On Fri, Dec 02, 2022 at 02:22:39PM +0200, Mathias Nyman wrote: > On 1.12.2022 11.01, Arnd Bergmann wrote: > >On Thu, Dec 1, 2022, at 09:06, Greg Kroah-Hartman wrote: > >>On Thu, Dec 01, 2022 at 11:13:31AM +0900, Daehwan Jung wrote: > >>>This driver works with xhci platform driver. It needs to override > >>>functions of xhci_plat_hc_driver. Wakelocks are used for sleep/wakeup > >>>scenario of system. > >> > >>So this means that no other platform xhci driver can be supported in the > >>same system at the same time. > >> > >>Which kind of makes sense as that's not anything a normal system would > >>have, BUT it feels very odd. This whole idea of "override the platform > >>driver" feels fragile, why not make these just real platform drivers and > >>have the xhci platform code be a library that the other ones can use? > >>That way you have more control overall, right? > > Agree that overriding the generic platform driver xhci_hc_platform_driver > from this exynos driver is odd. > > But I don't understand how this works. > Where are the hcds created and added when this xhci-exonys driver binds to > the device? all this driver does in probe is the overriding? > > Am I missing something here? > This works mainly with xhci platform driver. But xhci-exynos needs to override some funtions. xhci-exynos probes first with override own functons and it works with xhci platform driver. > > > >Agreed, having another layer here (hcd -> xhci -> xhcd_platform -> > >xhcd_exynos) would fit perfectly well into how other SoC specific > >drivers are abstracted. This could potentially also help reduce > >the amount of code duplication between other soc specific variants > >(mtk, tegra, mvebu, ...) that are all platform drivers but don't > >share code with xhci-plat.c. > > > >Alternatively, it seems that all of the xhci-exynos support could > >just be part of the generic xhci-platform driver: as far as I can > >tell, none of the added code is exynos specific at all, instead it > >is a generic xhci that is using the wakeup_source framework. > > Sounds reasonable as well, and if some exynos specific code is needed > then just create a xhci_plat_priv struct for exynos and pass it in > of_device_id data like other vendors that use the generic > xhci-platform driver do. > I considered using existing overrides like xhci_plat_priv but I couldn't find a solution. My driver invokes probing xhci platform driver in source code not device tree. Allocation of platform device is done in dwc3_host_init(usb/dwc3/host.c). That's why I can't pass device data to xhci platform driver. > -Mathias > >
