[PATCH] ASoC: tegra: tegra210-mixer: Use div_u64() for 64-bit division

[Rosen Penev]

A MIPS allmodconfig build with LLVM fails during modpost:

  ERROR: modpost: "__udivdi3"
  [sound/soc/tegra/snd-soc-tegra210-mixer.ko] undefined!

tegra210_mixer_configure_gain() divides a 64-bit BIT_ULL() value by the
fade duration. On 32-bit MIPS, clang emits a call to __udivdi3 for that
plain C division, but that compiler helper is not exported to modules.

Use div_u64() for the inverse duration calculation so the driver uses the
kernel's 64-bit division helper instead of emitting a compiler runtime
call.

Assisted-by: Codex:GPT-5.5
Signed-off-by: Rosen Penev <rosenp@xxxxxxxxx>
---
 sound/soc/tegra/tegra210_mixer.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/sound/soc/tegra/tegra210_mixer.c b/sound/soc/tegra/tegra210_mixer.c
index f05617b5f433..bfdd457f740c 100644
--- a/sound/soc/tegra/tegra210_mixer.c
+++ b/sound/soc/tegra/tegra210_mixer.c
@@ -7,6 +7,7 @@
 #include <linux/clk.h>
 #include <linux/device.h>
 #include <linux/io.h>
+#include <linux/math64.h>
 #include <linux/mod_devicetable.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
@@ -157,8 +158,8 @@ static int tegra210_mixer_configure_gain(struct snd_soc_component *cmpnt,
 			if (i == DURATION_N3_ID)
 				val = mixer->duration[id];
 			else if (i == DURATION_INV_N3_ID)
-				val = (u32)(BIT_ULL(31 + TEGRA210_MIXER_PRESCALAR) /
-					    mixer->duration[id]);
+				val = div_u64(BIT_ULL(31 + TEGRA210_MIXER_PRESCALAR),
+					      mixer->duration[id]);
 			else
 				val = gain_params.duration[i];
 		}
-- 
2.54.0