Messages in this thread | | | Date | Wed, 8 Jan 2014 13:21:47 +0000 | From | Mark Brown <> | Subject | Re: [PATCH] spi: atmel: Refactor spi-atmel to use SPI framework queue |
| |
On Wed, Jan 08, 2014 at 01:49:48PM +0800, Wenyou Yang wrote:
> The patch is based on for-next branch of > git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git
Sorry, there was a patch from Richard which got applied but not pushed out - I've pushed it now but it conflicts with this. Can you please rebase? It should be a simple update from the looks of things.
> - tasklet_schedule(&as->tasklet); > + atmel_spi_lock(as); > + complete(&as->xfer_completion); > + atmel_spi_unlock(as);
Why do you need to hold the lock to complete the transfer? That seems very odd.
> + /* > + * DMA map early, for performance (empties dcache ASAP) and > + * better fault reporting. > + */ > + if ((!msg->is_dma_mapped) > + && (atmel_spi_use_dma(as, xfer) || as->use_pdc)) { > + if (atmel_spi_dma_map_xfer(as, xfer) < 0) > + return -ENOMEM; > + }
Just a heads up at this point but this is most likely going to be moved into the core soon.
> + if (xfer->delay_usecs) > + udelay(xfer->delay_usecs);
If you convert to transfer_one() instead of transfer_one_message() then this will be handled for you. What you're doing at the minute is still an improvement so it should be OK but it'd be worth a look. There will be further changes in this to factor out the DMA and message push code.
> + if (xfer->cs_change) { > + cs_deactivate(as, msg->spi); > + udelay(1); > + cs_activate(as, msg->spi); > + }
This is buggy, cs_change should flip the polarity of /CS rather than bounce it on and off except if set on the last transfer in a message in which case it should cause /CS to remain asserted after the message is finished. Again, transfer_one() factors this out - you can at least look at this to see what should be done.
> + if (as->stopping) > + return -ESHUTDOWN;
You shouldn't need to worry about this, the core should handle this. [unhandled content-type:application/pgp-signature] | |