On Thu, Apr 30, 2009 at 10:31:53AM +0800, Eric Miao wrote:
On Thu, Apr 30, 2009 at 2:51 AM, Russell King - ARM Linux linux@arm.linux.org.uk wrote:
The transfers happen under control of PCON not the PXA; PCON asserts a GPIO to activate the DMA to control when the transfer happens.
That's too bad then. Does that GPIO act like a chip select or it's just a signal to inform the host to do a transfer? And it also depends on the SCLK direction.
If the GPIO behaves like an IRQ to inform the host for a transfer, maybe the driver can arrange a transfer initiated by that event.
I don't know what the timing requirement is. What I do know is what the current code does, which is to use the signal to control the transmit DMA when PCON wants to transfer data.
Now, remember that PCON has a habbit of resetting the PXA when things happen that it doesn't like, I really don't want to go round experimenting with this thing; as already stated it's really not worth trying to merge this code if that's what will be required.