Re: [PATCH v5 02/10] dt-bindings: phy: qcom,qmp-usb: Add Glymur USB UNI PHY compatible
From: Wesley Cheng
Date: Tue Oct 21 2025 - 18:51:21 EST
On 10/18/2025 8:39 AM, Krzysztof Kozlowski wrote:
On 18/10/2025 02:20, Wesley Cheng wrote:
On 10/16/2025 9:41 PM, Krzysztof Kozlowski wrote:
On 17/10/2025 02:15, Wesley Cheng wrote:
To me it looks like:Technically its all handling the same clock branch (CXO), we have the
TCSR clkref register that allows us to gate the CXO to the USB PHY, as
Ah, exactly. Then clkref is not a clock. You need rather proper clock
hierarchy.
CXO is shared across several HW blocks, so it allows us to properly
powerdown the PHY even though other clients are voting for CXO on. Then
we obviously have to remove our vote to the overall CXO, so that it can
potentially be shutdown.
Maybe we can rename it to "clkref" for the CXO handle and
"clkref_switch" for the TCSRCC handle?
Naming is better, but it is still not correct. This is not independent
clock signal. It is the same clock.
Hmmm... I guess that's why I kept the same clkref tag, to denote that
its the same clock, but one is a switch/gate for it. Would you happen
to have any suggestions you might have that makes it clearer for
everyone to understand?
|-----| |-----------| |------------------|
|clock|------------|TCSRCC gate|-----------|clkref to this dev|
|-----| |-----------| |------------------|
So you need proper clock controller for TCSR (TCSR Clock Controller, in
short TCSRCC, what a surprise!) which will take input, add gate and
produce clock for this device.
Nothing non-standard, all Qualcomm SoCs have it, every other platform
has it in some way.
Hi Krzystof,
Yes, the design is exactly how you outlined it above. How about clkref
Hm? There is no connection between the clock and the device. Do you see
any line going there?
for the clock and tcsrcc_switch for the clkref switch? That removes any
notation that the gate/switch is an actual clock...
You really did not get the point of this entire discussion.
I won't argue how I interpreted this conversation vs your understanding. We can remove our vote to the clock itself, since tcsrcc registers the CXO as its parent, so it'll handle the reference counting for us whenever we vote on the tcsr clkref. Thank you for taking the time to explain what you were looking for.
Thanks
Wesley Cheng