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From: noralf@tronnes.org (Noralf Trønnes)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 8/8] ARM: bcm2835: Disable i2c2 in the Device Tree
Date: Tue, 27 Sep 2016 21:23:41 +0200	[thread overview]
Message-ID: <72440b3c-526d-e7fb-bae1-69df6ef29a97@tronnes.org> (raw)
In-Reply-To: <256118042.194076.147d5d83-f402-4ba4-b7de-4ab57a0e29ad.open-xchange@email.1und1.de>


Den 27.09.2016 19:25, skrev Stefan Wahren:
>> Noralf Tr?nnes <noralf@tronnes.org> 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 Tr?nnes <noralf@tronnes.org>
>> ---
>>   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 at lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

      parent reply	other threads:[~2016-09-27 19:23 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-27 11:56 [PATCH v2 0/8] i2c: bcm2835: Bring in changes from downstream Noralf Trønnes
2016-09-27 11:56 ` [PATCH v2 1/8] i2c: bcm2835: Fix hang for writing messages larger than 16 bytes Noralf Trønnes
2016-09-27 11:57 ` [PATCH v2 2/8] i2c: bcm2835: Protect against unexpected TXW/RXR interrupts Noralf Trønnes
2016-09-27 11:57 ` [PATCH v2 3/8] i2c: bcm2835: Use ratelimited logging on transfer errors Noralf Trønnes
2016-09-27 13:01   ` Martin Sperl
2016-09-27 19:27     ` Noralf Trønnes
2016-09-27 11:57 ` [PATCH v2 4/8] i2c: bcm2835: Can't support I2C_M_IGNORE_NAK Noralf Trønnes
2016-09-27 11:57 ` [PATCH v2 5/8] i2c: bcm2835: Add support for Repeated Start Condition Noralf Trønnes
2016-09-27 11:57 ` [PATCH v2 6/8] i2c: bcm2835: Support i2c-dev ioctl I2C_TIMEOUT Noralf Trønnes
2016-09-27 11:57 ` [PATCH v2 7/8] i2c: bcm2835: Add support for dynamic clock Noralf Trønnes
2016-09-27 11:57 ` [PATCH v2 8/8] ARM: bcm2835: Disable i2c2 in the Device Tree Noralf Trønnes
2016-09-27 17:25   ` Stefan Wahren
2016-09-27 18:53     ` Jan Kandziora
2016-09-27 19:23     ` Noralf Trønnes [this message]

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