Hi Tony, On Friday 14 February 2014 02:16 PM, Rajendra Nayak wrote: > On Friday 14 February 2014 04:49 AM, Tony Lindgren wrote: >> * Lokesh Vutla <lokeshvutla@xxxxxx> [140207 02:24]: >>> From: Rajendra Nayak <rnayak@xxxxxx> >>> >>> The SyncTimer in AM43x is clocked using the following two sources: >>> 1) An inaccuarte 32k clock (CLK_32KHZ) derived from PER DPLL, causing system >>> time to go slowly (~10% deviation). >>> 2) external 32KHz RTC clock, which may not always be available on board like >>> in the case of ePOS EVM >>> >>> Use gptimer as clocksource instead, as is done in the case of AM335x >>> (which does not have a SyncTimer). With this, system time keeping works >>> accurately. >> >> Hmm doesn't this also mean that PM for any deeper idle states won't >> work properly? > > Thats true. This would mean we cannot put the peripheral/core domain down > in idle. Suspend however can still work if suspend/resume callbacks are added > to the clockevent and clocksource code to shut the non-wakeup domain timer. This is a platform level limitation that only MPU domain can be put down in idle, just like AM335x. Thanks and regards, Lokesh > > regards, > Rajendra > >> >> Regards, >> >> Tony >> >>> Signed-off-by: Rajendra Nayak <rnayak@xxxxxx> >>> Signed-off-by: Lokesh Vutla <lokeshvutla@xxxxxx> >>> --- >>> arch/arm/mach-omap2/board-generic.c | 2 +- >>> arch/arm/mach-omap2/timer.c | 3 ++- >>> 2 files changed, 3 insertions(+), 2 deletions(-) >>> >>> diff --git a/arch/arm/mach-omap2/board-generic.c b/arch/arm/mach-omap2/board-generic.c >>> index 8e3daa1..5679464a 100644 >>> --- a/arch/arm/mach-omap2/board-generic.c >>> +++ b/arch/arm/mach-omap2/board-generic.c >>> @@ -229,7 +229,7 @@ DT_MACHINE_START(AM43_DT, "Generic AM43 (Flattened Device Tree)") >>> .init_late = am43xx_init_late, >>> .init_irq = omap_gic_of_init, >>> .init_machine = omap_generic_init, >>> - .init_time = omap3_sync32k_timer_init, >>> + .init_time = omap3_gptimer_timer_init, >>> .dt_compat = am43_boards_compat, >>> MACHINE_END >>> #endif >>> diff --git a/arch/arm/mach-omap2/timer.c b/arch/arm/mach-omap2/timer.c >>> index 74044aa..b62de9f 100644 >>> --- a/arch/arm/mach-omap2/timer.c >>> +++ b/arch/arm/mach-omap2/timer.c >>> @@ -604,7 +604,8 @@ OMAP_SYS_32K_TIMER_INIT(3_secure, 12, "secure_32k_fck", "ti,timer-secure", >>> 2, "timer_sys_ck", NULL); >>> #endif /* CONFIG_ARCH_OMAP3 */ >>> >>> -#if defined(CONFIG_ARCH_OMAP3) || defined(CONFIG_SOC_AM33XX) >>> +#if defined(CONFIG_ARCH_OMAP3) || defined(CONFIG_SOC_AM33XX) || \ >>> + defined(CONFIG_SOC_AM43XX) >>> OMAP_SYS_GP_TIMER_INIT(3, 2, "timer_sys_ck", NULL, >>> 1, "timer_sys_ck", "ti,timer-alwon"); >>> #endif >>> -- >>> 1.7.9.5 >>> > -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
