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linux/drivers/iio/adc/ad7791.c
Lars-Peter Clausen 488a21827a iio:ad7791: Report scale as fractional value 
Move the complexity of calculating the fixed point scale to the core.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-01 16:19:12 +01:00

454 lines
12 KiB
C
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/*
* AD7787/AD7788/AD7789/AD7790/AD7791 SPI ADC driver
*
* Copyright 2012 Analog Devices Inc.
* Author: Lars-Peter Clausen <lars@metafoo.de>
*
* Licensed under the GPL-2.
*/
#include <linux/interrupt.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/sysfs.h>
#include <linux/spi/spi.h>
#include <linux/regulator/consumer.h>
#include <linux/err.h>
#include <linux/sched.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/buffer.h>
#include <linux/iio/trigger.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/iio/adc/ad_sigma_delta.h>
#include <linux/platform_data/ad7791.h>
#define AD7791_REG_COMM 0x0 /* For writes */
#define AD7791_REG_STATUS 0x0 /* For reads */
#define AD7791_REG_MODE 0x1
#define AD7791_REG_FILTER 0x2
#define AD7791_REG_DATA 0x3
#define AD7791_MODE_CONTINUOUS 0x00
#define AD7791_MODE_SINGLE 0x02
#define AD7791_MODE_POWERDOWN 0x03
#define AD7791_CH_AIN1P_AIN1N 0x00
#define AD7791_CH_AIN2 0x01
#define AD7791_CH_AIN1N_AIN1N 0x02
#define AD7791_CH_AVDD_MONITOR 0x03
#define AD7791_FILTER_CLK_DIV_1 (0x0 << 4)
#define AD7791_FILTER_CLK_DIV_2 (0x1 << 4)
#define AD7791_FILTER_CLK_DIV_4 (0x2 << 4)
#define AD7791_FILTER_CLK_DIV_8 (0x3 << 4)
#define AD7791_FILTER_CLK_MASK (0x3 << 4)
#define AD7791_FILTER_RATE_120 0x0
#define AD7791_FILTER_RATE_100 0x1
#define AD7791_FILTER_RATE_33_3 0x2
#define AD7791_FILTER_RATE_20 0x3
#define AD7791_FILTER_RATE_16_6 0x4
#define AD7791_FILTER_RATE_16_7 0x5
#define AD7791_FILTER_RATE_13_3 0x6
#define AD7791_FILTER_RATE_9_5 0x7
#define AD7791_FILTER_RATE_MASK 0x7
#define AD7791_MODE_BUFFER BIT(1)
#define AD7791_MODE_UNIPOLAR BIT(2)
#define AD7791_MODE_BURNOUT BIT(3)
#define AD7791_MODE_SEL_MASK (0x3 << 6)
#define AD7791_MODE_SEL(x) ((x) << 6)
#define DECLARE_AD7787_CHANNELS(name, bits, storagebits) \
const struct iio_chan_spec name[] = { \
AD_SD_DIFF_CHANNEL(0, 0, 0, AD7791_CH_AIN1P_AIN1N, \
(bits), (storagebits), 0), \
AD_SD_CHANNEL(1, 1, AD7791_CH_AIN2, (bits), (storagebits), 0), \
AD_SD_SHORTED_CHANNEL(2, 0, AD7791_CH_AIN1N_AIN1N, \
(bits), (storagebits), 0), \
AD_SD_SUPPLY_CHANNEL(3, 2, AD7791_CH_AVDD_MONITOR, \
(bits), (storagebits), 0), \
IIO_CHAN_SOFT_TIMESTAMP(4), \
}
#define DECLARE_AD7791_CHANNELS(name, bits, storagebits) \
const struct iio_chan_spec name[] = { \
AD_SD_DIFF_CHANNEL(0, 0, 0, AD7791_CH_AIN1P_AIN1N, \
(bits), (storagebits), 0), \
AD_SD_SHORTED_CHANNEL(1, 0, AD7791_CH_AIN1N_AIN1N, \
(bits), (storagebits), 0), \
AD_SD_SUPPLY_CHANNEL(2, 1, AD7791_CH_AVDD_MONITOR, \
(bits), (storagebits), 0), \
IIO_CHAN_SOFT_TIMESTAMP(3), \
}
static DECLARE_AD7787_CHANNELS(ad7787_channels, 24, 32);
static DECLARE_AD7791_CHANNELS(ad7790_channels, 16, 16);
static DECLARE_AD7791_CHANNELS(ad7791_channels, 24, 32);
enum {
