->client,
512 AD7746_REG_CAP_OFFH, swab16(val));
518 case (1 << IIO_CHAN_INFO_OFFSET_SEPARATE):
519 if ((val < 0) | (val > 43008000)) { /* 21pF */
524 /* CAPDAC Scale = 21pF_typ / 127
525 * CIN Scale = 8.192pF / 2^24
526 * Offset Scale = CAPDAC Scale / CIN Scale = 338646
531 chip->capdac[chan->channel][chan->differential] = (val > 0 ?
532 AD7746_CAPDAC_DACP(val) | AD7746_CAPDAC_DACEN : 0);
534 ret = i2c_smbus_write_byte_data(chip->client,
536 chip->capdac[chan->channel][0]);
539 ret = i2c_smbus_write_byte_data(chip->client,
541 chip->capdac[chan->channel][1]);
545 chip->capdac_set = chan->channel;
554 mutex_unlock(&indio_dev->mlock);
558 static int ad7746_read_raw(struct iio_dev *indio_dev,
559 struct iio_chan_spec const *chan,
563 struct ad7746_chip_info *chip = iio_priv(indio_dev);
572 mutex_lock(&indio_dev->mlock);
576 ret = ad7746_select_channel(indio_dev, chan);
581 regval = chip->config | AD7746_CONF_MODE_SINGLE_CONV;
582 ret = i2c_smbus_write_byte_data(chip->client, AD7746_REG_CFG,
588 /* Now read the actual register */
590 ret = i2c_smbus_read_i2c_block_data(chip->client,
591 chan->address >> 8, 3, &data.d8[1]);
596 *val = (be32_to_cpu(data.d32) & 0xFFFFFF) - 0x800000;
598 switch (chan->type) {
600 /* temperature in milli degrees Celsius
601 * T = ((*val / 2048) - 4096) * 1000
603 *val = (*val * 125) / 256;
606 if (chan->channel == 1) /* supply_raw*/
615 case (1 << IIO_CHAN_INFO_CALIBSCALE_SEPARATE):
616 switch (chan->type) {
617 case IIO_CAPACITANCE:
618 reg = AD7746_REG_CAP_GAINH;
621 reg = AD7746_REG_VOLT_GAINH;
628 ret = i2c_smbus_read_word_data(chip->client, reg);
631 /* 1 + gain_val / 2^16 */
633 *val2 = (15625 * swab16(ret)) / 1024;
635 ret = IIO_VAL_INT_PLUS_MICRO;
637 case (1 << IIO_CHAN_INFO_CALIBBIAS_SHARED):
638 ret = i2c_smbus_read_word_data(chip->client,
639 AD7746_REG_CAP_OFFH);
646 case (1 << IIO_CHAN_INFO_OFFSET_SEPARATE):
647 *val = AD7746_CAPDAC_DACP(chip->capdac[chan->channel]
648 [chan->differential]) * 338646;
652 case (1 << IIO_CHAN_INFO_SCALE_SHARED):
653 switch (chan->type) {
654 case IIO_CAPACITANCE:
669 ret = IIO_VAL_INT_PLUS_NANO;
675 mutex_unlock(&indio_dev->mlock);
679 static const struct iio_info ad7746_info = {
680 .attrs = &ad7746_attribute_group,
681 .read_raw = &ad7746_read_raw,
682 .write_raw = &ad7746_write_raw,
683 .driver_module = THIS_MODULE,
687 * device probe and remove
690 static int __devinit ad7746_probe(struct i2c_client *client,
691 const struct i2c_device_id *id)
693 struct ad7746_platform_data *pdata = client->dev.platform_data;
694 struct ad7746_chip_info *chip;
695 struct iio_dev *indio_dev;
697 unsigned char regval = 0;
699 indio_dev = iio_allocate_device(sizeof(*chip));
700 if (indio_dev == NULL) {
704 chip = iio_priv(indio_dev);
705 /* this is only used for device removal purposes */
706 i2c_set_clientdata(client, indio_dev);
708 chip->client = client;
709 chip->capdac_set = -1;
711 /* Establish that the iio_dev is a child of the i2c device */
712 indio_dev->name = id->name;
713 indio_dev->dev.parent = &client->dev;
714 indio_dev->info = &ad7746_info;
715 indio_dev->channels = ad7746_channels;
716 if (id->driver_data == 7746)
717 indio_dev->num_channels = ARRAY_SIZE(ad7746_channels);
719 indio_dev->num_channels = ARRAY_SIZE(ad7746_channels) - 2;
720 indio_dev->num_channels = ARRAY_SIZE(ad7746_channels);
721 indio_dev->modes = INDIO_DIRECT_MODE;
724 if (pdata->exca_en) {
725 if (pdata->exca_inv_en)
726 regval |= AD7746_EXCSETUP_NEXCA;
728 regval |= AD7746_EXCSETUP_EXCA;
731 if (pdata->excb_en) {
732 if (pdata->excb_inv_en)
733 regval |= AD7746_EXCSETUP_NEXCB;
735 regval |= AD7746_EXCSETUP_EXCB;
738 regval |= AD7746_EXCSETUP_EXCLVL(pdata->exclvl);
740 dev_warn(&client->dev, "No platform data? using default\n");
741 regval = AD7746_EXCSETUP_EXCA | AD7746_EXCSETUP_EXCB |
742 AD7746_EXCSETUP_EXCLVL(3);
745 ret = i2c_smbus_write_byte_data(chip->client,
746 AD7746_REG_EXC_SETUP, regval);
750 ret = iio_device_register(indio_dev);
754 dev_info(&client->dev, "%s capacitive sensor registered\n", id->name);
759 iio_free_device(indio_dev);
764 static int __devexit ad7746_remove(struct i2c_client *client)
766 struct iio_dev *indio_dev = i2c_get_clientdata(client);
768 iio_device_unregister(indio_dev);
769 iio_free_device(indio_dev);
774 static const struct i2c_device_id ad7746_id[] = {
781 MODULE_DEVICE_TABLE(i2c, ad7746_id);
783 static struct i2c_driver ad7746_driver = {
785 .name = KBUILD_MODNAME,
787 .probe = ad7746_probe,
788 .remove = __devexit_p(ad7746_remove),
789 .id_table = ad7746_id,
792 static __init int ad7746_init(void)
794 return i2c_add_driver(&ad7746_driver);
797 static __exit void ad7746_exit(void)
799 i2c_del_driver(&ad7746_driver);
802 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
803 MODULE_DESCRIPTION("Analog Devices AD7746/5/7 capacitive sensor driver");
804 MODULE_LICENSE("GPL v2");
806 module_init(ad7746_init);
807 module_exit(ad7746_exit);