imx6: clock: improve calculations to get the PLL video rate

During some tests to check the pixel clock rate in the transition from
U-Boot to the Linux kernel, I noticed that with the same configuration
of the registers the debug messages reported different rates.

The same Linux kernel calculations are now used to get the PLL video
rate.

Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
Reviewed-by: Michael Trimarchi <michael@amarulasolutions.com>

diff --git a/arch/arm/mach-imx/mx6/clock.c b/arch/arm/mach-imx/mx6/clock.c
index cb9d629be4084d13ba56421b6d77c3eb3b319940..17d8dcd5c841c6bb828658d86bc21c6f4d2d3cdc 100644 (file)
--- a/arch/arm/mach-imx/mx6/clock.c
+++ b/arch/arm/mach-imx/mx6/clock.c
@@ -213,6 +213,7 @@ int enable_spi_clk(unsigned char enable, unsigned spi_num)
 static u32 decode_pll(enum pll_clocks pll, u32 infreq)
 {
        u32 div, test_div, pll_num, pll_denom;
+       u64 temp64;
 
        switch (pll) {
        case PLL_SYS:
@@ -272,7 +273,10 @@ static u32 decode_pll(enum pll_clocks pll, u32 infreq)
                }
                test_div = 1 << (2 - test_div);
 
-               return infreq * (div + pll_num / pll_denom) / test_div;
+               temp64 = (u64)infreq;
+               temp64 *= pll_num;
+               do_div(temp64, pll_denom);
+               return infreq * div + (unsigned long)temp64;
        default:
                return 0;
        }