Re: Fwd: iio_trigger doesn't work

[Lars-Peter Clausen <lars@metafoo.de>]

On 09/20/2012 09:43 AM, Denis Ciocca wrote:
> a little bit of code:
> 
> accelerometer_core.c
> 
> **
> static irqreturn_t acc_trigger_handler(int irq, void *p)
> {
> 	struct iio_poll_func *pf = p;
> 	struct iio_dev *indio_dev = pf->indio_dev;
> 	struct acc_data *adata = iio_priv(indio_dev);
> 	struct iio_buffer *buffer = indio_dev->buffer;
> 
> 	pr_info("test.\n");
> 
> 	iio_trigger_notify_done(indio_dev->trig);
> 	return IRQ_HANDLED;
> }
> 
> static int __devinit acc_probe(struct i2c_client *client,
> 				const struct i2c_device_id *id)
> {
> ...
> 	err = acc_probe_trigger(indio_dev);
> 	if(err < 0)
> 	{
> 		pr_err("%s(0x%x): acc_probe_trigger failed.\n",
> 					client->name, (u8)client->addr);
> 		goto acc_probe_trigger_error;
> 	}
> indio_dev->pollfunc = iio_alloc_pollfunc(
> 						&iio_pollfunc_store_time,
> 						&acc_trigger_handler,
> 						IRQF_ONESHOT,
> 						indio_dev,
> 						"consumer%d",
> 						indio_dev->id);
> 	if(indio_dev->pollfunc == NULL)
> 	{
> 		ret = -ENOMEM;
> 		goto iio_alloc_pollfunc_error;
> 	}
> 	indio_dev->modes |= INDIO_BUFFER_TRIGGERED;
> ...
> }
> **
> 
> 
> accelerometer_trigger.c
> 
> static enum hrtimer_restart iio_trig_hrtimer_trig(struct hrtimer *time)
> {
> 	struct acc_data *adata = container_of(time, struct acc_data, timer);
> 	ktime_t period;
> 
> 	period = ktime_set(0, NSEC_PER_SEC / adata->odr);
> 	hrtimer_forward_now(&adata->timer, period);
> 	pr_info("prova\n");
> 	iio_trigger_poll_chained(adata->trig, iio_get_time_ns());
> 	return HRTIMER_RESTART;
> }
> 
> static const struct iio_trigger_ops iio_acc_trigger_ops = {
> 	.owner = THIS_MODULE,
> };
> 
> int acc_probe_trigger(struct iio_dev *indio_dev)
> {
> 	struct acc_data *adata;
> 	int err;
> 
> 	adata = iio_priv(indio_dev);
> 	pr_info("%s(0x%x): trigger probe start.\n", adata->client->name,
> 						(u8)adata->client->addr);
> 
> 	adata->trig = iio_trigger_alloc("%s-periodic_task-%d",
> 					indio_dev->name, indio_dev->id);
> 	if(adata->trig == NULL)
> 	{
> 		err = -ENOMEM;
> 		pr_err("%s(0x%x): failed to allocate iio trigger."
> 			"\n", adata->client->name, (u8)adata->client->addr);
> 		goto iio_trigger_alloc_error;
> 	}
> 
> 	adata->trig->private_data = indio_dev;
> 	adata->trig->ops = &iio_acc_trigger_ops;
> 	adata->trig->dev.parent = &adata->client->dev;
> 
> 	hrtimer_init(&adata->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
> 	adata->timer.function = iio_trig_hrtimer_trig;
> 
> 	err = iio_trigger_register(adata->trig);
> 	if (err < 0)
> 	{
> 		pr_err("%s(0x%x): failed to register iio trigger."
> 			"\n", adata->client->name, (u8)adata->client->addr);
> 		goto iio_trigger_register_error;
> 	}
> 	indio_dev->trig = adata->trig;
> hrtimer_start(&adata->timer, ktime_set(0, NSEC_PER_SEC/adata->odr),
> 			HRTIMER_MODE_REL);
> 	return 0;
> 
> iio_trigger_register_error:
> 	iio_trigger_free(adata->trig);
> iio_trigger_alloc_error:
> 	return err;
> }
> 
> 
> I expect the message by pr_info is printed every delta time, but it
> doesn't work. Can you help me? It is mandatory use buffer?

Yes, you need a buffer. The trigger won't be activated until the buffer is
active. To activate the buffer you need to select at least one scan element
in the scan_elements subfolder of you IIO device, then set the buffer size
by writing to buffer/length and finally write a 1 to buffer/enable. Now you
should see your acc_trigger_handler being called.

Btw. Marten Svanfeldt wrote a generic higres timer trigger for IIO.
Unfortunately this driver is not ready for mainline yet, but I've pushed it
to https://github.com/lclausen-adi/linux-2.6/commit/6f34757 in case you want
to take a look at it or use it.

- Lars