On Tuesday 19 February 2013, Felipe Balbi wrote: > On Tue, Feb 19, 2013 at 12:33:54PM +0000, Arnd Bergmann wrote: > > > Currently drivers/phy and drivers/net/phy are independent and are not > > > related to each other. There are some fundamental differences on how > > > these frameworks work. IIUC, the *net* uses bus layer (MDIO bus) to > > > match a PHY device with a PHY driver and the Ethernet device uses the > > > bus layer to get the PHY. > > > The Generic PHY Framework however doesn't have any bus layer. The PHY > > > should be like any other Platform Devices and Drivers and the framework > > > will provide some APIs to register with the framework. And there are > > > other APIs which any controller can use to get the PHY (for e.g., in the > > > case of dt boot, it can use phandle to get a reference to the PHY). > > > > Hmm, I think the use of a bus_type for a PHY actually sounds quite > > appropriate. The actual PHY device would then be a child of the > > really ? I'm not so sure, the *bus* used by the PHY is ULPI, UTMI, > UTMI+, PIP3, I2C, etc... adding another 'fake' bus representation is a > bit overkill IMO. > > Imagine an I2C-controlled PHY driver like isp1301, that driver will have > to register i2c_driver and phy_driver, which looks weird to me. If the > only substitute for class is a bus, we can't drop classes just yet, I'm > afraid. > > Imagine a regulator bus, a pwm bus, an LED bus etc. They don't make > sense IMHO. It's a fine line, but I think a phy is something that resembles a device more than an LED does. When I read patch 1, I also noticed and commented on the fact that it does use a 'class'. Now, according to Greg, we should use 'bus_type' instead of 'class' in new code. I originally disagreed with that concept, but he's the boss here and it's good if he has a vision how things should be lined out. In practice, there is little difference between a 'bus_type' and a 'class', so just replace any instance of the former with the latter in your head when reading the code ;-) I understand that there is not a real common bus here, and the bus_type infrastructure would basically be used as a way to represent each PHY in sysfs and provide a way to enumerate and look them up inside of the kernel. Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
