On Monday 20 March 2006 8:21 pm, rakesh kn wrote: > Hi, > > I am relatively a newbie at USB development. > My doubts are simple . Can any one shed some lights on these. > > 1) What is the relevance of "suspend and resume" call backs that we > find in struct device_driver.?
Obsolete-do-not-use-in-new-code. That's driver model stuff; the suspend/resume calls are slowly being moved to the bus glue where they belong. > There are also the same call backs in > struct hc_driver?. What are they used for. ? Are the "suspend/resume" > call backs are in hc_driver are supported for PCI controllers only ? You must not be used to reading comments in the source code; get used to doing that. Otherwise you would not have been able to overlook the comment next to those callbacks, which says they're for the PCI bus glue. > 2) When we write a EHCI-HCD driver for a non-pci controller driver , > like that one for ARM-AMBA bus, which driver registration structure > should we use , > Is it > struct platform_driver (As used in omap_ohci.c) > or > struct device_driver (As used in ehci-auxxx.c ) Use platform_driver ... that ehci-au1xxx.c code should be updated to use it, but "platform_driver" is kind of new, and not all the old code has been updated accordingly. > 3) ARC controller has an embedded TT (transaction translators) built > in to it.? This allows Low Speed and Full Speed devices to be directly > connected to it, which can be identified from the PSPD(port speed > bit). My doubt is whether the ehci-hub.c and ehci-hcd.c in linux > 2.6.15 and above have been modified to support the operational > differnces with respect to QH setup( like setting TTHA). I don't know why you have any "doubt" about that, given the CONFIG_USB_EHCI_ROOT_HUB_TT support in the driver ... which was added specifically to support the ARC controller, and which has been part of the kernel for several years now. > 4) To put the above doubt briefly ,, can i reuse the files in the > 2.6.15 and above kernel usb-ehci tree for implementing my controller > driver. Please remember that my controller has an embedded TT. I've not heard anyone complaining that the EHCI driver doesn't work for ARC-based cores. You should be able to just add platform glue to support EHCI as provided on your chip; it's been done several times. - Dave ------------------------------------------------------- This SF.Net email is sponsored by xPML, a groundbreaking scripting language that extends applications into web and mobile media. Attend the live webcast and join the prime developer group breaking into this new coding territory! http://sel.as-us.falkag.net/sel?cmd=lnk&kid=110944&bid=241720&dat=121642 _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
