linux/drivers/hwmon/iio_hwmon.c
Michal Simek bc34301b10 hwmon: (iio_hwmon) Enable power exporting from IIO
There is no reason why power channel shouldn't be exported as is done for
voltage, current, temperature and humidity.

Power channel is available on iio ina226 driver.

Sysfs IIO documentation for power attribute added by commit 7c6d5c7ee8
("iio: Documentation: Add missing documentation for power attribute")
is declaring that value is in mili-Watts but hwmon interface is expecting
value in micro-Watts that's why there is a need for mili-Watts to
micro-Watts conversion.

Tested on Xilinx ZCU102 board.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Link: https://lore.kernel.org/r/db71f5ae87e4521a2856a1be5544de0b6cede575.1566483741.git.michal.simek@xilinx.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2019-09-03 12:47:17 -07:00

185 lines
4.3 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/* Hwmon client for industrial I/O devices
*
* Copyright (c) 2011 Jonathan Cameron
*/
#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);
struct iio_channel *chan = &state->channels[sattr->index];
enum iio_chan_type type;
ret = iio_read_channel_processed(chan, &result);
if (ret < 0)
return ret;
ret = iio_get_channel_type(chan, &type);
if (ret < 0)
return ret;
if (type == IIO_POWER)
result *= 1000; /* mili-Watts to micro-Watts conversion */
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, power_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++) {
const char *prefix;
int n;
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:
n = in_i++;
prefix = "in";
break;
case IIO_TEMP:
n = temp_i++;
prefix = "temp";
break;
case IIO_CURRENT:
n = curr_i++;
prefix = "curr";
break;
case IIO_POWER:
n = power_i++;
prefix = "power";
break;
case IIO_HUMIDITYRELATIVE:
n = humidity_i++;
prefix = "humidity";
break;
default:
return -EINVAL;
}
a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL,
"%s%d_input",
prefix, n);
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");