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 */
iio_hwmon_read_val(struct device * dev,struct device_attribute * attr,char * buf)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
iio_hwmon_probe(struct platform_device * pdev)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;
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 default:
127 ret = -EINVAL;
128 goto error_release_channels;
129 }
130 if (a->dev_attr.attr.name == NULL) {
131 ret = -ENOMEM;
132 goto error_release_channels;
133 }
134 a->dev_attr.show = iio_hwmon_read_val;
135 a->dev_attr.attr.mode = S_IRUGO;
136 a->index = i;
137 st->attrs[i] = &a->dev_attr.attr;
138 }
139
140 st->attr_group.attrs = st->attrs;
141 st->groups[0] = &st->attr_group;
142 st->hwmon_dev = hwmon_device_register_with_groups(dev, name, st,
143 st->groups);
144 if (IS_ERR(st->hwmon_dev)) {
145 ret = PTR_ERR(st->hwmon_dev);
146 goto error_release_channels;
147 }
148 platform_set_drvdata(pdev, st);
149 return 0;
150
151 error_release_channels:
152 iio_channel_release_all(channels);
153 return ret;
154 }
155
iio_hwmon_remove(struct platform_device * pdev)156 static int iio_hwmon_remove(struct platform_device *pdev)
157 {
158 struct iio_hwmon_state *st = platform_get_drvdata(pdev);
159
160 hwmon_device_unregister(st->hwmon_dev);
161 iio_channel_release_all(st->channels);
162
163 return 0;
164 }
165
166 static const struct of_device_id iio_hwmon_of_match[] = {
167 { .compatible = "iio-hwmon", },
168 { }
169 };
170 MODULE_DEVICE_TABLE(of, iio_hwmon_of_match);
171
172 static struct platform_driver __refdata iio_hwmon_driver = {
173 .driver = {
174 .name = "iio_hwmon",
175 .owner = THIS_MODULE,
176 .of_match_table = iio_hwmon_of_match,
177 },
178 .probe = iio_hwmon_probe,
179 .remove = iio_hwmon_remove,
180 };
181
182 module_platform_driver(iio_hwmon_driver);
183
184 MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
185 MODULE_DESCRIPTION("IIO to hwmon driver");
186 MODULE_LICENSE("GPL v2");
187