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);