spi: bcm2835: added comment about different bus behaviour of DMA mode (c41d62b0) · Commits · 戴 / test

The DMA mode behaves slightly different than polling or interrupt driven mode, so just document the fact Signed-off-by:

Martin Sperl <kernel@martin.sperl.org> Changelog: V1 -> V2: applied feedback by Stefan Wahren new in V2 Signed-off-by:

drivers/spi/spi-bcm2835.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -800,7 +800,10 @@ static int bcm2835_spi_transfer_one(struct spi_master *master,
		if (tfr->len < spi_used_hz / HZ_PER_BYTE)
		return bcm2835_spi_transfer_one_poll(master, spi, tfr, cs);

		/* run in dma mode if conditions are right */
		/* run in dma mode if conditions are right
		* Note that unlike poll or interrupt mode DMA mode does not have
		* this 1 idle clock cycle pattern but runs the spi clock without gaps
		*/
		if (master->can_dma && bcm2835_spi_can_dma(master, spi, tfr))
		return bcm2835_spi_transfer_one_dma(master, spi, tfr, cs);