2022-03-17 20:04:59

by Leo Li

Subject: [PATCH 5/6] arm64: dts: ls208xa-rdb: fix errata E-00013

From: Biwen Li <[email protected]>

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 <[email protected]>
Signed-off-by: Li Yang <[email protected]>
---
arch/arm64/boot/dts/freescale/fsl-ls208xa-rdb.dtsi | 2 ++
1 file changed, 2 insertions(+)

diff --git a/arch/arm64/boot/dts/freescale/fsl-ls208xa-rdb.dtsi b/arch/arm64/boot/dts/freescale/fsl-ls208xa-rdb.dtsi
index 4b71c4fcb35f..a752f06a2e74 100644
--- a/arch/arm64/boot/dts/freescale/fsl-ls208xa-rdb.dtsi
+++ b/arch/arm64/boot/dts/freescale/fsl-ls208xa-rdb.dtsi
@@ -49,6 +49,8 @@ pca9547@75 {
reg = <0x75>;
#address-cells = <1>;
#size-cells = <0>;
+ idle-state = <0>;
+
i2c@1 {
#address-cells = <1>;
#size-cells = <0>;
--
2.25.1

2022-04-11 14:51:18

by Shawn Guo

Subject: Re: [PATCH 5/6] arm64: dts: ls208xa-rdb: fix errata E-00013

On Thu, Mar 17, 2022 at 02:01:08PM -0500, Li Yang wrote:
> From: Biwen Li <[email protected]>
>
> Specify a channel zero in idle state to
> avoid enterring tri-stated state for PCA9547.

Please check Documentation/process/submitting-patches.rst for commit log
wrapping requirement.

> About E-00013:
> - Description: I2C1 and I2C3 buses

Use space instead of tab for bullet indent.

Shawn

> 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 <[email protected]>
> Signed-off-by: Li Yang <[email protected]>
> ---
> arch/arm64/boot/dts/freescale/fsl-ls208xa-rdb.dtsi | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/arch/arm64/boot/dts/freescale/fsl-ls208xa-rdb.dtsi b/arch/arm64/boot/dts/freescale/fsl-ls208xa-rdb.dtsi
> index 4b71c4fcb35f..a752f06a2e74 100644
> --- a/arch/arm64/boot/dts/freescale/fsl-ls208xa-rdb.dtsi
> +++ b/arch/arm64/boot/dts/freescale/fsl-ls208xa-rdb.dtsi
> @@ -49,6 +49,8 @@ pca9547@75 {
> reg = <0x75>;
> #address-cells = <1>;
> #size-cells = <0>;
> + idle-state = <0>;
> +
> i2c@1 {
> #address-cells = <1>;
> #size-cells = <0>;
> --
> 2.25.1
>