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>
23 * AD7746 Register Definition
26 #define AD7746_REG_STATUS 0
27 #define AD7746_REG_CAP_DATA_HIGH 1
28 #define AD7746_REG_CAP_DATA_MID 2
29 #define AD7746_REG_CAP_DATA_LOW 3
30 #define AD7746_REG_VT_DATA_HIGH 4
31 #define AD7746_REG_VT_DATA_MID 5
32 #define AD7746_REG_VT_DATA_LOW 6
33 #define AD7746_REG_CAP_SETUP 7
34 #define AD7746_REG_VT_SETUP 8
35 #define AD7746_REG_EXC_SETUP 9
36 #define AD7746_REG_CFG 10
37 #define AD7746_REG_CAPDACA 11
38 #define AD7746_REG_CAPDACB 12
39 #define AD7746_REG_CAP_OFFH 13
40 #define AD7746_REG_CAP_OFFL 14
41 #define AD7746_REG_CAP_GAINH 15
42 #define AD7746_REG_CAP_GAINL 16
43 #define AD7746_REG_VOLT_GAINH 17
44 #define AD7746_REG_VOLT_GAINL 18
46 /* Status Register Bit Designations (AD7746_REG_STATUS) */
47 #define AD7746_STATUS_EXCERR (1 << 3)
48 #define AD7746_STATUS_RDY (1 << 2)
49 #define AD7746_STATUS_RDYVT (1 << 1)
50 #define AD7746_STATUS_RDYCAP (1 << 0)
52 /* Capacitive Channel Setup Register Bit Designations (AD7746_REG_CAP_SETUP) */
53 #define AD7746_CAPSETUP_CAPEN (1 << 7)
54 #define AD7746_CAPSETUP_CIN2 (1 << 6) /* AD7746 only */
55 #define AD7746_CAPSETUP_CAPDIFF (1 << 5)
56 #define AD7746_CAPSETUP_CACHOP (1 << 0)
58 /* Voltage/Temperature Setup Register Bit Designations (AD7746_REG_VT_SETUP) */
59 #define AD7746_VTSETUP_VTEN (1 << 7)
60 #define AD7746_VTSETUP_VTMD_INT_TEMP (0 << 5)
61 #define AD7746_VTSETUP_VTMD_EXT_TEMP (1 << 5)
62 #define AD7746_VTSETUP_VTMD_VDD_MON (2 << 5)
63 #define AD7746_VTSETUP_VTMD_EXT_VIN (3 << 5)
64 #define AD7746_VTSETUP_EXTREF (1 << 4)
65 #define AD7746_VTSETUP_VTSHORT (1 << 1)
66 #define AD7746_VTSETUP_VTCHOP (1 << 0)
68 /* Excitation Setup Register Bit Designations (AD7746_REG_EXC_SETUP) */
69 #define AD7746_EXCSETUP_CLKCTRL (1 << 7)
70 #define AD7746_EXCSETUP_EXCON (1 << 6)
71 #define AD7746_EXCSETUP_EXCB (1 << 5)
72 #define AD7746_EXCSETUP_NEXCB (1 << 4)
73 #define AD7746_EXCSETUP_EXCA (1 << 3)
74 #define AD7746_EXCSETUP_NEXCA (1 << 2)
75 #define AD7746_EXCSETUP_EXCLVL(x) (((x) & 0x3) << 0)
77 /* Config Register Bit Designations (AD7746_REG_CFG) */
78 #define AD7746_CONF_VTFS(x) ((x) << 6)
79 #define AD7746_CONF_CAPFS(x) ((x) << 3)
80 #define AD7746_CONF_MODE_IDLE (0 << 0)
81 #define AD7746_CONF_MODE_CONT_CONV (1 << 0)
82 #define AD7746_CONF_MODE_SINGLE_CONV (2 << 0)
83 #define AD7746_CONF_MODE_PWRDN (3 << 0)
84 #define AD7746_CONF_MODE_OFFS_CAL (5 << 0)
85 #define AD7746_CONF_MODE_GAIN_CAL (6 << 0)
87 /* CAPDAC Register Bit Designations (AD7746_REG_CAPDACx) */
88 #define AD7746_CAPDAC_DACEN (1 << 7)
89 #define AD7746_CAPDAC_DACP(x) ((x) & 0x7F)
92 * struct ad7746_chip_info - chip specifc information
95 struct ad7746_chip_info {
96 struct i2c_client *client;
