Good afternoon, I'm using the 3.0.3 kernel running on an MPC8308 and am trying to interface to a Cypress CY14B256Q2A non-volatile RAM via SPI. I've got the SPI infrastructure, the Freescale SPI driver (drivers/spi/spi_fsl_spi.c), and spidev built into the kernel and everything on the user space/kernel side appears to be working correctly (at least when I try to read the NvRAM's config register all the right places in the kernel get hit and I see the SPI signals active with an o-scope).
I think what I'm hitting is a lack of understanding/documentation on the SPI controller in the 8308. To read data from the NvRAM, the Master (the 8308 in this case) needs to clock out a byte long "read" command, two bytes of address, and then clock in the data from the NvRAM. However, I never get any data back. I think the problem is that (direct quote from the 8308 reference manual) "SPICLK is a gated clock, active only during data transfers". So once the read command and address are sent, the 8308 considers the data transfer complete and gates off SPICLK. Without SPICLK, the NvRAM has no way to clock out it's data. I think it's ready to, it just can't. So the question is, how do I use spidev (or any other means) to get the 8308 SPI controller to keep SPICLK active so that the output data from the NvRAM gets clocked out to the 8308? Thanks. Bruce _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
