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/*
* AD7298 SPI ADC driver
*
* Copyright 2011 Analog Devices Inc.
*
* Licensed under the GPL-2.
*/
#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/delay.h>
#include <linux/module.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/buffer.h>
#include "ad7298.h"
#define AD7298_V_CHAN(index) \
{ \
.type = IIO_VOLTAGE, \
.indexed = 1, \
.channel = index, \
.info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT | \
IIO_CHAN_INFO_SCALE_SHARED_BIT, \
.address = index, \
.scan_index = index, \
.scan_type = { \
.sign = 'u', \
.realbits = 12, \
.storagebits = 16, \
}, \
}
static struct iio_chan_spec ad7298_channels[] = {
{
.type = IIO_TEMP,
.indexed = 1,
.channel = 0,
.info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |
IIO_CHAN_INFO_SCALE_SEPARATE_BIT,
.address = 9,
.scan_index = AD7298_CH_TEMP,
.scan_type = {
.sign = 's',
.realbits = 32,
.storagebits = 32,
},
},
AD7298_V_CHAN(0),
AD7298_V_CHAN(1),
AD7298_V_CHAN(2),
AD7298_V_CHAN(3),
AD7298_V_CHAN(4),
AD7298_V_CHAN(5),
AD7298_V_CHAN(6),
AD7298_V_CHAN(7),
IIO_CHAN_SOFT_TIMESTAMP(8),
};
static int ad7298_scan_direct(struct ad7298_state *st, unsigned ch)
{
int ret;
st->tx_buf[0] = cpu_to_be16(AD7298_WRITE | st->ext_ref |
(AD7298_CH(0) >> ch));
ret = spi_sync(st->spi, &st->scan_single_msg);
if (ret)
return ret;
return be16_to_cpu(st->rx_buf[0]);
}
static int ad7298_scan_temp(struct ad7298_state *st, int *val)
{
int tmp, ret;
__be16 buf;
buf = cpu_to_be16(AD7298_WRITE | AD7298_TSENSE |
AD7298_TAVG | st->ext_ref);
ret = spi_write(st->spi, (u8 *)&buf, 2);
if (ret)
return ret;
buf = cpu_to_be16(0);
ret = spi_write(st->spi, (u8 *)&buf, 2);
if (ret)
return ret;
usleep_range(101, 1000); /* sleep > 100us */
ret = spi_read(st->spi, (u8 *)&buf, 2);
if (ret)
return ret;
tmp = be16_to_cpu(buf) & RES_MASK(AD7298_BITS);
/*
* One LSB of the ADC corresponds to 0.25 deg C.
* The temperature reading is in 12-bit twos complement format
*/
if (tmp & (1 << (AD7298_BITS - 1))) {
tmp = (4096 - tmp) * 250;
tmp -= (2 * tmp);
} else {
tmp *= 250; /* temperature in milli degrees Celsius */
}
*val = tmp;
return 0;
}
static int ad7298_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val,
int *val2,
long m)
{
int ret;
struct ad7298_state *st = iio_priv(indio_dev);
unsigned int scale_uv;
switch (m) {
case IIO_CHAN_INFO_RAW:
mutex_lock(&indio_dev->mlock);
if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
ret = -EBUSY;
} else {
if (chan->address == AD7298_CH_TEMP)
ret = ad7298_scan_temp(st, val);
else
ret = ad7298_scan_direct(st, chan->address);
}
mutex_unlock(&indio_dev->mlock);
if (ret < 0)
return ret;
if (chan->address != AD7298_CH_TEMP)
*val = ret & RES_MASK(AD7298_BITS);
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
switch (chan->type) {
case IIO_VOLTAGE:
scale_uv = (st->int_vref_mv * 1000) >> AD7298_BITS;
*val = scale_uv / 1000;
*val2 = (scale_uv % 1000) * 1000;
return IIO_VAL_INT_PLUS_MICRO;
case IIO_TEMP:
*val = 1;
*val2 = 0;
return IIO_VAL_INT_PLUS_MICRO;
default:
return -EINVAL;
}
}
