mirror of https://lore.kernel.org/lkml/
 help / color / mirror / Atom feed
From: Alexander Kochetkov <al.kochet@gmail.com>
To: Felipe Balbi <balbi@ti.com>
Cc: Kevin Hilman <khilman@kernel.org>,
	Tony Lindgren <tony@atomide.com>,
	Wolfram Sang <wsa@the-dreams.de>,
	linux-omap <linux-omap@vger.kernel.org>,
	linux-i2c@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>
Subject: Question about patch "i2c: omap: resize fifos before each message"
Date: Wed, 3 Dec 2014 18:11:18 +0300	[thread overview]
Message-ID: <A20987D6-DEEC-488D-9655-36A4D186599B@gmail.com> (raw)

Felipe,

Question about the patch[1].

I want to change the code in a way to not touch fifo thresholds for each message.
Because:
1. dev->threshold is valid only with checking of transfer direction.
   So, if last transfer was transmission and ISR get RRDY interrupt from slave receiver,
   then dev->threshold is invalid. We must read threshold value from BUF register, to
   process correctly.
2. I want to avoid changing fifos before message submission, because IP can start receiving
   message in a slave mode (race).
3. dev->threshold is changed in range 1-fifo_size/2. So instead of RDR we get RRDY and
   for messages larger then fifo_size/2 we still get RRDY and RDR.

Felipe, do you have in mind why do you want to avoid RDR and XDR events?
Something about errata?

[1] https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/drivers/i2c/busses/i2c-omap.c?id=dd74548ddece4b9d68e5528287a272fa552c81d0


             reply	other threads:[~2014-12-03 15:11 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-12-03 15:11 Alexander Kochetkov [this message]
2014-12-03 15:49 ` Felipe Balbi
2014-12-03 17:34   ` Alexander Kochetkov
2014-12-03 17:49     ` Felipe Balbi
2014-12-03 19:01       ` Alexander Kochetkov
2014-12-03 19:38         ` Felipe Balbi
2014-12-03 20:04           ` Alexander Kochetkov

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=A20987D6-DEEC-488D-9655-36A4D186599B@gmail.com \
    --to=al.kochet@gmail.com \
    --cc=balbi@ti.com \
    --cc=khilman@kernel.org \
    --cc=linux-i2c@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-omap@vger.kernel.org \
    --cc=tony@atomide.com \
    --cc=wsa@the-dreams.de \
    /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®