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spi: rockchip: handle zero length transfers without timing out

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[ 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
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Tobias Schramm 2021-08-27 07:03:57 +02:00 committed by Greg Kroah-Hartman
parent 5cd40b137c
commit 2ababcd8c2
1 changed files with 6 additions and 0 deletions
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6
drivers/spi/spi-rockchip.c
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@ -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));