98 * Capacitive channel digital filter setup;
99 * conversion time/update rate setup per channel
119 static const struct iio_chan_spec ad7746_channels[] = {
124 .info_mask = (1 << IIO_CHAN_INFO_SCALE_SHARED),
125 .address = AD7746_REG_VT_DATA_HIGH << 8 |
126 AD7746_VTSETUP_VTMD_EXT_VIN,
132 .extend_name = "supply",
133 .info_mask = (1 << IIO_CHAN_INFO_SCALE_SHARED),
134 .address = AD7746_REG_VT_DATA_HIGH << 8 |
135 AD7746_VTSETUP_VTMD_VDD_MON,
141 .processed_val = IIO_PROCESSED,
142 .address = AD7746_REG_VT_DATA_HIGH << 8 |
143 AD7746_VTSETUP_VTMD_INT_TEMP,
149 .processed_val = IIO_PROCESSED,
150 .address = AD7746_REG_VT_DATA_HIGH << 8 |
151 AD7746_VTSETUP_VTMD_EXT_TEMP,
154 .type = IIO_CAPACITANCE,
157 .info_mask = (1 << IIO_CHAN_INFO_CALIBSCALE_SEPARATE) |
158 (1 << IIO_CHAN_INFO_CALIBBIAS_SHARED) |
159 (1 << IIO_CHAN_INFO_OFFSET_SEPARATE) |
160 (1 << IIO_CHAN_INFO_SCALE_SHARED),
161 .address = AD7746_REG_CAP_DATA_HIGH << 8,
164 .type = IIO_CAPACITANCE,
169 .info_mask = (1 << IIO_CHAN_INFO_CALIBSCALE_SEPARATE) |
170 (1 << IIO_CHAN_INFO_CALIBBIAS_SHARED) |
171 (1 << IIO_CHAN_INFO_OFFSET_SEPARATE) |
172 (1 << IIO_CHAN_INFO_SCALE_SHARED),
173 .address = AD7746_REG_CAP_DATA_HIGH << 8 |
174 AD7746_CAPSETUP_CAPDIFF
177 .type = IIO_CAPACITANCE,
180 .info_mask = (1 << IIO_CHAN_INFO_CALIBSCALE_SEPARATE) |
181 (1 << IIO_CHAN_INFO_CALIBBIAS_SHARED) |
182 (1 << IIO_CHAN_INFO_OFFSET_SEPARATE) |
183 (1 << IIO_CHAN_INFO_SCALE_SHARED),
184 .address = AD7746_REG_CAP_DATA_HIGH << 8 |
185 AD7746_CAPSETUP_CIN2,
188 .type = IIO_CAPACITANCE,
193 .info_mask = (1 << IIO_CHAN_INFO_CALIBSCALE_SEPARATE) |
194 (1 << IIO_CHAN_INFO_CALIBBIAS_SHARED) |
195 (1 << IIO_CHAN_INFO_OFFSET_SEPARATE) |
196 (1 << IIO_CHAN_INFO_SCALE_SHARED),
197 .address = AD7746_REG_CAP_DATA_HIGH << 8 |
198 AD7746_CAPSETUP_CAPDIFF | AD7746_CAPSETUP_CIN2,
202 /* Values are Update Rate (Hz), Conversion Time (ms) + 1*/
203 static const unsigned char ad7746_vt_filter_rate_table[][2] = {
204 {50, 20 + 1}, {31, 32 + 1}, {16, 62 + 1}, {8, 122 + 1},
207 static const unsigned char ad7746_cap_filter_rate_table[][2] = {
208 {91, 11 + 1}, {84, 12 + 1}, {50, 20 + 1}, {26, 38 + 1},
209 {16, 62 + 1}, {13, 77 + 1}, {11, 92 + 1}, {9, 110 + 1},
212 static int ad7746_select_channel(struct iio_dev *indio_dev,
213 struct iio_chan_spec const *chan)
215 struct ad7746_chip_info *chip = iio_priv(indio_dev);
217 u8 vt_setup, cap_setup;
219 switch (chan->type) {
220 case IIO_CAPACITANCE:
221 cap_setup = (chan->address & 0xFF) | AD7746_CAPSETUP_CAPEN;
222 vt_setup = chip->vt_setup & ~AD7746_VTSETUP_VTEN;
223 delay = ad7746_cap_filter_rate_table[(chip->config >> 3) &
226 if (chip->capdac_set != chan->channel) {
227 ret = i2c_smbus_write_byte_data(chip->client,
229 chip->capdac[chan->channel][0]);
232 ret = i2c_smbus_write_byte_data(chip->client,
