1 /* Hwmon client for industrial I/O devices
3 * Copyright (c) 2011 Jonathan Cameron
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 as published by
7 * the Free Software Foundation.
10 #include <linux/kernel.h>
11 #include <linux/slab.h>
12 #include <linux/module.h>
13 #include <linux/err.h>
14 #include <linux/platform_device.h>
15 #include <linux/hwmon.h>
16 #include <linux/hwmon-sysfs.h>
17 #include <linux/iio/consumer.h>
18 #include <linux/iio/types.h>
21 * struct iio_hwmon_state - device instance state
22 * @channels: filled with array of channels from iio
23 * @num_channels: number of channels in channels (saves counting twice)
24 * @hwmon_dev: associated hwmon device
25 * @attr_group: the group of attributes
26 * @attrs: null terminated array of attribute pointers.
28 struct iio_hwmon_state {
29 struct iio_channel *channels;
31 struct device *hwmon_dev;
32 struct attribute_group attr_group;
33 struct attribute **attrs;
37 * Assumes that IIO and hwmon operate in the same base units.
38 * This is supposed to be true, but needs verification for
41 static ssize_t iio_hwmon_read_val(struct device *dev,
42 struct device_attribute *attr,
47 struct sensor_device_attribute *sattr = to_sensor_dev_attr(attr);
48 struct iio_hwmon_state *state = dev_get_drvdata(dev);
50 ret = iio_read_channel_processed(&state->channels[sattr->index],
55 return sprintf(buf, "%d\n", result);
58 static ssize_t show_name(struct device *dev, struct device_attribute *attr,
61 return sprintf(buf, "iio_hwmon\n");
64 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
66 static int iio_hwmon_probe(struct platform_device *pdev)
68 struct device *dev = &pdev->dev;
69 struct iio_hwmon_state *st;
70 struct sensor_device_attribute *a;
72 int in_i = 1, temp_i = 1, curr_i = 1;
73 enum iio_chan_type type;
74 struct iio_channel *channels;
76 channels = iio_channel_get_all(dev);
78 return PTR_ERR(channels);
80 st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL);
84 st->channels = channels;
86 /* count how many attributes we have */
87 while (st->channels[st->num_channels].indio_dev)
90 st->attrs = devm_kzalloc(dev,
91 sizeof(*st->attrs) * (st->num_channels + 2),
93 if (st->attrs == NULL) {
95 goto error_release_channels;
98 for (i = 0; i < st->num_channels; i++) {
99 a = devm_kzalloc(dev, sizeof(*a), GFP_KERNEL);
102 goto error_release_channels;
105 sysfs_attr_init(&a->dev_attr.attr);
106 ret = iio_get_channel_type(&st->channels[i], &type);
108 goto error_release_channels;
112 a->dev_attr.attr.name = kasprintf(GFP_KERNEL,
117 a->dev_attr.attr.name = kasprintf(GFP_KERNEL,
122 a->dev_attr.attr.name = kasprintf(GFP_KERNEL,
128 goto error_release_channels;
130 if (a->dev_attr.attr.name == NULL) {
132 goto error_release_channels;
134 a->dev_attr.show = iio_hwmon_read_val;
135 a->dev_attr.attr.mode = S_IRUGO;
137 st->attrs[i] = &a->dev_attr.attr;
139 st->attrs[st->num_channels] = &dev_attr_name.attr;
140 st->attr_group.attrs = st->attrs;
141 platform_set_drvdata(pdev, st);
142 ret = sysfs_create_group(&dev->kobj, &st->attr_group);
144 goto error_release_channels;
146 st->hwmon_dev = hwmon_device_register(dev);
147 if (IS_ERR(st->hwmon_dev)) {
148 ret = PTR_ERR(st->hwmon_dev);
149 goto error_remove_group;
154 sysfs_remove_group(&dev->kobj, &st->attr_group);
155 error_release_channels:
156 iio_channel_release_all(st->channels);
160 static int iio_hwmon_remove(struct platform_device *pdev)
162 struct iio_hwmon_state *st = platform_get_drvdata(pdev);
164 hwmon_device_unregister(st->hwmon_dev);
165 sysfs_remove_group(&pdev->dev.kobj, &st->attr_group);
166 iio_channel_release_all(st->channels);
171 static struct of_device_id iio_hwmon_of_match[] = {
172 { .compatible = "iio-hwmon", },
176 static struct platform_driver __refdata iio_hwmon_driver = {
179 .owner = THIS_MODULE,
180 .of_match_table = iio_hwmon_of_match,
182 .probe = iio_hwmon_probe,
183 .remove = iio_hwmon_remove,
186 module_platform_driver(iio_hwmon_driver);
188 MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
189 MODULE_DESCRIPTION("IIO to hwmon driver");
190 MODULE_LICENSE("GPL v2");