2023-09-13 14:58:32

by Konrad Dybcio

[permalink] [raw]
Subject: Re: [PATCH v11 13/13] arm64: dts: qcom: sa8540-ride: Enable first port of tertiary usb controller

On 7.09.2023 05:36, Krishna Kurapati PSSNV wrote:
>
>
> On 9/6/2023 10:28 PM, Konrad Dybcio wrote:
>> On 28.08.2023 15:30, Krishna Kurapati wrote:
>>> From: Andrew Halaney <[email protected]>
>>>
>>> There is now support for the multiport USB controller this uses so
>>> enable it.
>>>
>>> The board only has a single port hooked up (despite it being wired up to
>>> the multiport IP on the SoC). There's also a USB 2.0 mux hooked up,
>>> which by default on boot is selected to mux properly. Grab the gpio
>>> controlling that and ensure it stays in the right position so USB 2.0
>>> continues to be routed from the external port to the SoC.
>>>
>>> Co-developed-by: Andrew Halaney <[email protected]>
>>> Signed-off-by: Andrew Halaney <[email protected]>
>>> [Krishna: Rebased on top of usb-next]
>>> Co-developed-by: Krishna Kurapati <[email protected]>
>>> Signed-off-by: Krishna Kurapati <[email protected]>
>>> ---
>> Is there any benefit to removing the other ports?
>>
>> i.e. are ports 1-3 not parked properly by the dwc3 driver if
>> they're never connected to anything?
>>
> Hi Konrad,
>
>  Whether or not the phy is connected to a port, the controller would modify the GUSB2PHYCFG/GUSB3PIPECTL registers. But if we don't specify only one phy and let phys from base DTSI take effect (4 HS / 2 SS), we would end up initializing and powering on phy's which are never connected to a port. To avoid that we need to specify only one phy for this platform.
And does that have any major effect on power use?

Do these PHYs not have some dormant/low power mode?

Konrad


2023-09-14 17:50:26

by Krishna Kurapati PSSNV

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Subject: Re: [PATCH v11 13/13] arm64: dts: qcom: sa8540-ride: Enable first port of tertiary usb controller



On 9/13/2023 5:40 PM, Konrad Dybcio wrote:
> On 7.09.2023 05:36, Krishna Kurapati PSSNV wrote:
>>
>>
>>> Is there any benefit to removing the other ports?
>>>
>>> i.e. are ports 1-3 not parked properly by the dwc3 driver if
>>> they're never connected to anything?
>>>
>> Hi Konrad,
>>
>>  Whether or not the phy is connected to a port, the controller would modify the GUSB2PHYCFG/GUSB3PIPECTL registers. But if we don't specify only one phy and let phys from base DTSI take effect (4 HS / 2 SS), we would end up initializing and powering on phy's which are never connected to a port. To avoid that we need to specify only one phy for this platform.
> And does that have any major effect on power use?
>
> Do these PHYs not have some dormant/low power mode?
>
Hi Konrad,

I believe there will be some minimal power use. IMO its best to keep
only one phy enabled for this variant instead of giving all and
initializing/powering-on all 4 of them.

Regards,
Krishna,

2023-10-02 19:04:31

by Konrad Dybcio

[permalink] [raw]
Subject: Re: [PATCH v11 13/13] arm64: dts: qcom: sa8540-ride: Enable first port of tertiary usb controller



On 9/14/23 17:45, Krishna Kurapati PSSNV wrote:
>
>
> On 9/13/2023 5:40 PM, Konrad Dybcio wrote:
>> On 7.09.2023 05:36, Krishna Kurapati PSSNV wrote:
>>>
>>>
>>>> Is there any benefit to removing the other ports?
>>>>
>>>> i.e. are ports 1-3 not parked properly by the dwc3 driver if
>>>> they're never connected to anything?
>>>>
>>> Hi Konrad,
>>>
>>>   Whether or not the phy is connected to a port, the controller would
>>> modify the GUSB2PHYCFG/GUSB3PIPECTL registers. But if we don't
>>> specify only one phy and let phys from base DTSI take effect (4 HS /
>>> 2 SS), we would end up initializing and powering on phy's which are
>>> never connected to a port. To avoid that we need to specify only one
>>> phy for this platform.
>> And does that have any major effect on power use?
>>
>> Do these PHYs not have some dormant/low power mode?
>>
> Hi Konrad,
>
>  I believe there will be some minimal power use. IMO its best to keep
> only one phy enabled for this variant instead of giving all and
> initializing/powering-on all 4 of them.
Okay let's not waste power..

Konrad