From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?UTF-8?Q?Noralf_Tr=c3=b8nnes?= Subject: Re: [PATCH v2 8/8] ARM: bcm2835: Disable i2c2 in the Device Tree Date: Tue, 27 Sep 2016 21:23:41 +0200 Message-ID: <72440b3c-526d-e7fb-bae1-69df6ef29a97@tronnes.org> References: <1474977426-3272-1-git-send-email-noralf@tronnes.org> <1474977426-3272-9-git-send-email-noralf@tronnes.org> <256118042.194076.147d5d83-f402-4ba4-b7de-4ab57a0e29ad.open-xchange@email.1und1.de> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Return-path: Received: from smtp.domeneshop.no ([194.63.252.55]:57707 "EHLO smtp.domeneshop.no" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752609AbcI0TXs (ORCPT ); Tue, 27 Sep 2016 15:23:48 -0400 In-Reply-To: <256118042.194076.147d5d83-f402-4ba4-b7de-4ab57a0e29ad.open-xchange@email.1und1.de> Sender: linux-i2c-owner@vger.kernel.org List-Id: linux-i2c@vger.kernel.org To: Stefan Wahren , eric@anholt.net, wsa@the-dreams.de, swarren@wwwdotorg.org Cc: linux-kernel@vger.kernel.org, linux-i2c@vger.kernel.org, linux-rpi-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org Den 27.09.2016 19:25, skrev Stefan Wahren: >> Noralf Trønnes hat am 27. September 2016 um 13:57 >> geschrieben: >> >> >> i2c2 is connected to the HDMI connector and is controlled by the >> firmware. Disable it to stay out of harms way. > Until this point the commit message is okay, the rest is more confusing. > > Btw this should avoid a warning about missing clock frequency. > >> From the downstream commit: >> i2c-bcm2708/BCM270X_DT: Add support for I2C2 >> >> The third I2C bus (I2C2) is normally reserved for HDMI use. Careless >> use of this bus can break an attached display - use with caution. >> >> It is recommended to disable accesses by VideoCore by setting >> hdmi_ignore_edid=1 or hdmi_edid_file=1 in config.txt. >> >> Signed-off-by: Noralf Trønnes >> --- >> arch/arm/boot/dts/bcm2835-rpi.dtsi | 4 ---- >> 1 file changed, 4 deletions(-) >> >> diff --git a/arch/arm/boot/dts/bcm2835-rpi.dtsi >> b/arch/arm/boot/dts/bcm2835-rpi.dtsi >> index e9b47b2..8bffbee 100644 >> --- a/arch/arm/boot/dts/bcm2835-rpi.dtsi >> +++ b/arch/arm/boot/dts/bcm2835-rpi.dtsi >> @@ -59,10 +59,6 @@ >> clock-frequency = <100000>; >> }; >> >> -&i2c2 { >> - status = "okay"; >> -}; >> - > I'm not sure if this the right fix. According to bcm283x.dtsi the 3 i2c busses > have the same compatible string "brcm,bcm2835-i2c", but the changelog suggests > that this bus is "special". I just rounded up all the differences from downstream that I knew about into this patchset. But looking closer I see that the vc4 driver uses i2c2. So I'll drop this patch. Noralf. > Shouldn't we use a different compatible string? Our intention isn't to disable > i2c2 but avoid any claims of the usual i2c driver. > >> &sdhci { >> status = "okay"; >> bus-width = <4>; >> -- >> 2.8.2 >> >> >> _______________________________________________ >> linux-arm-kernel mailing list >> linux-arm-kernel@lists.infradead.org >> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel