From: Wolfram Sang <wsa@the-dreams.de>
To: Harini Katakam <harinikatakamlinux@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
"grant.likely@linaro.org" <grant.likely@linaro.org>,
"robh+dt@kernel.org" <robh+dt@kernel.org>,
Pawel Moll <Pawel.Moll@arm.com>,
"ijc+devicetree@hellion.org.uk" <ijc+devicetree@hellion.org.uk>,
"galak@codeaurora.org" <galak@codeaurora.org>,
"michal.simek@xilinx.com" <michal.simek@xilinx.com>,
"soren.brinkmann@xilinx.com" <soren.brinkmann@xilinx.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-i2c@vger.kernel.org" <linux-i2c@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
"vishnum@xilinx.com" <vishnum@xilinx.com>
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@mail.gmail.com>
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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
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
2014-12-02 12:52 ` Wolfram Sang
2014-12-02 13:10 ` Harini Katakam
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
2014-12-02 11:21 ` Mark Rutland
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