On Fri, May 16, 2008 at 3:25 PM, Jon Smirl <[EMAIL PROTECTED]> wrote: > On 5/16/08, Grant Likely <[EMAIL PROTECTED]> wrote: >> On Fri, May 16, 2008 at 2:27 PM, Jon Smirl <[EMAIL PROTECTED]> wrote: >> > On 5/16/08, Grant Likely <[EMAIL PROTECTED]> wrote: >> >> This series is a set of changes to allow the slaves on an SPI bus to be >> >> described in the OF device tree (useful in arch/powerpc) and adds a >> driver >> >> that uses it (the Freescale MPC5200 SoC's SPI device). >> > >> > Right now we have SPI hooked up to PSC3. Hardware engineer is gone but >> > I'll see if I can get him to alter things to use the SPI controller. I >> > have an old mail from him where he thinks the Phytec board is missing >> > a signal needed to use the SPI controller. >> >> >> While I'd appreciate the testing, I suspect that you really don't want >> to do that. The dedicated SPI controller isn't very good. It only >> does a byte at a time and so is rather slow. A PSC is SPI mode should >> be better (but I haven't tried it personally it yet). > > What is the device tree node for PSC3 supposed to look like when it > has both serial and spi enabled?
The *PSC3 device* cannot support both serial and SPI at the same time. Only one mode works at a time... However, *PSC3 pin group* has can be configured to route both the *PSC3 device* and the *SPI device* signal out to the board at the same time. Pin routing is not something that is described by the device tree. It's viewed as a board level initialization thing, similar to how DDR RAM initialization is viewed. Ideally, the bootloader will write the correct value into port_config for pin routing and Linux will never need to touch it. If the bootloader cannot be changed, then board-specific platform code can be added to fixup the port_config setting. However, the drivers should never touch or care about pin routing. Cheers, g. -- Grant Likely, B.Sc., P.Eng. Secret Lab Technologies Ltd. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
