> On 09.05.2019, at 19:03, Lukas Wunner <lukas@xxxxxxxxx> wrote: > > Without this, the driver for the BCM2835 SPI controller uses interrupt > mode instead of DMA mode, incurring a significant performance penalty. > The Foundation's device tree has had these attributes for years, but for > some reason they were never upstreamed. > > They were originally contributed by Noralf Trønnes and Martin Sperl: > https://github.com/raspberrypi/linux/commit/25f3e064afc8 > https://github.com/raspberrypi/linux/commit/e0edb52b47e6 I believe the the original patch that I had provided has been turned down was because: * we do not want to “consume” dma resources automatically * to use spi correctly you have to apply several changes to the dt already (think GPIO mode for CS and status=enable). If this mindset has changed, then I am happy. > Tested-by: Nicolas Saenz Julienne <nsaenzjulienne@xxxxxxx> > Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx> > Cc: Martin Sperl <kernel@xxxxxxxxxxxxxxxx> > Cc: Noralf Trønnes <noralf@xxxxxxxxxxx> Reviewed-by: Martin Sperl <kernel@xxxxxxxxxxxxxxxx>
