1/* Hwmon client for industrial I/O devices
2 *
3 * Copyright (c) 2011 Jonathan Cameron
4 *
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.
8 */
9
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/of.h>
17#include <linux/hwmon-sysfs.h>
18#include <linux/iio/consumer.h>
19#include <linux/iio/types.h>
20
21/**
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 * @attr_group: the group of attributes
26 * @groups: null terminated array of attribute groups
27 * @attrs: null terminated array of attribute pointers.
28 */
29struct iio_hwmon_state {
30 struct iio_channel *channels;
31 int num_channels;
32 struct attribute_group attr_group;
33 const struct attribute_group *groups[2];
34 struct attribute **attrs;
35};
36
37/*
38 * Assumes that IIO and hwmon operate in the same base units.
39 * This is supposed to be true, but needs verification for
40 * new channel types.
41 */
42static ssize_t iio_hwmon_read_val(struct device *dev,
43 struct device_attribute *attr,
44 char *buf)
45{
46 int result;
47 int ret;
48 struct sensor_device_attribute *sattr = to_sensor_dev_attr(attr);
49 struct iio_hwmon_state *state = dev_get_drvdata(dev);
50
51 ret = iio_read_channel_processed(&state->channels[sattr->index],
52 &result);
53 if (ret < 0)
54 return ret;
55
56 return sprintf(buf, "%d\n", result);
57}
58
59static int iio_hwmon_probe(struct platform_device *pdev)
60{
61 struct device *dev = &pdev->dev;
62 struct iio_hwmon_state *st;
63 struct sensor_device_attribute *a;
64 int ret, i;
65 int in_i = 1, temp_i = 1, curr_i = 1, humidity_i = 1;
66 enum iio_chan_type type;
67 struct iio_channel *channels;
68 struct device *hwmon_dev;
69 char *sname;
70
71 channels = devm_iio_channel_get_all(dev);
72 if (IS_ERR(channels)) {
73 if (PTR_ERR(channels) == -ENODEV)
74 return -EPROBE_DEFER;
75 return PTR_ERR(channels);
76 }
77
78 st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL);
79 if (st == NULL)
80 return -ENOMEM;
81
82 st->channels = channels;
83
84 /* count how many attributes we have */
85 while (st->channels[st->num_channels].indio_dev)
86 st->num_channels++;
87
88 st->attrs = devm_kcalloc(dev,
89 st->num_channels + 1, sizeof(*st->attrs),
90 GFP_KERNEL);
91 if (st->attrs == NULL)
92 return -ENOMEM;
93
94 for (i = 0; i < st->num_channels; i++) {
95 a = devm_kzalloc(dev, sizeof(*a), GFP_KERNEL);
96 if (a == NULL)
97 return -ENOMEM;
98
99 sysfs_attr_init(&a->dev_attr.attr);
100 ret = iio_get_channel_type(&st->channels[i], &type);
101 if (ret < 0)
102 return ret;
103
104 switch (type) {
105 case IIO_VOLTAGE:
106 a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL,
107 "in%d_input",
108 in_i++);
109 break;
110 case IIO_TEMP:
111 a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL,
112 "temp%d_input",
113 temp_i++);
114 break;
115 case IIO_CURRENT:
116 a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL,
117 "curr%d_input",
118 curr_i++);
119 break;
120 case IIO_HUMIDITYRELATIVE:
121 a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL,
122 "humidity%d_input",
123 humidity_i++);
124 break;
125 default:
126 return -EINVAL;
127 }
128 if (a->dev_attr.attr.name == NULL)
129 return -ENOMEM;
130
131 a->dev_attr.show = iio_hwmon_read_val;
132 a->dev_attr.attr.mode = 0444;
133 a->index = i;
134 st->attrs[i] = &a->dev_attr.attr;
135 }
136
137 st->attr_group.attrs = st->attrs;
138 st->groups[0] = &st->attr_group;
139
140 if (dev->of_node) {
141 sname = devm_kasprintf(dev, GFP_KERNEL, "%pOFn", dev->of_node);
142 if (!sname)
143 return -ENOMEM;
144 strreplace(sname, '-', '_');
145 } else {
146 sname = "iio_hwmon";
147 }
148
149 hwmon_dev = devm_hwmon_device_register_with_groups(dev, sname, st,
150 st->groups);
151 return PTR_ERR_OR_ZERO(hwmon_dev);
152}
153
154static const struct of_device_id iio_hwmon_of_match[] = {
155 { .compatible = "iio-hwmon", },
156 { }
157};
158MODULE_DEVICE_TABLE(of, iio_hwmon_of_match);
159
160static struct platform_driver __refdata iio_hwmon_driver = {
161 .driver = {
162 .name = "iio_hwmon",
163 .of_match_table = iio_hwmon_of_match,
164 },
165 .probe = iio_hwmon_probe,
166};
167
168module_platform_driver(iio_hwmon_driver);
169
170MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
171MODULE_DESCRIPTION("IIO to hwmon driver");
172MODULE_LICENSE("GPL v2");
173