Re: [PATCH V4 3/4] arm64: dts: qcom: sc7180: Add sleep state for BT UART

[Matthias Kaehlcke <mka@chromium.org>]

On Thu, Sep 03, 2020 at 08:34:57PM +0530, satya priya wrote:
> Add sleep state for BT uart to support the wakeup feature.
> 
> Signed-off-by: satya priya <skakit@codeaurora.org>
> Reviewed-by: Akash Asthana <akashast@codeaurora.org>
> ---
> Changes in V2:
>  - This patch adds sleep state for BT UART. Newly added in V2.
> 
> Changes in V3:
>  - Remove "output-high" for TX from both sleep and default states
>    as it is not required. Configure pull-up for TX in sleep state.
> 
> Changes in V4:
>  - As per Matthias's comment, removed drive-strength for sleep state
>    and fixed nit-pick.
> 
>  arch/arm64/boot/dts/qcom/sc7180-idp.dts | 37 +++++++++++++++++++++++++++++++++
>  1 file changed, 37 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/qcom/sc7180-idp.dts b/arch/arm64/boot/dts/qcom/sc7180-idp.dts
> index cecac3e..77e3523 100644
> --- a/arch/arm64/boot/dts/qcom/sc7180-idp.dts
> +++ b/arch/arm64/boot/dts/qcom/sc7180-idp.dts
> @@ -507,6 +507,43 @@
>  	};
>  };
>  
> +&qup_uart3_sleep {
> +	pinconf-cts {
> +		/*
> +		 * Configure no-pull on CTS. As this is driven by BT, do not
> +		 * specify any pull in order to not conflict with BT pulls.
> +		 */
> +		pins = "gpio38";
> +		bias-disable;
> +	};
> +
> +	pinconf-rts {
> +		/*
> +		 * Configure pull-down on RTS to make sure that the BT SoC can
> +		 * wake up the system by sending wakeup bytes during suspend.
> +		 */
> +		pins = "gpio39";
> +		bias-pull-down;
> +	};
> +
> +	pinconf-tx {
> +		/* Configure pull-up on TX when it isn't actively driven */
> +		pins = "gpio40";
> +		bias-pull-up;
> +	};
> +
> +	pinconf-rx {
> +		/*
> +		 * Configure a pull-up on RX. This is needed to avoid
> +		 * garbage data when the TX pin of the Bluetooth module is
> +		 * in tri-state (module powered off or not driving the
> +		 * signal yet).
> +		 */
> +		pins = "gpio41";
> +		bias-pull-up;
> +	};
> +};
> +
>  &qup_uart8_default {
>  	pinconf-tx {
>  		pins = "gpio44";

Reviewed-by: Matthias Kaehlcke <mka@chromium.org>