Re: [PATCH v2 2/3] usb: chipidea: imx: support disabling runtime-pm

[Luca Ceresoli]

Hello Jun,

On Mon, 8 May 2023 15:17:56 +0200
Luca Ceresoli <luca.ceresoli@xxxxxxxxxxx> wrote:

> Hello Jun, Francesco,
> 
> On Mon, 8 May 2023 13:17:11 +0200
> Francesco Dolcini <francesco@xxxxxxxxxx> wrote:
> 
> > On Sat, May 06, 2023 at 09:02:39AM +0000, Jun Li wrote:  
> > > > -----Original Message-----
> > > > From: Francesco Dolcini <francesco@xxxxxxxxxx>
> > > > Sent: Friday, May 5, 2023 7:00 PM
> > > > To: Luca Ceresoli <luca.ceresoli@xxxxxxxxxxx>; Jun Li <jun.li@xxxxxxx>
> > > > Cc: Francesco Dolcini <francesco@xxxxxxxxxx>; devicetree@xxxxxxxxxxxxxxx;
> > > > festevam@xxxxxxxxx; gregkh@xxxxxxxxxxxxxxxxxxx; kernel@xxxxxxxxxxxxxx;
> > > > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; dl-linux-imx <linux-imx@xxxxxxx>;
> > > > linux-kernel@xxxxxxxxxxxxxxx; linux-usb@xxxxxxxxxxxxxxx;
> > > > peter.chen@xxxxxxx; robh+dt@xxxxxxxxxx; s.hauer@xxxxxxxxxxxxxx;
> > > > shawnguo@xxxxxxxxxx; Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>;
> > > > Francesco Dolcini <francesco.dolcini@xxxxxxxxxxx>
> > > > Subject: Re: [PATCH v2 2/3] usb: chipidea: imx: support disabling runtime-pm
> > > > 
> > > > On Fri, May 05, 2023 at 12:06:18PM +0200, Luca Ceresoli wrote:    
> > > > > On Fri, 5 May 2023 09:49:16 +0000
> > > > > Jun Li <jun.li@xxxxxxx> wrote:    
> > > > > > Is your board design similar like Francesco's as below?    
> > > > >
> > > > > Possibly, but I'm afraid I can't say: I am using the Toradex Colibri
> > > > > i.MX6ULL SoM, whose schematics are not public.    
> > > > 
> > > > I can confirm that it's the same.    
> > > 
> > > Thanks Francesco for the confirmation, had a check with design team,
> > > there is no status bit which can be used to judge the VDD_USB_CAP is
> > > powered or not, so we have to add a board level dts property to tell
> > > this usb phy driver to bypass MXS_PHY_DISCONNECT_LINE_WITHOUT_VBUS.
> > > 
> > > Before send a formal patch, I want to confirm this should work for your
> > > HW design, like below simple hack:    
> > 
> > Thanks Li Jun, I tested it with v6.3.1 kernel and it's all good.
> > I would be happy to test the patch as soon as you send it.  
> 
> Thanks Jun, it works here as well, on 6.1.27!

Have you managed to make progress on the patch after Francesco's and my
tests?

As I see it, a proper fix for mainline could be as simple as a new DT
property to describe this specific hardware configuration and a patch
to ignore the flag when the property is present. Is my understanding
correct?

Best regards,
Luca

-- 
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com