On Wed, Apr 29, 2009 at 05:14:13PM +0800, Eric Miao wrote: > On Wed, Apr 29, 2009 at 4:41 PM, Russell King - ARM Linux > <linux@xxxxxxxxxxxxxxxx> wrote: > > On Wed, Apr 29, 2009 at 09:21:53AM +0100, Mark Brown wrote: > >> On Wed, Apr 29, 2009 at 08:27:06AM +0100, Russell King - ARM Linux wrote: > >> > On Tue, Apr 28, 2009 at 08:06:08PM -0300, Daniel Ribeiro wrote: > >> > >> > > The SPI subsystem? > >> > >> > Can the SPI system cope with the other chip being the master of the > >> > interface. In other words, can SPI sit around primed for a transfer, > >> > and notify the user of SPI that new data has arrived? > >> > >> > If not, the SPI subsystem is totally unsuitable for this. > >> > >> It's slave only at the minute - there's holes in the API someone could > >> fill in but that's not happened yet. > > > > Well, I guess someone else will have to do that; I don't spend much time > > on the LX stuff, and so if it requires any time consuming work, it won't > > be worth trying to get it into mainline. > > > > However, the patch itself doesn't looks like to be a SPI slave > (I mean from the view of the processor). > > 'struct spi_message' does support simultaneous rx/tx transfer > and multiple such transfers being queued. The transfers happen under control of PCON not the PXA; PCON asserts a GPIO to activate the DMA to control when the transfer happens. We can not just start the SSP for a 32 byte transfer and hope it happens. PCON has to be totally in control. _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
