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/* Hwmon client for industrial I/O devices
*
* Copyright (c) 2011 Jonathan Cameron
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published by
* the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/hwmon.h>
#include <linux/of.h>
#include <linux/hwmon-sysfs.h>
#include <linux/iio/consumer.h>
#include <linux/iio/types.h>
/**
* struct iio_hwmon_state - device instance state
* @channels: filled with array of channels from iio
* @num_channels: number of channels in channels (saves counting twice)
* @attr_group: the group of attributes
* @groups: null terminated array of attribute groups
* @attrs: null terminated array of attribute pointers.
*/
struct iio_hwmon_state {
struct iio_channel *channels;
int num_channels;
struct attribute_group attr_group;
const struct attribute_group *groups[2];
struct attribute **attrs;
};
/*
* Assumes that IIO and hwmon operate in the same base units.
* This is supposed to be true, but needs verification for
* new channel types.
*/
static ssize_t iio_hwmon_read_val(struct device *dev,
struct device_attribute *attr,
char *buf)
{
int result;
int ret;
struct sensor_device_attribute *sattr = to_sensor_dev_attr(attr);
struct iio_hwmon_state *state = dev_get_drvdata(dev);
ret = iio_read_channel_processed(&state->channels[sattr->index],
&result);
if (ret < 0)
return ret;
return sprintf(buf, "%d\n", result);
}
static int iio_hwmon_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct iio_hwmon_state *st;
struct sensor_device_attribute *a;
int ret, i;
int in_i = 1, temp_i = 1, curr_i = 1, humidity_i = 1;
enum iio_chan_type type;
struct iio_channel *channels;
struct device *hwmon_dev;
char *sname;
channels = devm_iio_channel_get_all(dev);
if (IS_ERR(channels)) {
if (PTR_ERR(channels) == -ENODEV)
return -EPROBE_DEFER;
return PTR_ERR(channels);
}
st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL);
if (st == NULL)
return -ENOMEM;
st->channels = channels;
/* count how many attributes we have */
while (st->channels[st->num_channels].indio_dev)
st->num_channels++;
st->attrs = devm_kcalloc(dev,
st->num_channels + 1, sizeof(*st->attrs),
GFP_KERNEL);
if (st->attrs == NULL)
return -ENOMEM;
for (i = 0; i < st->num_channels; i++) {
a = devm_kzalloc(dev, sizeof(*a), GFP_KERNEL);
if (a == NULL)
return -ENOMEM;
sysfs_attr_init(&a->dev_attr.attr);
ret = iio_get_channel_type(&st->channels[i], &type);
if (ret < 0)
return ret;
switch (type) {
case IIO_VOLTAGE:
a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL,
"in%d_input",
in_i++);
break;
case IIO_TEMP:
a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL,
"temp%d_input",
temp_i++);
break;
case IIO_CURRENT:
a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL,
"curr%d_input",
curr_i++);
break;
case IIO_HUMIDITYRELATIVE:
a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL,
"humidity%d_input",
humidity_i++);
break;
default:
return -EINVAL;
}
if (a->dev_attr.attr.name == NULL)
return -ENOMEM;
a->dev_attr.show = iio_hwmon_read_val;
a->dev_attr.attr.mode = 0444;
a->index = i;
st->attrs[i] = &a->dev_attr.attr;
}
st->attr_group.attrs = st->attrs;
st->groups[0] = &st->attr_group;
if (dev->of_node) {
sname = devm_kasprintf(dev, GFP_KERNEL, "%pOFn", dev->of_node);
if (!sname)
return -ENOMEM;
strreplace(sname, '-', '_');
} else {
sname = "iio_hwmon";
}
hwmon_dev = devm_hwmon_device_register_with_groups(dev, sname, st,
st->groups);
return PTR_ERR_OR_ZERO(hwmon_dev);
}
static const struct of_device_id iio_hwmon_of_match[] = {
{ .compatible = "iio-hwmon", },
{ }
};
MODULE_DEVICE_TABLE(of, iio_hwmon_of_match);
static struct platform_driver __refdata iio_hwmon_driver = {
.driver = {
.name = "iio_hwmon",
.of_match_table = iio_hwmon_of_match,
},
.probe = iio_hwmon_probe,
};
module_platform_driver(iio_hwmon_driver);
MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
MODULE_DESCRIPTION("IIO to hwmon driver");
MODULE_LICENSE("GPL v2");
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