Subject: [PATCH] ARM: AM43xx: clk: Change the wdt1 func clk src to per_32k clk

From: [email-masked] (Tero Kristo)
Date: Tue, 22 Apr 2014 13:06:37 +0300

On 04/16/2014 07:14 AM, Lokesh Vutla wrote:
> WDT1 module can take one of the below clocks as input functional
> clock -
> 	- On-Chip 32K RC Osc [default/reset]
> 	- 32K from PRCM
>
> The On-Chip 32K RC Osc clock is not an accurate clock-source as per
> the design/spec, so as a result, for example, timer which supposed
> to get expired @60Sec, but will expire somewhere ~@40Sec, which is
> not expected by any use-case.
>
> The solution here is to switch the input clock-source to PRCM
> generated 32K clock-source during boot-time itself.
> This is derived from AM33xx clock file.

I guess this patch should wait until we have a proper solution upstream 
for selecting parents based on DT data, unless you have pressing need to 
merge this as a temporary hack.

-Tero

>
> Signed-off-by: Lokesh Vutla <[email-masked]>
> ---
>   drivers/clk/ti/clk-43xx.c |   13 +++++++++++++
>   1 file changed, 13 insertions(+)
>
> diff --git a/drivers/clk/ti/clk-43xx.c b/drivers/clk/ti/clk-43xx.c
> index 67c8de5..ae2524e 100644
> --- a/drivers/clk/ti/clk-43xx.c
> +++ b/drivers/clk/ti/clk-43xx.c
> @@ -110,9 +110,22 @@ static struct ti_dt_clk am43xx_clks[] = {
>
>   int __init am43xx_dt_clk_init(void)
>   {
> +	struct clk *clk1, *clk2;
> +
>   	ti_dt_clocks_register(am43xx_clks);
>
>   	omap2_clk_disable_autoidle_all();
>
> +	/*
> +	 * The On-Chip 32K RC Osc clock is not an accurate clock-source as per
> +	 * the design/spec, so as a result, for example, timer which supposed
> +	 * to get expired @60Sec, but will expire somewhere ~@40Sec, which is
> +	 * not expected by any use-case, so change WDT1 clock source to PRCM
> +	 * 32KHz clock.
> +	 */
> +	clk1 = clk_get_sys(NULL, "wdt1_fck");
> +	clk2 = clk_get_sys(NULL, "clkdiv32k_ick");
> +	clk_set_parent(clk1, clk2);
> +
>   	return 0;
>   }
>