[PATCH AUTOSEL 5.10 01/23] spi: rockchip: handle zero length transfers without timing out
From: Sasha Levin <sashal@kernel.org>
Date: 2021-09-28 05:58:39
Also in:
linux-rockchip, linux-spi, lkml, stable
Subsystem:
arm/rockchip soc support, spi subsystem, the rest · Maintainers:
Heiko Stuebner, Mark Brown, Linus Torvalds
From: Tobias Schramm <t.schramm@manjaro.org> [ 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@manjaro.org> Link: https://lore.kernel.org/r/20210827050357.165409-1-t.schramm@manjaro.org (local) Signed-off-by: Mark Brown <broonie@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> --- 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
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