linux-kernel - Re: Query: Phy: How to find consumer device on dt platform

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Message-Id: <201401291524.36131.arnd@arndb.de>
Date:	Wed, 29 Jan 2014 15:24:35 +0100
From:	Arnd Bergmann <arnd@...db.de>
To:	Pratyush Anand <pratyush.anand@...com>
Cc:	Kishon Vijay Abraham I <kishon@...com>,
	Mohit KUMAR DCG <Mohit.KUMAR@...com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	spear-devel@...t.st.com
Subject: Re: Query: Phy: How to find consumer device on dt platform

On Wednesday 29 January 2014, Pratyush Anand wrote:
> On Wed, Jan 29, 2014 at 01:41:56PM +0800, Kishon Vijay Abraham I wrote:
> > > 
> > > I would instead recommend making the mode of the PHY device the
> > > argument to the phy handle in DT, so that the sata node uses
> > > 
> > > 	phys = <&phyA 0>;
> > > 
> > > and the PCIe node uses
> > > 
> > > 	phys = <&phyB 1>;
> > > 
> > > Then the binding for the phy defines that an argument of '0' means sata mode,
> > > while '1' means pcie mode, plus you should define all other valid modes.
> 
> Probably, it may  not help in this case. How would *phys* defining as
> above with PCIe/SATA node help phy driver to decide whether current
> phy instance is associated with PCIe or SATA. Actually, there is no
> way to pass information from phy consumer driver(pcie/sata driver in
> this case) to phy driver.

I don't understand what is unclear about my example where I do just that.
The argument (0 or 1) gets passed into the driver's xlate function
when the consumer calls of_phy_get().

> > Anyway phyA and phyB points to different nodes and just from phyA and phyB we
> > should be able to tell whether it is sata or pcie.
> 
> We have multiple instances (say 3) of same phy, which can be
> programmed either for pcie or for sata. We have multiple instances of
> ahci and pcie controller. phy_n will be connected to either ahci_n or
> pcie_n.
> 
> What Kishon has suggested here is exactly what I was thinking.
> I think, we should go with this.

I still find it highly inconsistent.

	Arnd
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