AD7787,
AD7788,
AD7789,
AD7790,
AD7791,
};
enum ad7791_chip_info_flags {
AD7791_FLAG_HAS_FILTER = (1 << 0),
AD7791_FLAG_HAS_BUFFER = (1 << 1),
AD7791_FLAG_HAS_UNIPOLAR = (1 << 2),
AD7791_FLAG_HAS_BURNOUT = (1 << 3),
};
struct ad7791_chip_info {
const struct iio_chan_spec *channels;
unsigned int num_channels;
enum ad7791_chip_info_flags flags;
};
static const struct ad7791_chip_info ad7791_chip_infos[] = {
[AD7787] = {
.channels = ad7787_channels,
.num_channels = ARRAY_SIZE(ad7787_channels),
.flags = AD7791_FLAG_HAS_FILTER | AD7791_FLAG_HAS_BUFFER |
AD7791_FLAG_HAS_UNIPOLAR | AD7791_FLAG_HAS_BURNOUT,
},
[AD7788] = {
.channels = ad7790_channels,
.num_channels = ARRAY_SIZE(ad7790_channels),
.flags = AD7791_FLAG_HAS_UNIPOLAR,
},
[AD7789] = {
.channels = ad7791_channels,
.num_channels = ARRAY_SIZE(ad7791_channels),
.flags = AD7791_FLAG_HAS_UNIPOLAR,
},
[AD7790] = {
.channels = ad7790_channels,
.num_channels = ARRAY_SIZE(ad7790_channels),
.flags = AD7791_FLAG_HAS_FILTER | AD7791_FLAG_HAS_BUFFER |
AD7791_FLAG_HAS_BURNOUT,
},
[AD7791] = {
.channels = ad7791_channels,
.num_channels = ARRAY_SIZE(ad7791_channels),
.flags = AD7791_FLAG_HAS_FILTER | AD7791_FLAG_HAS_BUFFER |
AD7791_FLAG_HAS_UNIPOLAR | AD7791_FLAG_HAS_BURNOUT,
},
};
struct ad7791_state {
struct ad_sigma_delta sd;
uint8_t mode;
uint8_t filter;
struct regulator *reg;
const struct ad7791_chip_info *info;
};
static struct ad7791_state *ad_sigma_delta_to_ad7791(struct ad_sigma_delta *sd)
{
return container_of(sd, struct ad7791_state, sd);
}
static int ad7791_set_channel(struct ad_sigma_delta *sd, unsigned int channel)
{
ad_sd_set_comm(sd, channel);
return 0;
}
static int ad7791_set_mode(struct ad_sigma_delta *sd,
enum ad_sigma_delta_mode mode)
{
struct ad7791_state *st = ad_sigma_delta_to_ad7791(sd);
switch (mode) {
case AD_SD_MODE_CONTINUOUS:
mode = AD7791_MODE_CONTINUOUS;
break;
case AD_SD_MODE_SINGLE:
mode = AD7791_MODE_SINGLE;
break;
case AD_SD_MODE_IDLE:
case AD_SD_MODE_POWERDOWN:
mode = AD7791_MODE_POWERDOWN;
break;
}
st->mode &= ~AD7791_MODE_SEL_MASK;
st->mode |= AD7791_MODE_SEL(mode);
return ad_sd_write_reg(sd, AD7791_REG_MODE, sizeof(st->mode), st->mode);
}
static const struct ad_sigma_delta_info ad7791_sigma_delta_info = {
.set_channel = ad7791_set_channel,
.set_mode = ad7791_set_mode,
.has_registers = true,
.addr_shift = 4,
.read_mask = BIT(3),
};
static int ad7791_read_raw(struct iio_dev *indio_dev,
const struct iio_chan_spec *chan, int *val, int *val2, long info)
{
struct ad7791_state *st = iio_priv(indio_dev);
bool unipolar = !!(st->mode & AD7791_MODE_UNIPOLAR);
switch (info) {
case IIO_CHAN_INFO_RAW:
return ad_sigma_delta_single_conversion(indio_dev, chan, val);
case IIO_CHAN_INFO_OFFSET:
/**
* Unipolar: 0 to VREF
* Bipolar -VREF to VREF
**/
if (unipolar)
*val = 0;
else
*val = -(1 << (chan->scan_type.realbits - 1));
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
/* The monitor channel uses an internal reference. */
if (chan->address == AD7791_CH_AVDD_MONITOR) {
/*
* The signal is attenuated by a factor of 5 and
* compared against a 1.17V internal reference.
