Re: [net-next RFC PATCH v2 01/11] net: phy: extend PHY package API to support multiple global address

[Christian Marangi]

On Sat, Nov 25, 2023 at 06:51:54PM +0100, Andrew Lunn wrote:
> On Sat, Nov 25, 2023 at 01:11:17AM +0100, Christian Marangi wrote:
> > Current API for PHY package are limited to single address to configure
> > global settings for the PHY package.
> > 
> > It was found that some PHY package (for example the qca807x, a PHY
> > package that is shipped with a bundle of 5 PHY) require multiple PHY
> > address to configure global settings. An example scenario is a PHY that
> > have a dedicated PHY for PSGMII/serdes calibrarion and have a specific
> > PHY in the package where the global PHY mode is set and affects every
> > other PHY in the package.
> > 
> > Change the API in the following way:
> > - Make phy_package_join() require a list of address to be passed and the
> >   number of address in the list
> > - On shared data init, each address is the list is checked and added to
> >   the shared struct.
> > - Make __/phy_package_write/read() require an additional arg that
> >   select what global PHY address to use in the provided list.
> 
> I think this is overly complex.
> 
> I would rename struct phy_package_shared addr to base_addr.
> phy_package_join() would then pass the base address of the package,
> which is the same as your reg property for the package in DT.
> 
> I think all current users of devm_phy_package_join() already do pass
> the lowest address in the package, so this should not cause any
> problems. Most drivers even call it base address, rather than cookie,
> which the documentation uses.
> 
> I would then extend __phy_package_read() etc to take an offset, which
> is added to base_addr, and the read is performed on that address. All
> the existing users would pass 0, and your new driver can pass other
> values.
> 
> I also think you can split this out from the DT binding. Make it two
> patch sets. One patch set is about extended the package concept to
> allow access to global registers at addresses other than the base. The
> DT patch is about properties which are shared by the package. These
> seems like two mostly orthogonal concepts.
>

Yes can be detached. Making addr to base_addr would change the thing but
can confirm, any user of the API always used the base addr as cookie, so
it won't change a thing.

Will have to make the separate commit a dependency to this series but i
expect this change to be merged before this RFC is completed. Good idea.

-- 
	Ansuel