linux-arm-kernel.lists.infradead.org archive mirror
 help / color / mirror / Atom feed
From: marex@denx.de (Marek Vasut)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] IIO: Add basic MXS LRADC driver
Date: Thu, 19 Jul 2012 21:26:31 +0200	[thread overview]
Message-ID: <201207192126.31772.marex@denx.de> (raw)
In-Reply-To: <50081AC0.10703@metafoo.de>

Dear Lars-Peter Clausen,

> On 07/19/2012 04:23 PM, Marek Vasut wrote:
> > Dear Lars-Peter Clausen,
> > 
> > Sorry for my late reply, got busy with other crazy stuff.
> > 
> > [...]
> > 
> >>>> Is there any reason not to use the mxs_lradc struct directly has the
> >>>> iio data?
> >>> 
> >>> I explained it below in the patch. I hope we'll eventually support the
> >>> delay triggers, which will need 4 separate IIO devices. And this is
> >>> where this structure will be augmented by other components.
> >> 
> >> Ok I saw the comment, but it wasn't obvious to me that delay channels
> >> will require multiple IIO devices. Might make sense to state this
> >> explicitly.
> > 
> > Fixed.
> > 
> >>>>> [...]
> >>>>> 
> >>>>> +
> >>>>> +/*
> >>>>> + * Channel management
> >>>>> + *
> >>>>> + * This involves crazy mapping between 8 virtual channels the CTRL4
> >>>>> register + * can harbor and 16 channels total this hardware supports.
> >>>>> + */
> >>>> 
> >>>> I suppose this means only a maximum 8 channels can be active at a
> >>>> time. I've recently posted a patch which makes it easy to implement
> >>>> such a restriction.
> >>>> http://www.spinics.net/lists/linux-iio/msg05936.html and
> >>>> http://www.spinics.net/lists/linux-iio/msg05935.html for an example
> >>>> validate callback implementation. In your case you'd check for
> >>>> bitmap_weight(...) <= 8. Those patches are not yet in IIO though.
> >>> 
> >>> This is good. When do you expect this to hit linux-next possibly? Or at
> >>> least linux-iio?
> >> 
> >> soon, hopefully.
> > 
> > So I checked this, not sure how it'll help me though.
> 
> Right now with your driver you can enable any combination of channels. If
> more than 8 channels are enabled and you start sampling it will fail, since
> not all channels can be mapped. With those patch you can implement a
> validate callback and check for bitmap_weight(scan_mask) <= 8. This will
> ensure that it is not possible to select more than 8 channels at once,
> which again means that starting sampling can't fail of this.

Ok, I fixed this one. One last thing that I don't really understand is this. I 
run generic_buffer.c to source samples from the LRADC. Is there any way to 
continuously sample them? Because right now, I get one sample and that's it, no 
more samples happen later on (I can 0 data in subsequent read() call).

Best regards,
Marek Vasut

  parent reply	other threads:[~2012-07-19 19:26 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-07-04  2:15 [PATCH] IIO: Add basic MXS LRADC driver Marek Vasut
2012-07-04  4:30 ` Wolfgang Denk
2012-07-04  8:35 ` Lars-Peter Clausen
2012-07-04 23:48   ` Marek Vasut
2012-07-05  8:33     ` Lars-Peter Clausen
2012-07-05 19:53       ` Marek Vasut
2012-07-19 14:23       ` Marek Vasut
2012-07-19 14:33         ` Lars-Peter Clausen
2012-07-19 15:15           ` Marek Vasut
2012-07-19 19:26           ` Marek Vasut [this message]
2012-07-20  2:18             ` Marek Vasut
2012-07-20  8:39               ` Robert Schwebel
2012-07-20 11:32                 ` Marek Vasut
2012-07-20 14:09               ` Lars-Peter Clausen
2012-07-22 19:48                 ` Jonathan Cameron
2012-07-20 14:11             ` Lars-Peter Clausen
2012-07-20 15:12               ` Marek Vasut
2012-07-09  9:19 ` Juergen Beisert
2012-07-09  9:52   ` Lars-Peter Clausen
2012-07-09 10:03   ` Marek Vasut
2012-07-10  9:20     ` Juergen Beisert
2012-07-10  9:26       ` Marek Vasut
2012-07-10  9:49         ` Juergen Beisert
2012-07-10 10:08           ` Marek Vasut
2012-07-10 10:26             ` Juergen Beisert
2012-07-10 10:35               ` Lars-Peter Clausen
2012-07-10 10:41                 ` Juergen Beisert
2012-07-10 10:45                   ` Marek Vasut

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=201207192126.31772.marex@denx.de \
    --to=marex@denx.de \
    --cc=linux-arm-kernel@lists.infradead.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).