Hi Jon, On Wed, Jan 30, 2013 at 22:34:31, Hunter, Jon wrote: > When booting with device-tree for OMAP3 and AM335x devices and a gptimer > is used as the clocksource (which is always the case for AM335x), a > gptimer located in a power domain that is not always-on is selected. > Ideally we should use a gptimer located in a power domain that is always > on (such as the wake-up domain) so that time can be maintained during a > kernel suspend without keeping on additional power domains unnecessarily. > > In order to fix this so that we can select a gptimer located in a power > domain that is always-on, the following changes were made ... > 1. Currently, only when selecting a gptimer to use for a clockevent > timer, do we pass a timer property that can be used to select a > specific gptimer. Change this so that we can pass a property when > selecting a gptimer to use for a clocksource timer too. > 2. Currently, when selecting either a gptimer to use for a clockevent > timer or a clocksource timer and no timer property is passed, then > the first available timer is selected regardless of the properties > it has. Change this so that if no properties are passed, then a timer > that does not have additional features (such as always-on, dsp-irq, > pwm, and secure) is selected. > > Please note that using a gptimer for both clocksource and clockevents > can have a system power impact during idle. The reason being is that > OMAP and AMxxx devices typically only have one gptimer in a power domain > that is always-on. Therefore when the kernel is idle both the clocksource > and clockevent timers will be active and this will keep additional power > domains on. During kernel suspend, only the clocksource timer is active > and therefore, it is better to use a gptimer in a power domain that is > always-on for clocksource. > It's always a pleasure reading the changelog in your patches :) [...] > > #if defined(CONFIG_ARCH_OMAP3) || defined(CONFIG_SOC_AM33XX) > -OMAP_SYS_GP_TIMER_INIT(3, 1, "timer_sys_ck", "ti,timer-alwon", > - 2, "timer_sys_ck"); > +OMAP_SYS_GP_TIMER_INIT(3, 2, "timer_sys_ck", NULL, > + 1, "timer_sys_ck", "ti,timer-alwon"); > #endif > Minor point... was the intention of changing of clkev_nr and clksrc_nr to make it consistent with what happens on AM33xx which is DT-only? Regards, Vaibhav -- 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
