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// SPDX-License-Identifier: GPL-2.0-only
/*
* Helpers for parsing common ADC information from a firmware node.
*
* Copyright (c) 2025 Matti Vaittinen <mazziesaccount@gmail.com>
*/
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/export.h>
#include <linux/module.h>
#include <linux/property.h>
#include <linux/types.h>
#include <linux/iio/adc-helpers.h>
#include <linux/iio/iio.h>
/**
* devm_iio_adc_device_alloc_chaninfo_se - allocate and fill iio_chan_spec for ADC
*
* Scan the device node for single-ended ADC channel information. Channel ID is
* expected to be found from the "reg" property. Allocate and populate the
* iio_chan_spec structure corresponding to channels that are found. The memory
* for iio_chan_spec structure will be freed upon device detach.
*
* @dev: Pointer to the ADC device.
* @template: Template iio_chan_spec from which the fields of all
* found and allocated channels are initialized.
* @max_chan_id: Maximum value of a channel ID. Use negative value if no
* checking is required.
* @cs: Location where pointer to allocated iio_chan_spec
* should be stored.
*
* Return: Number of found channels on success. Negative value to indicate
* failure. Specifically, -ENOENT if no channel nodes were found.
*/
int devm_iio_adc_device_alloc_chaninfo_se(struct device *dev,
const struct iio_chan_spec *template,
int max_chan_id,
struct iio_chan_spec **cs)
{
struct iio_chan_spec *chan_array, *chan;
int num_chan, ret;
num_chan = iio_adc_device_num_channels(dev);
if (num_chan < 0)
return num_chan;
if (!num_chan)
return -ENOENT;
chan_array = devm_kcalloc(dev, num_chan, sizeof(*chan_array),
GFP_KERNEL);
if (!chan_array)
return -ENOMEM;
chan = &chan_array[0];
device_for_each_named_child_node_scoped(dev, child, "channel") {
u32 ch;
ret = fwnode_property_read_u32(child, "reg", &ch);
if (ret)
return ret;
if (max_chan_id >= 0 && ch > max_chan_id)
return -ERANGE;
*chan = *template;
chan->channel = ch;
chan++;
}
*cs = chan_array;
return num_chan;
}
EXPORT_SYMBOL_NS_GPL(devm_iio_adc_device_alloc_chaninfo_se, "IIO_DRIVER");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Matti Vaittinen <mazziesaccount@gmail.com>");
MODULE_DESCRIPTION("IIO ADC fwnode parsing helpers");
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