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// SPDX-License-Identifier: GPL-2.0-only
/*
* Analog Devices AD7405 driver
*
* Copyright 2025 Analog Devices Inc.
*/
#include <linux/clk.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/math64.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/regulator/consumer.h>
#include <linux/util_macros.h>
#include <linux/iio/backend.h>
#include <linux/iio/iio.h>
static const unsigned int ad7405_dec_rates_range[] = {
32, 1, 4096,
};
struct ad7405_chip_info {
const char *name;
const unsigned int full_scale_mv;
};
struct ad7405_state {
struct iio_backend *back;
const struct ad7405_chip_info *info;
unsigned int ref_frequency;
unsigned int dec_rate;
};
static int ad7405_set_dec_rate(struct iio_dev *indio_dev,
const struct iio_chan_spec *chan,
unsigned int dec_rate)
{
struct ad7405_state *st = iio_priv(indio_dev);
int ret;
if (dec_rate > 4096 || dec_rate < 32)
return -EINVAL;
if (!iio_device_claim_direct(indio_dev))
return -EBUSY;
ret = iio_backend_oversampling_ratio_set(st->back, chan->scan_index, dec_rate);
iio_device_release_direct(indio_dev);
if (ret < 0)
return ret;
st->dec_rate = dec_rate;
return 0;
}
static int ad7405_read_raw(struct iio_dev *indio_dev,
const struct iio_chan_spec *chan, int *val,
int *val2, long info)
{
struct ad7405_state *st = iio_priv(indio_dev);
switch (info) {
case IIO_CHAN_INFO_SCALE:
*val = st->info->full_scale_mv;
*val2 = indio_dev->channels[0].scan_type.realbits - 1;
return IIO_VAL_FRACTIONAL_LOG2;
case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
*val = st->dec_rate;
return IIO_VAL_INT;
case IIO_CHAN_INFO_SAMP_FREQ:
*val = DIV_ROUND_CLOSEST_ULL(st->ref_frequency, st->dec_rate);
return IIO_VAL_INT;
case IIO_CHAN_INFO_OFFSET:
*val = -(1 << (indio_dev->channels[0].scan_type.realbits - 1));
return IIO_VAL_INT;
default:
return -EINVAL;
}
}
static int ad7405_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan, int val,
int val2, long info)
{
switch (info) {
case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
if (val < 0)
return -EINVAL;
return ad7405_set_dec_rate(indio_dev, chan, val);
default:
return -EINVAL;
}
}
static int ad7405_read_avail(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
const int **vals, int *type, int *length,
long info)
{
switch (info) {
case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
*vals = ad7405_dec_rates_range;
*type = IIO_VAL_INT;
return IIO_AVAIL_RANGE;
default:
return -EINVAL;
}
}
static const struct iio_info ad7405_iio_info = {
.read_raw = &ad7405_read_raw,
.write_raw = &ad7405_write_raw,
.read_avail = &ad7405_read_avail,
};
static const struct iio_chan_spec ad7405_channel = {
.type = IIO_VOLTAGE,
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |
BIT(IIO_CHAN_INFO_OFFSET),
.info_mask_shared_by_all = IIO_CHAN_INFO_SAMP_FREQ |
BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
.info_mask_shared_by_all_available =
BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
.indexed = 1,
.channel = 0,
.channel2 = 1,
.differential = 1,
.scan_index = 0,
.scan_type = {
.sign = 'u',
.realbits = 16,
.storagebits = 16,
},
};
static const struct ad7405_chip_info ad7405_chip_info = {
.name = "ad7405",
.full_scale_mv = 320,
};
static const struct ad7405_chip_info adum7701_chip_info = {
.name = "adum7701",
.full_scale_mv = 320,
};
static const struct ad7405_chip_info adum7702_chip_info = {
.name = "adum7702",
.full_scale_mv = 64,
};
static const struct ad7405_chip_info adum7703_chip_info = {
.name = "adum7703",
.full_scale_mv = 320,
};
static const char * const ad7405_power_supplies[] = {
"vdd1", "vdd2",
};
static int ad7405_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct iio_dev *indio_dev;
struct ad7405_state *st;
struct clk *clk;
int ret;
indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
if (!indio_dev)
return -ENOMEM;
st = iio_priv(indio_dev);
st->info = device_get_match_data(dev);
if (!st->info)
return dev_err_probe(dev, -EINVAL, "no chip info\n");
ret = devm_regulator_bulk_get_enable(dev, ARRAY_SIZE(ad7405_power_supplies),
ad7405_power_supplies);
if (ret)
return dev_err_probe(dev, ret, "failed to get and enable supplies");
clk = devm_clk_get_enabled(dev, NULL);
if (IS_ERR(clk))
return PTR_ERR(clk);
st->ref_frequency = clk_get_rate(clk);
if (!st->ref_frequency)
return -EINVAL;
indio_dev->name = st->info->name;
indio_dev->channels = &ad7405_channel;
indio_dev->num_channels = 1;
indio_dev->info = &ad7405_iio_info;
st->back = devm_iio_backend_get(dev, NULL);
if (IS_ERR(st->back))
return dev_err_probe(dev, PTR_ERR(st->back),
"failed to get IIO backend");
ret = iio_backend_chan_enable(st->back, 0);
if (ret)
return ret;
ret = devm_iio_backend_request_buffer(dev, st->back, indio_dev);
if (ret)
return ret;
ret = devm_iio_backend_enable(dev, st->back);
if (ret)
return ret;
/*
* Set 256 decimation rate. The default value in the AXI_ADC register
* is 0, so we set the register with a decimation rate value that is
* functional for all parts.
*/
ret = ad7405_set_dec_rate(indio_dev, &indio_dev->channels[0], 256);
if (ret)
return ret;
return devm_iio_device_register(dev, indio_dev);
}
static const struct of_device_id ad7405_of_match[] = {
{ .compatible = "adi,ad7405", .data = &ad7405_chip_info, },
{ .compatible = "adi,adum7701", .data = &adum7701_chip_info, },
{ .compatible = "adi,adum7702", .data = &adum7702_chip_info, },
{ .compatible = "adi,adum7703", .data = &adum7703_chip_info, },
{ }
};
MODULE_DEVICE_TABLE(of, ad7405_of_match);
static struct platform_driver ad7405_driver = {
.driver = {
.name = "ad7405",
.of_match_table = ad7405_of_match,
},
.probe = ad7405_probe,
};
module_platform_driver(ad7405_driver);
MODULE_AUTHOR("Dragos Bogdan <dragos.bogdan@analog.com>");
MODULE_AUTHOR("Pop Ioan Daniel <pop.ioan-daniel@analog.com>");
MODULE_DESCRIPTION("Analog Devices AD7405 driver");
MODULE_LICENSE("GPL");
MODULE_IMPORT_NS("IIO_BACKEND");
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