[PATCH v3 6/7] ARM: smp_twd: add clock api support

[Colin Cross]

On Tue, Mar 8, 2011 at 3:34 PM, Rob Herring <robherring2 at gmail.com> wrote:
> From: Rob Herring <rob.herring at calxeda.com>
>
> The private timer freq is currently dynamically detected
> using jiffies count to determine the rate. This method adds
> a delay to boot-up, so use the clock api instead to get the
> clock rate.
>
> Signed-off-by: Rob Herring <rob.herring at calxeda.com>
> ---
> v3: Save struct clk pointer for later use (cpufreq).
>
>  arch/arm/include/asm/smp_twd.h |    1 +
>  arch/arm/kernel/smp_twd.c      |   14 ++++++++++++++
>  2 files changed, 15 insertions(+), 0 deletions(-)
>
> diff --git a/arch/arm/include/asm/smp_twd.h b/arch/arm/include/asm/smp_twd.h
> index fed9981..6b0f591 100644
> --- a/arch/arm/include/asm/smp_twd.h
> +++ b/arch/arm/include/asm/smp_twd.h
> @@ -24,5 +24,6 @@ extern void __iomem *twd_base;
>
>  int twd_timer_ack(void);
>  void twd_timer_setup(struct clock_event_device *);
> +void twd_timer_init(void __iomem *base);
>
>  #endif
> diff --git a/arch/arm/kernel/smp_twd.c b/arch/arm/kernel/smp_twd.c
> index 60636f4..cce1171 100644
> --- a/arch/arm/kernel/smp_twd.c
> +++ b/arch/arm/kernel/smp_twd.c
> @@ -8,6 +8,8 @@
>  * it under the terms of the GNU General Public License version 2 as
>  * published by the Free Software Foundation.
>  */
> +#include <linux/clk.h>
> +#include <linux/err.h>
>  #include <linux/init.h>
>  #include <linux/kernel.h>
>  #include <linux/delay.h>
> @@ -24,6 +26,7 @@
>  /* set up by the platform code */
>  void __iomem *twd_base;
>
> +static struct clk *twd_clk;
>  static unsigned long twd_timer_rate;
>
>  static void twd_set_mode(enum clock_event_mode mode,
> @@ -142,3 +145,14 @@ void __cpuinit twd_timer_setup(struct clock_event_device *clk)
>
>        clockevents_register_device(clk);
>  }
> +
> +void __init twd_timer_init(void __iomem *base)
> +{
> +       twd_clk = clk_get_sys("smp_twd", NULL);
> +       if (!IS_ERR(twd_clk))
> +               twd_timer_rate = clk_get_rate(twd_clk);
> +       else
> +               twd_clk = NULL;
> +
> +       twd_base = base;
> +}
Why not leave the old twd_base intitialization and put the clock stuff
in twd_timer_setup?

Would it make sense to drop twd_calibrate_rate entirely and require a twd clock?