[PATCH 00/16] Add initial USB support for the Renesas RZ/G3S SoC

[Biju Das]

> -----Original Message-----
> From: Biju Das <biju.das.jz at bp.renesas.com>
> Sent: Tuesday, September 3, 2024 12:07 PM
> To: Claudiu.Beznea <claudiu.beznea at tuxon.dev>; Ulf Hansson <ulf.hansson at linaro.org>
> Cc: vkoul at kernel.org; kishon at kernel.org; robh at kernel.org; krzk+dt at kernel.org; conor+dt at kernel.org;
> p.zabel at pengutronix.de; geert+renesas at glider.be; magnus.damm at gmail.com; gregkh at linuxfoundation.org;
> mturquette at baylibre.com; sboyd at kernel.org; Yoshihiro Shimoda <yoshihiro.shimoda.uh at renesas.com>;
> linux-phy at lists.infradead.org; devicetree at vger.kernel.org; linux-kernel at vger.kernel.org; linux-
> renesas-soc at vger.kernel.org; linux-usb at vger.kernel.org; linux-arm-kernel at lists.infradead.org; linux-
> clk at vger.kernel.org; linux-pm at vger.kernel.org; Claudiu Beznea <claudiu.beznea.uj at bp.renesas.com>
> Subject: RE: [PATCH 00/16] Add initial USB support for the Renesas RZ/G3S SoC
> 
> Hi Claudiu,
> 
> > -----Original Message-----
> > From: claudiu beznea <claudiu.beznea at tuxon.dev>
> > Sent: Tuesday, September 3, 2024 12:00 PM
> > Subject: Re: [PATCH 00/16] Add initial USB support for the Renesas
> > RZ/G3S SoC
> >
> >
> >
> > On 03.09.2024 13:31, Biju Das wrote:
> > >>> During boot clr USB PWR READY signal in TF-A.
> > >>> STR case, suspend set USB PWR READY signal in TF-A.
> > >>> STR case, resume clr USB PWR READY signal in TF-A.
> > >> As I said previously, it can be done in different ways. My point
> > >> was to let Linux set what it needs for all it's devices to work. I
> > >> think the way to go forward is a
> > maintainer decision.
> > >
> > > I agree, there can be n number of solution for a problem.
> > >
> > > Since you modelled system state signal (USB PWRRDY) as reset control
> > > signal, it is reset/DT maintainer's decision to say the final word
> > > whether this signal fits in reset
> > system framework or not?
> >
> > I was thinking:
> > 1/ Geert would be the best to say if he considers it OK to handle this
> >    in Linux
> 
> I agree Geert is the right person for taking SYSTEM decisions, since the signal is used only during
> state transitions (Table 41.6.4 AWO to ALL_ON and 41.6.3 ALL_ON to AWO)

One more info, as per [1], this USB PWRRDY signal setting to be before Linux kernel boots.

All clocks/reset happens after setting USB PWRRDY signal

https://pasteboard.co/qbz021q7KPyi.png

Cheers,
Biju