From: Alexander Kochetkov <al.kochet-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
To: Felipe Balbi <balbi-l0cyMroinI0@public.gmane.org>
Cc: Kevin Hilman <khilman-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
Tony Lindgren <tony-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org>,
Wolfram Sang <wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org>,
linux-omap <linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
LKML <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.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
next 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]
[not found] ` <A20987D6-DEEC-488D-9655-36A4D186599B-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2014-12-03 15:49 ` Question about patch "i2c: omap: resize fifos before each message" Felipe Balbi
2014-12-03 17:34 ` Alexander Kochetkov
[not found] ` <8C51B585-BFD6-48CC-A2C4-EB88CB820426-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
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
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