linux-kernel - Re: [PATCH net-next v3 14/14] net: dsa: b53: ensure BCM5325 PHYs are enabled

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Message-ID: <CAKR-sGf3kLphXKcmPsB0ZPFY1dQ-TpgDDFHEw9Fv8_vowD8dfg@mail.gmail.com>
Date: Thu, 12 Jun 2025 11:41:18 +0200
From: Álvaro Fernández Rojas <noltari@...il.com>
To: Jonas Gorski <jonas.gorski@...il.com>
Cc: florian.fainelli@...adcom.com, andrew@...n.ch, olteanv@...il.com, 
	davem@...emloft.net, edumazet@...gle.com, kuba@...nel.org, pabeni@...hat.com, 
	horms@...nel.org, vivien.didelot@...il.com, netdev@...r.kernel.org, 
	linux-kernel@...r.kernel.org, dgcbueu@...il.com
Subject: Re: [PATCH net-next v3 14/14] net: dsa: b53: ensure BCM5325 PHYs are enabled

Hi Jonas,

El jue, 12 jun 2025 a las 11:19, Jonas Gorski
(<jonas.gorski@...il.com>) escribió:
>
> On Thu, Jun 12, 2025 at 10:38 AM Álvaro Fernández Rojas
> <noltari@...il.com> wrote:
> >
> > According to the datasheet, BCM5325 uses B53_PD_MODE_CTRL_25 register to
> > disable clocking to individual PHYs.
> > Only ports 1-4 can be enabled or disabled and the datasheet is explicit
> > about not toggling BIT(0) since it disables the PLL power and the switch.
> >
> > Signed-off-by: Álvaro Fernández Rojas <noltari@...il.com>
> > ---
> >  drivers/net/dsa/b53/b53_common.c | 12 ++++++++++++
> >  drivers/net/dsa/b53/b53_regs.h   |  2 ++
> >  2 files changed, 14 insertions(+)
> >
> >  v3: add changes requested by Florian:
> >   - Use in_range() helper.
> >
> >  v2: add changes requested by Florian:
> >   - Move B53_PD_MODE_CTRL_25 to b53_setup_port().
> >
> > diff --git a/drivers/net/dsa/b53/b53_common.c b/drivers/net/dsa/b53/b53_common.c
> > index 3503f363e2419..eac40e95c8c53 100644
> > --- a/drivers/net/dsa/b53/b53_common.c
> > +++ b/drivers/net/dsa/b53/b53_common.c
> > @@ -660,6 +660,18 @@ int b53_setup_port(struct dsa_switch *ds, int port)
> >         if (dsa_is_user_port(ds, port))
> >                 b53_set_eap_mode(dev, port, EAP_MODE_SIMPLIFIED);
> >
> > +       if (is5325(dev) &&
> > +           in_range(port, B53_PD_MODE_PORT_MIN, B53_PD_MODE_PORT_MAX)) {
>
> This happen to match, but the third argument of in_range() isn't the
> maximum, but the range (max - start), so semantically this looks
> wrong.

I can change it in order to avoid confusion.
Which one do you prefer?

1. Change defines:
#define B53_PD_MODE_PORT_START 1
#define B53_PD_MODE_PORT_LEN 4
in_range(port, B53_PD_MODE_PORT_START, B53_PD_MODE_PORT_LEN)

2. Just use magic numbers and avoid adding defines:
in_range(port, 1, 4)

>
> > +               u8 reg;
> > +
> > +               b53_read8(dev, B53_CTRL_PAGE, B53_PD_MODE_CTRL_25, &reg);
> > +               if (dsa_is_unused_port(ds, port))
> > +                       reg |= BIT(port);
> > +               else
> > +                       reg &= ~BIT(port);
> > +               b53_write8(dev, B53_CTRL_PAGE, B53_PD_MODE_CTRL_25, reg);
> > +       }
> > +
> >         return 0;
> >  }
> >  EXPORT_SYMBOL(b53_setup_port);
> > diff --git a/drivers/net/dsa/b53/b53_regs.h b/drivers/net/dsa/b53/b53_regs.h
> > index d6849cf6b0a3a..880c67130a9fc 100644
> > --- a/drivers/net/dsa/b53/b53_regs.h
> > +++ b/drivers/net/dsa/b53/b53_regs.h
> > @@ -105,6 +105,8 @@
> >
> >  /* Power-down mode control */
> >  #define B53_PD_MODE_CTRL_25            0x0f
> > +#define  B53_PD_MODE_PORT_MIN          1
> > +#define  B53_PD_MODE_PORT_MAX          4
> >
> >  /* IP Multicast control (8 bit) */
> >  #define B53_IP_MULTICAST_CTRL          0x21
> > --
> > 2.39.5
> >
>
> Regards,
> Jonas