From 8bae8a08571789d566fb93ba1cb4f18acfbb51d2 Mon Sep 17 00:00:00 2001 From: Tobias Schramm Date: Fri, 27 Aug 2021 07:03:57 +0200 Subject: [PATCH] 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. Signed-off-by: Jon Lin (cherry picked from commit 5457773ef99f25fcc4b238ac76b68e28273250f4) Change-Id: I0c14eee10fbf0ffd2938d52b6d0c88910d8fd9d7 Signed-off-by: Tobias Schramm --- 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 2cd31ec56691..e5fcdf18b7d5 100644 --- a/drivers/spi/spi-rockchip.c +++ b/drivers/spi/spi-rockchip.c @@ -684,6 +684,12 @@ static int rockchip_spi_transfer_one( struct rockchip_spi *rs = spi_controller_get_devdata(ctlr); 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));