On 25/08/2021 06:51, Felipe Balbi wrote:
Hi Peter, I took a proper look at this again, hoping to find a way to
pass a callback pointer from dwc3-qcom to the dwc3 core, that can be
called from __dwc3_set_mode() to inform the Qualcomm glue about mode
changes.
I would rather keep the strict separation between glue and core.
# 1 __dwc3_set_mode
Felipe wants to keep a strict separation between core and glue
# notifier
Requires the core probe() to complete before the glue probe to work
reliably. This then would lead us to remaking the dwc3-qcom::probe() to
facilitate probe deferral.
We can be sure bugs would be introduced in this process.
AFAIK Felipe is not opposed to this, Bjorn likes it
# 2 extcon
Works but a) is deprecated and b) even if it weren't deprecated has no
way to layer the messages - that I know of.
# 3 USB role switch
Already in-place for the producer {phy, type-c port, usb-gpio typec,
google ecros} to consumer dwc-core. It already has a layering 1:1 of
that array of producers to the consumer.
Unlike extcon though it cannot relay messages to more than one consumer.
As I see it we can either
A. Rewrite the dwc3-qcom probe to make it synchronous with dwc3-core
probe taking the hit of whatever bugs get thrown up as a result of that
over the next while, potentially years.
B. Use USB role switch in some format.
Either
X. as I've submitted here based on a bit of code in dwc3-core or
Y. maybe trying to hide the "relay" aspect in DTS and USB role-switch core
It seems to me our choices are notifier + pain and churn - perhaps low,
perhaps high or USB role switch
3.B.X works and is what has been submitted here but, if it is
objectionable is 3.B.Y viable ?
As in make USB role switch propigate to multiple consumers via DTS and
whatever additional work is required in the role-switch layer ?
+ Heikki on that one.
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bod
