spi: ep93xx: fix error pointer deref after DMA setup failure

The driver falls back to PIO mode if DMA setup fails during probe.

Make sure to the clear the DMA channel pointers on setup failure to
avoid dereferencing an error pointer on later probe errors or driver
unbind.

This issue was flagged by Sashiko when reviewing a devres allocation
conversion patch.

Fixes: e79e7c2df627 ("spi: ep93xx: add DT support for Cirrus EP93xx")
Link: https://sashiko.dev/#/patchset/20260429091333.165363-1-johan%40kernel.org?part=10
Cc: stable@vger.kernel.org	# 6.12
Cc: Nikita Shubin <nikita.shubin@maquefel.me>
Signed-off-by: Johan Hovold <johan@kernel.org>
Acked-by: Nikita Shubin <nikita.shubin@maquefel.me>
Link: https://patch.msgid.link/20260512074849.915143-1-johan@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/spi/spi-ep93xx.c b/drivers/spi/spi-ep93xx.c
index db50018050e5498536f7de3ef32ffbbc9c4fde23..f716c9607be4af640956c5d5bc3a21ead25a8b25 100644 (file)
--- a/drivers/spi/spi-ep93xx.c
+++ b/drivers/spi/spi-ep93xx.c
@@ -582,12 +582,14 @@ static int ep93xx_spi_setup_dma(struct device *dev, struct ep93xx_spi *espi)
        espi->dma_rx = dma_request_chan(dev, "rx");
        if (IS_ERR(espi->dma_rx)) {
                ret = dev_err_probe(dev, PTR_ERR(espi->dma_rx), "rx DMA setup failed");
+               espi->dma_rx = NULL;
                goto fail_free_page;
        }
 
        espi->dma_tx = dma_request_chan(dev, "tx");
        if (IS_ERR(espi->dma_tx)) {
                ret = dev_err_probe(dev, PTR_ERR(espi->dma_tx), "tx DMA setup failed");
+               espi->dma_tx = NULL;
                goto fail_release_rx;
        }