From: Wolfram Sang <wsa@the-dreams.de>
To: Mark Rutland <mark.rutland@arm.com>
Cc: "atull@opensource.altera.com" <atull@opensource.altera.com>,
"baruch@tkos.co.il" <baruch@tkos.co.il>,
"mika.westerberg@linux.intel.com"
<mika.westerberg@linux.intel.com>,
"grant.likely@linaro.org" <grant.likely@linaro.org>,
"robh+dt@kernel.org" <robh+dt@kernel.org>,
"skuribay@pobox.com" <skuribay@pobox.com>,
"Romain.Baeriswyl@abilis.com" <Romain.Baeriswyl@abilis.com>,
"rafael.j.wysocki@intel.com" <rafael.j.wysocki@intel.com>,
"alan@linux.intel.com" <alan@linux.intel.com>,
"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>,
"delicious.quinoa@gmail.com" <delicious.quinoa@gmail.com>,
"dinguyen@opensource.altera.com" <dinguyen@opensource.altera.com>,
"yvanderv@opensource.altera.com" <yvanderv@opensource.altera.com>
Subject: Re: [PATCH] i2c: designware: deduce speed mode from device tree setting
Date: Wed, 20 Aug 2014 07:36:18 -0500 [thread overview]
Message-ID: <20140820123617.GB1373@katana> (raw)
In-Reply-To: <20140820092257.GA21174@leverpostej>
[-- Attachment #1: Type: text/plain, Size: 697 bytes --]
> > +
> > + ret = of_property_read_u32(pdev->dev.of_node,
> > + "clock-frequency", &bus_rate);
> > + if (!ret && (bus_rate <= 100000))
> > + speed = DW_IC_CON_SPEED_STD;
>
> This looks a bit odd.
>
> If the device only supports two particular speeds why do we accept any
> other speed in the clock-frequency property?
"clock-frequency" is the default binding for specifying i2c bus speeds
today. Some controllers can be programmed to do various speeds, some can
only do a set of fixed values.
> Surely we should at least warn that something was off?
Yes, I was going to say the same until Romain's old patch showed up
which does that.
Thanks,
Wolfram
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next prev parent reply other threads:[~2014-08-20 12:36 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-19 20:18 [PATCH] i2c: designware: deduce speed mode from device tree setting atull-yzvPICuk2ABMcg4IHK0kFoH6Mc4MB0Vx
[not found] ` <1408479529-24249-1-git-send-email-atull-yzvPICuk2ABMcg4IHK0kFoH6Mc4MB0Vx@public.gmane.org>
2014-08-20 7:52 ` Mika Westerberg
2014-08-20 9:22 ` Mark Rutland
2014-08-20 9:49 ` Romain Baeriswyl
2014-08-20 12:07 ` Romain Baeriswyl
[not found] ` <944257148.1724.1408528177642.JavaMail.root-ux6zf3SgZrrQT0dZR+AlfA@public.gmane.org>
2014-08-20 12:32 ` Wolfram Sang
2014-08-20 14:24 ` atull
2014-08-20 14:38 ` Romain Baeriswyl
[not found] ` <1791089693.2989.1408545513401.JavaMail.root-ux6zf3SgZrrQT0dZR+AlfA@public.gmane.org>
2014-08-20 15:12 ` atull
2014-08-20 12:36 ` Wolfram Sang [this message]
2014-08-20 12:42 ` Mark Rutland
2014-08-20 14:29 ` [PATCH] i2c designware add support of I2C standard mode Romain Baeriswyl
[not found] ` <1408544948-22339-1-git-send-email-romainba-ux6zf3SgZrrQT0dZR+AlfA@public.gmane.org>
2014-08-20 14:32 ` atull
2014-08-20 15:25 ` atull
2014-09-20 9:24 ` Wolfram Sang
2014-09-28 3:40 ` atull
2014-09-18 15:52 ` atull
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