From: Andrey Pronin <apronin@chromium.org>
To: Mark Brown <broonie@kernel.org>
Cc: Doug Anderson <dianders@chromium.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
linux-spi <linux-spi@vger.kernel.org>
Subject: Re: [PATCH 1/4] spi: Add option to wake a device by toggling CS
Date: Fri, 1 Jul 2016 19:02:17 -0700 [thread overview]
Message-ID: <20160702020216.GA31918@apronin0.mtv.corp.google.com> (raw)
In-Reply-To: <20160701171708.GC6247@sirena.org.uk>
On Fri, Jul 01, 2016 at 07:17:08PM +0200, Mark Brown wrote:
> On Fri, Jul 01, 2016 at 10:05:50AM -0700, Doug Anderson wrote:
>
> > I'm curious why you you need a timer at all. Can't you just keep
> > track of the jiffies that you last sent and do subtraction? ...or you
> > could get even more accurate and use a ktime_t. That avoids a whole
> > lot of synchronization / locking issues too...
>
> Yeah, that'd be a lot better.
>
> > Also: presumably you'll need to make sure that there's some margin in
> > this whole thing. I'd imagine that if the timeout is 10000
> > nanoseconds and you do the calculation and you last sent 9999
> > nanoseconds ago then you might decide that the other side isn't asleep
> > yet. ...but by the time the transfer starts it might be asleep...
>
> Indeed.
Lots of godd points in the feedback. Let me re-visit the whole idea.
And may be I'll move it to a more device-specific driver.
next prev parent reply other threads:[~2016-07-02 2:02 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-30 3:54 apronin
2016-06-30 3:54 ` [PATCH 2/4] spi: Document " apronin
2016-06-30 7:12 ` Geert Uytterhoeven
2016-07-01 4:32 ` Doug Anderson
2016-06-30 3:54 ` [PATCH 3/4] spi: Add option to insert delay between transactions apronin
2016-07-01 4:44 ` Doug Anderson
2016-07-01 8:16 ` Mark Brown
2016-06-30 3:54 ` [PATCH 4/4] spi: Document " apronin
2016-06-30 7:12 ` Geert Uytterhoeven
2016-07-01 4:45 ` Doug Anderson
2016-07-01 4:23 ` [PATCH 1/4] spi: Add option to wake a device by toggling CS Doug Anderson
2016-07-01 8:21 ` Mark Brown
2016-07-01 17:05 ` Doug Anderson
2016-07-01 17:17 ` Mark Brown
2016-07-02 2:02 ` Andrey Pronin [this message]
2016-07-01 8:02 ` Mark Brown
2016-07-02 1:45 ` Andrey Pronin
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=20160702020216.GA31918@apronin0.mtv.corp.google.com \
--to=apronin@chromium.org \
--cc=broonie@kernel.org \
--cc=dianders@chromium.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-spi@vger.kernel.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
all inboxes | Powered by JetHome®