234 chip->capdac[chan->channel][1]);
238 chip->capdac_set = chan->channel;
243 vt_setup = (chan->address & 0xFF) | AD7746_VTSETUP_VTEN;
244 cap_setup = chip->cap_setup & ~AD7746_CAPSETUP_CAPEN;
245 delay = ad7746_cap_filter_rate_table[(chip->config >> 6) &
252 if (chip->cap_setup != cap_setup) {
253 ret = i2c_smbus_write_byte_data(chip->client,
254 AD7746_REG_CAP_SETUP,
259 chip->cap_setup = cap_setup;
262 if (chip->vt_setup != vt_setup) {
263 ret = i2c_smbus_write_byte_data(chip->client,
269 chip->vt_setup = vt_setup;
275 static inline ssize_t ad7746_start_calib(struct device *dev,
276 struct device_attribute *attr,
281 struct iio_dev *indio_dev = dev_get_drvdata(dev);
282 struct ad7746_chip_info *chip = iio_priv(indio_dev);
284 int ret, timeout = 10;
286 ret = strtobool(buf, &doit);
293 mutex_lock(&indio_dev->mlock);
294 regval |= chip->config;
295 ret = i2c_smbus_write_byte_data(chip->client, AD7746_REG_CFG, regval);
297 mutex_unlock(&indio_dev->mlock);
303 ret = i2c_smbus_read_byte_data(chip->client, AD7746_REG_CFG);
305 mutex_unlock(&indio_dev->mlock);
308 } while ((ret == regval) && timeout--);
310 mutex_unlock(&indio_dev->mlock);
315 static ssize_t ad7746_start_offset_calib(struct device *dev,
316 struct device_attribute *attr,
320 struct iio_dev *indio_dev = dev_get_drvdata(dev);
321 int ret = ad7746_select_channel(indio_dev,
322 &ad7746_channels[to_iio_dev_attr(attr)->address]);
326 return ad7746_start_calib(dev, attr, buf, len,
327 AD7746_CONF_MODE_OFFS_CAL);
330 static ssize_t ad7746_start_gain_calib(struct device *dev,
331 struct device_attribute *attr,
335 struct iio_dev *indio_dev = dev_get_drvdata(dev);
336 int ret = ad7746_select_channel(indio_dev,
337 &ad7746_channels[to_iio_dev_attr(attr)->address]);
341 return ad7746_start_calib(dev, attr, buf, len,
342 AD7746_CONF_MODE_GAIN_CAL);
345 static IIO_DEVICE_ATTR(in_capacitance0_calibbias_calibration,
346 S_IWUSR, NULL, ad7746_start_offset_calib, CIN1);
347 static IIO_DEVICE_ATTR(in_capacitance1_calibbias_calibration,
348 S_IWUSR, NULL, ad7746_start_offset_calib, CIN2);
349 static IIO_DEVICE_ATTR(in_capacitance0_calibscale_calibration,
350 S_IWUSR, NULL, ad7746_start_gain_calib, CIN1);
351 static IIO_DEVICE_ATTR(in_capacitance1_calibscale_calibration,
352 S_IWUSR, NULL, ad7746_start_gain_calib, CIN2);
353 static IIO_DEVICE_ATTR(in_voltage0_calibscale_calibration,
354 S_IWUSR, NULL, ad7746_start_gain_calib, VIN);
356 static ssize_t ad7746_show_cap_filter_rate_setup(struct device *dev,
357 struct device_attribute *attr,
360 struct iio_dev *indio_dev = dev_get_drvdata(dev);
361 struct ad7746_chip_info *chip = iio_priv(indio_dev);
363 return sprintf(buf, "%d\n", ad7746_cap_filter_rate_table[
364 (chip->config >> 3) & 0x7][0]);
