linux-kernel - Re: [PATCH V4 1/2] pinctrl: tegra: Add DT binding for io pads control

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Message-ID: <71fe4550-52ac-d176-b1c5-fe64083a95e7@nvidia.com>
Date:   Fri, 25 Nov 2016 17:19:51 +0000
From:   Jon Hunter <jonathanh@...dia.com>
To:     Laxman Dewangan <ldewangan@...dia.com>, <linus.walleij@...aro.org>,
        <robh+dt@...nel.org>, <mark.rutland@....com>,
        <swarren@...dotorg.org>, <thierry.reding@...il.com>,
        <gnurou@...il.com>, <joe@...ches.com>
CC:     <yamada.masahiro@...ionext.com>, <linux-gpio@...r.kernel.org>,
        <devicetree@...r.kernel.org>, <linux-tegra@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH V4 1/2] pinctrl: tegra: Add DT binding for io pads control


On 24/11/16 08:38, Laxman Dewangan wrote:
> NVIDIA Tegra124 and later SoCs support the multi-voltage level and
> low power state of some of its IO pads. The IO pads can work in
> the voltage of the 1.8V and 3.3V of IO voltage from IO power rail
> sources.

Can you fix the above sentence?

> When IO interfaces are not used then IO pads can be
> configure in low power state to reduce the power consumption from
> that IO pads.
> 
> On Tegra124, the voltage level of IO power rail source is auto
> detected by hardware(SoC) and hence it is only require to configure
> in low power mode if IO pads are not used.
> 
> On T210 onwards, the auto-detection of voltage level from IO power
> rail is removed from SoC and hence SW need to configure the PMC
> register explicitly to set proper voltage in IO pads based on
> IO rail power source voltage.
> 
> Add DT binding document for detailing the DT properties for
> configuring IO pads voltage levels and its power state.
> 
> Signed-off-by: Laxman Dewangan <ldewangan@...dia.com>
> 
> ---
> Changes from V1:
>  New in series based on pinctrl driver requirement.
> 
> Changes from V2:
>  Updated the statement to say 1.8V and 3.3V as nominal voltage.
>  Corrected DT example by adding -supply and taken care of V1 review
>  from Rob.
> 
>  .../bindings/pinctrl/nvidia,tegra-io-pad.txt       | 126 +++++++++++++++++++++
>  1 file changed, 126 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/pinctrl/nvidia,tegra-io-pad.txt
> 
> diff --git a/Documentation/devicetree/bindings/pinctrl/nvidia,tegra-io-pad.txt b/Documentation/devicetree/bindings/pinctrl/nvidia,tegra-io-pad.txt
> new file mode 100644
> index 0000000..a88c484
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/pinctrl/nvidia,tegra-io-pad.txt
> @@ -0,0 +1,126 @@
> +NVIDIA Tegra PMC IO pad controller
> +
> +NVIDIA Tegra124 and later SoCs support the multi-voltage level and low power
> +state of some of its IO pads. When IO interface are not used then IO pads can
> +be configure in low power state to reduce the power from that IO pads. The IO
> +pads can work in the nominal IO voltage of 1.8V and 3.3V from power rail
> +sources.

I would replace the above sentence with ...

"The IO pads can operate at the nominal IO voltage of either 1.8V or 3.3V".

Cheers
Jon

-- 
nvpublic