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From: Andrew Lunn <andrew@lunn•ch>
To: Kai-Heng Feng <kai.heng.feng@canonical•com>
Cc: Heiner Kallweit <hkallweit1@gmail•com>,
	linux@armlinux•org.uk, "David S. Miller" <davem@davemloft•net>,
	Jakub Kicinski <kuba@kernel•org>,
	netdev@vger•kernel.org, linux-kernel@vger•kernel.org
Subject: Re: [PATCH v2] net: phy: marvell: Honor phy LED set by system firmware on a Dell hardware
Date: Wed, 16 Feb 2022 08:39:16 +0100	[thread overview]
Message-ID: <YgyqJAokWhXvDPik@lunn.ch> (raw)
In-Reply-To: <CAAd53p4QXHe7XTv5ntsdnC1Z9EpDfXQECKHDEsRA++SEQSdbYQ@mail.gmail.com>

> > > This is an ACPI based platform and we are working on new firmware
> > > property "use-firmware-led" to give driver a hint:
> > > ...
> > >     Scope (_SB.PC00.OTN0)
> > >     {
> > >         Name (_DSD, Package (0x02)  // _DSD: Device-Specific Data
> > >         {
> > >             ToUUID ("daffd814-6eba-4d8c-8a91-bc9bbf4aa301") /* Device
> > > Properties for _DSD */,
> > >             Package (0x01)
> > >             {
> > >                 Package (0x02)
> > >                 {
> > >                     "use-firmware-led",
> > >                     One
> > >                 }
> > >             }
> > >         })
> > >     }
> > > ...
> > >
> > > Because the property is under PCI device namespace, I am not sure how
> > > to (cleanly) bring the property from the phylink side to phydev side.
> > > Do you have any suggestion?
> >
> > I'm no ACPI expert, but i think
> > Documentation/firmware-guide/acpi/dsd/phy.rst gives you the basis:
> >
> >     During the MDIO bus driver initialization, PHYs on this bus are probed
> >     using the _ADR object as shown below and are registered on the MDIO bus.
> >
> >       Scope(\_SB.MDI0)
> >       {
> >         Device(PHY1) {
> >           Name (_ADR, 0x1)
> >         } // end of PHY1
> >
> >         Device(PHY2) {
> >           Name (_ADR, 0x2)
> >         } // end of PHY2
> >       }
> >
> > These are the PHYs on the MDIO bus. I _think_ that next to the Name,
> > you can add additional properties, like your "use-firmware-led". This
> > would then be very similar to DT, which is in effect what ACPI is
> > copying. So you need to update this document with your new property,
> > making it clear that this property only applies to boot, not
> > suspend/resume. And fwnode_mdiobus_register_phy() can look for the
> > property and set a flag in the phydev structure indicating that ACPI
> > is totally responsible for LEDs at boot time.
> 
> The problem here is there's no MDIO bus in ACPI namespace, namely no
> "Scope(\_SB.MDI0)" on this platform.

So add it. Basically, copy what DT does. I assume there is a node for
the Ethernet device? And is the MDIO bus driver instantiated by the
Ethernet device? So you can add the MDIO node as a sub node of the
Ethernet device. When you register the MDIO bus using
acpi_mdiobus_register() pass a pointer to this MDIO sub node.

     Andrew

  reply	other threads:[~2022-02-16  7:58 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-20  5:19 [PATCH v2] net: phy: marvell: Honor phy LED set by system firmware on a Dell hardware Kai-Heng Feng
2022-01-20  7:58 ` Heiner Kallweit
2022-01-20 11:40   ` Kai-Heng Feng
2022-01-20 13:46 ` Andrew Lunn
2022-01-21  3:54   ` Kai-Heng Feng
2022-01-21 13:04     ` Andrew Lunn
2022-01-21 14:04       ` Kai-Heng Feng
2022-01-21 15:05         ` Andrew Lunn
2022-01-21 13:10     ` Andrew Lunn
2022-01-21 14:06       ` Kai-Heng Feng
2022-01-21 15:08         ` Andrew Lunn
2022-01-21  7:49   ` Heiner Kallweit
2022-01-20 14:26 ` Andrew Lunn
2022-01-21  4:01   ` Kai-Heng Feng
2022-01-21 13:22     ` Andrew Lunn
2022-01-21 14:17       ` Kai-Heng Feng
2022-01-21 15:15         ` Andrew Lunn
2022-01-22 19:13           ` Heiner Kallweit
2022-01-22 21:18             ` Andrew Lunn
2022-02-14  5:40               ` Kai-Heng Feng
2022-02-15 20:27                 ` Andrew Lunn
2022-02-16  2:30                   ` Kai-Heng Feng
2022-02-16  7:39                     ` Andrew Lunn [this message]
2022-01-20 15:33 ` kernel test robot
2022-01-21  6:47 ` kernel test robot

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