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

[Luca Ceresoli]

Hello Jun,

On Fri, 5 May 2023 09:49:16 +0000
Jun Li <jun.li at nxp.com> wrote:

> > -----Original Message-----
> > From: Francesco Dolcini <francesco at dolcini.it>
> > Sent: Friday, May 5, 2023 12:50 AM
> > To: Luca Ceresoli <luca.ceresoli at bootlin.com>
> > Cc: devicetree at vger.kernel.org; festevam at gmail.com;
> > gregkh at linuxfoundation.org; Jun Li <jun.li at nxp.com>;
> > kernel at pengutronix.de; linux-arm-kernel at lists.infradead.org;
> > dl-linux-imx <linux-imx at nxp.com>; linux-kernel at vger.kernel.org;
> > linux-usb at vger.kernel.org; peter.chen at nxp.com; robh+dt at kernel.org;
> > s.hauer at pengutronix.de; shawnguo at kernel.org; Krzysztof Kozlowski
> > <krzysztof.kozlowski at linaro.org>; Francesco Dolcini
> > <francesco.dolcini at toradex.com>
> > Subject: Re: [PATCH v2 2/3] usb: chipidea: imx: support disabling runtime-pm
> >
> > Hello Luca,
> > I guess your mail to Philippe bounced, let me try to answer since I am aware
> > of the issue here.
> >
> > On Thu, May 04, 2023 at 06:23:12PM +0200, Luca Ceresoli wrote:  
> > > I found this thread after several hours spent in debugging why USB host  
> > is  
> > > not detecting new devices on a custom board using the iMX6ULL Colibri
> > > SoM.
> > >
> > > My best workaround at the moment is:  
> > We have the same workaround in our BSP since quite some time, see
> > https://git.t/
> > oradex.com%2Fcgit%2Fmeta-toradex-bsp-common.git%2Ftree%2Frecipes-kernel
> > %2Flinux%2Flinux-toradex-mainline-git%2F0002-drivers-chipidea-disable-r
> > untime-pm-for-imx6ul.patch&data=05%7C01%7Cjun.li%40nxp.com%7C776dc1e71a
> > 554ee20ed908db4cbfa5aa%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C638
> > 188158228795706%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2l
> > uMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=3cFsUurgKBfic
> > LNfRxMOErukGiMczhJREFGvaFYTH34%3D&reserved=0
> >  
> > > I haven't found any follow-up patches from you, so I'm wondering whether
> > > you have made any progress on this issue.  
> > You can find the latest discussion on that regard here
> > https://lore/.
> > kernel.org%2Fall%2FY1vLpaxpc5WBCuGD%40francesco-nb.int.toradex.com%2F&d
> > ata=05%7C01%7Cjun.li%40nxp.com%7C776dc1e71a554ee20ed908db4cbfa5aa%7C686
> > ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C638188158228795706%7CUnknown%7C
> > TWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI
> > 6Mn0%3D%7C3000%7C%7C%7C&sdata=xgIAlY5Az9zQgOBaUTHeGJDXNIyNRmEBlcR49JOVB
> > sI%3D&reserved=0
> >  
> > > As I see it, a quirk in the driver would make sense.  
> > I am not sure.
> >
> > The reason this is not working is that the VBUS is not directly
> > connected to the SOC and the USB IP is powered in a different way (all
> > of that was reviewed/acked by NXP when the board was designed).  
> 
> Hi Luca,
> 
> 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.

Best regards,
Luca

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