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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 | struct attribute **attrs; | |
35 | }; | |
36 | ||
37 | /* | |
38 | * Assumes that IIO and hwmon operate in the same base units. | |
39 | * This is supposed to be true, but needs verification for | |
40 | * new channel types. | |
41 | */ | |
42 | static ssize_t iio_hwmon_read_val(struct device *dev, | |
43 | struct device_attribute *attr, | |
44 | char *buf) | |
45 | { | |
46 | int result; | |
47 | int ret; | |
48 | struct sensor_device_attribute *sattr = to_sensor_dev_attr(attr); | |
49 | struct iio_hwmon_state *state = dev_get_drvdata(dev); | |
50 | ||
51 | ret = iio_read_channel_processed(&state->channels[sattr->index], | |
52 | &result); | |
53 | if (ret < 0) | |
54 | return ret; | |
55 | ||
56 | return sprintf(buf, "%d\n", result); | |
57 | } | |
58 | ||
59 | static ssize_t show_name(struct device *dev, struct device_attribute *attr, | |
60 | char *buf) | |
61 | { | |
62 | const char *name = "iio_hwmon"; | |
63 | ||
64 | if (dev->of_node && dev->of_node->name) | |
65 | name = dev->of_node->name; | |
66 | ||
67 | return sprintf(buf, "%s\n", name); | |
68 | } | |
69 | ||
70 | static DEVICE_ATTR(name, S_IRUGO, show_name, NULL); | |
71 | ||
72 | static int iio_hwmon_probe(struct platform_device *pdev) | |
73 | { | |
74 | struct device *dev = &pdev->dev; | |
75 | struct iio_hwmon_state *st; | |
76 | struct sensor_device_attribute *a; | |
77 | int ret, i; | |
78 | int in_i = 1, temp_i = 1, curr_i = 1; | |
79 | enum iio_chan_type type; | |
80 | struct iio_channel *channels; | |
81 | ||
82 | channels = iio_channel_get_all(dev); | |
83 | if (IS_ERR(channels)) | |
84 | return PTR_ERR(channels); | |
85 | ||
86 | st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL); | |
87 | if (st == NULL) | |
88 | return -ENOMEM; | |
89 | ||
90 | st->channels = channels; | |
91 | ||
92 | /* count how many attributes we have */ | |
93 | while (st->channels[st->num_channels].indio_dev) | |
94 | st->num_channels++; | |
95 | ||
96 | st->attrs = devm_kzalloc(dev, | |
97 | sizeof(*st->attrs) * (st->num_channels + 2), | |
98 | GFP_KERNEL); | |
99 | if (st->attrs == NULL) { | |
100 | ret = -ENOMEM; | |
101 | goto error_release_channels; | |
102 | } | |
103 | ||
104 | for (i = 0; i < st->num_channels; i++) { | |
105 | a = devm_kzalloc(dev, sizeof(*a), GFP_KERNEL); | |
106 | if (a == NULL) { | |
107 | ret = -ENOMEM; | |
108 | goto error_release_channels; | |
109 | } | |
110 | ||
111 | sysfs_attr_init(&a->dev_attr.attr); | |
112 | ret = iio_get_channel_type(&st->channels[i], &type); | |
113 | if (ret < 0) | |
114 | goto error_release_channels; | |
115 | ||
116 | switch (type) { | |
117 | case IIO_VOLTAGE: | |
118 | a->dev_attr.attr.name = kasprintf(GFP_KERNEL, | |
119 | "in%d_input", | |
120 | in_i++); | |
121 | break; | |
122 | case IIO_TEMP: | |
123 | a->dev_attr.attr.name = kasprintf(GFP_KERNEL, | |
124 | "temp%d_input", | |
125 | temp_i++); | |
126 | break; | |
127 | case IIO_CURRENT: | |
128 | a->dev_attr.attr.name = kasprintf(GFP_KERNEL, | |
129 | "curr%d_input", | |
130 | curr_i++); | |
131 | break; | |
132 | default: | |
133 | ret = -EINVAL; | |
134 | goto error_release_channels; | |
135 | } | |
136 | if (a->dev_attr.attr.name == NULL) { | |
137 | ret = -ENOMEM; | |
138 | goto error_release_channels; | |
139 | } | |
140 | a->dev_attr.show = iio_hwmon_read_val; | |
141 | a->dev_attr.attr.mode = S_IRUGO; | |
142 | a->index = i; | |
143 | st->attrs[i] = &a->dev_attr.attr; | |
144 | } | |
145 | st->attrs[st->num_channels] = &dev_attr_name.attr; | |
146 | st->attr_group.attrs = st->attrs; | |
147 | platform_set_drvdata(pdev, st); | |
148 | ret = sysfs_create_group(&dev->kobj, &st->attr_group); | |
149 | if (ret < 0) | |
150 | goto error_release_channels; | |
151 | ||
152 | st->hwmon_dev = hwmon_device_register(dev); | |
153 | if (IS_ERR(st->hwmon_dev)) { | |
154 | ret = PTR_ERR(st->hwmon_dev); | |
155 | goto error_remove_group; | |
156 | } | |
157 | return 0; | |
158 | ||
159 | error_remove_group: | |
160 | sysfs_remove_group(&dev->kobj, &st->attr_group); | |
161 | error_release_channels: | |
162 | iio_channel_release_all(st->channels); | |
163 | return ret; | |
164 | } | |
165 | ||
166 | static int iio_hwmon_remove(struct platform_device *pdev) | |
167 | { | |
168 | struct iio_hwmon_state *st = platform_get_drvdata(pdev); | |
169 | ||
170 | hwmon_device_unregister(st->hwmon_dev); | |
171 | sysfs_remove_group(&pdev->dev.kobj, &st->attr_group); | |
172 | iio_channel_release_all(st->channels); | |
173 | ||
174 | return 0; | |
175 | } | |
176 | ||
177 | static struct of_device_id iio_hwmon_of_match[] = { | |
178 | { .compatible = "iio-hwmon", }, | |
179 | { } | |
180 | }; | |
181 | ||
182 | static struct platform_driver __refdata iio_hwmon_driver = { | |
183 | .driver = { | |
184 | .name = "iio_hwmon", | |
185 | .owner = THIS_MODULE, | |
186 | .of_match_table = iio_hwmon_of_match, | |
187 | }, | |
188 | .probe = iio_hwmon_probe, | |
189 | .remove = iio_hwmon_remove, | |
190 | }; | |
191 | ||
192 | module_platform_driver(iio_hwmon_driver); | |
193 | ||
194 | MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>"); | |
195 | MODULE_DESCRIPTION("IIO to hwmon driver"); | |
196 | MODULE_LICENSE("GPL v2"); |