On Fri, Sep 13, 2024 at 10:37:30AM +0000, Wojciech Siudy (Nokia) wrote:
> From: Wojciech Siudy <wojciech.siudy@xxxxxxxxx>
>
> For cases when the mux shares reset line with other chips we cannot
> use it when channel selection or deselection times out, because it
> could break them without proper init/probe.
>
> Signed-off-by: Wojciech Siudy <wojciech.siudy@xxxxxxxxx>
> ---
> .../devicetree/bindings/i2c/i2c-mux-pca954x.yaml | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.yaml b/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.yaml
> index 9aa0585200c9..872be72da965 100644
> --- a/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.yaml
> +++ b/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.yaml
> @@ -63,6 +63,12 @@ properties:
> necessary for example, if there are several multiplexers on the bus and
> the devices behind them use same I2C addresses.
>
> + i2c-mux-timeout-reset:
> + type: boolean
> + description: Sends reset pulse if channel selection or deselection times
> + out. Works only if reset GPIO provided. Do not use if other chips share
> + the same reset line.
Why is a dedicated property required for this? Why is it not sufficient to
attempt an exclusive request of the reset line, and always perform a
reset if selection or deselection times out?
Rather than "Works only if reset GPIO provided", enforce this with a
dependency.
Thanks,
Conor.
> +
> idle-state:
> description: if present, overrides i2c-mux-idle-disconnect
> $ref: /schemas/mux/mux-controller.yaml#/properties/idle-state
> @@ -146,6 +152,8 @@ examples:
> interrupt-parent = <&ipic>;
> interrupts = <17 IRQ_TYPE_LEVEL_LOW>;
> interrupt-controller;
> + i2c-mux-idle-disconnect;
> + i2c-mux-timeout-reset;
> #interrupt-cells = <2>;
>
> i2c@2 {
> --
> 2.34.1
>
>
Attachment:
signature.asc
Description: PGP signature
