Commit 2b280540 authored by Arnd Bergmann's avatar Arnd Bergmann Committed by Andi Shyti
Browse files

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: 05385900 ("i2c: mlxbf: Allow build with COMPILE_TEST")
Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20250520152600.1975628-1-arnd@kernel.org


Signed-off-by: default avatarAndi Shyti <andi@smida.it>
parent 3b7d8d15

drivers/i2c/busses/i2c-mlxbf.c

+3 −5
Original line number Diff line number Diff line
@@ -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,