*/
*val = 1170 * 5;
} else {
int voltage_uv;
voltage_uv = regulator_get_voltage(st->reg);
if (voltage_uv < 0)
return voltage_uv;
*val = voltage_uv / 1000;
}
if (unipolar)
*val2 = chan->scan_type.realbits;
else
*val2 = chan->scan_type.realbits - 1;
return IIO_VAL_FRACTIONAL_LOG2;
}
return -EINVAL;
}
static const char * const ad7791_sample_freq_avail[] = {
[AD7791_FILTER_RATE_120] = "120",
[AD7791_FILTER_RATE_100] = "100",
[AD7791_FILTER_RATE_33_3] = "33.3",
[AD7791_FILTER_RATE_20] = "20",
[AD7791_FILTER_RATE_16_6] = "16.6",
[AD7791_FILTER_RATE_16_7] = "16.7",
[AD7791_FILTER_RATE_13_3] = "13.3",
[AD7791_FILTER_RATE_9_5] = "9.5",
};
static ssize_t ad7791_read_frequency(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct ad7791_state *st = iio_priv(indio_dev);
unsigned int rate = st->filter & AD7791_FILTER_RATE_MASK;
return sprintf(buf, "%s\n", ad7791_sample_freq_avail[rate]);
}
static ssize_t ad7791_write_frequency(struct device *dev,
struct device_attribute *attr, const char *buf, size_t len)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct ad7791_state *st = iio_priv(indio_dev);
int i, ret;
mutex_lock(&indio_dev->mlock);
if (iio_buffer_enabled(indio_dev)) {
mutex_unlock(&indio_dev->mlock);
return -EBUSY;
}
mutex_unlock(&indio_dev->mlock);
ret = -EINVAL;
for (i = 0; i < ARRAY_SIZE(ad7791_sample_freq_avail); i++) {
if (sysfs_streq(ad7791_sample_freq_avail[i], buf)) {
mutex_lock(&indio_dev->mlock);
st->filter &= ~AD7791_FILTER_RATE_MASK;
st->filter |= i;
ad_sd_write_reg(&st->sd, AD7791_REG_FILTER,
sizeof(st->filter), st->filter);
mutex_unlock(&indio_dev->mlock);
ret = 0;
break;
}
}
return ret ? ret : len;
}
static IIO_DEV_ATTR_SAMP_FREQ(S_IWUSR | S_IRUGO,
ad7791_read_frequency,
ad7791_write_frequency);
static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("120 100 33.3 20 16.7 16.6 13.3 9.5");
static struct attribute *ad7791_attributes[] = {
&iio_dev_attr_sampling_frequency.dev_attr.attr,
&iio_const_attr_sampling_frequency_available.dev_attr.attr,
NULL
};
static const struct attribute_group ad7791_attribute_group = {
.attrs = ad7791_attributes,
};
static const struct iio_info ad7791_info = {
.read_raw = &ad7791_read_raw,
.attrs = &ad7791_attribute_group,
.validate_trigger = ad_sd_validate_trigger,
.driver_module = THIS_MODULE,
};
static const struct iio_info ad7791_no_filter_info = {
.read_raw = &ad7791_read_raw,
.validate_trigger = ad_sd_validate_trigger,
.driver_module = THIS_MODULE,
};
static int ad7791_setup(struct ad7791_state *st,
struct ad7791_platform_data *pdata)
{
/* Set to poweron-reset default values */
st->mode = AD7791_MODE_BUFFER;
st->filter = AD7791_FILTER_RATE_16_6;
if (!pdata)
return 0;
