Hi Fabrizio, Prabhakar,
On Di, 2025-03-18 at 12:31 +0000, Fabrizio Castro wrote:
> Hi Philipp,
>
> Thanks for your feedback!
>
> > From: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
> > Sent: 13 March 2025 13:06
> > Subject: Re: [PATCH v2 2/2] reset: Add USB2PHY control driver for Renesas RZ/V2H(P)
> >
> > Hi Fabrizio,
> >
> > On Do, 2025-03-13 at 10:14 +0000, Fabrizio Castro wrote:
> > > Hi Philipp,
> > >
> > > Thanks for your feedback!
> > >
> > > > From: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
> > > > Sent: 13 March 2025 08:37
> > > > Subject: Re: [PATCH v2 2/2] reset: Add USB2PHY control driver for Renesas RZ/V2H(P)
> > > >
> > > > On Mi, 2025-03-05 at 12:39 +0000, Prabhakar wrote:
> > > > > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
> > > > >
> > > > > Add support for the USB2PHY control driver on the Renesas RZ/V2H(P) SoC.
> > > > > Make the driver handle reset and power-down operations for the USB2PHY.
> > > > >
> > > > > Pass OF data to support future SoCs with similar USB2PHY hardware but
> > > > > different register configurations. Define device-specific initialization
> > > > > values and control register settings in OF data to ensure flexibility
> > > > > for upcoming SoCs.
> > > > >
> > > > > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
> > > > > ---
> > > > > drivers/reset/Kconfig | 7 +
> > > > > drivers/reset/Makefile | 1 +
> > > > > drivers/reset/reset-rzv2h-usb2phy-ctrl.c | 223 +++++++++++++++++++++++
> > > > > 3 files changed, 231 insertions(+)
> > > > > create mode 100644 drivers/reset/reset-rzv2h-usb2phy-ctrl.c
> > > > >
> > [...]
> > > > > diff --git a/drivers/reset/reset-rzv2h-usb2phy-ctrl.c b/drivers/reset/reset-rzv2h-usb2phy-ctrl.c
> > > > > new file mode 100644
> > > > > index 000000000000..a6daeaf37e1c
> > > > > --- /dev/null
> > > > > +++ b/drivers/reset/reset-rzv2h-usb2phy-ctrl.c
> > > > > @@ -0,0 +1,223 @@
> > [...]
> > > > > +static const struct rzv2h_usb2phy_regval rzv2h_init_vals[] = {
> > > > > + { .reg = 0xc10, .val = 0x67c },
> > > > > + { .reg = 0xc14, .val = 0x1f },
> > > > > + { .reg = 0x600, .val = 0x909 },
> > > >
> > > > What are these registers and what are those values doing?
> > >
> > > Unfortunately, there are some licensing restrictions on this IP, this is
> > > the best that we can do, as per the license agreement.
> >
> > How am I expected to review this?
> >
> > For now, I'll assume that these registers are not related to reset
> > functionality at all, and that this driver should be a phy controller
> > driver instead of a reset controller driver.
> >
> > Can you convince me otherwise without breaking license agreements?
>
> Sorry about the delay, as you may have figured out, we had to double check with
> the LSI team before making any statement.
>
> We can confirm that `rzv2h_init_vals` contains the registers and corresponding
> initialization values required to prepare the PHY to receive assert and deassert
> requests. This is a one time only thing, done at probe.
Thank you. Please document this in a comment next to the
rzv2h_init_vals[] table.
> After looking into things again, I have noticed that the probe function is missing
> calling into the assert sequence, and the status of the reset is undefined, so
> that's something to fix for v3 to make it initialize in asserted state.
>
> The assert, deassert, and status operations are only touching reset related registers.
> Nothing else.
>
> Therefore we believe this should be a port reset driver.
>
> Thanks for your patience so far, and sorry for being cryptic.
Let's go ahead with this driver. I'd be happy about a MAINTAINERS entry
for it.
regards
Philipp
