* Alexandre Bailon <abailon@xxxxxxxxxxxx> [170110 07:23]: > On 01/10/2017 11:05 AM, Sekhar Nori wrote: > > On DA8xx, CPPI 4.1 DMAengine is not an independent system resource, but > > embedded within the USB 2.0 controller. So, I think all that is needed > > is for MUSB DA8xx glue to trigger probe of CPPI 4.1 dmaengine driver > > when it is ready. I am not sure all this DA850-specific clock handling > > is really necessary. > Actually, we have a circular dependency. > USB core tries to get DMA channels during the probe, which fails because > CPPI 4.1 driver is not ready. > But it will never be ready because the USB clock must be enabled before > DMA driver probe, what will not happen because USB driver have disabled > the clock when probe failed. > > Someone in the office suggested me to use the component API, > that could help me to probe the DMA from the USB probe. > > Another way to workaround the dependency would be to do defer the > function calls that access to hardware to avoid to control clock from > DMA driver. Or you really have some wrapper IP block around musb and cppi41 just like am335x has. See drivers/usb/musb/musb_am335x.c and compatible properties for "ti,am33xx-usb" and it's children in am33xx.dtsi. Regards, Tony -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
