From: Arnd Bergmann <arnd@arndb.de>

A plain 64-bit division causes a link failure in some configurations:

ERROR: modpost: "__aeabi_uldivmod" [sound/soc/codecs/snd-soc-rt1320-sdw.ko] undefined!

Since this divides by a constant, using the div_u64() macro ends up
turning this into an efficient multiply/shift operation where possible.

In rt1320_calc_r0(), the open-coded shift seems a litle simpler.

Fixes: da1682d5e8b5 ("ASoC: rt1320: support calibration and temperature/r0 loading")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 sound/soc/codecs/rt1320-sdw.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/sound/soc/codecs/rt1320-sdw.c b/sound/soc/codecs/rt1320-sdw.c
index 342494e0fc5a..245b9d9980f9 100644
--- a/sound/soc/codecs/rt1320-sdw.c
+++ b/sound/soc/codecs/rt1320-sdw.c
@@ -1065,8 +1065,8 @@ static int rt1320_invrs_load(struct rt1320_sdw_priv *rt1320)
 	r_rsratio = rt1320_rsgain_to_rsratio(rt1320, r_rsgain);
 	dev_dbg(dev, "%s, LR rsratio=%lld, %lld\n", __func__, l_rsratio, r_rsratio);
 
-	l_invrs = (l_rsratio * factor) / 1000000000U;
-	r_invrs = (r_rsratio * factor) / 1000000000U;
+	l_invrs = div_u64(l_rsratio * factor, 1000000000U);
+	r_invrs = div_u64(r_rsratio * factor, 1000000000U);
 
 	rt1320_fw_param_protocol(rt1320, RT1320_GET_PARAM, 6, &r0_data[0], sizeof(struct rt1320_datafixpoint));
 	rt1320_fw_param_protocol(rt1320, RT1320_GET_PARAM, 7, &r0_data[1], sizeof(struct rt1320_datafixpoint));
@@ -1087,15 +1087,15 @@ static int rt1320_invrs_load(struct rt1320_sdw_priv *rt1320)
 static void rt1320_calc_r0(struct rt1320_sdw_priv *rt1320)
 {
 	struct device *dev = &rt1320->sdw_slave->dev;
-	unsigned long long l_calir0, r_calir0;
-	const unsigned int factor = (1 << 27);
+	unsigned long long l_calir0, r_calir0, l_calir0_lo, r_calir0_lo;
 
-	l_calir0 = (rt1320->r0_l_reg * 1000) / factor;
-	r_calir0 = (rt1320->r0_r_reg * 1000) / factor;
+	l_calir0 = rt1320->r0_l_reg >> 27;
+	r_calir0 = rt1320->r0_r_reg >> 27;
+	l_calir0_lo = (rt1320->r0_l_reg & ((1ull << 27) - 1) * 1000) >> 27;
+	r_calir0_lo = (rt1320->r0_r_reg & ((1ull << 27) - 1) * 1000) >> 27;
 
 	dev_dbg(dev, "%s, l_calir0=%lld.%03lld ohm, r_calir0=%lld.%03lld ohm\n", __func__,
-		l_calir0 / 1000, l_calir0 % 1000,
-		r_calir0 / 1000, r_calir0 % 1000);
+		l_calir0, l_calir0_lo, r_calir0, r_calir0_lo);
 }
 
 static void rt1320_calibrate(struct rt1320_sdw_priv *rt1320)
-- 
2.39.5

On Tue, 23 Dec 2025 22:52:53 +0100, Arnd Bergmann wrote:
> A plain 64-bit division causes a link failure in some configurations:
> 
> ERROR: modpost: "__aeabi_uldivmod" [sound/soc/codecs/snd-soc-rt1320-sdw.ko] undefined!
> 
> Since this divides by a constant, using the div_u64() macro ends up
> turning this into an efficient multiply/shift operation where possible.
> 
> [...]

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git for-next

Thanks!

[1/1] ASoC: rt1320: fix 32-bit link failure
      commit: 836ecc740ca829040d86a5371f1fcb276110df84

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark