# \[PATCH v6 10/14\] mfd: lm3533: Set DMA mask

- From: Svyatoslav Ryhel \<hidden\>
- Date: 2026-07-31 11:37:59 
- List: linux-fbdev
- Page: https://ratatoskr.run/linux-fbdev/2026/07/17348633
- Thread: https://ratatoskr.run/dri-devel/2026/07/17348620/t.md

```text
Missing coherent_dma_mask assigning triggers the following warning in
dmesg:

[    3.287872] platform lm3533-backlight.0: DMA mask not set

Since this warning might be elevated to an error in the future, set
coherent_dma_mask to zero because both the core and cells do not utilize
DMA.

Signed-off-by: Svyatoslav Ryhel <redacted>
---
 drivers/mfd/lm3533-core.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/mfd/lm3533-core.c b/drivers/mfd/lm3533-core.c
index 2a63df034171e..9233da7ce0996 100644
--- a/drivers/mfd/lm3533-core.c
+++ b/drivers/mfd/lm3533-core.c
@@ -479,6 +479,10 @@ static int lm3533_i2c_probe(struct i2c_client *i2c)
 				   LM3533_BOOST_FREQ_MAX);
 	lm3533->boost_freq = lm3533->boost_freq / (500 * KILO) - 1;
 
+	/* LM3533 and child devices do not use DMA */
+	i2c->dev.coherent_dma_mask = 0;
+	i2c->dev.dma_mask = &i2c->dev.coherent_dma_mask;
+
 	return lm3533_device_init(lm3533);
 }
 
-- 
2.53.0

```