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 */
29struct 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 */
43static 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
60static 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
156error_release_channels:
157	iio_channel_release_all(channels);
158	return ret;
159}
160
161static 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
171static const struct of_device_id iio_hwmon_of_match[] = {
172	{ .compatible = "iio-hwmon", },
173	{ }
174};
175MODULE_DEVICE_TABLE(of, iio_hwmon_of_match);
176
177static 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
186module_platform_driver(iio_hwmon_driver);
187
188MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
189MODULE_DESCRIPTION("IIO to hwmon driver");
190MODULE_LICENSE("GPL v2");
191