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 * @groups: null terminated array of attribute groups
28 * @attrs: null terminated array of attribute pointers.
30 struct iio_hwmon_state {
31 struct iio_channel *channels;
33 struct device *hwmon_dev;
34 struct attribute_group attr_group;
35 const struct attribute_group *groups[2];
36 struct attribute **attrs;
40 * Assumes that IIO and hwmon operate in the same base units.
41 * This is supposed to be true, but needs verification for
44 static ssize_t iio_hwmon_read_val(struct device *dev,
45 struct device_attribute *attr,
50 struct sensor_device_attribute *sattr = to_sensor_dev_attr(attr);
51 struct iio_hwmon_state *state = dev_get_drvdata(dev);
53 ret = iio_read_channel_processed(&state->channels[sattr->index],
58 return sprintf(buf, "%d\n", result);
61 static int iio_hwmon_probe(struct platform_device *pdev)
63 struct device *dev = &pdev->dev;
64 struct iio_hwmon_state *st;
65 struct sensor_device_attribute *a;
67 int in_i = 1, temp_i = 1, curr_i = 1, humidity_i = 1;
68 enum iio_chan_type type;
69 struct iio_channel *channels;
70 const char *name = "iio_hwmon";
73 if (dev->of_node && dev->of_node->name)
74 name = dev->of_node->name;
76 channels = iio_channel_get_all(dev);
77 if (IS_ERR(channels)) {
78 if (PTR_ERR(channels) == -ENODEV)
80 return PTR_ERR(channels);
83 st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL);
86 goto error_release_channels;
89 st->channels = channels;
91 /* count how many attributes we have */
92 while (st->channels[st->num_channels].indio_dev)
95 st->attrs = devm_kzalloc(dev,
96 sizeof(*st->attrs) * (st->num_channels + 1),
98 if (st->attrs == NULL) {
100 goto error_release_channels;
103 for (i = 0; i < st->num_channels; i++) {
104 a = devm_kzalloc(dev, sizeof(*a), GFP_KERNEL);
107 goto error_release_channels;
110 sysfs_attr_init(&a->dev_attr.attr);
111 ret = iio_get_channel_type(&st->channels[i], &type);
113 goto error_release_channels;
117 a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL,
122 a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL,
127 a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL,
131 case IIO_HUMIDITYRELATIVE:
132 a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL,
138 goto error_release_channels;
140 if (a->dev_attr.attr.name == NULL) {
142 goto error_release_channels;
144 a->dev_attr.show = iio_hwmon_read_val;
145 a->dev_attr.attr.mode = S_IRUGO;
147 st->attrs[i] = &a->dev_attr.attr;
150 st->attr_group.attrs = st->attrs;
151 st->groups[0] = &st->attr_group;
153 sname = devm_kstrdup(dev, name, GFP_KERNEL);
156 goto error_release_channels;
159 strreplace(sname, '-', '_');
160 st->hwmon_dev = hwmon_device_register_with_groups(dev, sname, st,
162 if (IS_ERR(st->hwmon_dev)) {
163 ret = PTR_ERR(st->hwmon_dev);
164 goto error_release_channels;
166 platform_set_drvdata(pdev, st);
169 error_release_channels:
170 iio_channel_release_all(channels);
174 static int iio_hwmon_remove(struct platform_device *pdev)
176 struct iio_hwmon_state *st = platform_get_drvdata(pdev);
178 hwmon_device_unregister(st->hwmon_dev);
179 iio_channel_release_all(st->channels);
184 static const struct of_device_id iio_hwmon_of_match[] = {
185 { .compatible = "iio-hwmon", },
188 MODULE_DEVICE_TABLE(of, iio_hwmon_of_match);
190 static struct platform_driver __refdata iio_hwmon_driver = {
193 .of_match_table = iio_hwmon_of_match,
195 .probe = iio_hwmon_probe,
196 .remove = iio_hwmon_remove,
199 module_platform_driver(iio_hwmon_driver);
201 MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
202 MODULE_DESCRIPTION("IIO to hwmon driver");
203 MODULE_LICENSE("GPL v2");