linux-kernel - Re: [PATCH v2 2/2] arm64: dts: qcom: sa8295p: Enable tertiary controller and its 4 USB ports

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Date: Thu, 15 Feb 2024 09:19:39 +0100
From: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To: Bjorn Andersson <andersson@...nel.org>
Cc: Krishna Kurapati <quic_kriskura@...cinc.com>,
 Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
 Rob Herring <robh+dt@...nel.org>, Konrad Dybcio <konrad.dybcio@...aro.org>,
 Conor Dooley <conor+dt@...nel.org>, devicetree@...r.kernel.org,
 linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org,
 quic_ppratap@...cinc.com, quic_jackp@...cinc.com
Subject: Re: [PATCH v2 2/2] arm64: dts: qcom: sa8295p: Enable tertiary
 controller and its 4 USB ports

On 15/02/2024 03:41, Bjorn Andersson wrote:
> On Tue, Feb 13, 2024 at 09:39:51AM +0100, Krzysztof Kozlowski wrote:
>> On 13/02/2024 09:27, Krishna Kurapati wrote:
>>> Multiport USB controller (host-only) of SA8295 ADP has 4 Type-A ports
>>> exposed for connecting peripherals. The VBUS to these peripherals is
>>> provided by TPS2559QWDRCTQ1 regulators connected to these ports. Each
>>> regulator has an enable pin controlled by PMM8540. Since these regulators
>>> are GPIO controlled regulators, model them as fixed regulators and keep
>>> them Always-On at boot since we are wakeup capable and we don't need to
>>> turn them off on suspend. Also since we don't enter device mode, these
>>> regulators can be kept on.
>>>
>>> Signed-off-by: Krishna Kurapati <quic_kriskura@...cinc.com>
>>> ---
>>>  arch/arm64/boot/dts/qcom/sa8295p-adp.dts | 83 ++++++++++++++++++++++++
>>>  1 file changed, 83 insertions(+)
>>>
>>> diff --git a/arch/arm64/boot/dts/qcom/sa8295p-adp.dts b/arch/arm64/boot/dts/qcom/sa8295p-adp.dts
>>> index fd253942e5e5..49418843c214 100644
>>> --- a/arch/arm64/boot/dts/qcom/sa8295p-adp.dts
>>> +++ b/arch/arm64/boot/dts/qcom/sa8295p-adp.dts
>>> @@ -9,6 +9,7 @@
>>>  #include <dt-bindings/gpio/gpio.h>
>>>  #include <dt-bindings/regulator/qcom,rpmh-regulator.h>
>>>  #include <dt-bindings/spmi/spmi.h>
>>> +#include <dt-bindings/pinctrl/qcom,pmic-gpio.h>
>>>  
>>>  #include "sa8540p.dtsi"
>>>  #include "sa8540p-pmics.dtsi"
>>> @@ -108,6 +109,46 @@ edp3_connector_in: endpoint {
>>>  			};
>>>  		};
>>>  	};
>>> +
>>> +	regulator-usb2-vbus {
>>> +		compatible = "regulator-fixed";
>>> +		regulator-name = "USB2_VBUS";
>>> +		gpio = <&pmm8540c_gpios 9 GPIO_ACTIVE_HIGH>;
>>> +		pinctrl-0 = <&usb2_en>;
>>> +		pinctrl-names = "default";
>>> +		enable-active-high;
>>> +		regulator-always-on;
>>> +	};
>>> +
>>> +	regulator-usb3-vbus {
>>> +		compatible = "regulator-fixed";
>>> +		regulator-name = "USB3_VBUS";
>>> +		gpio = <&pmm8540e_gpios 5 GPIO_ACTIVE_HIGH>;
>>> +		pinctrl-0 = <&usb3_en>;
>>> +		pinctrl-names = "default";
>>> +		enable-active-high;
>>> +		regulator-always-on;
>>> +	};
>>> +
>>> +	regulator-usb4-vbus {
>>> +		compatible = "regulator-fixed";
>>> +		regulator-name = "USB4_VBUS";
>>> +		gpio = <&pmm8540g_gpios 5 GPIO_ACTIVE_HIGH>;
>>> +		pinctrl-0 = <&usb4_en>;
>>> +		pinctrl-names = "default";
>>> +		enable-active-high;
>>> +		regulator-always-on;
>>> +	};
>>> +
>>> +	regulator-usb5-vbus {
>>> +		compatible = "regulator-fixed";
>>> +		regulator-name = "USB5_VBUS";
>>> +		gpio = <&pmm8540g_gpios 9 GPIO_ACTIVE_HIGH>;
>>> +		pinctrl-0 = <&usb5_en>;
>>> +		pinctrl-names = "default";
>>> +		enable-active-high;
>>> +		regulator-always-on;
>>
>> Why all these regulators are always on? If USB controller does not probe
>> for any reason, why keeping them enabled? These must not be always-on,
>> but instead used by connector as VBUS supply (or by whatever you have
>> there for USB).
>>
> 
> I'm not too concerned about keeping the lights on in this scenario, but
> if we can describe this properly let's do so (and let's do so on other
> boards with connectors as well).
> 
> We'd have a set of usb-a-connector nodes, that we can tie to the nodes
> in the USB/phy, and the supply. But so far we've associated a connector
> with a port manager, here we don't have one of those, so where would the
> node reside and who should acquire and drive the vbus-supply?

usb-connector binding has vbus-supply and its node could be top-level.
However don't some USB phys also take that regulator?

Best regards,
Krzysztof