From: Wolfram Sang <wsa@the-dreams.de>
To: Scott Wood <scottwood@freescale.com>
Cc: Valentin Longchamp <valentin.longchamp@keymile.com>,
Linux device trees <devicetree@vger.kernel.org>,
"Boschung, Rainer" <Rainer.Boschung@keymile.com>,
"Brunck, Holger" <Holger.Brunck@keymile.com>,
Linux I2C <linux-i2c@vger.kernel.org>,
Linux PowerPC Kernel <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [PATCH] i2c-qoriq: modified compatibility for correct prescaler
Date: Tue, 25 Nov 2014 19:13:47 +0100 [thread overview]
Message-ID: <20141125181347.GC9716@katana> (raw)
In-Reply-To: <1416274083.15957.96.camel@freescale.com>
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On Mon, Nov 17, 2014 at 07:28:03PM -0600, Scott Wood wrote:
> On Fri, 2014-11-14 at 09:28 +0100, Wolfram Sang wrote:
> > > >
> > > > If we're going to change the device tree I'd rather just add a property
> > > > to say what the prescaler is.
> > >
> > > We would however, leave the boards' device trees that use things like
> > > "fsl,mpc8543-i2c" as is and introduce the prescaler for the others requiring it.
> > >
> > >
> > > Now the drawback is that the driver would require a change, to parse this
> > > prescaler new prescaler property. Would this be OK from your point of view
> > > Wolfram ? If yes, I will send the patches for it.
> >
> > I don't think it is OK.
>
> Why?
Because I thought it could be deduced. Then, a seperate property would
not be OK.
> > I'd think it can be deduced from the compatible property.
>
> For almost all existing device trees it cannot be.
Pity :( If we do introduce a new property, it should probably be
"clock-div". Grepping through binding documentation, that seems
accepted. We should ask DT maintainers, too, to be safe.
> If you want something that will work without changing device trees,
> you'll need to use SVR to identify the SoC.
The driver is doing that already, see mpc_i2c_get_sec_cfg_8xxx(). Dunno
if it makes sense to add to it for consistency reasons?
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next prev parent reply other threads:[~2014-11-25 18:12 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-17 9:27 [PATCH] i2c-qoriq: modified compatibility for correct prescaler Valentin Longchamp
2014-10-28 23:08 ` Scott Wood
2014-10-29 8:59 ` Valentin Longchamp
2014-11-06 21:58 ` Scott Wood
2014-11-13 0:34 ` Wolfram Sang
2014-11-14 7:43 ` Valentin Longchamp
2014-11-14 8:28 ` Wolfram Sang
2014-11-18 1:28 ` Scott Wood
2014-11-25 18:13 ` Wolfram Sang [this message]
2014-11-26 1:41 ` Scott Wood
2014-11-30 4:30 ` Danielle Costantino
2014-12-01 17:23 ` Wolfram Sang
2014-12-11 13:44 ` Valentin Longchamp
2014-12-23 13:23 ` Valentin Longchamp
2014-12-23 13:49 ` Wolfram Sang
2014-12-27 2:43 ` Scott Wood
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