netdev - Re: [PATCH 4/5] net: phy: marvell: Add LED accessors for Marvell 88E1510

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Date:   Thu, 21 Apr 2022 11:11:55 +0800
From:   Kai-Heng Feng <kai.heng.feng@...onical.com>
To:     Andrew Lunn <andrew@...n.ch>
Cc:     hkallweit1@...il.com, linux@...linux.org.uk,
        peppe.cavallaro@...com, alexandre.torgue@...s.st.com,
        joabreu@...opsys.com, davem@...emloft.net, kuba@...nel.org,
        pabeni@...hat.com, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 4/5] net: phy: marvell: Add LED accessors for Marvell 88E1510

On Wed, Apr 20, 2022 at 11:03 PM Andrew Lunn <andrew@...n.ch> wrote:
>
> On Wed, Apr 20, 2022 at 08:40:51PM +0800, Kai-Heng Feng wrote:
> > Implement get_led_config() and set_led_config() callbacks so phy core
> > can use firmware LED as platform requested.
> >
> > Signed-off-by: Kai-Heng Feng <kai.heng.feng@...onical.com>
> > ---
> >  drivers/net/phy/marvell.c | 26 ++++++++++++++++++++++++++
> >  1 file changed, 26 insertions(+)
> >
> > diff --git a/drivers/net/phy/marvell.c b/drivers/net/phy/marvell.c
> > index 2702faf7b0f60..c5f13e09b0692 100644
> > --- a/drivers/net/phy/marvell.c
> > +++ b/drivers/net/phy/marvell.c
> > @@ -750,6 +750,30 @@ static int m88e1510_config_aneg(struct phy_device *phydev)
> >       return err;
> >  }
> >
> > +static int marvell_get_led_config(struct phy_device *phydev)
> > +{
> > +     int led;
> > +
> > +     led = phy_read_paged(phydev, MII_MARVELL_LED_PAGE, MII_PHY_LED_CTRL);
> > +     if (led < 0) {
> > +             phydev_warn(phydev, "Fail to get marvell phy LED.\n");
> > +             led = 0;
> > +     }
>
> I've said this multiple times, there are three LED registers, The
> Function Control register, the Priority Control register and the Timer
> control register. It is the combination of all three that defines how
> the LEDs work. You need to save all of them.

OK, will do.

>
> And you need to make your API generic enough that the PHY driver can
> save anywhere from 1 bit to 42 bytes of configuration.

OK, I guess I'll let the implementation stays within driver callback,
so each driver can decide how many bits need to be saved.

>
> I don't know ACPI, but i'm pretty sure this is not the ACPI way of
> doing this. I think you should be defining an ACPI method, which
> phylib can call after initialising the hardware to allow the firmware
> to configure the LED.

This is not feasible.
If BIOS can define a method and restore the LED by itself, it can put
the method inside its S3 method and I don't have to work on this at
the first place.

Kai-Heng

>
>      Andrew