[U-Boot] video: ipu_common: fix build error

[Eric Nelson]

Hi Peng,

Can you tell that I'm hunting a bug in an old version?

I'm seeing a **very** intermittent regression between U-Boot
versions 2015.07 and 2016.05 and happened to spot something
in this patch.

On 04/27/2016 07:07 PM, Peng Fan wrote:
> Some toolchains fail to build
> "clk->rate = (u64)(clk->parent->rate * 16) / div;"
> And the cast usage is wrong.
> 
> Use the following code to fix the issue,
> "
>    do_div(parent_rate, div);
>    clk->rate = parent_rate;
> "
> 
> Reported-by: Peter Robinson <pbrobinson at gmail.com>
> Signed-off-by: Peng Fan <van.freenix at gmail.com>
> Cc: Stefano Babic <sbabic at denx.de>
> Cc: Fabio Estevam <fabio.estevam at nxp.com>
> Cc: Tom Rini <trini at konsulko.com>
> Cc: Anatolij Gustschin <agust at denx.de>
> Cc: Peter Robinson <pbrobinson at gmail.com>
> Reviewed-by: Tom Rini <trini at konsulko.com>
> Tested-by: Peter Robinson <pbrobinson at gmail.com>
> ---
> 
> Hi Peter,
> 
>   Please help test this patch to see whether this fix your issue or not.
>   Thanks for pointing out this issue.
> 
> Thanks,
> Peng.
> 
>   drivers/video/ipu_common.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/video/ipu_common.c b/drivers/video/ipu_common.c
> index 36d4b23..5676a0f 100644
> --- a/drivers/video/ipu_common.c
> +++ b/drivers/video/ipu_common.c
> @@ -352,7 +352,9 @@ static int ipu_pixel_clk_set_rate(struct clk *clk, unsigned long rate)
>   	 */
>   	__raw_writel((div / 16) << 16, DI_BS_CLKGEN1(clk->id));
>   

Did we lose a multiply by 16 in this change?

> -	clk->rate = (u64)(clk->parent->rate * 16) / div;
> +	do_div(parent_rate, div);
> +
> +	clk->rate = parent_rate;
>   
>   	return 0;
>   }
> 

Please advise,


Eric