367 static ssize_t ad7746_store_cap_filter_rate_setup(struct device *dev,
368 struct device_attribute *attr,
372 struct iio_dev *indio_dev = dev_get_drvdata(dev);
373 struct ad7746_chip_info *chip = iio_priv(indio_dev);
377 ret = kstrtou8(buf, 10, &data);
381 for (i = 0; i < ARRAY_SIZE(ad7746_cap_filter_rate_table); i++)
382 if (data >= ad7746_cap_filter_rate_table[i][0])
385 if (i >= ARRAY_SIZE(ad7746_cap_filter_rate_table))
386 i = ARRAY_SIZE(ad7746_cap_filter_rate_table) - 1;
388 mutex_lock(&indio_dev->mlock);
389 chip->config &= ~AD7746_CONF_CAPFS(0x7);
390 chip->config |= AD7746_CONF_CAPFS(i);
391 mutex_unlock(&indio_dev->mlock);
396 static ssize_t ad7746_show_vt_filter_rate_setup(struct device *dev,
397 struct device_attribute *attr,
400 struct iio_dev *indio_dev = dev_get_drvdata(dev);
401 struct ad7746_chip_info *chip = iio_priv(indio_dev);
403 return sprintf(buf, "%d\n", ad7746_vt_filter_rate_table[
404 (chip->config >> 6) & 0x3][0]);
407 static ssize_t ad7746_store_vt_filter_rate_setup(struct device *dev,
408 struct device_attribute *attr,
412 struct iio_dev *indio_dev = dev_get_drvdata(dev);
413 struct ad7746_chip_info *chip = iio_priv(indio_dev);
417 ret = kstrtou8(buf, 10, &data);
421 for (i = 0; i < ARRAY_SIZE(ad7746_vt_filter_rate_table); i++)
422 if (data >= ad7746_vt_filter_rate_table[i][0])
425 if (i >= ARRAY_SIZE(ad7746_vt_filter_rate_table))
426 i = ARRAY_SIZE(ad7746_vt_filter_rate_table) - 1;
428 mutex_lock(&indio_dev->mlock);
429 chip->config &= ~AD7746_CONF_VTFS(0x3);
430 chip->config |= AD7746_CONF_VTFS(i);
431 mutex_unlock(&indio_dev->mlock);
436 static IIO_DEVICE_ATTR(in_capacitance_sampling_frequency,
437 S_IRUGO | S_IWUSR, ad7746_show_cap_filter_rate_setup,
438 ad7746_store_cap_filter_rate_setup, 0);
440 static IIO_DEVICE_ATTR(in_voltage_sampling_frequency,
441 S_IRUGO | S_IWUSR, ad7746_show_vt_filter_rate_setup,
442 ad7746_store_vt_filter_rate_setup, 0);
444 static IIO_CONST_ATTR(in_voltage_sampling_frequency_available, "50 31 16 8");
445 static IIO_CONST_ATTR(in_capacitance_sampling_frequency_available,
446 "91 84 50 26 16 13 11 9");
448 static struct attribute *ad7746_attributes[] = {
449 &iio_dev_attr_in_capacitance_sampling_frequency.dev_attr.attr,
450 &iio_dev_attr_in_voltage_sampling_frequency.dev_attr.attr,
451 &iio_dev_attr_in_capacitance0_calibbias_calibration.dev_attr.attr,
452 &iio_dev_attr_in_capacitance0_calibscale_calibration.dev_attr.attr,
453 &iio_dev_attr_in_capacitance1_calibscale_calibration.dev_attr.attr,
454 &iio_dev_attr_in_capacitance1_calibbias_calibration.dev_attr.attr,
455 &iio_dev_attr_in_voltage0_calibscale_calibration.dev_attr.attr,
456 &iio_const_attr_in_voltage_sampling_frequency_available.dev_attr.attr,
457 &iio_const_attr_in_capacitance_sampling_frequency_available.
