patch "iio: adc: nxp-sar-adc: Fix DMA channel leak in trigger mode" added to char-misc-linus

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    iio: adc: nxp-sar-adc: Fix DMA channel leak in trigger mode

to my char-misc git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-linus branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.

If you have any questions about this process, please let me know.


From 2452969ca1081fea6bd9ab7ad5e168a5d11f28ec Mon Sep 17 00:00:00 2001
From: Felix Gu <ustc.gu@gmail.com>
Date: Sun, 22 Feb 2026 17:45:39 +0800
Subject: iio: adc: nxp-sar-adc: Fix DMA channel leak in trigger mode

The DMA channel was requested in nxp_sar_adc_buffer_postenable() but
was only released in nxp_sar_adc_buffer_software_do_predisable().
This caused a DMA channel resource leak when operating in trigger mode.

Fix this by moving dma_request_chan() from
nxp_sar_adc_buffer_postenable() into
nxp_sar_adc_buffer_software_do_postenable(), ensuring the DMA channel
is only requested in software mode.

Fixes: 4434072a893e ("iio: adc: Add the NXP SAR ADC support for the s32g2/3 platforms")
Signed-off-by: Felix Gu <ustc.gu@gmail.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 drivers/iio/adc/nxp-sar-adc.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/iio/adc/nxp-sar-adc.c b/drivers/iio/adc/nxp-sar-adc.c
index 9efa883c277d..58103bf16aff 100644
--- a/drivers/iio/adc/nxp-sar-adc.c
+++ b/drivers/iio/adc/nxp-sar-adc.c
@@ -718,6 +718,10 @@ static int nxp_sar_adc_buffer_software_do_postenable(struct iio_dev *indio_dev)
 	struct nxp_sar_adc *info = iio_priv(indio_dev);
 	int ret;
 
+	info->dma_chan = dma_request_chan(indio_dev->dev.parent, "rx");
+	if (IS_ERR(info->dma_chan))
+		return PTR_ERR(info->dma_chan);
+
 	nxp_sar_adc_dma_channels_enable(info, *indio_dev->active_scan_mask);
 
 	nxp_sar_adc_dma_cfg(info, true);
@@ -738,6 +742,7 @@ static int nxp_sar_adc_buffer_software_do_postenable(struct iio_dev *indio_dev)
 out_dma_channels_disable:
 	nxp_sar_adc_dma_cfg(info, false);
 	nxp_sar_adc_dma_channels_disable(info, *indio_dev->active_scan_mask);
+	dma_release_channel(info->dma_chan);
 
 	return ret;
 }
@@ -765,10 +770,6 @@ static int nxp_sar_adc_buffer_postenable(struct iio_dev *indio_dev)
 	unsigned long channel;
 	int ret;
 
-	info->dma_chan = dma_request_chan(indio_dev->dev.parent, "rx");
-	if (IS_ERR(info->dma_chan))
-		return PTR_ERR(info->dma_chan);
-
 	info->channels_used = 0;
 
 	/*
-- 
2.53.0