[PATCH v2] mfd: wcd934x: set DMA mask on parent to silence "DMA mask not set"

[PATCH v2] mfd: wcd934x: set DMA mask on parent to silence "DMA mask not set"

[David Heidelberg via B4 Relay]

From: David Heidelberg <david@ixit.cz>

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>
---
Changes in v2:
- Use dma_coerce_mask_and_coherent. (Lee)
- Link to v1: https://patch.msgid.link/20260823-wcd-dma-v1-1-95e44a315ccf@ixit.cz
---
 drivers/mfd/wcd934x.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/mfd/wcd934x.c b/drivers/mfd/wcd934x.c
index 3c3080e8c8cf7..853edda9b6da7 100644
--- a/drivers/mfd/wcd934x.c
+++ b/drivers/mfd/wcd934x.c
@@ -1,12 +1,13 @@
 // SPDX-License-Identifier: GPL-2.0
 // 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>
 #include <linux/mfd/core.h>
 #include <linux/mfd/wcd934x/registers.h>
 #include <linux/mfd/wcd934x/wcd934x.h>
 #include <linux/module.h>
 #include <linux/of.h>
@@ -212,16 +213,21 @@ static int wcd934x_slim_status(struct slim_device *sdev,
 static int wcd934x_slim_probe(struct slim_device *sdev)
 {
 	struct device *dev = &sdev->dev;
 	struct device_node *np = dev->of_node;
 	struct wcd934x_ddata *ddata;
 	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;
 
 	ddata->irq = of_irq_get(np, 0);
 	if (ddata->irq < 0)
 		return dev_err_probe(ddata->dev, ddata->irq,
 				     "Failed to get IRQ\n");

---
base-commit: 7079a12d7506b07fb53b54a664bfad5fa9b16d70
change-id: 20260823-wcd-dma-bd621ee39887

Best regards,
--  
David Heidelberg <david@ixit.cz>

Re: (subset) [PATCH v2] mfd: wcd934x: set DMA mask on parent to silence "DMA mask not set"

[Lee Jones]

On Thu, 03 Sep 2026 16:42:05 +0200, David Heidelberg wrote:
> 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.

Applied, thanks!

[1/1] mfd: wcd934x: set DMA mask on parent to silence "DMA mask not set"
      commit: 5a5f978cf3cd2f50b9e123f851f5c6577519ee89

--
Lee Jones [李琼斯]

Re: (subset) [PATCH v2] mfd: wcd934x: set DMA mask on parent to silence "DMA mask not set"

[Lee Jones]

On Thu, 10 Sep 2026, Lee Jones wrote:

> On Thu, 03 Sep 2026 16:42:05 +0200, David Heidelberg wrote:
> > 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.
> 
> Applied, thanks!
> 
> [1/1] mfd: wcd934x: set DMA mask on parent to silence "DMA mask not set"
>       commit: 5a5f978cf3cd2f50b9e123f851f5c6577519ee89

Note that I changed s/dma/DMA/ when applying.

-- 
Lee Jones