FAILED: patch "[PATCH] mfd: wcd934x: set DMA mask on parent to silence "DMA mask not set"" failed to apply to 5.15-stable tree

[Sasha Levin <sashal@kernel.org>]

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x b296be1dc008fe3a536341afae01f66bb302e67f
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '20261107060004-failed-5.15-b296be1dc008@kernel.org' --subject-prefix 'PATCH 5.15.y' 'HEAD^..'

Thanks,
Sasha

------------------ original commit in Linus's tree ------------------

From b296be1dc008fe3a536341afae01f66bb302e67f Mon Sep 17 00:00:00 2001
From: David Heidelberg <david@ixit.cz>
Date: Thu, 3 Sep 2026 16:42:05 +0200
Subject: [PATCH] mfd: wcd934x: set DMA mask on parent to silence "DMA mask not
 set"

The wcd934x MFD parent (a slim_device) never initializes its
dma_mask/coherent_dma_mask. When the DT-aware children pass through
of_dma_configure() this triggers the "DMA mask not set" warning for
each child.

Cc: stable@vger.kernel.org
Fixes: f959dcd6ddfd ("dma-direct: Fix potential NULL pointer dereference")
Assisted-by: tencent:hy3
Signed-off-by: David Heidelberg <david@ixit.cz>
Link: https://patch.msgid.link/20260903-wcd-dma-v2-1-189cff560a28@ixit.cz
Signed-off-by: Lee Jones <lee@kernel.org>
---
 drivers/mfd/wcd934x.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/mfd/wcd934x.c b/drivers/mfd/wcd934x.c
index 3c3080e8c8cf7..7bea64fc09562 100644
--- a/drivers/mfd/wcd934x.c
+++ b/drivers/mfd/wcd934x.c
@@ -2,6 +2,7 @@
 // Copyright (c) 2019, Linaro Limited
 
 #include <linux/clk.h>
+#include <linux/dma-mapping.h>
 #include <linux/gpio/consumer.h>
 #include <linux/interrupt.h>
 #include <linux/kernel.h>
@@ -217,6 +218,11 @@ static int wcd934x_slim_probe(struct slim_device *sdev)
 	struct gpio_desc *reset_gpio;
 	int ret;
 
+	ret = dma_coerce_mask_and_coherent(dev, DMA_BIT_MASK(32));
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "Failed to set DMA mask\n");
+
 	ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL);
 	if (!ddata)
 		return	-ENOMEM;
-- 
2.53.0