if ((st->info->flags & AD7791_FLAG_HAS_BUFFER) && !pdata->buffered)
st->mode &= ~AD7791_MODE_BUFFER;
if ((st->info->flags & AD7791_FLAG_HAS_BURNOUT) &&
pdata->burnout_current)
st->mode |= AD7791_MODE_BURNOUT;
if ((st->info->flags & AD7791_FLAG_HAS_UNIPOLAR) && pdata->unipolar)
st->mode |= AD7791_MODE_UNIPOLAR;
return ad_sd_write_reg(&st->sd, AD7791_REG_MODE, sizeof(st->mode),
st->mode);
}
static int ad7791_probe(struct spi_device *spi)
{
struct ad7791_platform_data *pdata = spi->dev.platform_data;
struct iio_dev *indio_dev;
struct ad7791_state *st;
int ret;
if (!spi->irq) {
dev_err(&spi->dev, "Missing IRQ.\n");
return -ENXIO;
}
indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
if (!indio_dev)
return -ENOMEM;
st = iio_priv(indio_dev);
st->reg = devm_regulator_get(&spi->dev, "refin");
if (IS_ERR(st->reg))
return PTR_ERR(st->reg);
ret = regulator_enable(st->reg);
if (ret)
return ret;
st->info = &ad7791_chip_infos[spi_get_device_id(spi)->driver_data];
ad_sd_init(&st->sd, indio_dev, spi, &ad7791_sigma_delta_info);
spi_set_drvdata(spi, indio_dev);
indio_dev->dev.parent = &spi->dev;
indio_dev->name = spi_get_device_id(spi)->name;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = st->info->channels;
indio_dev->num_channels = st->info->num_channels;
if (st->info->flags & AD7791_FLAG_HAS_FILTER)
indio_dev->info = &ad7791_info;
else
indio_dev->info = &ad7791_no_filter_info;
ret = ad_sd_setup_buffer_and_trigger(indio_dev);
if (ret)
goto error_disable_reg;
ret = ad7791_setup(st, pdata);
if (ret)
goto error_remove_trigger;
ret = iio_device_register(indio_dev);
if (ret)
goto error_remove_trigger;
return 0;
error_remove_trigger:
ad_sd_cleanup_buffer_and_trigger(indio_dev);
error_disable_reg:
regulator_disable(st->reg);
return ret;
}
static int ad7791_remove(struct spi_device *spi)
{
struct iio_dev *indio_dev = spi_get_drvdata(spi);
struct ad7791_state *st = iio_priv(indio_dev);
iio_device_unregister(indio_dev);
ad_sd_cleanup_buffer_and_trigger(indio_dev);
regulator_disable(st->reg);
return 0;
}
static const struct spi_device_id ad7791_spi_ids[] = {
{ "ad7787", AD7787 },
{ "ad7788", AD7788 },
{ "ad7789", AD7789 },
{ "ad7790", AD7790 },
{ "ad7791", AD7791 },
{}
};
MODULE_DEVICE_TABLE(spi, ad7791_spi_ids);
static struct spi_driver ad7791_driver = {
.driver = {
.name = "ad7791",
.owner = THIS_MODULE,
},
.probe = ad7791_probe,
.remove = ad7791_remove,
.id_table = ad7791_spi_ids,
};
module_spi_driver(ad7791_driver);
MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
MODULE_DESCRIPTION("Analog Device AD7787/AD7788/AD7789/AD7790/AD7791 ADC driver");
MODULE_LICENSE("GPL v2");
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