From: Tobias Schramm <t.schramm@xxxxxxxxxxx> [ Upstream commit 5457773ef99f25fcc4b238ac76b68e28273250f4 ] Previously zero length transfers submitted to the Rokchip SPI driver would time out in the SPI layer. This happens because the SPI peripheral does not trigger a transfer completion interrupt for zero length transfers. Fix that by completing zero length transfers immediately at start of transfer. Signed-off-by: Tobias Schramm <t.schramm@xxxxxxxxxxx> Link: https://lore.kernel.org/r/20210827050357.165409-1-t.schramm@xxxxxxxxxxx Signed-off-by: Mark Brown <broonie@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/spi/spi-rockchip.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/spi/spi-rockchip.c b/drivers/spi/spi-rockchip.c index 0aab37cd64e7..624273d0e727 100644 --- a/drivers/spi/spi-rockchip.c +++ b/drivers/spi/spi-rockchip.c @@ -582,6 +582,12 @@ static int rockchip_spi_transfer_one( int ret; bool use_dma; + /* Zero length transfers won't trigger an interrupt on completion */ + if (!xfer->len) { + spi_finalize_current_transfer(ctlr); + return 1; + } + WARN_ON(readl_relaxed(rs->regs + ROCKCHIP_SPI_SSIENR) && (readl_relaxed(rs->regs + ROCKCHIP_SPI_SR) & SR_BUSY)); -- 2.33.0
