From: Wolfram Sang <wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org>
To: Harini Katakam
<harinikatakamlinux-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>,
"grant.likely-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org"
<grant.likely-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>,
"robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org"
<robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
Pawel Moll <Pawel.Moll-5wv7dgnIgG8@public.gmane.org>,
"ijc+devicetree-KcIKpvwj1kUDXYZnReoRVg@public.gmane.org"
<ijc+devicetree-KcIKpvwj1kUDXYZnReoRVg@public.gmane.org>,
"galak-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org"
<galak-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>,
"michal.simek-gjFFaj9aHVfQT0dZR+AlfA@public.gmane.org"
<michal.simek-gjFFaj9aHVfQT0dZR+AlfA@public.gmane.org>,
"soren.brinkmann-gjFFaj9aHVfQT0dZR+AlfA@public.gmane.org"
<soren.brinkmann-gjFFaj9aHVfQT0dZR+AlfA@public.gmane.org>,
"linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org"
<linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org>,
"linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
<linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
"linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
<linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
"devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
<devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
"vishnum-gjFFaj9aHVfQT0dZR+AlfA@public.gmane.org"
<vishnum-gjFFaj9aHVfQT0dZR+AlfA@public.gmane.org>
Subject: Re: [PATCH 3/4] devicetree: bindings: Add defeature-repeated-start property for Cadence I2C
Date: Tue, 2 Dec 2014 14:16:11 +0100 [thread overview]
Message-ID: <20141202131611.GC4072@katana> (raw)
In-Reply-To: <CAFcVECJwFoFd6GrmF282CG+fELnYb=FNCTDq=RYKky_dHha=Jg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
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> But given the bugs, it will be useful to just disable it if the system doesn't
> require repeated start.
What do you do when disable repeated start? Sending STOP and START? If
so, this is really something different than repeated start. By using
I2C_FUNC_I2C a user expects repeated start, so if the HW does not
support it, we should say so and don't try to emulate it with something
different.
> If you think DT entry is not the way to go, do you think a CONFIG option or
> something better will work?
No, check at runtime if the transfer is possible on this HW. Bail out if
not.
> We chose a DT property because there is a good chance the user has multiple
> cadence I2C controllers - one connected to a slave that needs repeated start
> (like a power controller) and another that doesn't care.
The user should not need to know with this level of detail if we can
avoid it IMO.
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next prev parent reply other threads:[~2014-12-02 13:16 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-02 10:05 [PATCH 0/4] Cadence I2C driver fixes Harini Katakam
2014-12-02 10:05 ` [PATCH 1/4] i2c: cadence: Handle > 252 byte transfers Harini Katakam
[not found] ` <1417514749-24319-1-git-send-email-harinik-gjFFaj9aHVfQT0dZR+AlfA@public.gmane.org>
2014-12-02 10:05 ` [PATCH 2/4] i2c: cadence: Set the hardware time-out register to maximum value Harini Katakam
2014-12-03 11:28 ` Wolfram Sang
2014-12-02 10:05 ` [PATCH 3/4] devicetree: bindings: Add defeature-repeated-start property for Cadence I2C Harini Katakam
2014-12-02 11:19 ` Mark Rutland
2014-12-02 12:13 ` Harini Katakam
[not found] ` <CAFcVECLtPx6shBXJbg9Uf_8fnhkMoO1zpoxGcdda7PSA7z_2rA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-12-02 12:52 ` Wolfram Sang
2014-12-02 13:10 ` Harini Katakam
[not found] ` <CAFcVECJwFoFd6GrmF282CG+fELnYb=FNCTDq=RYKky_dHha=Jg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-12-02 13:16 ` Wolfram Sang [this message]
2014-12-02 13:30 ` Harini Katakam
2014-12-02 14:15 ` Wolfram Sang
2014-12-02 15:12 ` Lars-Peter Clausen
2014-12-02 10:05 ` [PATCH 4/4] i2c: cadence: Defeature repeated start based on devicetree property Harini Katakam
[not found] ` <1417514749-24319-5-git-send-email-harinik-gjFFaj9aHVfQT0dZR+AlfA@public.gmane.org>
2014-12-02 11:21 ` Mark Rutland
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