On Thu, Oct 10, 2013 at 09:21:36PM +0200, Arokux X wrote: > Hi, > > recently I have been working on mainlining a simple bus glue driver > for the USB EHCI for the Allwinner family of the ARM SoCs aka sunxi. > The patches are almost ready and can be found at [1] and will be > submitted once completely ready. The most interesting patch is [2] > which is a driver itself. > > Currently everything works. Recently Maxime Ripard brought the reset > framework to my attention which I am going to use, since each of the > PHYs has a reset bit. Right now those bits are treated as clocks. > > Later I am going to add the OHCI support. OHCI and EHCI will be > different drivers in different modules but they will share the same > PHY. I do not quite understand how can I correctly use reset framework > in the case of the common PHY. Imagine a situation if EHCI and OHCI > drivers got loaded and deassert the (same) reset bit. Then a user > decides to rmmod one of the drivers. This will cause it to assert the > reset bit, which will make the other driver to fail. So it is clear > there is a need for some central manager for the reset bit which is > going to be poked by both EHCI and OHCI. > > Maxime Ripard also brought to my attention the new USB phy framework > which was merged into usb-next. However I'm not sure it should be used > in my driver since as far as I understand a PHY of a USB Host > Controller I'm dealing with is built into the controller itself. The > only parts of the driver that touche a PHY are reset bits (different > for each controller) and some initialization bits [3]. In addition the > in the doc file phy.txt I read > > "This framework will be of use only to devices that use external PHY > (PHY functionality is not embedded within the controller)." More exactly, it your PHY is not the same register mapping with controller's you can use it. > > So can you please give me some hints about the possibilities to share > single reset bit? Should I use PHY framework, or create some kind of a > common module that is going to be used by EHCI and OHCI. In addition I > wanted to ask where I should normally put a common code like [4]. For your situation, you may need to create a controller driver, and call ehci, ohci, and phy init at this probe routine, in that way, your ohci and ehci controller will need to be unloaded together. -- Best Regards, Peter Chen -- 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