462 static const struct attribute_group ad7746_attribute_group = {
463 .attrs = ad7746_attributes,
466 static int ad7746_write_raw(struct iio_dev *indio_dev,
467 struct iio_chan_spec const *chan,
472 struct ad7746_chip_info *chip = iio_priv(indio_dev);
475 mutex_lock(&indio_dev->mlock);
478 case (1 << IIO_CHAN_INFO_CALIBSCALE_SEPARATE):
484 val = (val2 * 1024) / 15625;
486 switch (chan->type) {
487 case IIO_CAPACITANCE:
488 reg = AD7746_REG_CAP_GAINH;
491 reg = AD7746_REG_VOLT_GAINH;
498 ret = i2c_smbus_write_word_data(chip->client, reg, swab16(val));
504 case (1 << IIO_CHAN_INFO_CALIBBIAS_SHARED):
505 if ((val < 0) | (val > 0xFFFF)) {
509 ret = i2c_smbus_write_word_data(chip->client,
510 AD7746_REG_CAP_OFFH, swab16(val));
516 case (1 << IIO_CHAN_INFO_OFFSET_SEPARATE):
517 if ((val < 0) | (val > 43008000)) { /* 21pF */
522 /* CAPDAC Scale = 21pF_typ / 127
523 * CIN Scale = 8.192pF / 2^24
524 * Offset Scale = CAPDAC Scale / CIN Scale = 338646
529 chip->capdac[chan->channel][chan->differential] = (val > 0 ?
530 AD7746_CAPDAC_DACP(val) | AD7746_CAPDAC_DACEN : 0);
532 ret = i2c_smbus_write_byte_data(chip->client,
534 chip->capdac[chan->channel][0]);
537 ret = i2c_smbus_write_byte_data(chip->client,
539 chip->capdac[chan->channel][1]);
543 chip->capdac_set = chan->channel;
552 mutex_unlock(&indio_dev->mlock);
556 static int ad7746_read_raw(struct iio_dev *indio_dev,
557 struct iio_chan_spec const *chan,
561 struct ad7746_chip_info *chip = iio_priv(indio_dev);
570 mutex_lock(&indio_dev->mlock);
574 ret = ad7746_select_channel(indio_dev, chan);
579 regval = chip->config | AD7746_CONF_MODE_SINGLE_CONV;
580 ret = i2c_smbus_write_byte_data(chip->client, AD7746_REG_CFG,
586 /* Now read the actual register */
588 ret = i2c_smbus_read_i2c_block_data(chip->client,
589 chan->address >> 8, 3, &data.d8[1]);
594 *val = (be32_to_cpu(data.d32) & 0xFFFFFF) - 0x800000;
596 switch (chan->type) {
598 /* temperature in milli degrees Celsius
599 * T = ((*val / 2048) - 4096) * 1000
601 *val = (*val * 125) / 256;
604 if (chan->channel == 1) /* supply_raw*/
613 case (1 << IIO_CHAN_INFO_CALIBSCALE_SEPARATE):
614 switch (chan->type) {
615 case IIO_CAPACITANCE:
616 reg = AD7746_REG_CAP_GAINH;
619 reg = AD7746_REG_VOLT_GAINH;
626 ret = i2c_smbus_read_word_data(chip->client, reg);
629 /* 1 + gain_val / 2^16 */
631 *val2 = (15625 * swab16(ret)) / 1024;
633 ret = IIO_VAL_INT_PLUS_MICRO;
635 case (1 << IIO_CHAN_INFO_CALIBBIAS_SHARED):
636 ret = i2c_smbus_read_word_data(chip->client,
637 AD7746_REG_CAP_OFFH);
644 case (1 << IIO_CHAN_INFO_OFFSET_SEPARATE):
645 *val = AD7746_CAPDAC_DACP(chip->capdac[chan->channel]
646 [chan->differential]) * 338646;
650 case (1 << IIO_CHAN_INFO_SCALE_SHARED):
651 switch (chan->type) {
652 case IIO_CAPACITANCE:
667 ret = IIO_VAL_INT_PLUS_NANO;
