Re: [PATCH iwl-net] ice: dpll: refuse pin states that are not valid for the pin

[Ivan Vecera <ivecera@redhat.com>]

On 11/10/26 15:31, Petr Oros wrote:
> The DPLL core checks only that a pin may change its state, which states
> a pin accepts is left to the driver. The ice callbacks turn the
> requested state into an enable flag by comparing it with the one state
> that enables the pin, so every other state disables it, including the
> one that has no meaning for the pin.
> 
> The inputs of the EEC and PPS DPLLs are enabled by selectable, as these
> DPLLs select their reference automatically. A request for connected,
> which Documentation/driver-api/dpll.rst reserves for manual mode and
> for pins with the state-connected-override capability, disables the
> input. On an E810:
> 
>    # dpll pin set id 1 parent-device 0 state connected
>    # dpll pin show id 1
>    ... state disconnected on both DPLLs
> 
> A recovered clock pin is connected to or disconnected from its parent
> pin, and a request for selectable disconnects it:
> 
>    # dpll pin set id 2109 parent-pin 2094 state selectable
>    # dpll pin show id 2109
>    ... state disconnected on parent 2094
> 
> Add a helper that translates the state for a pin given the state that
> enables it. Disconnected disables the pin and anything else is refused
> with -EINVAL and an extack message. Use it for the input and recovered
> clock pins, and for the output pins, which already refused selectable
> and now tell the user why.
> 
> The SMA pins have the same problem. It is left out here, as the rework
> of the SMA and U.FL pin control that is queued for net-next refuses the
> states these pins cannot serve.
> 
> Found with the pin state selftest of the dpllsim series running against
> an ice E810.

;-) good catch!
> 
> Fixes: d7999f5ea64bb1 ("ice: implement dpll interface to control cgu")
> Signed-off-by: Petr Oros<poros@redhat.com>

Reviewed-by: Ivan Vecera <ivecera@redhat.com>