[PATCH] spi: qup: fix error pointer deref after DMA setup failure

[Johan Hovold <johan@kernel.org>]

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 (or attempting to release a channel
a second time) on later probe errors or driver unbind.

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

Fixes: 612762e82ae6 ("spi: qup: Add DMA capabilities")
Link: https://sashiko.dev/#/patchset/20260505072909.618363-1-johan%40kernel.org?part=4
Cc: stable@vger.kernel.org	# 4.1
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/spi/spi-qup.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/spi/spi-qup.c b/drivers/spi/spi-qup.c
index 45d9b4cb75e4..50bb7701b9d5 100644
--- a/drivers/spi/spi-qup.c
+++ b/drivers/spi/spi-qup.c
@@ -996,8 +996,11 @@ static int spi_qup_init_dma(struct spi_controller *host, resource_size_t base)
 
 err:
 	dma_release_channel(host->dma_tx);
+	host->dma_tx = NULL;
 err_tx:
 	dma_release_channel(host->dma_rx);
+	host->dma_rx = NULL;
+
 	return ret;
 }
 
-- 
2.53.0