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 | */ |
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, val: &result); |
53 | if (ret < 0) |
54 | return ret; |
55 | |
56 | ret = iio_get_channel_type(channel: chan, type: &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, fmt: "%d\n" , result); |
64 | } |
65 | |
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(ptr: channels)) { |
80 | ret = PTR_ERR(ptr: channels); |
81 | if (ret == -ENODEV) |
82 | ret = -EPROBE_DEFER; |
83 | return dev_err_probe(dev, err: ret, |
84 | fmt: "Failed to get channels\n" ); |
85 | } |
86 | |
87 | st = devm_kzalloc(dev, size: 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 | n: st->num_channels + 1, size: 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, size: 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(channel: &st->channels[i], type: &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 | fmt: "%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, fmt: "%pfwP" , dev_fwnode(dev)); |
158 | if (!sname) |
159 | return -ENOMEM; |
160 | strreplace(str: sname, old: '-', new: '_'); |
161 | } else { |
162 | sname = "iio_hwmon" ; |
163 | } |
164 | |
165 | hwmon_dev = devm_hwmon_device_register_with_groups(dev, name: sname, drvdata: st, |
166 | groups: st->groups); |
167 | return PTR_ERR_OR_ZERO(ptr: 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 | |