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// SPDX-License-Identifier: GPL-2.0-only
/*
* IIO DAC driver for Analog Devices AD8801 DAC
*
* Copyright (C) 2016 Gwenhael Goavec-Merou
*/
#include <linux/iio/iio.h>
#include <linux/module.h>
#include <linux/regulator/consumer.h>
#include <linux/spi/spi.h>
#include <linux/sysfs.h>
#define AD8801_CFG_ADDR_OFFSET 8
enum ad8801_device_ids {
ID_AD8801,
ID_AD8803,
};
struct ad8801_state {
struct spi_device *spi;
unsigned char dac_cache[8]; /* Value write on each channel */
unsigned int vrefh_mv;
unsigned int vrefl_mv;
__be16 data __aligned(IIO_DMA_MINALIGN);
};
static int ad8801_spi_write(struct ad8801_state *state,
u8 channel, unsigned char value)
{
state->data = cpu_to_be16((channel << AD8801_CFG_ADDR_OFFSET) | value);
return spi_write(state->spi, &state->data, sizeof(state->data));
}
static int ad8801_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan, int val, int val2, long mask)
{
struct ad8801_state *state = iio_priv(indio_dev);
int ret;
switch (mask) {
case IIO_CHAN_INFO_RAW:
if (val >= 256 || val < 0)
return -EINVAL;
ret = ad8801_spi_write(state, chan->channel, val);
if (ret == 0)
state->dac_cache[chan->channel] = val;
break;
default:
ret = -EINVAL;
}
return ret;
}
static int ad8801_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan, int *val, int *val2, long info)
{
struct ad8801_state *state = iio_priv(indio_dev);
switch (info) {
case IIO_CHAN_INFO_RAW:
*val = state->dac_cache[chan->channel];
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
*val = state->vrefh_mv - state->vrefl_mv;
*val2 = 8;
return IIO_VAL_FRACTIONAL_LOG2;
case IIO_CHAN_INFO_OFFSET:
*val = state->vrefl_mv;
return IIO_VAL_INT;
default:
return -EINVAL;
}
return -EINVAL;
}
static const struct iio_info ad8801_info = {
.read_raw = ad8801_read_raw,
.write_raw = ad8801_write_raw,
};
#define AD8801_CHANNEL(chan) { \
.type = IIO_VOLTAGE, \
.indexed = 1, \
.output = 1, \
.channel = chan, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
BIT(IIO_CHAN_INFO_OFFSET), \
}
static const struct iio_chan_spec ad8801_channels[] = {
AD8801_CHANNEL(0),
AD8801_CHANNEL(1),
AD8801_CHANNEL(2),
AD8801_CHANNEL(3),
AD8801_CHANNEL(4),
AD8801_CHANNEL(5),
AD8801_CHANNEL(6),
AD8801_CHANNEL(7),
};
static int ad8801_probe(struct spi_device *spi)
{
struct iio_dev *indio_dev;
struct ad8801_state *state;
const struct spi_device_id *id;
int ret;
indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*state));
if (indio_dev == NULL)
return -ENOMEM;
state = iio_priv(indio_dev);
state->spi = spi;
id = spi_get_device_id(spi);
ret = devm_regulator_get_enable_read_voltage(&spi->dev, "vrefh");
if (ret < 0)
return dev_err_probe(&spi->dev, ret,
"failed to get Vrefh voltage\n");
state->vrefh_mv = ret / 1000;
if (id->driver_data == ID_AD8803) {
ret = devm_regulator_get_enable_read_voltage(&spi->dev, "vrefl");
if (ret < 0)
return dev_err_probe(&spi->dev, ret,
"failed to get Vrefl voltage\n");
state->vrefl_mv = ret / 1000;
}
indio_dev->info = &ad8801_info;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = ad8801_channels;
indio_dev->num_channels = ARRAY_SIZE(ad8801_channels);
indio_dev->name = id->name;
ret = devm_iio_device_register(&spi->dev, indio_dev);
if (ret)
return dev_err_probe(&spi->dev, ret,
"Failed to register iio device\n");
return 0;
}
static const struct spi_device_id ad8801_ids[] = {
{"ad8801", ID_AD8801},
{"ad8803", ID_AD8803},
{}
};
MODULE_DEVICE_TABLE(spi, ad8801_ids);
static struct spi_driver ad8801_driver = {
.driver = {
.name = "ad8801",
},
.probe = ad8801_probe,
.id_table = ad8801_ids,
};
module_spi_driver(ad8801_driver);
MODULE_AUTHOR("Gwenhael Goavec-Merou <gwenhael.goavec-merou@trabucayre.com>");
MODULE_DESCRIPTION("Analog Devices AD8801/AD8803 DAC");
MODULE_LICENSE("GPL v2");
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