Messages in this thread | | | Date | Thu, 3 Aug 2023 00:21:03 +0200 | From | Andrew Lunn <> | Subject | Re: [PATCH net-next v3 02/11] net: phy: introduce phy_has_c45_registers() |
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On Wed, Aug 02, 2023 at 06:10:27PM +0100, Russell King (Oracle) wrote: > On Wed, Aug 02, 2023 at 06:15:19PM +0200, Andrew Lunn wrote: > > > I'm confused now. Andrew suggested to split it into four different > > > functions: > > > > > > phy_has_c22_registers() > > > phy_has_c45_registers() > > > phy_has_c22_transfers() > > > phy_has_c45_transfers() > > > > > > Without a functional change. That is, either return phydev->is_c45 > > > or the inverse. > > > > Without a functional change at this step of introducing the four > > functions. Then later really implement them to do what the name > > implies. Doing it in steps helps with bisect when it breaks something. > > > > It could also be that not all four are needed, or not all four are > > possible. But the four express the full combinations of transfers and > > registers. > > I'm left wondering how you think that phy_has_c45_registers() can > be implemented in a useful way, because I'm at a total loss...
get_phy_c22_id() looks at the ID registers, and see if its mostly Fs. If so, it says -ENODEV. So phy_has_c22_registers() could be get_phy_c22_id() != -ENODEV. And you can extend that with the logic you quoted from the standard. get_phy_c45_ids() also returns -ENODEV if there are no devices in the package. So phy_has_c45_registers() could be get_phy_c45_id() != -ENODEV.
This is heuristics, not something explicitly from the standard, but the basic idea of looking for not mostly Fs has been used for a long time.
Andrew
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