commit 3a70dd2d050331ee4cf5ad9d5c0a32d83ead9a43
author Peter Hess <peter.hess@ph-home.de> Tue Jul 06 14:16:09 2021 +0200
committer Mark Brown <broonie@kernel.org> Sun Jul 11 23:44:40 2021 +0100
tree bba5ea41919e4d9e327213fabaa1eae696a17e21
parent 69e1818ad27bae167eeaaf6829d4a08900ef5153

spi: mediatek: fix fifo rx mode

In FIFO mode were two problems:
- RX mode was never handled and
- in this case the tx_buf pointer was NULL and caused an exception

fix this by handling RX mode in mtk_spi_fifo_transfer

Fixes: a568231f4632 ("spi: mediatek: Add spi bus for Mediatek MT8173")
Signed-off-by: Peter Hess <peter.hess@ph-home.de>
Signed-off-by: Frank Wunderlich <frank-w@public-files.de>
Link: https://lore.kernel.org/r/20210706121609.680534-1-linux@fw-web.de
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-mt65xx.c

diff --git a/drivers/spi/spi-mt65xx.c b/drivers/spi/spi-mt65xx.c
index 976f73b..8d5fa7f 100644
--- a/drivers/spi/spi-mt65xx.c
+++ b/drivers/spi/spi-mt65xx.c
@@ -427,13 +427,23 @@ static int mtk_spi_fifo_transfer(struct spi_master *master,
 	mtk_spi_setup_packet(master);
 
 	cnt = xfer->len / 4;
-	iowrite32_rep(mdata->base + SPI_TX_DATA_REG, xfer->tx_buf, cnt);
+	if (xfer->tx_buf)
+		iowrite32_rep(mdata->base + SPI_TX_DATA_REG, xfer->tx_buf, cnt);
+
+	if (xfer->rx_buf)
+		ioread32_rep(mdata->base + SPI_RX_DATA_REG, xfer->rx_buf, cnt);
 
 	remainder = xfer->len % 4;
 	if (remainder > 0) {
 		reg_val = 0;
-		memcpy(&reg_val, xfer->tx_buf + (cnt * 4), remainder);
-		writel(reg_val, mdata->base + SPI_TX_DATA_REG);
+		if (xfer->tx_buf) {
+			memcpy(&reg_val, xfer->tx_buf + (cnt * 4), remainder);
+			writel(reg_val, mdata->base + SPI_TX_DATA_REG);
+		}
+		if (xfer->rx_buf) {
+			reg_val = readl(mdata->base + SPI_RX_DATA_REG);
+			memcpy(xfer->rx_buf + (cnt * 4), &reg_val, remainder);
+		}
 	}
 
 	mtk_spi_enable_transfer(master);