On Thu, Feb 28, 2013 at 01:21:58PM +0100, 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@xxxxxx>
This patch seems to be ready to be applied.
Magnus, could I get a review from you?
> ---
>
> As noted in patch 0/3, this patch affects existing systems, but AFAICS
> only theoretically - so far nobody is changing clock rates of any of the
> FRQCRA and FRQCRB clocks. Still, please, handle with care.
>
> arch/arm/mach-shmobile/clock-sh73a0.c | 23 +++++++++++++++++------
> 1 files changed, 17 insertions(+), 6 deletions(-)
>
> diff --git a/arch/arm/mach-shmobile/clock-sh73a0.c b/arch/arm/mach-shmobile/clock-sh73a0.c
> index 71843dd..34b5c5a 100644
> --- a/arch/arm/mach-shmobile/clock-sh73a0.c
> +++ b/arch/arm/mach-shmobile/clock-sh73a0.c
> @@ -21,6 +21,7 @@
> #include <linux/io.h>
> #include <linux/sh_clk.h>
> #include <linux/clkdev.h>
> +#include <asm/processor.h>
> #include <mach/common.h>
>
> #define FRQCRA IOMEM(0xe6150000)
> @@ -234,14 +235,24 @@ static struct clk *main_clks[] = {
> &sh73a0_extalr_clk,
> };
>
> -static void div4_kick(struct clk *clk)
> +static int frqcr_kick(void)
> {
> - unsigned long value;
> + int i;
> +
> + /* set KICK bit in FRQCRB to update hardware setting, check success */
> + __raw_writel(__raw_readl(FRQCRB) | (1 << 31), FRQCRB);
> + for (i = 1000; i; i--)
> + if (__raw_readl(FRQCRB) & (1 << 31))
> + cpu_relax();
> + else
> + return i;
> +
> + return -ETIMEDOUT;
> +}
>
> - /* set KICK bit in FRQCRB to update hardware setting */
> - value = __raw_readl(FRQCRB);
> - value |= (1 << 31);
> - __raw_writel(value, FRQCRB);
> +static void div4_kick(struct clk *clk)
> +{
> + frqcr_kick();
> }
>
> static int divisors[] = { 2, 3, 4, 6, 8, 12, 16, 18,
> --
> 1.7.2.5
>
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