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>
17 #include <linux/hwmon-sysfs.h>
18 #include <linux/iio/consumer.h>
19 #include <linux/iio/types.h>
22 * struct iio_hwmon_state - device instance state
23 * @channels: filled with array of channels from iio
24 * @num_channels: number of channels in channels (saves counting twice)
25 * @hwmon_dev: associated hwmon device
26 * @attr_group: the group of attributes
27 * @attrs: null terminated array of attribute pointers.
29 struct iio_hwmon_state {
30 struct iio_channel *channels;
32 struct device *hwmon_dev;
33 struct attribute_group attr_group;
34 const struct attribute_group *groups[2];
35 struct attribute **attrs;
39 * Assumes that IIO and hwmon operate in the same base units.
40 * This is supposed to be true, but needs verification for
43 static ssize_t iio_hwmon_read_val(struct device *dev,
44 struct device_attribute *attr,
49 struct sensor_device_attribute *sattr = to_sensor_dev_attr(attr);
50 struct iio_hwmon_state *state = dev_get_drvdata(dev);
52 ret = iio_read_channel_processed(&state->channels[sattr->index],
57 return sprintf(buf, "%d\n", result);
60 static int iio_hwmon_probe(struct platform_device *pdev)
62 struct device *dev = &pdev->dev;
63 struct iio_hwmon_state *st;
64 struct sensor_device_attribute *a;
66 int in_i = 1, temp_i = 1, curr_i = 1, humidity_i = 1;
67 enum iio_chan_type type;
68 struct iio_channel *channels;
69 const char *name = "iio_hwmon";
72 if (dev->of_node && dev->of_node->name)
73 name = dev->of_node->name;
75 channels = iio_channel_get_all(dev);
77 return PTR_ERR(channels);
79 st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL);
82 goto error_release_channels;
85 st->channels = channels;
87 /* count how many attributes we have */
88 while (st->channels[st->num_channels].indio_dev)
91 st->attrs = devm_kzalloc(dev,
92 sizeof(*st->attrs) * (st->num_channels + 1),
94 if (st->attrs == NULL) {
96 goto error_release_channels;
99 for (i = 0; i < st->num_channels; i++) {
100 a = devm_kzalloc(dev, sizeof(*a), GFP_KERNEL);
103 goto error_release_channels;
106 sysfs_attr_init(&a->dev_attr.attr);
107 ret = iio_get_channel_type(&st->channels[i], &type);
109 goto error_release_channels;
113 a->dev_attr.attr.name = kasprintf(GFP_KERNEL,
118 a->dev_attr.attr.name = kasprintf(GFP_KERNEL,
123 a->dev_attr.attr.name = kasprintf(GFP_KERNEL,
127 case IIO_HUMIDITYRELATIVE:
128 a->dev_attr.attr.name = kasprintf(GFP_KERNEL,
134 goto error_release_channels;
136 if (a->dev_attr.attr.name == NULL) {
138 goto error_release_channels;
140 a->dev_attr.show = iio_hwmon_read_val;
141 a->dev_attr.attr.mode = S_IRUGO;
143 st->attrs[i] = &a->dev_attr.attr;
146 st->attr_group.attrs = st->attrs;
147 st->groups[0] = &st->attr_group;
149 sname = devm_kstrdup(dev, name, GFP_KERNEL);
152 goto error_release_channels;
155 strreplace(sname, '-', '_');
156 st->hwmon_dev = hwmon_device_register_with_groups(dev, sname, st,
158 if (IS_ERR(st->hwmon_dev)) {
159 ret = PTR_ERR(st->hwmon_dev);
160 goto error_release_channels;
162 platform_set_drvdata(pdev, st);
165 error_release_channels:
166 iio_channel_release_all(channels);
170 static int iio_hwmon_remove(struct platform_device *pdev)
172 struct iio_hwmon_state *st = platform_get_drvdata(pdev);
174 hwmon_device_unregister(st->hwmon_dev);
175 iio_channel_release_all(st->channels);
180 static const struct of_device_id iio_hwmon_of_match[] = {
181 { .compatible = "iio-hwmon", },
184 MODULE_DEVICE_TABLE(of, iio_hwmon_of_match);
186 static struct platform_driver __refdata iio_hwmon_driver = {
189 .of_match_table = iio_hwmon_of_match,
191 .probe = iio_hwmon_probe,
192 .remove = iio_hwmon_remove,
195 module_platform_driver(iio_hwmon_driver);
197 MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
198 MODULE_DESCRIPTION("IIO to hwmon driver");
199 MODULE_LICENSE("GPL v2");