linux-kernel - Re: [PATCH v3 1/2] dt-bindings: wkup-m3-ipc: Add ti,set-io-isolation property

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Message-ID: <Ylh5qPs57uruokUh@x1>
Date:   Thu, 14 Apr 2022 12:44:40 -0700
From:   Drew Fustini <dfustini@...libre.com>
To:     Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>
Cc:     devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, Nishanth Menon <nm@...com>,
        Santosh Shilimkar <ssantosh@...nel.org>,
        Dave Gerlach <d-gerlach@...com>,
        Tony Lindgren <tony@...mide.com>
Subject: Re: [PATCH v3 1/2] dt-bindings: wkup-m3-ipc: Add ti,set-io-isolation
 property

On Thu, Apr 14, 2022 at 12:27:23PM -0700, Drew Fustini wrote:
> Add documentation for the ti,set-io-isolation DT property on the wkup_m3_ipc
> node which tells the wkup_m3_ipc driver to use the wkup_m3 to enable
> IO Isolation during low power mode transitions on am43xx platforms.
> 
> Signed-off-by: Dave Gerlach <d-gerlach@...com>
> [dfustini: convert to YAML, make DTS example that passes check]
> Signed-off-by: Drew Fustini <dfustini@...libre.com>
> ---
> Changes from v2:
> - correct indentation of the 'allOf:' block
> 
> Changes from v1:
> - correct typo of 'ti,set-io-isolation' property in subject
> - make 'ti,set-io-isolation' only valid for 'ti,am4372-wkup-m3-ipc'
> 
>  .../bindings/soc/ti/wkup-m3-ipc.yaml          | 78 +++++++++++++++++--
>  1 file changed, 73 insertions(+), 5 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/soc/ti/wkup-m3-ipc.yaml b/Documentation/devicetree/bindings/soc/ti/wkup-m3-ipc.yaml
> index 7f4a75c5fcaa..f0ae86250fe4 100644
> --- a/Documentation/devicetree/bindings/soc/ti/wkup-m3-ipc.yaml
> +++ b/Documentation/devicetree/bindings/soc/ti/wkup-m3-ipc.yaml
> @@ -24,14 +24,22 @@ description: |+
>    A wkup_m3_ipc device node is used to represent the IPC registers within an
>    SoC.
>  
> -  Support for VTT Toggle
> -  ==================================
> +  Support for VTT Toggle with GPIO pin
> +  ====================================
>    On some boards like the AM335x EVM-SK and the AM437x GP EVM, a GPIO pin is
>    connected to the enable pin on the DDR VTT regulator. This allows the
>    regulator to be disabled upon suspend and enabled upon resume. Please note
>    that the GPIO pin must be part of the GPIO0 module as only this GPIO module
>    is in the wakeup power domain.
>  
> +  Support for IO Isolation
> +  ========================
> +  On AM437x SoCs, certain pins can be forced into an alternate state when IO
> +  isolation is activated. Those pins have pad control registers prefixed by
> +  'CTRL_CONF_' that contain DS0 (e.g. deep sleep) configuration bits that can
> +  override the pin's existing bias (pull-up/pull-down) and value (high/low) when
> +  IO isolation is active.
> +
>  properties:
>    compatible:
>      enum:
> @@ -63,6 +71,24 @@ properties:
>      $ref: /schemas/types.yaml#/definitions/uint32
>      description: GPIO pin connected to enable pin on VTT regulator
>  
> +  ti,set-io-isolation:
> +    type: boolean
> +    description:
> +      If this property is present, then the wkup_m3_ipc driver will instruct
> +      the CM3 firmware to activate IO isolation when suspending to deep sleep.
> +      This can be leveraged by a board design to put other devices on the board
> +      into a low power state.
> +allOf:

Rob - sorry for the churn.  I realize now that there should have been a
blank line before 'allOf:'.  Should I send a v4 or (if there are not
other issues) could that just added when applying?

Thank you,
Drew