Re: [Outreachy kernel] [PATCH] iio: accel: bma180: Set up buffer timestamps for non-zero values

[Alison Schofield]

On Wed, Mar 29, 2017 at 07:41:31PM +0530, simran singhal wrote:
> Use the iio_pollfunc_store_time parameter during triggered buffer set-up
> to get valid timestamps.
> 
> Signed-off-by: simran singhal <singhalsimran0@xxxxxxxxx>

Hi Simran,
I guess you knew I'd recognize this one ;)

My first thought were - "Wow that was a short and sweet description!
Is that all I said when I made similar patches?"  So, I went back
in history and sure enough - that is all I said in the changelog.

But I knew I had thought more about it than that changelog showed.
So, I went back to the mailing list and found the patchset cover
sheet where I had placed the greater explanation and options.

Note to myself: don't bury too much stuff in cover letters!

Note to you: Defects do repeat themselves so your method of hunting
is fine.  If you haven't done it already, add the step where you go
find the mailing list discussion of the patch.  That can be helpful.

Here's a link to the patchset on linux-iio:
http://marc.info/?l=linux-iio&m=146825066822274&w=2

The piece of interest is:
Alternative change would be to use iio_get_time_ns() directly in the
push_to_buffers call in the handler.  We can do this if you are not
one of those "devices (who) need a timestamp grabbed as soon as possible
after the trigger" (from iio_poll_func definition)

This is all just FYI for you now.

Leave the patch for the reviewers to comment.

Thanks,
alisons

> ---
>  drivers/iio/accel/bma180.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/iio/accel/bma180.c b/drivers/iio/accel/bma180.c
> index efc6773..4ae5c80 100644
> --- a/drivers/iio/accel/bma180.c
> +++ b/drivers/iio/accel/bma180.c
> @@ -762,7 +762,7 @@ static int bma180_probe(struct i2c_client *client,
>  			goto err_trigger_free;
>  	}
>  
> -	ret = iio_triggered_buffer_setup(indio_dev, NULL,
> +	ret = iio_triggered_buffer_setup(indio_dev, iio_pollfunc_store_time,
>  			bma180_trigger_handler, NULL);
>  	if (ret < 0) {
>  		dev_err(&client->dev, "unable to setup iio triggered buffer\n");
> -- 
> 2.7.4
> 
> -- 
> You received this message because you are subscribed to the Google Groups "outreachy-kernel" group.
> To unsubscribe from this group and stop receiving emails from it, send an email to outreachy-kernel+unsubscribe@xxxxxxxxxxxxxxxxx
> To post to this group, send email to outreachy-kernel@xxxxxxxxxxxxxxxxx
> To view this discussion on the web visit https://groups.google.com/d/msgid/outreachy-kernel/20170329141131.GA23646%40singhal-Inspiron-5558.
> For more options, visit https://groups.google.com/d/optout.