tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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 * @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.
29 */
30struct iio_hwmon_state {
31 struct iio_channel *channels;
32 int num_channels;
33 struct device *hwmon_dev;
34 struct attribute_group attr_group;
35 const struct attribute_group *groups[2];
36 struct attribute **attrs;
37};
38
39/*
40 * Assumes that IIO and hwmon operate in the same base units.
41 * This is supposed to be true, but needs verification for
42 * new channel types.
43 */
44static ssize_t iio_hwmon_read_val(struct device *dev,
45 struct device_attribute *attr,
46 char *buf)
47{
48 int result;
49 int ret;
50 struct sensor_device_attribute *sattr = to_sensor_dev_attr(attr);
51 struct iio_hwmon_state *state = dev_get_drvdata(dev);
52
53 ret = iio_read_channel_processed(&state->channels[sattr->index],
54 &result);
55 if (ret < 0)
56 return ret;
57
58 return sprintf(buf, "%d\n", result);
59}
60
61static int iio_hwmon_probe(struct platform_device *pdev)
62{
63 struct device *dev = &pdev->dev;
64 struct iio_hwmon_state *st;
65 struct sensor_device_attribute *a;
66 int ret, i;
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";
71 char *sname;
72
73 if (dev->of_node && dev->of_node->name)
74 name = dev->of_node->name;
75
76 channels = iio_channel_get_all(dev);
77 if (IS_ERR(channels)) {
78 if (PTR_ERR(channels) == -ENODEV)
79 return -EPROBE_DEFER;
80 return PTR_ERR(channels);
81 }
82
83 st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL);
84 if (st == NULL) {
85 ret = -ENOMEM;
86 goto error_release_channels;
87 }
88
89 st->channels = channels;
90
91 /* count how many attributes we have */
92 while (st->channels[st->num_channels].indio_dev)
93 st->num_channels++;
94
95 st->attrs = devm_kzalloc(dev,
96 sizeof(*st->attrs) * (st->num_channels + 1),
97 GFP_KERNEL);
98 if (st->attrs == NULL) {
99 ret = -ENOMEM;
100 goto error_release_channels;
101 }
102
103 for (i = 0; i < st->num_channels; i++) {
104 a = devm_kzalloc(dev, sizeof(*a), GFP_KERNEL);
105 if (a == NULL) {
106 ret = -ENOMEM;
107 goto error_release_channels;
108 }
109
110 sysfs_attr_init(&a->dev_attr.attr);
111 ret = iio_get_channel_type(&st->channels[i], &type);
112 if (ret < 0)
113 goto error_release_channels;
114
115 switch (type) {
116 case IIO_VOLTAGE:
117 a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL,
118 "in%d_input",
119 in_i++);
120 break;
121 case IIO_TEMP:
122 a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL,
123 "temp%d_input",
124 temp_i++);
125 break;
126 case IIO_CURRENT:
127 a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL,
128 "curr%d_input",
129 curr_i++);
130 break;
131 case IIO_HUMIDITYRELATIVE:
132 a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL,
133 "humidity%d_input",
134 humidity_i++);
135 break;
136 default:
137 ret = -EINVAL;
138 goto error_release_channels;
139 }
140 if (a->dev_attr.attr.name == NULL) {
141 ret = -ENOMEM;
142 goto error_release_channels;
143 }
144 a->dev_attr.show = iio_hwmon_read_val;
145 a->dev_attr.attr.mode = S_IRUGO;
146 a->index = i;
147 st->attrs[i] = &a->dev_attr.attr;
148 }
149
150 st->attr_group.attrs = st->attrs;
151 st->groups[0] = &st->attr_group;
152
153 sname = devm_kstrdup(dev, name, GFP_KERNEL);
154 if (!sname) {
155 ret = -ENOMEM;
156 goto error_release_channels;
157 }
158
159 strreplace(sname, '-', '_');
160 st->hwmon_dev = hwmon_device_register_with_groups(dev, sname, st,
161 st->groups);
162 if (IS_ERR(st->hwmon_dev)) {
163 ret = PTR_ERR(st->hwmon_dev);
164 goto error_release_channels;
165 }
166 platform_set_drvdata(pdev, st);
167 return 0;
168
169error_release_channels:
170 iio_channel_release_all(channels);
171 return ret;
172}
173
174static int iio_hwmon_remove(struct platform_device *pdev)
175{
176 struct iio_hwmon_state *st = platform_get_drvdata(pdev);
177
178 hwmon_device_unregister(st->hwmon_dev);
179 iio_channel_release_all(st->channels);
180
181 return 0;
182}
183
184static const struct of_device_id iio_hwmon_of_match[] = {
185 { .compatible = "iio-hwmon", },
186 { }
187};
188MODULE_DEVICE_TABLE(of, iio_hwmon_of_match);
189
190static struct platform_driver __refdata iio_hwmon_driver = {
191 .driver = {
192 .name = "iio_hwmon",
193 .of_match_table = iio_hwmon_of_match,
194 },
195 .probe = iio_hwmon_probe,
196 .remove = iio_hwmon_remove,
197};
198
199module_platform_driver(iio_hwmon_driver);
200
201MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
202MODULE_DESCRIPTION("IIO to hwmon driver");
203MODULE_LICENSE("GPL v2");