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