drivers/iio/trigger/iio-trig-hrtimer.c

Source file repositories/reference/linux-study-clean/drivers/iio/trigger/iio-trig-hrtimer.c

File Facts

System
Linux kernel
Corpus path
drivers/iio/trigger/iio-trig-hrtimer.c
Extension
.c
Size
5183 bytes
Lines
201
Domain
Driver Families
Bucket
drivers/iio
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_hrtimer_info {
	struct iio_sw_trigger swt;
	struct hrtimer timer;
	int sampling_frequency[2];
	ktime_t period;
};

static const struct config_item_type iio_hrtimer_type = {
	.ct_owner = THIS_MODULE,
};

static
ssize_t iio_hrtimer_show_sampling_frequency(struct device *dev,
					    struct device_attribute *attr,
					    char *buf)
{
	struct iio_trigger *trig = to_iio_trigger(dev);
	struct iio_hrtimer_info *info = iio_trigger_get_drvdata(trig);

	return iio_format_value(buf, IIO_VAL_INT_PLUS_MICRO,
			ARRAY_SIZE(info->sampling_frequency),
			info->sampling_frequency);
}

static
ssize_t iio_hrtimer_store_sampling_frequency(struct device *dev,
					     struct device_attribute *attr,
					     const char *buf, size_t len)
{
	struct iio_trigger *trig = to_iio_trigger(dev);
	struct iio_hrtimer_info *info = iio_trigger_get_drvdata(trig);
	unsigned long long val;
	u64 period;
	int integer, fract, ret;

	ret = iio_str_to_fixpoint(buf, 100, &integer, &fract);
	if (ret)
		return ret;
	if (integer < 0 || fract < 0)
		return -ERANGE;

	val = fract + 1000ULL * integer;  /* mHz */

	if (!val || val > UINT_MAX)
		return -EINVAL;

	info->sampling_frequency[0] = integer;  /* Hz */
	info->sampling_frequency[1] = fract * 1000;  /* uHz */
	period = PSEC_PER_SEC;
	do_div(period, val);
	info->period = period;  /* nS */

	return len;
}

static DEVICE_ATTR(sampling_frequency, S_IRUGO | S_IWUSR,
		   iio_hrtimer_show_sampling_frequency,
		   iio_hrtimer_store_sampling_frequency);

static struct attribute *iio_hrtimer_attrs[] = {
	&dev_attr_sampling_frequency.attr,
	NULL
};

static const struct attribute_group iio_hrtimer_attr_group = {
	.attrs = iio_hrtimer_attrs,
};

static const struct attribute_group *iio_hrtimer_attr_groups[] = {
	&iio_hrtimer_attr_group,
	NULL
};

static enum hrtimer_restart iio_hrtimer_trig_handler(struct hrtimer *timer)
{
	struct iio_hrtimer_info *info;

	info = container_of(timer, struct iio_hrtimer_info, timer);

	hrtimer_forward_now(timer, info->period);
	iio_trigger_poll(info->swt.trigger);

	return HRTIMER_RESTART;
}

static int iio_trig_hrtimer_set_state(struct iio_trigger *trig, bool state)
{
	struct iio_hrtimer_info *trig_info;

	trig_info = iio_trigger_get_drvdata(trig);

Annotation

Implementation Notes