Hi Anson,
thanks for taking care of adding the clock-frequency handling in the
timer-of.
On 28/06/2019 05:30, Anson.Huang@xxxxxxx wrote:
> From: Anson Huang <Anson.Huang@xxxxxxx>
>
> More and more platforms use platform driver model for clock driver,
> so the clock driver is NOT ready during timer initialization phase,
> it will cause timer initialization failed.
>
> To support those platforms with upper scenario, introducing a new
> flag TIMER_OF_CLOCK_FREQUENCY which is mutually exclusive with
> TIMER_OF_CLOCK flag to support getting timer clock frequency from
> DT, then of_clk operations can be skipped.
>
> User needs to select either TIMER_OF_CLOCK_FREQUENCY or TIMER_OF_CLOCK
> flag if want to use timer-of driver to initialize the clock rate,
> and the corresponding clock name or property name needs to be specified.
>
> Signed-off-by: Anson Huang <Anson.Huang@xxxxxxx>
> ---
> New patch:
> - Add new flag of TIMER_OF_CLOCK_FREQUENCY, mutually exclusive with TIMER_OF_CLOCK, to support
> getting clock frequency from DT directly;
> - Add prop_name to of_timer_clk structure, if using TIMER_OF_CLOCK_FREQUENCY flag, user needs
> to pass the property name for timer-of driver to get clock frequency from DT, this is to avoid
> the couple of timer-of driver and DT, so timer-of driver does NOT use a fixed property name.
> ---
> drivers/clocksource/timer-of.c | 23 +++++++++++++++++++++++
> drivers/clocksource/timer-of.h | 8 +++++---
> 2 files changed, 28 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/clocksource/timer-of.c b/drivers/clocksource/timer-of.c
> index 8054228..c91a8b6 100644
> --- a/drivers/clocksource/timer-of.c
> +++ b/drivers/clocksource/timer-of.c
> @@ -161,6 +161,21 @@ static __init int timer_of_base_init(struct device_node *np,
> return 0;
> }
>
> +static __init int timer_of_clk_frequency_init(struct device_node *np,
> + struct of_timer_clk *of_clk)
> +{
> + int ret;
> + u32 rate;
> +
> + ret = of_property_read_u32(np, of_clk->prop_name, &rate);
> + if (!ret) {
> + of_clk->rate = rate;
> + of_clk->period = DIV_ROUND_UP(rate, HZ);
> + }
> +
> + return ret;
> +}
> +
> int __init timer_of_init(struct device_node *np, struct timer_of *to)
> {
> int ret = -EINVAL;
> @@ -178,6 +193,11 @@ int __init timer_of_init(struct device_node *np, struct timer_of *to)
> if (ret)
> goto out_fail;
> flags |= TIMER_OF_CLOCK;
> + } else if (to->flags & TIMER_OF_CLOCK_FREQUENCY) {
> + ret = timer_of_clk_frequency_init(np, &to->of_clk);
> + if (ret)
> + goto out_fail;
> + flags |= TIMER_OF_CLOCK_FREQUENCY;
> }
/* Pre-condition */
if (to->flags & (TIMER_OF_CLOCK | TIMER_OF_CLOCK_FREQUENCY))
return -EINVAL;
[ ... ]
if (to->flags & TIMER_OF_CLOCK) {
}
if (to->flags & TIMER_OF_CLOCK_FREQUENCY) {
}
> if (to->flags & TIMER_OF_IRQ) {
> @@ -201,6 +221,9 @@ int __init timer_of_init(struct device_node *np, struct timer_of *to)
> if (flags & TIMER_OF_CLOCK)
> timer_of_clk_exit(&to->of_clk);
>
> + if (flags & TIMER_OF_CLOCK_FREQUENCY)
> + to->of_clk.rate = 0;
> +
> if (flags & TIMER_OF_BASE)
> timer_of_base_exit(&to->of_base);
> return ret;
> diff --git a/drivers/clocksource/timer-of.h b/drivers/clocksource/timer-of.h
> index a5478f3..f1a083e 100644
> --- a/drivers/clocksource/timer-of.h
> +++ b/drivers/clocksource/timer-of.h
> @@ -4,9 +4,10 @@
>
> #include <linux/clockchips.h>
>
> -#define TIMER_OF_BASE 0x1
> -#define TIMER_OF_CLOCK 0x2
> -#define TIMER_OF_IRQ 0x4
> +#define TIMER_OF_BASE 0x1
> +#define TIMER_OF_CLOCK 0x2
> +#define TIMER_OF_IRQ 0x4
> +#define TIMER_OF_CLOCK_FREQUENCY 0x8
>
> struct of_timer_irq {
> int irq;
> @@ -26,6 +27,7 @@ struct of_timer_base {
> struct of_timer_clk {
> struct clk *clk;
> const char *name;
> + const char *prop_name;
For the moment, keep it hardcoded with "clock-frequency" directly in the
function.
> int index;
> unsigned long rate;
> unsigned long period;
>
--
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