[PATCH 1/2] ARM: shmobile: r8a73a4: wait for completion when kicking the clock

[Simon Horman]

On Wed, May 22, 2013 at 11:12:33AM +0200, Guennadi Liakhovetski wrote:
> To reconfigure clocks, controlled by FRQCRA and FRQCRB, a kick bit has to
> be set and to make sure the setting has taken effect, it has to be read
> back repeatedly until it is cleared by the hardware. This patch adds the
> waiting part, that was missing until now.
> 
> Signed-off-by: Guennadi Liakhovetski <g.liakhovetski+renesas at gmail.com>

I have queued this up for v3.12 in the soc branch of the renesas tree.
I have included an Ack from Morimoto-san which he provided here:

"Re: [PATCH 0/4] Add DVFS support on APE6EVM"
http://www.spinics.net/lists/arm-kernel/msg255480.html

> ---
>  arch/arm/mach-shmobile/clock-r8a73a4.c |   22 ++++++++++++++++------
>  1 files changed, 16 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/arm/mach-shmobile/clock-r8a73a4.c b/arch/arm/mach-shmobile/clock-r8a73a4.c
> index 5f7fe62..d5176d0 100644
> --- a/arch/arm/mach-shmobile/clock-r8a73a4.c
> +++ b/arch/arm/mach-shmobile/clock-r8a73a4.c
> @@ -184,6 +184,21 @@ PLL_CLOCK(pll2h_clk, &main_div2_clk, pll_parent_main_extal, 3, 5, PLL2HCR, 5);
>  
>  SH_FIXED_RATIO_CLK(pll1_div2_clk,	pll1_clk,	div2);
>  
> +static int frqcr_kick_do(struct clk *clk)
> +{
> +	int i;
> +
> +	/* set KICK bit in FRQCRB to update hardware setting, check success */
> +	iowrite32(ioread32(CPG_MAP(FRQCRB)) | BIT(31), CPG_MAP(FRQCRB));
> +	for (i = 1000; i; i--)
> +		if (ioread32(CPG_MAP(FRQCRB)) & BIT(31))
> +			cpu_relax();
> +		else
> +			return 0;
> +
> +	return -ETIMEDOUT;
> +}
> +
>  static struct clk *main_clks[] = {
>  	&extalr_clk,
>  	&extal1_clk,
> @@ -205,12 +220,7 @@ static struct clk *main_clks[] = {
>  /* DIV4 */
>  static void div4_kick(struct clk *clk)
>  {
> -	unsigned long value;
> -
> -	/* set KICK bit in FRQCRB to update hardware setting */
> -	value = ioread32(CPG_MAP(FRQCRB));
> -	value |= (1 << 31);
> -	iowrite32(value, CPG_MAP(FRQCRB));
> +	frqcr_kick_do(clk);
>  }
>  
>  static int divisors[] = { 2, 3, 4, 6, 8, 12, 16, 18, 24, 0, 36, 48, 10};
> -- 
> 1.7.2.5
> 
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