[PATCH v3 2/3] clk: nuvoton: ma35d1: fix PLL_CTL1_FRAC bit field width and fractional calc

[Brian Masney]

On Thu, May 21, 2026 at 09:42:19AM +0800, Joey Lu wrote:
> PLL_CTL1_FRAC was defined as GENMASK(31, 24), covering only 8 bits.
> The hardware fractional field occupies bits [31:8] (24 bits), so the
> mask must be GENMASK(31, 8).
> 
> The previous fractional-mode calculation used FIELD_MAX(PLL_CTL1_FRAC)
> as the denominator to obtain 2 decimal places.  With the corrected 24-bit
> mask the old divisor is wrong; replace the arithmetic with a proper
> 24-bit fixed-point rounding to 3 decimal places using the kernel's
> DIV_ROUND_CLOSEST_ULL helper:
> 
>   n_frac = n * 1000 + DIV_ROUND_CLOSEST_ULL(x * 1000, 1 << 24)
> 
> Fixes: 691521a367cf ("clk: nuvoton: Add clock driver for ma35d1 clock controller")
> Signed-off-by: Joey Lu <a0987203069 at gmail.com>

Reviewed-by: Brian Masney <bmasney at redhat.com>