Messages in this thread Patch in this message | | | From | Priit Laes <> | Subject | [PATCH 2/2] ARM: sunxi: spi: add notice about SPI FIFO limit. | Date | Fri, 26 Feb 2016 07:56:57 +0200 |
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From: Michal Suchanek <hramrach@gmail.com>
When testing SPI without DMA I noticed that filling the FIFO on the spi controller causes timeout. This should never happen with DMA support so just adding a comment.
Signed-off-by: Michal Suchanek <hramrach@gmail.com> --- drivers/spi/spi-sun4i.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/spi/spi-sun4i.c b/drivers/spi/spi-sun4i.c index 78141a6..b750664 100644 --- a/drivers/spi/spi-sun4i.c +++ b/drivers/spi/spi-sun4i.c @@ -333,7 +333,9 @@ static int sun4i_spi_transfer_one(struct spi_master *master, sun4i_spi_write(sspi, SUN4I_DMA_CTL_REG, 0); /* Fill the TX FIFO */ - sun4i_spi_fill_fifo(sspi, SUN4I_FIFO_DEPTH); + /* Filling the fifo fully causes timeout for some reason - at least on spi2 on a10s */ + /* The can_dma check is txlen >= SUN4I_FIFO_DEPTH so with DMA this should never happen anyway. */ + sun4i_spi_fill_fifo(sspi, SUN4I_FIFO_DEPTH - 1); } /* Start the transfer */ -- 2.7.2
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