On 9/7/26 18:26, BurningHoryd wrote:
On 9/7/26 08:40, Neil Armstrong wrote:
This means the nb7vpq904m is _not_ responsible for the AUX swapping, other
boards have the wcd9395 or the fsa4480 in the middle to use the AUX line
for the USB-C Alternate Audio support, and does the swap.
Could you check in the vendor tree if there's any reference to those ?
Checked Retroid's downstream Android DT for this board. There is an
FSA4480, plus a GPIO AUX switch, and my mainline port models neither.
1. fsa4480@43, on the same I2C controller as the redriver:
i2c@884000 {
fsa4480@43 {
compatible = "qcom,fsa4480-i2c";
reg = <0x43>;
};
redriver@1c { /* nb7vpq904m equivalent */
compatible = "onnn,redriver";
status = "disabled";
};
};
The only node that references it is the ASoC machine driver
(qcom,kona-asoc-snd, via "fsa4480-i2c-handle") - so downstream it is
used for the USB-C analog-audio / MBHC SBU routing, not by the DP
driver. The codec is a wcd9385, no USBSS block, so no wcd9395 here.
2. The downstream DP driver does its own AUX orientation over GPIO:
&dp_display {
qcom,dp-gpio-aux-switch;
qcom,aux-sel-gpio = <&tlmm 8 0>;
qcom,aux-en-gpio = <&tlmm 9 0>;
qcom,usbplug-cc-gpio = <&tlmm 65 0>;
};
TLMM 9 there is the same pin my mainline DT currently hands to the
nb7vpq904m as "enable-gpios", so that assignment is likely wrong, and
TLMM 8 (the orientation select) is not wired up in my port at all.
3. The redriver (onnn,redriver @ 0x1c, same I2C address as the
nb7vpq904m on my board) is left status = "disabled" downstream.
So the SBU / DP-AUX orientation switch on this board looks like a
discrete GPIO-controlled analog mux (TLMM 8 select, TLMM 9 enable), and
my port is missing it - I modeled the I2C redriver as the
orientation-switch instead, which is why poking its AUX_CC_REG did
nothing and only the DP_CC2 (pair-swapping, 2-lane) op-mode ever got an
AUX transaction through in reverse.
Does this look like a job for gpio-sbu-mux
(drivers/usb/typec/mux/gpio-sbu-mux.c) - a node with
select-gpios = <&tlmm 8>, enable-gpios = <&tlmm 9>, orientation-switch +
mode-switch, wired to the connector - with the nb7vpq904m kept as
retimer-switch only (or dropped, since downstream disables it)? Or is
the FSA4480 in the DP AUX path as well, making fsa,fsa4480 the right
orientation-switch to add?
Yes if it's a discrete SBU mux, gpio-sbu-mux was designed for that, and
keep the nb7vpq904m and just drop the SBU link to the redriver and replace
it with a link to the SBU mux instead.
Neil
I'll wire up gpio-sbu-mux and come back with reverse/normal traces
unless that's the wrong direction.
Thanks,
BurningHoryd
