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 */
 28struct 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
 36static 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 */
 52static 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
 78static 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
206static const struct of_device_id iio_hwmon_of_match[] = {
207	{ .compatible = "iio-hwmon", },
208	{ }
209};
210MODULE_DEVICE_TABLE(of, iio_hwmon_of_match);
211
212static 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
220module_platform_driver(iio_hwmon_driver);
221
222MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
223MODULE_DESCRIPTION("IIO to hwmon driver");
224MODULE_LICENSE("GPL v2");