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
iio_hwmon_read_label(struct device * dev,struct device_attribute * attr,char * buf)36 static ssize_t iio_hwmon_read_label(struct device *dev,
37 struct device_attribute *attr,
38 char *buf)
39 {
40 struct sensor_device_attribute *sattr = to_sensor_dev_attr(attr);
41 struct iio_hwmon_state *state = dev_get_drvdata(dev);
42 struct iio_channel *chan = &state->channels[sattr->index];
43
44 return iio_read_channel_label(chan, buf);
45 }
46
47 /*
48 * Assumes that IIO and hwmon operate in the same base units.
49 * This is supposed to be true, but needs verification for
50 * new channel types.
51 */
iio_hwmon_read_val(struct device * dev,struct device_attribute * attr,char * buf)52 static ssize_t iio_hwmon_read_val(struct device *dev,
53 struct device_attribute *attr,
54 char *buf)
55 {
56 int result;
57 int ret;
58 struct sensor_device_attribute *sattr = to_sensor_dev_attr(attr);
59 struct iio_hwmon_state *state = dev_get_drvdata(dev);
60 struct iio_channel *chan = &state->channels[sattr->index];
61 enum iio_chan_type type;
62
63 ret = iio_get_channel_type(chan, &type);
64 if (ret < 0)
65 return ret;
66
67 if (type == IIO_POWER)
68 /* mili-Watts to micro-Watts conversion */
69 ret = iio_read_channel_processed_scale(chan, &result, 1000);
70 else
71 ret = iio_read_channel_processed(chan, &result);
72 if (ret < 0)
73 return ret;
74
75 return sprintf(buf, "%d\n", result);
76 }
77
iio_hwmon_probe(struct platform_device * pdev)78 static int iio_hwmon_probe(struct platform_device *pdev)
79 {
80 struct device *dev = &pdev->dev;
81 struct iio_hwmon_state *st;
82 struct sensor_device_attribute *a;
83 int ret, i, attr = 0;
84 int in_i = 1, temp_i = 1, curr_i = 1, humidity_i = 1, power_i = 1;
85 enum iio_chan_type type;
86 struct iio_channel *channels;
87 struct device *hwmon_dev;
88 char *sname;
89 void *buf;
90
91 channels = devm_iio_channel_get_all(dev);
92 if (IS_ERR(channels)) {
93 ret = PTR_ERR(channels);
94 if (ret == -ENODEV)
95 ret = -EPROBE_DEFER;
96 return dev_err_probe(dev, ret,
97 "Failed to get channels\n");
98 }
99
100 st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL);
101 buf = (void *)devm_get_free_pages(dev, GFP_KERNEL, 0);
102 if (!st || !buf)
103 return -ENOMEM;
104
105 st->channels = channels;
106
107 /* count how many channels we have */
108 while (st->channels[st->num_channels].indio_dev)
109 st->num_channels++;
110
111 st->attrs = devm_kcalloc(dev,
112 2 * st->num_channels + 1, sizeof(*st->attrs),
113 GFP_KERNEL);
114 if (st->attrs == NULL)
115 return -ENOMEM;
116
117 for (i = 0; i < st->num_channels; i++) {
118 const char *prefix;
119 int n;
120
121 a = devm_kzalloc(dev, sizeof(*a), GFP_KERNEL);
122 if (a == NULL)
123 return -ENOMEM;
124
125 sysfs_attr_init(&a->dev_attr.attr);
126 ret = iio_get_channel_type(&st->channels[i], &type);
127 if (ret < 0)
128 return ret;
129
130 switch (type) {
131 case IIO_VOLTAGE:
132 n = in_i++;
133 prefix = "in";
134 break;
135 case IIO_TEMP:
136 n = temp_i++;
137 prefix = "temp";
138 break;
139 case IIO_CURRENT:
140 n = curr_i++;
141 prefix = "curr";
142 break;
143 case IIO_POWER:
144 n = power_i++;
145 prefix = "power";
146 break;
147 case IIO_HUMIDITYRELATIVE:
148 n = humidity_i++;
149 prefix = "humidity";
150 break;
151 default:
152 return -EINVAL;
153 }
154
155 a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL,
156 "%s%d_input",
157 prefix, n);
158 if (a->dev_attr.attr.name == NULL)
159 return -ENOMEM;
160
161 a->dev_attr.show = iio_hwmon_read_val;
162 a->dev_attr.attr.mode = 0444;
163 a->index = i;
164 st->attrs[attr++] = &a->dev_attr.attr;
165
166 /* Let's see if we have a label... */
167 if (iio_read_channel_label(&st->channels[i], buf) < 0)
168 continue;
169
170 a = devm_kzalloc(dev, sizeof(*a), GFP_KERNEL);
171 if (a == NULL)
172 return -ENOMEM;
173
174 sysfs_attr_init(&a->dev_attr.attr);
175 a->dev_attr.attr.name = devm_kasprintf(dev, GFP_KERNEL,
176 "%s%d_label",
177 prefix, n);
178 if (!a->dev_attr.attr.name)
179 return -ENOMEM;
180
181 a->dev_attr.show = iio_hwmon_read_label;
182 a->dev_attr.attr.mode = 0444;
183 a->index = i;
184 st->attrs[attr++] = &a->dev_attr.attr;
185 }
186
187 devm_free_pages(dev, (unsigned long)buf);
188
189 st->attr_group.attrs = st->attrs;
190 st->groups[0] = &st->attr_group;
191
192 if (dev_fwnode(dev)) {
193 sname = devm_kasprintf(dev, GFP_KERNEL, "%pfwP", dev_fwnode(dev));
194 if (!sname)
195 return -ENOMEM;
196 strreplace(sname, '-', '_');
197 } else {
198 sname = "iio_hwmon";
199 }
200
201 hwmon_dev = devm_hwmon_device_register_with_groups(dev, sname, st,
202 st->groups);
203 return PTR_ERR_OR_ZERO(hwmon_dev);
204 }
205
206 static const struct of_device_id iio_hwmon_of_match[] = {
207 { .compatible = "iio-hwmon", },
208 { }
209 };
210 MODULE_DEVICE_TABLE(of, iio_hwmon_of_match);
211
212 static struct platform_driver iio_hwmon_driver = {
213 .driver = {
214 .name = "iio_hwmon",
215 .of_match_table = iio_hwmon_of_match,
216 },
217 .probe = iio_hwmon_probe,
218 };
219
220 module_platform_driver(iio_hwmon_driver);
221
222 MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
223 MODULE_DESCRIPTION("IIO to hwmon driver");
224 MODULE_LICENSE("GPL v2");
225