On Fri, Sep 21, 2012 at 08:42:47AM -0700, Tony Lindgren wrote: > * Arnd Bergmann <a...@arndb.de> [120921 02:19]: > > On Thursday 20 September 2012, Tony Lindgren wrote: > > > > /* use PIO for small transfers, avoiding DMA setup/teardown overhead > > > > and > > > > @@ -798,14 +801,26 @@ static int omap2_mcspi_request_dma(struct > > > > spi_device *spi) > > > > dma_cap_zero(mask); > > > > dma_cap_set(DMA_SLAVE, mask); > > > > sig = mcspi_dma->dma_rx_sync_dev; > > > > - mcspi_dma->dma_rx = dma_request_channel(mask, omap_dma_filter_fn, > > > > &sig); > > > > + if (spi->dev.of_node) > > > > + mcspi_dma->dma_rx = > > > > + dma_request_slave_channel(&master->dev, > > > > + > > > > mcspi_dma->dma_rx_ch_name); > > > > + else > > > > + mcspi_dma->dma_rx = > > > > + dma_request_channel(mask, omap_dma_filter_fn, > > > > &sig); > > > > if (!mcspi_dma->dma_rx) { > > > > dev_err(&spi->dev, "no RX DMA engine channel for > > > > McSPI\n"); > > > > return -EAGAIN; > > > > } > > > > > > > > > > Hmm this does not look nice.. We should be able to somehow not to care > > > about > > > the configuration at the mcspi driver level. > > > > I agree, but as far as I understand Vinod's plans, we would actually move > > all drivers over to dma_request_slave_channel() when we have an interface > > to register the lookup tables from platform code. > > > > I think the above is ok for a transitional phase and we can remove the > > fallback path when we have converted all platforms using this driver > > to either use DT or move to the new style way of passing the channel > > configuration. > > Can't we come up with a version of dma_request_slave_channel that works > both ways for now: > > mcspi_dma->dma_rx = > dma_request_slave_channel_compat(mask, omap_dma_filter_fn, &sig, > &master->dev, > mcspi_dma->dma_rx_ch_name); > ... > > Then it's just question of patching away two lines later on rather than > having to add all this if else to all the drivers first, then patching > it away again.
I think that something like that is workable with the implementation simply checking for of_node to do the right thing. -Matt _______________________________________________ Davinci-linux-open-source mailing list Davinci-linux-open-source@linux.davincidsp.com http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source