673 mutex_unlock(&indio_dev->mlock);
677 static const struct iio_info ad7746_info = {
678 .attrs = &ad7746_attribute_group,
679 .read_raw = &ad7746_read_raw,
680 .write_raw = &ad7746_write_raw,
681 .driver_module = THIS_MODULE,
685 * device probe and remove
688 static int __devinit ad7746_probe(struct i2c_client *client,
689 const struct i2c_device_id *id)
691 struct ad7746_platform_data *pdata = client->dev.platform_data;
692 struct ad7746_chip_info *chip;
693 struct iio_dev *indio_dev;
695 unsigned char regval = 0;
697 indio_dev = iio_allocate_device(sizeof(*chip));
698 if (indio_dev == NULL) {
702 chip = iio_priv(indio_dev);
703 /* this is only used for device removal purposes */
704 i2c_set_clientdata(client, indio_dev);
706 chip->client = client;
707 chip->capdac_set = -1;
709 /* Establish that the iio_dev is a child of the i2c device */
710 indio_dev->name = id->name;
711 indio_dev->dev.parent = &client->dev;
712 indio_dev->info = &ad7746_info;
713 indio_dev->channels = ad7746_channels;
714 if (id->driver_data == 7746)
715 indio_dev->num_channels = ARRAY_SIZE(ad7746_channels);
717 indio_dev->num_channels = ARRAY_SIZE(ad7746_channels) - 2;
718 indio_dev->num_channels = ARRAY_SIZE(ad7746_channels);
719 indio_dev->modes = INDIO_DIRECT_MODE;
722 if (pdata->exca_en) {
723 if (pdata->exca_inv_en)
724 regval |= AD7746_EXCSETUP_NEXCA;
726 regval |= AD7746_EXCSETUP_EXCA;
729 if (pdata->excb_en) {
730 if (pdata->excb_inv_en)
731 regval |= AD7746_EXCSETUP_NEXCB;
733 regval |= AD7746_EXCSETUP_EXCB;
736 regval |= AD7746_EXCSETUP_EXCLVL(pdata->exclvl);
738 dev_warn(&client->dev, "No platform data? using default\n");
739 regval = AD7746_EXCSETUP_EXCA | AD7746_EXCSETUP_EXCB |
740 AD7746_EXCSETUP_EXCLVL(3);
743 ret = i2c_smbus_write_byte_data(chip->client,
744 AD7746_REG_EXC_SETUP, regval);
748 ret = iio_device_register(indio_dev);
752 dev_info(&client->dev, "%s capacitive sensor registered\n", id->name);
757 iio_free_device(indio_dev);
762 static int __devexit ad7746_remove(struct i2c_client *client)
764 struct iio_dev *indio_dev = i2c_get_clientdata(client);
766 iio_device_unregister(indio_dev);
771 static const struct i2c_device_id ad7746_id[] = {
778 MODULE_DEVICE_TABLE(i2c, ad7746_id);
780 static struct i2c_driver ad7746_driver = {
782 .name = KBUILD_MODNAME,
784 .probe = ad7746_probe,
785 .remove = __devexit_p(ad7746_remove),
786 .id_table = ad7746_id,
789 static __init int ad7746_init(void)
791 return i2c_add_driver(&ad7746_driver);
794 static __exit void ad7746_exit(void)
796 i2c_del_driver(&ad7746_driver);
799 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
800 MODULE_DESCRIPTION("Analog Devices AD7746/5/7 capacitive sensor driver");
801 MODULE_LICENSE("GPL v2");
803 module_init(ad7746_init);
804 module_exit(ad7746_exit);