1 /* Hwmon client for industrial I/O devices
3 * Copyright (c) 2011 Jonathan Cameron
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.
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/hwmon-sysfs.h>
21 * struct iio_hwmon_state - device instance state
22 * @channels: filled with array of channels from iio
23 * @num_channels: number of channels in channels (saves counting twice)
24 * @hwmon_dev: associated hwmon device
25 * @attr_group: the group of attributes
26 * @attrs: null terminated array of attribute pointers.
28 struct iio_hwmon_state {
29 struct iio_channel *channels;
31 struct device *hwmon_dev;
32 struct attribute_group attr_group;
33 struct attribute **attrs;
37 * Assumes that IIO and hwmon operate in the same base units.
38 * This is supposed to be true, but needs verification for
41 static ssize_t iio_hwmon_read_val(struct device *dev,
42 struct device_attribute *attr,
46 int val, ret, scaleint, scalepart;
47 struct sensor_device_attribute *sattr = to_sensor_dev_attr(attr);
48 struct iio_hwmon_state *state = dev_get_drvdata(dev);
51 * No locking between this pair, so theoretically possible
52 * the scale has changed.
54 ret = iio_st_read_channel_raw(&state->channels[sattr->index],
59 ret = iio_st_read_channel_scale(&state->channels[sattr->index],
60 &scaleint, &scalepart);
65 result = val * scaleint;
67 case IIO_VAL_INT_PLUS_MICRO:
68 result = (s64)val * (s64)scaleint +
69 div_s64((s64)val * (s64)scalepart, 1000000LL);
71 case IIO_VAL_INT_PLUS_NANO:
72 result = (s64)val * (s64)scaleint +
73 div_s64((s64)val * (s64)scalepart, 1000000000LL);
78 return sprintf(buf, "%ld\n", result);
81 static void iio_hwmon_free_attrs(struct iio_hwmon_state *st)
84 struct sensor_device_attribute *a;
85 for (i = 0; i < st->num_channels; i++)
87 a = to_sensor_dev_attr(
88 container_of(st->attrs[i],
89 struct device_attribute,
95 static int __devinit iio_hwmon_probe(struct platform_device *pdev)
97 struct iio_hwmon_state *st;
98 struct sensor_device_attribute *a;
100 int in_i = 1, temp_i = 1, curr_i = 1;
101 enum iio_chan_type type;
103 st = kzalloc(sizeof(*st), GFP_KERNEL);
109 st->channels = iio_st_channel_get_all(dev_name(&pdev->dev));
110 if (IS_ERR(st->channels)) {
111 ret = PTR_ERR(st->channels);
112 goto error_free_state;
115 /* count how many attributes we have */
116 while (st->channels[st->num_channels].indio_dev)
119 st->attrs = kzalloc(sizeof(st->attrs) * (st->num_channels + 1),
121 if (st->attrs == NULL) {
123 goto error_release_channels;
125 for (i = 0; i < st->num_channels; i++) {
126 a = kzalloc(sizeof(*a), GFP_KERNEL);
129 goto error_free_attrs;
132 sysfs_attr_init(&a->dev_attr.attr);
133 ret = iio_st_get_channel_type(&st->channels[i], &type);
136 goto error_free_attrs;
140 a->dev_attr.attr.name = kasprintf(GFP_KERNEL,
145 a->dev_attr.attr.name = kasprintf(GFP_KERNEL,
150 a->dev_attr.attr.name = kasprintf(GFP_KERNEL,
157 goto error_free_attrs;
159 if (a->dev_attr.attr.name == NULL) {
162 goto error_free_attrs;
164 a->dev_attr.show = iio_hwmon_read_val;
165 a->dev_attr.attr.mode = S_IRUGO;
167 st->attrs[i] = &a->dev_attr.attr;
170 st->attr_group.attrs = st->attrs;
171 platform_set_drvdata(pdev, st);
172 ret = sysfs_create_group(&pdev->dev.kobj, &st->attr_group);
174 goto error_free_attrs;
176 st->hwmon_dev = hwmon_device_register(&pdev->dev);
177 if (IS_ERR(st->hwmon_dev)) {
178 ret = PTR_ERR(st->hwmon_dev);
179 goto error_remove_group;
184 sysfs_remove_group(&pdev->dev.kobj, &st->attr_group);
186 iio_hwmon_free_attrs(st);
188 error_release_channels:
189 iio_st_channel_release_all(st->channels);
196 static int __devexit iio_hwmon_remove(struct platform_device *pdev)
198 struct iio_hwmon_state *st = platform_get_drvdata(pdev);
200 hwmon_device_unregister(st->hwmon_dev);
201 sysfs_remove_group(&pdev->dev.kobj, &st->attr_group);
202 iio_hwmon_free_attrs(st);
204 iio_st_channel_release_all(st->channels);
209 static struct platform_driver __refdata iio_hwmon_driver = {
212 .owner = THIS_MODULE,
214 .probe = iio_hwmon_probe,
215 .remove = __devexit_p(iio_hwmon_remove),
218 static int iio_inkern_init(void)
220 return platform_driver_register(&iio_hwmon_driver);
222 module_init(iio_inkern_init);
224 static void iio_inkern_exit(void)
226 platform_driver_unregister(&iio_hwmon_driver);
228 module_exit(iio_inkern_exit);
230 MODULE_AUTHOR("Jonathan Cameron <jic23@cam.ac.uk>");
231 MODULE_DESCRIPTION("IIO to hwmon driver");
232 MODULE_LICENSE("GPL v2");