Re: [PATCH V4 2/4] arm64: dts: qcom: sc7180: Improve the pin config settings for CTS and TX

From: skakit
Date: Thu Sep 10 2020 - 09:07:14 EST

Hi Doug,

On 2020-09-10 02:58, Doug Anderson wrote:

On Thu, Sep 3, 2020 at 8:07 AM satya priya <skakit@xxxxxxxxxxxxxx> wrote:

--- 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;

Weird, how did that output-high sneak in there? Glad it's going away.

+ bias-disable;

I'm not convinced that the removal of the pul is the correct thing
here. Specifically for the rx line the comment makes the argument
that if we power off the Bluetooth module then it will stop driving
this pin. In that case if we remove the pull here then the line will
be floating and that can cause some extra power consumption as the
line floats between different logic levels. Do you really need to
remove this pull?

Okay, will keep the pull-down back for CTS.

Same comment for the next patch where you add the sleep settings.