Re: [PATCH v2 2/3] arm64: dts: qcom: kaanpaali: Add USB support for MTP platform

[Dmitry Baryshkov]

On Sat, Apr 04, 2026 at 09:41:16PM +0530, Akhil P Oommen wrote:
> On 4/4/2026 1:50 AM, Dmitry Baryshkov wrote:
> > On Sat, Apr 04, 2026 at 01:39:50AM +0530, Akhil P Oommen wrote:
> >> On 3/29/2026 11:22 PM, Krishna Kurapati wrote:
> >>> From: Ronak Raheja <ronak.raheja@xxxxxxxxxxxxxxxx>
> >>>
> >>> Enable USB support on Kaanapali MTP variant. Enable USB controller in
> >>> device mode till glink node is added.
> >>>
> >>> Signed-off-by: Ronak Raheja <ronak.raheja@xxxxxxxxxxxxxxxx>
> >>> Signed-off-by: Jingyi Wang <jingyi.wang@xxxxxxxxxxxxxxxx>
> >>> Signed-off-by: Krishna Kurapati <krishna.kurapati@xxxxxxxxxxxxxxxx>
> >>> ---
> >>>  arch/arm64/boot/dts/qcom/kaanapali-mtp.dts | 27 ++++++++++++++++++++++
> >>>  1 file changed, 27 insertions(+)
> >>>
> >>> +
> >>> +&usb {
> >>> +	dr_mode = "peripheral";
> >>
> >> I can see that the usb port in the MTP support 'host' mode too. Should
> >> this be 'otg'?
> > 
> > It's stated in the commit message: OTG requires glink, which is not
> > available yet.
> 
> If the issue is with switching between host vs device mode, isn't it
> more useful to use "host" here? 'Host' mode does work on this device and
> I use that to connect an ethernet dongle to ssh.

Another issue is VBUS. Without UCSI / pmic_glink control one will have
to set vbus regulators to always-on, which might be bad if it gets
plugged into another device.

Last, but not least, sadly enough of people ar still tied to the 'adb
push' mindset and workflow.

For all those reasons the USB is usually brought up as a peripheral
first, unless it comes together with the UCSI / TCPM implementation.

> 
> -Akhil.
> 
> > 
> > 
> 

-- 
With best wishes
Dmitry