From: Matthias Kaehlcke <mka@chromium.org>
To: satya priya <skakit@codeaurora.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>,
gregkh@linuxfoundation.org, Andy Gross <agross@kernel.org>,
Rob Herring <robh+dt@kernel.org>,
linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org, akashast@codeaurora.org,
rojay@codeaurora.org, msavaliy@qti.qualcomm.com
Subject: Re: [PATCH V4 2/4] arm64: dts: qcom: sc7180: Improve the pin config settings for CTS and TX
Date: Thu, 3 Sep 2020 09:14:34 -0700 [thread overview]
Message-ID: <20200903161434.GI3419728@google.com> (raw)
In-Reply-To: <1599145498-20707-3-git-send-email-skakit@codeaurora.org>
On Thu, Sep 03, 2020 at 08:34:56PM +0530, satya priya wrote:
> Configure no-pull for CTS, as this is driven by BT do not specify any pull
> in order to not conflict with BT pulls.
>
> Remove output-high from CTS and TX as this is not really required. During
> bringup to fix transfer failures this was added to match with console uart
> settings. Probably some boot loader config was missing then. As it is
> working fine now, remove it.
You might want to revisit the 'output-high' settings for the IDP console
uart too. I still think this shouldn't do anything on an input pin that
isn't configured as GPIO. Specifically this combination seems silly:
bias-pull-down;
output-high;
> Signed-off-by: satya priya <skakit@codeaurora.org>
> Reviewed-by: Akash Asthana <akashast@codeaurora.org>
> ---
> Changes in V4:
> - This is newly added in V4 to separate the improvements in pin settings
> and wakeup related changes.
>
> arch/arm64/boot/dts/qcom/sc7180-idp.dts | 14 ++++++--------
> 1 file changed, 6 insertions(+), 8 deletions(-)
>
> diff --git a/arch/arm64/boot/dts/qcom/sc7180-idp.dts b/arch/arm64/boot/dts/qcom/sc7180-idp.dts
> index d8b5507..cecac3e 100644
> --- a/arch/arm64/boot/dts/qcom/sc7180-idp.dts
> +++ b/arch/arm64/boot/dts/qcom/sc7180-idp.dts
> @@ -474,32 +474,30 @@
> &qup_uart3_default {
> pinconf-cts {
> /*
> - * Configure a pull-down on 38 (CTS) to match the pull of
> - * the Bluetooth module.
> + * 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-pull-down;
> - output-high;
> + bias-disable;
> };
>
> pinconf-rts {
> - /* We'll drive 39 (RTS), so no pull */
> + /* We'll drive RTS, so no pull */
> pins = "gpio39";
> drive-strength = <2>;
> bias-disable;
> };
>
> pinconf-tx {
> - /* We'll drive 40 (TX), so no pull */
> + /* We'll drive TX, so no pull */
> pins = "gpio40";
> drive-strength = <2>;
> bias-disable;
> - output-high;
> };
>
> pinconf-rx {
> /*
> - * Configure a pull-up on 41 (RX). This is needed to avoid
> + * 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).
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
next prev parent reply other threads:[~2020-09-03 16:14 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-03 15:04 [PATCH V4 0/4] Add wakeup support over UART RX satya priya
2020-09-03 15:04 ` [PATCH V4 1/4] arm64: dts: sc7180: " satya priya
2020-09-03 16:05 ` Matthias Kaehlcke
2020-09-09 14:19 ` skakit
2020-09-03 17:17 ` Matthias Kaehlcke
2020-09-09 14:20 ` skakit
2020-09-03 15:04 ` [PATCH V4 2/4] arm64: dts: qcom: sc7180: Improve the pin config settings for CTS and TX satya priya
2020-09-03 16:14 ` Matthias Kaehlcke [this message]
2020-09-09 21:28 ` Doug Anderson
2020-09-10 12:49 ` skakit
2020-09-03 15:04 ` [PATCH V4 3/4] arm64: dts: qcom: sc7180: Add sleep state for BT UART satya priya
2020-09-03 16:23 ` Matthias Kaehlcke
2020-09-09 21:29 ` Doug Anderson
2020-09-10 12:50 ` skakit
2020-09-03 15:04 ` [PATCH V4 4/4] tty: serial: qcom_geni_serial: Fix the UART wakeup issue satya priya
2020-09-03 16:50 ` Matthias Kaehlcke
2020-09-09 14:21 ` skakit
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