GNU Linux-libre 4.9.328-gnu1
[releases.git] / drivers / hwmon / iio_hwmon.c
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  * @attrs:              null terminated array of attribute pointers.
28  */
29 struct iio_hwmon_state {
30         struct iio_channel *channels;
31         int num_channels;
32         struct device *hwmon_dev;
33         struct attribute_group attr_group;
34         const struct attribute_group *groups[2];
35         struct attribute **attrs;
36 };
37
38 /*
39  * Assumes that IIO and hwmon operate in the same base units.
40  * This is supposed to be true, but needs verification for
41  * new channel types.
42  */
43 static ssize_t iio_hwmon_read_val(struct device *dev,
44                                   struct device_attribute *attr,
45                                   char *buf)
46 {
47         int result;
48         int ret;
49         struct sensor_device_attribute *sattr = to_sensor_dev_attr(attr);
50         struct iio_hwmon_state *state = dev_get_drvdata(dev);
51
52         ret = iio_read_channel_processed(&state->channels[sattr->index],
53                                         &result);
54         if (ret < 0)
55                 return ret;
56
57         return sprintf(buf, "%d\n", result);
58 }
59
60 static int iio_hwmon_probe(struct platform_device *pdev)
61 {
62         struct device *dev = &pdev->dev;
63         struct iio_hwmon_state *st;
64         struct sensor_device_attribute *a;
65         int ret, i;
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";
70         char *sname;
71
72         if (dev->of_node && dev->of_node->name)
73                 name = dev->of_node->name;
74
75         channels = iio_channel_get_all(dev);
76         if (IS_ERR(channels)) {
77                 if (PTR_ERR(channels) == -ENODEV)
78                         return -EPROBE_DEFER;
79                 return PTR_ERR(channels);
80         }
81
82         st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL);
83         if (st == NULL) {
84                 ret = -ENOMEM;
85                 goto error_release_channels;
86         }
87
88         st->channels = channels;
89
90         /* count how many attributes we have */
91         while (st->channels[st->num_channels].indio_dev)
92                 st->num_channels++;
93
94         st->attrs = devm_kzalloc(dev,
95                                  sizeof(*st->attrs) * (st->num_channels + 1),
96                                  GFP_KERNEL);
97         if (st->attrs == NULL) {
98                 ret = -ENOMEM;
99                 goto error_release_channels;
100         }
101
102         for (i = 0; i < st->num_channels; i++) {
103                 a = devm_kzalloc(dev, sizeof(*a), GFP_KERNEL);
104                 if (a == NULL) {
105                         ret = -ENOMEM;
106                         goto error_release_channels;
107                 }
108
109                 sysfs_attr_init(&a->dev_attr.attr);
110                 ret = iio_get_channel_type(&st->channels[i], &type);
111                 if (ret < 0)
112                         goto error_release_channels;
113
114                 switch (type) {
115                 case IIO_VOLTAGE:
116                         a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL,
117                                                                "in%d_input",
118                                                                in_i++);
119                         break;
120                 case IIO_TEMP:
121                         a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL,
122                                                                "temp%d_input",
123                                                                temp_i++);
124                         break;
125                 case IIO_CURRENT:
126                         a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL,
127                                                                "curr%d_input",
128                                                                curr_i++);
129                         break;
130                 case IIO_HUMIDITYRELATIVE:
131                         a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL,
132                                                                "humidity%d_input",
133                                                                humidity_i++);
134                         break;
135                 default:
136                         ret = -EINVAL;
137                         goto error_release_channels;
138                 }
139                 if (a->dev_attr.attr.name == NULL) {
140                         ret = -ENOMEM;
141                         goto error_release_channels;
142                 }
143                 a->dev_attr.show = iio_hwmon_read_val;
144                 a->dev_attr.attr.mode = S_IRUGO;
145                 a->index = i;
146                 st->attrs[i] = &a->dev_attr.attr;
147         }
148
149         st->attr_group.attrs = st->attrs;
150         st->groups[0] = &st->attr_group;
151
152         sname = devm_kstrdup(dev, name, GFP_KERNEL);
153         if (!sname) {
154                 ret = -ENOMEM;
155                 goto error_release_channels;
156         }
157
158         strreplace(sname, '-', '_');
159         st->hwmon_dev = hwmon_device_register_with_groups(dev, sname, st,
160                                                           st->groups);
161         if (IS_ERR(st->hwmon_dev)) {
162                 ret = PTR_ERR(st->hwmon_dev);
163                 goto error_release_channels;
164         }
165         platform_set_drvdata(pdev, st);
166         return 0;
167
168 error_release_channels:
169         iio_channel_release_all(channels);
170         return ret;
171 }
172
173 static int iio_hwmon_remove(struct platform_device *pdev)
174 {
175         struct iio_hwmon_state *st = platform_get_drvdata(pdev);
176
177         hwmon_device_unregister(st->hwmon_dev);
178         iio_channel_release_all(st->channels);
179
180         return 0;
181 }
182
183 static const struct of_device_id iio_hwmon_of_match[] = {
184         { .compatible = "iio-hwmon", },
185         { }
186 };
187 MODULE_DEVICE_TABLE(of, iio_hwmon_of_match);
188
189 static struct platform_driver __refdata iio_hwmon_driver = {
190         .driver = {
191                 .name = "iio_hwmon",
192                 .of_match_table = iio_hwmon_of_match,
193         },
194         .probe = iio_hwmon_probe,
195         .remove = iio_hwmon_remove,
196 };
197
198 module_platform_driver(iio_hwmon_driver);
199
200 MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
201 MODULE_DESCRIPTION("IIO to hwmon driver");
202 MODULE_LICENSE("GPL v2");