return -EINVAL;
}
static const struct iio_info ad7298_info = {
.read_raw = &ad7298_read_raw,
.driver_module = THIS_MODULE,
};
static int __devinit ad7298_probe(struct spi_device *spi)
{
struct ad7298_platform_data *pdata = spi->dev.platform_data;
struct ad7298_state *st;
int ret;
struct iio_dev *indio_dev = iio_device_alloc(sizeof(*st));
if (indio_dev == NULL)
return -ENOMEM;
st = iio_priv(indio_dev);
st->reg = regulator_get(&spi->dev, "vcc");
if (!IS_ERR(st->reg)) {
ret = regulator_enable(st->reg);
if (ret)
goto error_put_reg;
}
spi_set_drvdata(spi, indio_dev);
st->spi = spi;
indio_dev->name = spi_get_device_id(spi)->name;
indio_dev->dev.parent = &spi->dev;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = ad7298_channels;
indio_dev->num_channels = ARRAY_SIZE(ad7298_channels);
indio_dev->info = &ad7298_info;
/* Setup default message */
st->scan_single_xfer[0].tx_buf = &st->tx_buf[0];
st->scan_single_xfer[0].len = 2;
st->scan_single_xfer[0].cs_change = 1;
st->scan_single_xfer[1].tx_buf = &st->tx_buf[1];
st->scan_single_xfer[1].len = 2;
st->scan_single_xfer[1].cs_change = 1;
st->scan_single_xfer[2].rx_buf = &st->rx_buf[0];
st->scan_single_xfer[2].len = 2;
spi_message_init(&st->scan_single_msg);
spi_message_add_tail(&st->scan_single_xfer[0], &st->scan_single_msg);
spi_message_add_tail(&st->scan_single_xfer[1], &st->scan_single_msg);
spi_message_add_tail(&st->scan_single_xfer[2], &st->scan_single_msg);
if (pdata && pdata->vref_mv) {
st->int_vref_mv = pdata->vref_mv;
st->ext_ref = AD7298_EXTREF;
} else {
st->int_vref_mv = AD7298_INTREF_mV;
}
ret = ad7298_register_ring_funcs_and_init(indio_dev);
if (ret)
goto error_disable_reg;
ret = iio_buffer_register(indio_dev,
&ad7298_channels[1], /* skip temp0 */
ARRAY_SIZE(ad7298_channels) - 1);
if (ret)
goto error_cleanup_ring;
ret = iio_device_register(indio_dev);
if (ret)
goto error_unregister_ring;
return 0;
error_unregister_ring:
iio_buffer_unregister(indio_dev);
error_cleanup_ring:
ad7298_ring_cleanup(indio_dev);
error_disable_reg:
if (!IS_ERR(st->reg))
regulator_disable(st->reg);
error_put_reg:
if (!IS_ERR(st->reg))
regulator_put(st->reg);
iio_device_free(indio_dev);
return ret;
}
static int __devexit ad7298_remove(struct spi_device *spi)
{
struct iio_dev *indio_dev = spi_get_drvdata(spi);
struct ad7298_state *st = iio_priv(indio_dev);
iio_device_unregister(indio_dev);
iio_buffer_unregister(indio_dev);
ad7298_ring_cleanup(indio_dev);
if (!IS_ERR(st->reg)) {
regulator_disable(st->reg);
regulator_put(st->reg);
}
iio_device_free(indio_dev);
return 0;
}
static const struct spi_device_id ad7298_id[] = {
{"ad7298", 0},
{}
};
MODULE_DEVICE_TABLE(spi, ad7298_id);
static struct spi_driver ad7298_driver = {
.driver = {
.name = "ad7298",
.owner = THIS_MODULE,
},
.probe = ad7298_probe,
.remove = __devexit_p(ad7298_remove),
.id_table = ad7298_id,
};
module_spi_driver(ad7298_driver);
MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
MODULE_DESCRIPTION("Analog Devices AD7298 ADC");
MODULE_LICENSE("GPL v2");
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