Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
[firefly-linux-kernel-4.4.55.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
71         if (dev->of_node && dev->of_node->name)
72                 name = dev->of_node->name;
73
74         channels = iio_channel_get_all(dev);
75         if (IS_ERR(channels))
76                 return PTR_ERR(channels);
77
78         st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL);
79         if (st == NULL) {
80                 ret = -ENOMEM;
81                 goto error_release_channels;
82         }
83
84         st->channels = channels;
85
86         /* count how many attributes we have */
87         while (st->channels[st->num_channels].indio_dev)
88                 st->num_channels++;
89
90         st->attrs = devm_kzalloc(dev,
91                                  sizeof(*st->attrs) * (st->num_channels + 1),
92                                  GFP_KERNEL);
93         if (st->attrs == NULL) {
94                 ret = -ENOMEM;
95                 goto error_release_channels;
96         }
97
98         for (i = 0; i < st->num_channels; i++) {
99                 a = devm_kzalloc(dev, sizeof(*a), GFP_KERNEL);
100                 if (a == NULL) {
101                         ret = -ENOMEM;
102                         goto error_release_channels;
103                 }
104
105                 sysfs_attr_init(&a->dev_attr.attr);
106                 ret = iio_get_channel_type(&st->channels[i], &type);
107                 if (ret < 0)
108                         goto error_release_channels;
109
110                 switch (type) {
111                 case IIO_VOLTAGE:
112                         a->dev_attr.attr.name = kasprintf(GFP_KERNEL,
113                                                           "in%d_input",
114                                                           in_i++);
115                         break;
116                 case IIO_TEMP:
117                         a->dev_attr.attr.name = kasprintf(GFP_KERNEL,
118                                                           "temp%d_input",
119                                                           temp_i++);
120                         break;
121                 case IIO_CURRENT:
122                         a->dev_attr.attr.name = kasprintf(GFP_KERNEL,
123                                                           "curr%d_input",
124                                                           curr_i++);
125                         break;
126                 case IIO_HUMIDITYRELATIVE:
127                         a->dev_attr.attr.name = kasprintf(GFP_KERNEL,
128                                                           "humidity%d_input",
129                                                           humidity_i++);
130                         break;
131                 default:
132                         ret = -EINVAL;
133                         goto error_release_channels;
134                 }
135                 if (a->dev_attr.attr.name == NULL) {
136                         ret = -ENOMEM;
137                         goto error_release_channels;
138                 }
139                 a->dev_attr.show = iio_hwmon_read_val;
140                 a->dev_attr.attr.mode = S_IRUGO;
141                 a->index = i;
142                 st->attrs[i] = &a->dev_attr.attr;
143         }
144
145         st->attr_group.attrs = st->attrs;
146         st->groups[0] = &st->attr_group;
147         st->hwmon_dev = hwmon_device_register_with_groups(dev, name, st,
148                                                           st->groups);
149         if (IS_ERR(st->hwmon_dev)) {
150                 ret = PTR_ERR(st->hwmon_dev);
151                 goto error_release_channels;
152         }
153         platform_set_drvdata(pdev, st);
154         return 0;
155
156 error_release_channels:
157         iio_channel_release_all(channels);
158         return ret;
159 }
160
161 static int iio_hwmon_remove(struct platform_device *pdev)
162 {
163         struct iio_hwmon_state *st = platform_get_drvdata(pdev);
164
165         hwmon_device_unregister(st->hwmon_dev);
166         iio_channel_release_all(st->channels);
167
168         return 0;
169 }
170
171 static const struct of_device_id iio_hwmon_of_match[] = {
172         { .compatible = "iio-hwmon", },
173         { }
174 };
175 MODULE_DEVICE_TABLE(of, iio_hwmon_of_match);
176
177 static struct platform_driver __refdata iio_hwmon_driver = {
178         .driver = {
179                 .name = "iio_hwmon",
180                 .of_match_table = iio_hwmon_of_match,
181         },
182         .probe = iio_hwmon_probe,
183         .remove = iio_hwmon_remove,
184 };
185
186 module_platform_driver(iio_hwmon_driver);
187
188 MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
189 MODULE_DESCRIPTION("IIO to hwmon driver");
190 MODULE_LICENSE("GPL v2");