Re: [v5,3/3] arm64: dts: fsl-ls208xa-rdb: fix an errata E-00013

From: Peter Rosin
Date: Tue Nov 19 2019 - 17:00:17 EST


Hi!

This patch needs an ack from the arm64 dts maintainers. I cannot sneak it
in "behind their backs". So, it will have to wait. Sorry for not noticing
earlier.

Cheers,
Peter

On 2019-10-22 06:11, Biwen Li wrote:
> Specify a channel zero in idle state to
> avoid enterring tri-stated state for PCA9547.
> About E-00013:
> - Description: I2C1 and I2C3 buses
> are missing pull-up.
> - Impact: When the PCA954x device is tri-stated, the I2C bus
> will float. This makes the I2C bus and its associated
> downstream devices inaccessible.
> - Hardware fix: Populate resistors R189 and R190 for I2C1
> and resistors R228 and R229 for I2C3.
> - Software fix: Remove the tri-state option from the PCA954x
> driver(PCA954x always on enable status, specify a
> channel zero in dts to fix the errata E-00013).
>
> Signed-off-by: Biwen Li <biwen.li@xxxxxxx>
> ---
> Change in v5:
> - specify a channel zero when pca9547 in idle state.
>
> arch/arm64/boot/dts/freescale/fsl-ls208xa-rdb.dtsi | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/arm64/boot/dts/freescale/fsl-ls208xa-rdb.dtsi b/arch/arm64/boot/dts/freescale/fsl-ls208xa-rdb.dtsi
> index 6fd7f63085c9..412f1bc0db5f 100644
> --- a/arch/arm64/boot/dts/freescale/fsl-ls208xa-rdb.dtsi
> +++ b/arch/arm64/boot/dts/freescale/fsl-ls208xa-rdb.dtsi
> @@ -49,6 +49,7 @@
> reg = <0x75>;
> #address-cells = <1>;
> #size-cells = <0>;
> + idle-state = <0>;
> i2c@1 {
> #address-cells = <1>;
> #size-cells = <0>;
>