[V5 0/2] arm64: dts: qcom: Configure CTS pin to bias-bus-hold for bluetooth

[V5 0/2] arm64: dts: qcom: Configure CTS pin to bias-bus-hold for bluetooth

[Vijaya Krishna Nivarthi]

WLAN rail was leaking power during RBSC/sleep even after turning BT off.
Change pinctrl configuration to handle same.

Signed-off-by: Vijaya Krishna Nivarthi <quic_vnivarth@quicinc.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
---
v5: modify subject to include bluetooth
v4: modify subject of each patch to indicate what it is applying to
v3: apply same change to active state and other sc7280*.dts* as well
v2: used bias-bus-hold as per review comments
v1: intial patch used bias-disable for sleep pinctrl in sc7280-idp only
---

Vijaya Krishna Nivarthi (2):
  arm64: dts: qcom: sc7280-idp: Configure CTS pin to bias-bus-hold for
    bluetooth
  arm64: dts: qcom: sc7280-qcard: Configure CTS pin to bias-bus-hold for
    bluetooth

 arch/arm64/boot/dts/qcom/sc7280-idp.dtsi   | 12 ++++++------
 arch/arm64/boot/dts/qcom/sc7280-qcard.dtsi | 13 ++++++++-----
 2 files changed, 14 insertions(+), 11 deletions(-)

-- 
Qualcomm INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by the Linux Foundation.

[V5 1/2] arm64: dts: qcom: sc7280-idp: Configure CTS pin to bias-bus-hold for bluetooth

[Vijaya Krishna Nivarthi]

WLAN rail was leaking power during RBSC/sleep even after turning BT off.
Change active and sleep pinctrl configurations to handle same.

Signed-off-by: Vijaya Krishna Nivarthi <quic_vnivarth@quicinc.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
---
v5: modify subject to include bluetooth
v4: modify subject of patch to indicate file it is applying to
v3: apply same change to active state and other sc7280*.dts* as well
v2: used bias-bus-hold as per review comments
v1: intial patch used bias-disable for sleep pinctrl in sc7280-idp only
---
 arch/arm64/boot/dts/qcom/sc7280-idp.dtsi | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/arm64/boot/dts/qcom/sc7280-idp.dtsi b/arch/arm64/boot/dts/qcom/sc7280-idp.dtsi
index 015a347..85e7467 100644
--- a/arch/arm64/boot/dts/qcom/sc7280-idp.dtsi
+++ b/arch/arm64/boot/dts/qcom/sc7280-idp.dtsi
@@ -400,10 +400,10 @@
 
 &qup_uart7_cts {
 	/*
-	 * Configure a pull-down on CTS to match the pull of
-	 * the Bluetooth module.
+	 * Configure a bias-bus-hold on CTS to lower power usage
+	 * when BT is turned off.
 	 */
-	bias-pull-down;
+	bias-bus-hold;
 };
 
 &qup_uart7_rts {
@@ -495,10 +495,10 @@
 		pins = "gpio28";
 		function = "gpio";
 		/*
-		 * Configure a pull-down on CTS to match the pull of
-		 * the Bluetooth module.
+		 * Configure a bias-bus-hold on CTS to lower power usage
+		 * when BT is turned off.
 		 */
-		bias-pull-down;
+		bias-bus-hold;
 	};
 
 	qup_uart7_sleep_rts: qup-uart7-sleep-rts {
-- 
Qualcomm INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by the Linux Foundation.

[V5 2/2] arm64: dts: qcom: sc7280-qcard: Configure CTS pin to bias-bus-hold for bluetooth

[Vijaya Krishna Nivarthi]

WLAN rail was leaking power during RBSC/sleep even after turning BT off.
Change active and sleep pinctrl configurations to handle same.

Signed-off-by: Vijaya Krishna Nivarthi <quic_vnivarth@quicinc.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
---
v5: modify subject to include bluetooth
v4: modify subject of patch to indicate file it is applying to
v3: apply same change to active state and other sc7280*.dts* as well
v2: used bias-bus-hold as per review comments
v1: intial patch used bias-disable for sleep pinctrl in sc7280-idp only
---
 arch/arm64/boot/dts/qcom/sc7280-qcard.dtsi | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/boot/dts/qcom/sc7280-qcard.dtsi b/arch/arm64/boot/dts/qcom/sc7280-qcard.dtsi
index b833ba1..602ebd4 100644
--- a/arch/arm64/boot/dts/qcom/sc7280-qcard.dtsi
+++ b/arch/arm64/boot/dts/qcom/sc7280-qcard.dtsi
@@ -398,8 +398,11 @@ mos_bt_uart: &uart7 {
 
