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

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Den 27.09.2016 19:25, skrev Stefan Wahren:
Noralf Trønnes <noralf@xxxxxxxxxxx> 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@xxxxxxxxxxx>
---
  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


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