i2c: mlxbf: avoid 64-bit division

The 64-bit division in mlxbf_i2c_get_ticks() causes link failures
when compile-testing on 32-bit machines:

ERROR: modpost: "__udivdi3" [drivers/i2c/busses/i2c-mlxbf.ko] undefined!

Change this to a div_u64(), which should replace the constant division
with a a multiply/shift combination in the mlxbf_i2c_get_ticks().

The frequency calculation functions require a slow library call but
should be used much rarer.

Fixes: 053859002c20 ("i2c: mlxbf: Allow build with COMPILE_TEST")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20250520152600.1975628-1-arnd@kernel.org
Signed-off-by: Andi Shyti <andi@smida.it>

diff --git a/drivers/i2c/busses/i2c-mlxbf.c b/drivers/i2c/busses/i2c-mlxbf.c
index 39359942e4d740ee17c6ce52c51d054d42414462..8345f7e6385df64bcd3a82021df3f1e04524c6c5 100644 (file)
--- a/drivers/i2c/busses/i2c-mlxbf.c
+++ b/drivers/i2c/busses/i2c-mlxbf.c
@@ -1083,7 +1083,7 @@ static u32 mlxbf_i2c_get_ticks(struct mlxbf_i2c_priv *priv, u64 nanoseconds,
         *         Frequency
         */
        frequency = priv->frequency;
-       ticks = (nanoseconds * frequency) / MLXBF_I2C_FREQUENCY_1GHZ;
+       ticks = div_u64(nanoseconds * frequency, MLXBF_I2C_FREQUENCY_1GHZ);
        /*
         * The number of ticks is rounded down and if minimum is equal to 1
         * then add one tick.
@@ -1460,9 +1460,8 @@ static u64 mlxbf_i2c_calculate_freq_from_tyu(struct mlxbf_i2c_resource *corepll_
         * and PadFrequency, respectively.
         */
        core_frequency = MLXBF_I2C_PLL_IN_FREQ * (++core_f);
-       core_frequency /= (++core_r) * (++core_od);
 
-       return core_frequency;
+       return div_u64(core_frequency, (++core_r) * (++core_od));
 }
 
 static u64 mlxbf_i2c_calculate_freq_from_yu(struct mlxbf_i2c_resource *corepll_res)
@@ -1491,9 +1490,8 @@ static u64 mlxbf_i2c_calculate_freq_from_yu(struct mlxbf_i2c_resource *corepll_r
         * and PadFrequency, respectively.
         */
        corepll_frequency = (MLXBF_I2C_PLL_IN_FREQ * core_f) / MLNXBF_I2C_COREPLL_CONST;
-       corepll_frequency /= (++core_r) * (++core_od);
 
-       return corepll_frequency;
+       return div_u64(corepll_frequency, (++core_r) * (++core_od));
 }
 
 static int mlxbf_i2c_calculate_corepll_freq(struct platform_device *pdev,