 /* For mos_bt_uart */
 &qup_uart7_cts {
-	/* Configure a pull-down on CTS to match the pull of the Bluetooth module. */
-	bias-pull-down;
+	/*
+	 * Configure a bias-bus-hold on CTS to lower power usage
+	 * when BT is turned off.
+	 */
+	bias-bus-hold;
 };
 
 /* For mos_bt_uart */
@@ -490,10 +493,10 @@ mos_bt_uart: &uart7 {
 		pins = "gpio28";
 		function = "gpio";
 		/*
-		 * Configure a pull-down on CTS to match the pull of
-		 * the Bluetooth module.
+		 * Configure a bias-bus-hold on CTS to lower power usage
+		 * when BT is turned off.
 		 */
-		bias-pull-down;
+		bias-bus-hold;
 	};
 
 	/* For mos_bt_uart */
-- 
Qualcomm INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by the Linux Foundation.

Re: [V5 0/2] arm64: dts: qcom: Configure CTS pin to bias-bus-hold for bluetooth

[Doug Anderson]

Hi,

On Wed, Apr 20, 2022 at 12:27 AM Vijaya Krishna Nivarthi
<quic_vnivarth@quicinc.com> wrote:
>
> WLAN rail was leaking power during RBSC/sleep even after turning BT off.
> Change pinctrl configuration to handle same.
>
> Signed-off-by: Vijaya Krishna Nivarthi <quic_vnivarth@quicinc.com>
> Reviewed-by: Douglas Anderson <dianders@chromium.org>

Just as a note for future patches, you don't need tags on the cover
letter. If I respond to the cover letter and add tags it means that
they should be added to all the patches in the series but you don't
need to carry them forward on the cover letter itself.

Re: [V5 1/2] arm64: dts: qcom: sc7280-idp: Configure CTS pin to bias-bus-hold for bluetooth

[Doug Anderson]

Hi,

On Wed, Apr 20, 2022 at 12:27 AM Vijaya Krishna Nivarthi
<quic_vnivarth@quicinc.com> wrote:
>
> WLAN rail was leaking power during RBSC/sleep even after turning BT off.
> Change active and sleep pinctrl configurations to handle same.
>
> Signed-off-by: Vijaya Krishna Nivarthi <quic_vnivarth@quicinc.com>
> Reviewed-by: Douglas Anderson <dianders@chromium.org>
> ---
> v5: modify subject to include bluetooth
> v4: modify subject of patch to indicate file it is applying to
> v3: apply same change to active state and other sc7280*.dts* as well
> v2: used bias-bus-hold as per review comments
> v1: intial patch used bias-disable for sleep pinctrl in sc7280-idp only
> ---
>  arch/arm64/boot/dts/qcom/sc7280-idp.dtsi | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/arch/arm64/boot/dts/qcom/sc7280-idp.dtsi b/arch/arm64/boot/dts/qcom/sc7280-idp.dtsi
> index 015a347..85e7467 100644
> --- a/arch/arm64/boot/dts/qcom/sc7280-idp.dtsi
> +++ b/arch/arm64/boot/dts/qcom/sc7280-idp.dtsi
> @@ -400,10 +400,10 @@
>
>  &qup_uart7_cts {
>         /*
> -        * Configure a pull-down on CTS to match the pull of
> -        * the Bluetooth module.
> +        * Configure a bias-bus-hold on CTS to lower power usage
> +        * when BT is turned off.

So you skipped half of Bjorn's feedback here. He said:

--

This comment would just leave a future reader with the question about
_why_ does this lower the power usage...

This problem you're seeing is likely to come back in the next platform
and your successor (or even yourself) will have no use of this comment
to figure out what bias to configure on these pins.

--

I personally am not convinced the comment is super valuable now that
we're using bias-bus-hold. The reason we want bias-bus-hold is
basically the exact reason that bias-bus-hold exists in the first
place and I personally wouldn't expect a big comment every place we
use bias-bus-hold. That being said, Bjorn is the maintainer and not
me, so he's the one you need to make happy.

What about:

Configure a bias-bus-hold on CTS to lower power usage when BT is
turned off. Bus hold will maintain a low power state regardless of
whether the Bluetooth module drives the pin in either direction or
leaves the pin fully unpowered.

-Doug