clk: stratix10: use do_div() for 64-bit calculation

do_div() macro to perform u64 division and guards against overflow if
the result is too large for the unsigned long return type.

Signed-off-by: Dinh Nguyen <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Stephen Boyd <[email protected]>

Author: Dinh Nguyen

drivers/clk/socfpga/clk-pll-s10.c

@@ -39,7 +39,9 @@ static unsigned long clk_pll_recalc_rate(struct clk_hw *hwclk,
 	/* read VCO1 reg for numerator and denominator */
 	reg = readl(socfpgaclk->hw.reg);
 	refdiv = (reg & SOCFPGA_PLL_REFDIV_MASK) >> SOCFPGA_PLL_REFDIV_SHIFT;
-	vco_freq = (unsigned long long)parent_rate / refdiv;
+
+	vco_freq = parent_rate;
+	do_div(vco_freq, refdiv);
 
 	/* Read mdiv and fdiv from the fdbck register */
 	reg = readl(socfpgaclk->hw.reg + 0x4);