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spi: rockchip: handle zero length transfers without timing out 

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>
This commit is contained in:
Tobias Schramm 2021-08-27 07:03:57 +02:00 committed by Mark Brown
parent 26cfc0dbe4
commit 5457773ef9
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GPG Key ID: 24D68B725D5487D0
1 changed files with 6 additions and 0 deletions
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6
drivers/spi/spi-rockchip.c
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@ -600,6 +600,12 @@ 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));