1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Hwmon client for industrial I/O devices
3 *
4 * Copyright (c) 2011 Jonathan Cameron
5 */
6
7 #include <linux/kernel.h>
8 #include <linux/slab.h>
9 #include <linux/mod_devicetable.h>
10 #include <linux/module.h>
11 #include <linux/err.h>
12 #include <linux/platform_device.h>
13 #include <linux/property.h>
14
15 #include <linux/hwmon.h>
16 #include <linux/hwmon-sysfs.h>
17 #include <linux/iio/consumer.h>
18 #include <linux/iio/types.h>
19
20 /**
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 * @attr_group: the group of attributes
25 * @groups: null terminated array of attribute groups
26 * @attrs: null terminated array of attribute pointers.
27 */
28 struct iio_hwmon_state {
29 struct iio_channel *channels;
30 int num_channels;
31 struct attribute_group attr_group;
32 const struct attribute_group *groups[2];
33 struct attribute **attrs;
34 };
35
36 /*
37 * Assumes that IIO and hwmon operate in the same base units.
38 * This is supposed to be true, but needs verification for
39 * new channel types.
40 */
iio_hwmon_read_val(struct device * dev,struct device_attribute * attr,char * buf)41 static ssize_t iio_hwmon_read_val(struct device *dev,
42 struct device_attribute *attr,
43 char *buf)
44 {
45 int result;
46 int ret;
47 struct sensor_device_attribute *sattr = to_sensor_dev_attr(attr);
48 struct iio_hwmon_state *state = dev_get_drvdata(dev);
49 struct iio_channel *chan = &state->channels[sattr->index];
50 enum iio_chan_type type;
51
52 ret = iio_read_channel_processed(chan, &result);
53 if (ret < 0)
54 return ret;
55
56 ret = iio_get_channel_type(chan, &type);
57 if (ret < 0)
58 return ret;
59
60 if (type == IIO_POWER)
61 result *= 1000; /* mili-Watts to micro-Watts conversion */
62
63 return sprintf(buf, "%d\n", result);
64 }
65
iio_hwmon_probe(struct platform_device * pdev)66 static int iio_hwmon_probe(struct platform_device *pdev)
67 {
68 struct device *dev = &pdev->dev;
69 struct iio_hwmon_state *st;
70 struct sensor_device_attribute *a;
71 int ret, i;
72 int in_i = 1, temp_i = 1, curr_i = 1, humidity_i = 1, power_i = 1;
73 enum iio_chan_type type;
74 struct iio_channel *channels;
75 struct device *hwmon_dev;
76 char *sname;
77
78 channels = devm_iio_channel_get_all(dev);
79 if (IS_ERR(channels)) {
80 ret = PTR_ERR(channels);
81 if (ret == -ENODEV)
82 ret = -EPROBE_DEFER;
83 return dev_err_probe(dev, ret,
84 "Failed to get channels\n");
85 }
86
87 st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL);
88 if (st == NULL)
89 return -ENOMEM;
90
91 st->channels = channels;
92
93 /* count how many attributes we have */
94 while (st->channels[st->num_channels].indio_dev)
95 st->num_channels++;
96
97 st->attrs = devm_kcalloc(dev,
98 st->num_channels + 1, sizeof(*st->attrs),
99 GFP_KERNEL);
100 if (st->attrs == NULL)
101 return -ENOMEM;
102
103 for (i = 0; i < st->num_channels; i++) {
104 const char *prefix;
105 int n;
106
107 a = devm_kzalloc(dev, sizeof(*a), GFP_KERNEL);
108 if (a == NULL)
109 return -ENOMEM;
110
111 sysfs_attr_init(&a->dev_attr.attr);
112 ret = iio_get_channel_type(&st->channels[i], &type);
113 if (ret < 0)
114 return ret;
115
116 switch (type) {
117 case IIO_VOLTAGE:
118 n = in_i++;
119 prefix = "in";
120 break;
121 case IIO_TEMP:
122 n = temp_i++;
123 prefix = "temp";
124 break;
125 case IIO_CURRENT:
126 n = curr_i++;
127 prefix = "curr";
128 break;
129 case IIO_POWER:
130 n = power_i++;
131 prefix = "power";
132 break;
133 case IIO_HUMIDITYRELATIVE:
134 n = humidity_i++;
135 prefix = "humidity";
136 break;
137 default:
138 return -EINVAL;
139 }
140
141 a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL,
142 "%s%d_input",
143 prefix, n);
144 if (a->dev_attr.attr.name == NULL)
145 return -ENOMEM;
146
147 a->dev_attr.show = iio_hwmon_read_val;
148 a->dev_attr.attr.mode = 0444;
149 a->index = i;
150 st->attrs[i] = &a->dev_attr.attr;
151 }
152
153 st->attr_group.attrs = st->attrs;
154 st->groups[0] = &st->attr_group;
155
156 if (dev_fwnode(dev)) {
157 sname = devm_kasprintf(dev, GFP_KERNEL, "%pfwP", dev_fwnode(dev));
158 if (!sname)
159 return -ENOMEM;
160 strreplace(sname, '-', '_');
161 } else {
162 sname = "iio_hwmon";
163 }
164
165 hwmon_dev = devm_hwmon_device_register_with_groups(dev, sname, st,
166 st->groups);
167 return PTR_ERR_OR_ZERO(hwmon_dev);
168 }
169
170 static const struct of_device_id iio_hwmon_of_match[] = {
171 { .compatible = "iio-hwmon", },
172 { }
173 };
174 MODULE_DEVICE_TABLE(of, iio_hwmon_of_match);
175
176 static struct platform_driver iio_hwmon_driver = {
177 .driver = {
178 .name = "iio_hwmon",
179 .of_match_table = iio_hwmon_of_match,
180 },
181 .probe = iio_hwmon_probe,
182 };
183
184 module_platform_driver(iio_hwmon_driver);
185
186 MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
187 MODULE_DESCRIPTION("IIO to hwmon driver");
188 MODULE_LICENSE("GPL v2");
189