From: Wolfram Sang <wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org>
To: Janusz Uzycki <j.uzycki-9tnw74Q4ehaHKKo6LODCOg@public.gmane.org>
Cc: marex-ynQEQJNshbs@public.gmane.org,
linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH] i2c-mxs: detect No Slave Ack on SELECT in PIO mode
Date: Fri, 3 Oct 2014 02:51:59 +0200 [thread overview]
Message-ID: <20141003005159.GE1323@katana> (raw)
In-Reply-To: <1411469306-15390-1-git-send-email-j.uzycki-9tnw74Q4ehaHKKo6LODCOg@public.gmane.org>
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On Tue, Sep 23, 2014 at 12:48:26PM +0200, Janusz Uzycki wrote:
> i2cdetect scanned i2c bus slow because the i2c-mxs driver ignored
> the NO_SLAVE_ACK bit during busy-waiting loop.
> Thanks to the patch, the speedup happens.
> The change doesn't break anything else because:
> - on SELECT: NO_SLAVE_ACK bit checking is just welcome
> - on READ: master (the i2c controller, no slave device) generates
> ACK/NAK bit
> - on WRITE: NO_SLAVE_ACK can be treated as NAK (the same effect)
> so even the i2c controller sets NO_SLAVE_ACK on NAK (not confirmed)
> the WRITE is not effected
> - on clock stretching: SCL wire is involved, it has no influence
> on the ACK bit value on SDA wire
>
> Signed-off-by: Janusz Uzycki <j.uzycki-9tnw74Q4ehaHKKo6LODCOg@public.gmane.org>
Applied to for-next, thanks!
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next prev parent reply other threads:[~2014-10-03 0:51 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-23 10:48 [PATCH] i2c-mxs: detect No Slave Ack on SELECT in PIO mode Janusz Uzycki
[not found] ` <1411469306-15390-1-git-send-email-j.uzycki-9tnw74Q4ehaHKKo6LODCOg@public.gmane.org>
2014-09-23 10:48 ` Janusz Użycki
2014-10-03 0:51 ` Wolfram Sang [this message]
-- strict thread matches above, loose matches on Subject: below --
2014-09-10 15:18 Janusz Uzycki
[not found] ` <1410362286-1785-1-git-send-email-j.uzycki-9tnw74Q4ehaHKKo6LODCOg@public.gmane.org>
2014-09-10 15:57 ` Janusz Użycki
2014-09-19 2:45 ` Marek Vasut
[not found] ` <201409190445.21419.marex-ynQEQJNshbs@public.gmane.org>
2014-09-22 14:33 ` Janusz Użycki
[not found] ` <5420334D.8090809-9tnw74Q4ehaHKKo6LODCOg@public.gmane.org>
2014-09-22 15:04 ` Marek Vasut
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