[PATCH] ARM: mx28: Clear CLKGATE bit prior to changing DIV field

[Shawn Guo]

On Thu, Jan 19, 2012 at 01:57:45AM -0200, Fabio Estevam wrote:
> 2012/1/19 Shawn Guo <shawn.guo at linaro.org>:
> 
> > My proposal is we need to clk_prepare_enable before clk_set_rate a clock
> > if the clock is gated, and then clk_disable_unprepare the clock after
> > clk_set_rate is done.  This applies whatever codes that want to
> > clk_set_rate a mxs clock.
> 
> So something like:
> 
> --- a/arch/arm/mach-mxs/clock-mx28.c
> +++ b/arch/arm/mach-mxs/clock-mx28.c
> @@ -809,6 +809,8 @@ int __init mx28_clocks_init(void)
>         clk_prepare_enable(&xbus_clk);
>         clk_prepare_enable(&emi_clk);
>         clk_prepare_enable(&uart_clk);
> +       clk_prepare_enable(&saif0_clk);
> +       clk_prepare_enable(&saif1_clk);
> 
>         clk_set_parent(&lcdif_clk, &ref_pix_clk);
>         clk_set_parent(&saif0_clk, &pll0_clk);
> @@ -822,6 +824,8 @@ int __init mx28_clocks_init(void)
>          */
>         clk_set_rate(&saif0_clk, 24000000);
>         clk_set_rate(&saif1_clk, 24000000);
> +       clk_disable_unprepare(&saif0_clk);
> +       clk_disable_unprepare(&saif1_clk);
> 
>         clkdev_add_table(lookups, ARRAY_SIZE(lookups));
> ---
> 
> didn't work on my tests (probe of mxs-saif fails with the same timeout message).
> 
As far as I know, mxs-saif driver also has one clk_set_rate() being
called with the clock gated.

-- 
Regards,
Shawn