* Tarun Kanti DebBarma <tarun.kanti@xxxxxx> [100622 12:35]:
> +/**
> + * omap_dm_timer_ms_correction - hardware correction for millisecond timer
> + * @timer: GPTIMER on which the correction support is to be applied
> + * @load: timer load value, used here to extract the expiry count
> + */
> +static void omap_dm_timer_ms_correction(struct omap_dm_timer *timer, u32 load)
> +{
> + int pos_increment, neg_increment;
> + unsigned int count = (0xFFFFFFFF - load) * 1024;
> +
> + pos_increment = (DIV_ROUND_UP(count, 1000) * 1000000) \
> + - (count * 1000);
> + neg_increment = ((DIV_ROUND_UP(count, 1000) - 1) * 1000000) \
> + - (count * 1000);
> + omap_dm_timer_write_reg(timer, OMAP_TIMER_TICK_POS_REG, pos_increment);
> + omap_dm_timer_write_reg(timer, OMAP_TIMER_TICK_NEG_REG, neg_increment);
> +}
>
> struct omap_dm_timer *omap_dm_timer_request(void)
> {
> @@ -612,6 +639,10 @@ void omap_dm_timer_set_load_start(struct omap_dm_timer *timer, int autoreload,
> {
> u32 l;
>
> +#ifdef CONFIG_ARCH_OMAP2PLUS
> + if (timer->ms_correction)
> + omap_dm_timer_ms_correction(timer, load);
> +#endif
> l = omap_dm_timer_read_reg(timer, OMAP_TIMER_CTRL_REG);
> if (autoreload) {
> l |= OMAP_TIMER_CTRL_AR;
How do you know that the timer is configured to use the 32KiHZ source?
Also, since omap2_gp_timer_set_next_event calls all the time,
we don't want to do this calculation for every tick.. So we should
make it a separate optional function.
Or can we somehow calculate this drift once during init?
Regards,
Tony
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