Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1492065

Re: [PATCH v2 8/8] ARM: bcm2835: Disable i2c2 in the Device Tree

Show all headers | View raw

> Noralf Trønnes <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 Trønnes <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".

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

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH v2 0/8] i2c: bcm2835: Bring in changes from downstream Noralf Trønnes <noralf@tronnes.org> - 2016-09-27 14:00 +0200
  [PATCH v2 8/8] ARM: bcm2835: Disable i2c2 in the Device Tree Noralf Trønnes <noralf@tronnes.org> - 2016-09-27 14:00 +0200
    Re: [PATCH v2 8/8] ARM: bcm2835: Disable i2c2 in the Device Tree Stefan Wahren <stefan.wahren@i2se.com> - 2016-09-27 19:30 +0200
      Re: [PATCH v2 8/8] ARM: bcm2835: Disable i2c2 in the Device Tree Jan Kandziora <jjj@gmx.de> - 2016-09-27 21:00 +0200
      Re: [PATCH v2 8/8] ARM: bcm2835: Disable i2c2 in the Device Tree Noralf Trønnes <noralf@tronnes.org> - 2016-09-27 21:30 +0200
  [PATCH v2 2/8] i2c: bcm2835: Protect against unexpected TXW/RXR interrupts Noralf Trønnes <noralf@tronnes.org> - 2016-09-27 14:00 +0200
  [PATCH v2 7/8] i2c: bcm2835: Add support for dynamic clock Noralf Trønnes <noralf@tronnes.org> - 2016-09-27 14:00 +0200
  [PATCH v2 6/8] i2c: bcm2835: Support i2c-dev ioctl I2C_TIMEOUT Noralf Trønnes <noralf@tronnes.org> - 2016-09-27 14:00 +0200
  [PATCH v2 5/8] i2c: bcm2835: Add support for Repeated Start Condition Noralf Trønnes <noralf@tronnes.org> - 2016-09-27 14:00 +0200
  [PATCH v2 4/8] i2c: bcm2835: Can't support I2C_M_IGNORE_NAK Noralf Trønnes <noralf@tronnes.org> - 2016-09-27 14:10 +0200
  [PATCH v2 1/8] i2c: bcm2835: Fix hang for writing messages larger than 16 bytes Noralf Trønnes <noralf@tronnes.org> - 2016-09-27 14:10 +0200

csiph-web