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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/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)
* @hwmon_dev: associated hwmon device
* @attr_group: the group of attributes
* @attrs: null terminated array of attribute pointers.
*/
struct iio_hwmon_state {
struct iio_channel *channels;
int num_channels;
struct device *hwmon_dev;
struct attribute_group attr_group;
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)
{
long result;
int val, ret, scaleint, scalepart;
struct sensor_device_attribute *sattr = to_sensor_dev_attr(attr);
struct iio_hwmon_state *state = dev_get_drvdata(dev);
/*
* No locking between this pair, so theoretically possible
* the scale has changed.
*/
ret = iio_read_channel_raw(&state->channels[sattr->index],
&val);
if (ret < 0)
return ret;
ret = iio_read_channel_scale(&state->channels[sattr->index],
&scaleint, &scalepart);
if (ret < 0)
return ret;
switch (ret) {
case IIO_VAL_INT:
result = val * scaleint;
break;
case IIO_VAL_INT_PLUS_MICRO:
result = (s64)val * (s64)scaleint +
div_s64((s64)val * (s64)scalepart, 1000000LL);
break;
case IIO_VAL_INT_PLUS_NANO:
result = (s64)val * (s64)scaleint +
div_s64((s64)val * (s64)scalepart, 1000000000LL);
break;
default:
return -EINVAL;
}
return sprintf(buf, "%ld\n", result);
}
static void iio_hwmon_free_attrs(struct iio_hwmon_state *st)
{
int i;
struct sensor_device_attribute *a;
for (i = 0; i < st->num_channels; i++)
if (st->attrs[i]) {
a = to_sensor_dev_attr(
container_of(st->attrs[i],
struct device_attribute,
attr));
kfree(a);
}
}
static int __devinit iio_hwmon_probe(struct platform_device *pdev)
{
struct iio_hwmon_state *st;
struct sensor_device_attribute *a;
int ret, i;
int in_i = 1, temp_i = 1, curr_i = 1;
enum iio_chan_type type;
st = kzalloc(sizeof(*st), GFP_KERNEL);
if (st == NULL) {
ret = -ENOMEM;
goto error_ret;
}
st->channels = iio_channel_get_all(dev_name(&pdev->dev));
if (IS_ERR(st->channels)) {
ret = PTR_ERR(st->channels);
goto error_free_state;
}
/* count how many attributes we have */
while (st->channels[st->num_channels].indio_dev)
st->num_channels++;
st->attrs = kzalloc(sizeof(st->attrs) * (st->num_channels + 1),
GFP_KERNEL);
if (st->attrs == NULL) {
ret = -ENOMEM;
goto error_release_channels;
}
for (i = 0; i < st->num_channels; i++) {
a = kzalloc(sizeof(*a), GFP_KERNEL);
if (a == NULL) {
ret = -ENOMEM;
goto error_free_attrs;
}
sysfs_attr_init(&a->dev_attr.attr);
ret = iio_get_channel_type(&st->channels[i], &type);
if (ret < 0) {
kfree(a);
goto error_free_attrs;
}
switch (type) {
case IIO_VOLTAGE:
a->dev_attr.attr.name = kasprintf(GFP_KERNEL,
"in%d_input",
in_i++);
break;
case IIO_TEMP:
a->dev_attr.attr.name = kasprintf(GFP_KERNEL,
"temp%d_input",
temp_i++);
break;
case IIO_CURRENT:
a->dev_attr.attr.name = kasprintf(GFP_KERNEL,
"curr%d_input",
curr_i++);
break;
default:
ret = -EINVAL;
kfree(a);
goto error_free_attrs;
}
if (a->dev_attr.attr.name == NULL) {
kfree(a);
ret = -ENOMEM;
goto error_free_attrs;
}
a->dev_attr.show = iio_hwmon_read_val;
a->dev_attr.attr.mode = S_IRUGO;
a->index = i;
st->attrs[i] = &a->dev_attr.attr;
}
st->attr_group.attrs = st->attrs;
platform_set_drvdata(pdev, st);
ret = sysfs_create_group(&pdev->dev.kobj, &st->attr_group);
if (ret < 0)
goto error_free_attrs;
st->hwmon_dev = hwmon_device_register(&pdev->dev);
if (IS_ERR(st->hwmon_dev)) {
ret = PTR_ERR(st->hwmon_dev);
goto error_remove_group;
}
return 0;
error_remove_group:
sysfs_remove_group(&pdev->dev.kobj, &st->attr_group);
error_free_attrs:
iio_hwmon_free_attrs(st);
kfree(st->attrs);
error_release_channels:
iio_channel_release_all(st->channels);
error_free_state:
kfree(st);
error_ret:
return ret;
}
static int __devexit iio_hwmon_remove(struct platform_device *pdev)
{
struct iio_hwmon_state *st = platform_get_drvdata(pdev);
hwmon_device_unregister(st->hwmon_dev);
sysfs_remove_group(&pdev->dev.kobj, &st->attr_group);
iio_hwmon_free_attrs(st);
kfree(st->attrs);
iio_channel_release_all(st->channels);
return 0;
}
static struct platform_driver __refdata iio_hwmon_driver = {
.driver = {
.name = "iio_hwmon",
.owner = THIS_MODULE,
},
.probe = iio_hwmon_probe,
.remove = __devexit_p(iio_hwmon_remove),
};
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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