drivers/hwmon/iio_hwmon.c

Source file repositories/reference/linux-study-clean/drivers/hwmon/iio_hwmon.c

File Facts

System
Linux kernel
Corpus path
drivers/hwmon/iio_hwmon.c
Extension
.c
Size
5554 bytes
Lines
225
Domain
Driver Families
Bucket
drivers/hwmon
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

struct iio_hwmon_state {
	struct iio_channel *channels;
	int num_channels;
	struct attribute_group attr_group;
	const struct attribute_group *groups[2];
	struct attribute **attrs;
};

static ssize_t iio_hwmon_read_label(struct device *dev,
				  struct device_attribute *attr,
				  char *buf)
{
	struct sensor_device_attribute *sattr = to_sensor_dev_attr(attr);
	struct iio_hwmon_state *state = dev_get_drvdata(dev);
	struct iio_channel *chan = &state->channels[sattr->index];

	return iio_read_channel_label(chan, buf);
}

/*
 * Assumes that IIO and hwmon operate in the same base units.
 * This is supposed to be true, but needs verification for
 * new channel types.
 */
static ssize_t iio_hwmon_read_val(struct device *dev,
				  struct device_attribute *attr,
				  char *buf)
{
	int result;
	int ret;
	struct sensor_device_attribute *sattr = to_sensor_dev_attr(attr);
	struct iio_hwmon_state *state = dev_get_drvdata(dev);
	struct iio_channel *chan = &state->channels[sattr->index];
	enum iio_chan_type type;

	ret = iio_get_channel_type(chan, &type);
	if (ret < 0)
		return ret;

	if (type == IIO_POWER)
		/* mili-Watts to micro-Watts conversion */
		ret = iio_read_channel_processed_scale(chan, &result, 1000);
	else
		ret = iio_read_channel_processed(chan, &result);
	if (ret < 0)
		return ret;

	return sprintf(buf, "%d\n", result);
}

static int iio_hwmon_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct iio_hwmon_state *st;
	struct sensor_device_attribute *a;
	int ret, i, attr = 0;
	int in_i = 1, temp_i = 1, curr_i = 1, humidity_i = 1, power_i = 1;
	enum iio_chan_type type;
	struct iio_channel *channels;
	struct device *hwmon_dev;
	char *sname;
	void *buf;

	channels = devm_iio_channel_get_all(dev);
	if (IS_ERR(channels)) {
		ret = PTR_ERR(channels);
		if (ret == -ENODEV)
			ret = -EPROBE_DEFER;
		return dev_err_probe(dev, ret,
				     "Failed to get channels\n");
	}

	st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL);
	buf = (void *)devm_get_free_pages(dev, GFP_KERNEL, 0);
	if (!st || !buf)
		return -ENOMEM;

	st->channels = channels;

	/* count how many channels we have */
	while (st->channels[st->num_channels].indio_dev)
		st->num_channels++;

	st->attrs = devm_kcalloc(dev,
				 2 * st->num_channels + 1, sizeof(*st->attrs),
				 GFP_KERNEL);
	if (st->attrs == NULL)
		return -ENOMEM;

	for (i = 0; i < st->num_channels; i++) {

Annotation

Implementation Notes