UPSTREAM: 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.

(cherry picked from commit 5457773ef9)
Signed-off-by: Tobias Schramm <t.schramm@manjaro.org>
Signed-off-by: Jon Lin <jon.lin@rock-chips.com>
Change-Id: I0c14eee10fbf0ffd2938d52b6d0c88910d8fd9d7
This commit is contained in:
Tobias Schramm
2021-08-27 07:03:57 +02:00
committed by Tao Huang
parent d54e777875
commit 555b11d168

View File

@@ -679,6 +679,12 @@ 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));