[PATCH 5.10.y 2/2] i2c: mxs: fix DMA channel leak on probe error

[Sasha Levin <sashal@kernel.org>]

From: Ruoyu Wang <ruoyuw560@gmail.com>

[ Upstream commit 777979e627115734052b323d2721cdb500e81dcf ]

mxs_i2c_probe() requests an exclusive DMA channel before resetting the
controller and registering the I2C adapter. If either later operation
fails, probe returns without releasing the channel because the remove
callback is not invoked after a failed probe.

Use devm_dma_request_chan() so the device core releases the channel on
probe failure and driver detach. Remove the manual release from the
remove callback because the channel is now device-managed.

This issue was found by a static analysis checker and confirmed by
manual source review.

Fixes: 62885f59a261 ("MXS: Implement DMA support into mxs-i2c")
Assisted-by: unnamed:claude-opus-4.8 typestate
Signed-off-by: Ruoyu Wang <ruoyuw560@gmail.com>
Cc: <stable@vger.kernel.org> # v3.7+
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Link: https://patch.msgid.link/20260815151720.3757460-1-ruoyuw560@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/i2c/busses/i2c-mxs.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-mxs.c b/drivers/i2c/busses/i2c-mxs.c
index abad24808e855..cfd81b748ee0f 100644
--- a/drivers/i2c/busses/i2c-mxs.c
+++ b/drivers/i2c/busses/i2c-mxs.c
@@ -840,7 +840,7 @@ static int mxs_i2c_probe(struct platform_device *pdev)
 	}
 
 	/* Setup the DMA */
-	i2c->dmach = dma_request_chan(dev, "rx-tx");
+	i2c->dmach = devm_dma_request_chan(dev, "rx-tx");
 	if (IS_ERR(i2c->dmach)) {
 		return dev_err_probe(dev, PTR_ERR(i2c->dmach),
 				     "Failed to request dma\n");
@@ -878,9 +878,6 @@ static int mxs_i2c_remove(struct platform_device *pdev)
 
 	i2c_del_adapter(&i2c->adapter);
 
-	if (i2c->dmach)
-		dma_release_channel(i2c->dmach);
-
 	writel(MXS_I2C_CTRL0_SFTRST, i2c->regs + MXS_I2C_CTRL0_SET);
 
 	return 0;
-- 
2.53.0