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

[David Heidelberg <david@ixit.cz>]

On 03/09/2026 14:49, Lee Jones wrote:
> On Sun, 23 Aug 2026, David Heidelberg via B4 Relay wrote:
> 
>> 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>
>> ---
>>   drivers/mfd/wcd934x.c | 6 ++++++
>>   1 file changed, 6 insertions(+)
>>
>> diff --git a/drivers/mfd/wcd934x.c b/drivers/mfd/wcd934x.c
>> index 3c3080e8c8cf7..70ee13791d52b 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;
>>   
>> +	if (!dev->dma_mask) {
>> +		dev->dma_mask = &dev->coherent_dma_mask;
>> +		dev->coherent_dma_mask = DMA_BIT_MASK(32);
>> +	}
>> +
> 
> Any reason not to use dma_coerce_mask_and_coherent()?

Didn't knew about it. Sending v2.

David