On 01/09/16 09:27, Linus Walleij wrote:
> This adds a helper function to the IIO trigger framework:
>
> iio_trigger_using_own(): for an IIO device, this tells
> whether the device is using itself as a trigger.
> This is true if the indio device:
> (A) supplies a trigger and
> (B) has assigned its own buffer poll function to use this
> trigger.
>
> This helper function is good when constructing triggered,
> buffered drivers that can either use its own hardware *OR*
> an external trigger such as a HRTimer or even the trigger from
> a totally different sensor.
>
> Under such circumstances it is important to know for example
> if the timestamp from the same trigger hardware should be used
> when populating the buffer: if iio_trigger_using_own() is true,
> we can use this timestamp, else we need to pick a unique
> timestamp directly in the trigger handler.
>
> For this to work of course IIO devices registering hardware
> triggers must follow the convention to set the parent device
> properly, as as well as setting the parent of the IIO device
> itself.
>
> When a new poll function is attached, we check if the parent
> device of the IIO of the poll function is the same as the
> parent device of the trigger and in that case we conclude that
> the hardware is using itself as trigger.
>
> Cc: Giuseppe Barba <giuseppe.barba@xxxxxx>
> Cc: Denis Ciocca <denis.ciocca@xxxxxx>
> Cc: Crestez Dan Leonard <leonard.crestez@xxxxxxxxx>
> Cc: Gregor Boirie <gregor.boirie@xxxxxxxxxx>
> Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
Looks good to me, but I'll hold back on this one until we
have your driver in.
Kick me if I forget about it.
Thanks,
Jonathan
> ---
> drivers/iio/industrialio-trigger.c | 16 ++++++++++++++++
> include/linux/iio/trigger.h | 11 +++++++++++
> 2 files changed, 27 insertions(+)
>
> diff --git a/drivers/iio/industrialio-trigger.c b/drivers/iio/industrialio-trigger.c
> index 7ad82fdd3e5b..866d86832c50 100644
> --- a/drivers/iio/industrialio-trigger.c
> +++ b/drivers/iio/industrialio-trigger.c
> @@ -255,6 +255,14 @@ static int iio_trigger_attach_poll_func(struct iio_trigger *trig,
> goto out_free_irq;
> }
>
> + /*
> + * Check if we just registered to our own trigger: we determine that
> + * this is the case if the IIO device and the trigger device share the
> + * same parent device.
> + */
> + if (pf->indio_dev->dev.parent == trig->dev.parent)
> + trig->attached_own_device = true;
I guess that's valid in all cases. Was trying to think if we'd ever
have a more complex relationship but I don't think so...
> +
> return ret;
>
> out_free_irq:
> @@ -279,6 +287,8 @@ static int iio_trigger_detach_poll_func(struct iio_trigger *trig,
> if (ret)
> return ret;
> }
> + if (pf->indio_dev->dev.parent == trig->dev.parent)
> + trig->attached_own_device = false;
> iio_trigger_put_irq(trig, pf->irq);
> free_irq(pf->irq, pf);
> module_put(pf->indio_dev->info->driver_module);
> @@ -622,6 +632,12 @@ void devm_iio_trigger_free(struct device *dev, struct iio_trigger *iio_trig)
> }
> EXPORT_SYMBOL_GPL(devm_iio_trigger_free);
>
> +bool iio_trigger_using_own(struct iio_dev *indio_dev)
> +{
> + return indio_dev->trig->attached_own_device;
> +}
> +EXPORT_SYMBOL(iio_trigger_using_own);
> +
> void iio_device_register_trigger_consumer(struct iio_dev *indio_dev)
> {
> indio_dev->groups[indio_dev->groupcounter++] =
> diff --git a/include/linux/iio/trigger.h b/include/linux/iio/trigger.h
> index 1c9e028e0d4a..6e935ab0a47f 100644
> --- a/include/linux/iio/trigger.h
> +++ b/include/linux/iio/trigger.h
> @@ -56,6 +56,9 @@ struct iio_trigger_ops {
> * @subirqs: [INTERN] information about the 'child' irqs.
> * @pool: [INTERN] bitmap of irqs currently in use.
> * @pool_lock: [INTERN] protection of the irq pool.
> + * @attached_own_device:[INTERN] if we are using our own device as trigger,
> + * i.e. if we registered a poll function to the same
> + * device as the one providing the trigger.
> **/
> struct iio_trigger {
> const struct iio_trigger_ops *ops;
> @@ -73,6 +76,7 @@ struct iio_trigger {
> struct iio_subirq subirqs[CONFIG_IIO_CONSUMERS_PER_TRIGGER];
> unsigned long pool[BITS_TO_LONGS(CONFIG_IIO_CONSUMERS_PER_TRIGGER)];
> struct mutex pool_lock;
> + bool attached_own_device;
> };
>
>
> @@ -145,6 +149,13 @@ irqreturn_t iio_trigger_generic_data_rdy_poll(int irq, void *private);
> __printf(1, 2) struct iio_trigger *iio_trigger_alloc(const char *fmt, ...);
> void iio_trigger_free(struct iio_trigger *trig);
>
> +/**
> + * iio_trigger_using_own() - tells us if we use our own HW trigger ourselves
> + * @indio_dev: device to check
> + */
> +bool iio_trigger_using_own(struct iio_dev *indio_dev);
> +
> +
> #else
> struct iio_trigger;
> struct iio_trigger_ops;
>
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