233 lines
5.5 KiB
C
233 lines
5.5 KiB
C
/* Hwmon client for industrial I/O devices
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*
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* Copyright (c) 2011 Jonathan Cameron
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published by
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* the Free Software Foundation.
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*/
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/module.h>
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#include <linux/err.h>
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#include <linux/platform_device.h>
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#include <linux/hwmon.h>
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#include <linux/hwmon-sysfs.h>
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#include <linux/iio/consumer.h>
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#include <linux/iio/types.h>
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/**
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* struct iio_hwmon_state - device instance state
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* @channels: filled with array of channels from iio
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* @num_channels: number of channels in channels (saves counting twice)
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* @hwmon_dev: associated hwmon device
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* @attr_group: the group of attributes
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* @attrs: null terminated array of attribute pointers.
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*/
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struct iio_hwmon_state {
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struct iio_channel *channels;
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int num_channels;
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struct device *hwmon_dev;
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struct attribute_group attr_group;
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struct attribute **attrs;
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};
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/*
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* Assumes that IIO and hwmon operate in the same base units.
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* This is supposed to be true, but needs verification for
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* new channel types.
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*/
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static ssize_t iio_hwmon_read_val(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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long result;
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int val, ret, scaleint, scalepart;
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struct sensor_device_attribute *sattr = to_sensor_dev_attr(attr);
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struct iio_hwmon_state *state = dev_get_drvdata(dev);
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/*
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* No locking between this pair, so theoretically possible
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* the scale has changed.
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*/
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ret = iio_read_channel_raw(&state->channels[sattr->index],
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&val);
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if (ret < 0)
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return ret;
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ret = iio_read_channel_scale(&state->channels[sattr->index],
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&scaleint, &scalepart);
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if (ret < 0)
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return ret;
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switch (ret) {
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case IIO_VAL_INT:
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result = val * scaleint;
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break;
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case IIO_VAL_INT_PLUS_MICRO:
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result = (s64)val * (s64)scaleint +
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div_s64((s64)val * (s64)scalepart, 1000000LL);
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break;
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case IIO_VAL_INT_PLUS_NANO:
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result = (s64)val * (s64)scaleint +
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div_s64((s64)val * (s64)scalepart, 1000000000LL);
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break;
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default:
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return -EINVAL;
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}
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return sprintf(buf, "%ld\n", result);
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}
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static void iio_hwmon_free_attrs(struct iio_hwmon_state *st)
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{
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int i;
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struct sensor_device_attribute *a;
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for (i = 0; i < st->num_channels; i++)
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if (st->attrs[i]) {
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a = to_sensor_dev_attr(
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container_of(st->attrs[i],
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struct device_attribute,
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attr));
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kfree(a);
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}
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}
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static int __devinit iio_hwmon_probe(struct platform_device *pdev)
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{
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struct iio_hwmon_state *st;
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struct sensor_device_attribute *a;
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int ret, i;
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int in_i = 1, temp_i = 1, curr_i = 1;
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enum iio_chan_type type;
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st = kzalloc(sizeof(*st), GFP_KERNEL);
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if (st == NULL) {
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ret = -ENOMEM;
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goto error_ret;
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}
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st->channels = iio_channel_get_all(dev_name(&pdev->dev));
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if (IS_ERR(st->channels)) {
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ret = PTR_ERR(st->channels);
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goto error_free_state;
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}
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/* count how many attributes we have */
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while (st->channels[st->num_channels].indio_dev)
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st->num_channels++;
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st->attrs = kzalloc(sizeof(st->attrs) * (st->num_channels + 1),
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GFP_KERNEL);
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if (st->attrs == NULL) {
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ret = -ENOMEM;
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goto error_release_channels;
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}
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for (i = 0; i < st->num_channels; i++) {
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a = kzalloc(sizeof(*a), GFP_KERNEL);
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if (a == NULL) {
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ret = -ENOMEM;
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goto error_free_attrs;
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}
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sysfs_attr_init(&a->dev_attr.attr);
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ret = iio_get_channel_type(&st->channels[i], &type);
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if (ret < 0) {
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kfree(a);
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goto error_free_attrs;
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}
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switch (type) {
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case IIO_VOLTAGE:
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a->dev_attr.attr.name = kasprintf(GFP_KERNEL,
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"in%d_input",
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in_i++);
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break;
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case IIO_TEMP:
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a->dev_attr.attr.name = kasprintf(GFP_KERNEL,
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"temp%d_input",
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temp_i++);
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break;
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case IIO_CURRENT:
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a->dev_attr.attr.name = kasprintf(GFP_KERNEL,
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"curr%d_input",
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curr_i++);
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break;
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default:
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ret = -EINVAL;
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kfree(a);
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goto error_free_attrs;
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}
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if (a->dev_attr.attr.name == NULL) {
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kfree(a);
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ret = -ENOMEM;
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goto error_free_attrs;
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}
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a->dev_attr.show = iio_hwmon_read_val;
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a->dev_attr.attr.mode = S_IRUGO;
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a->index = i;
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st->attrs[i] = &a->dev_attr.attr;
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}
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st->attr_group.attrs = st->attrs;
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platform_set_drvdata(pdev, st);
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ret = sysfs_create_group(&pdev->dev.kobj, &st->attr_group);
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if (ret < 0)
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goto error_free_attrs;
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st->hwmon_dev = hwmon_device_register(&pdev->dev);
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if (IS_ERR(st->hwmon_dev)) {
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ret = PTR_ERR(st->hwmon_dev);
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goto error_remove_group;
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}
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return 0;
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error_remove_group:
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sysfs_remove_group(&pdev->dev.kobj, &st->attr_group);
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error_free_attrs:
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iio_hwmon_free_attrs(st);
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kfree(st->attrs);
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error_release_channels:
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iio_channel_release_all(st->channels);
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error_free_state:
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kfree(st);
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error_ret:
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return ret;
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}
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static int __devexit iio_hwmon_remove(struct platform_device *pdev)
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{
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struct iio_hwmon_state *st = platform_get_drvdata(pdev);
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hwmon_device_unregister(st->hwmon_dev);
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sysfs_remove_group(&pdev->dev.kobj, &st->attr_group);
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iio_hwmon_free_attrs(st);
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kfree(st->attrs);
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iio_channel_release_all(st->channels);
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return 0;
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}
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static struct platform_driver __refdata iio_hwmon_driver = {
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.driver = {
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.name = "iio_hwmon",
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.owner = THIS_MODULE,
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},
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.probe = iio_hwmon_probe,
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.remove = __devexit_p(iio_hwmon_remove),
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};
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static int iio_inkern_init(void)
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{
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return platform_driver_register(&iio_hwmon_driver);
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}
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module_init(iio_inkern_init);
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static void iio_inkern_exit(void)
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{
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platform_driver_unregister(&iio_hwmon_driver);
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}
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module_exit(iio_inkern_exit);
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MODULE_AUTHOR("Jonathan Cameron <jic23@cam.ac.uk>");
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MODULE_DESCRIPTION("IIO to hwmon driver");
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MODULE_LICENSE("GPL v2");
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