On 01/31/2013 03:08 AM, Igor Grinberg wrote:

On 01/30/13 19:04, Jon Hunter wrote:

quoted

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.

This should explain the gptimer number switch in the
#if defined(CONFIG_ARCH_OMAP3) || defined(CONFIG_SOC_AM33XX)
section below, right?
I would really like to see that clearly stated in the commit message.
For instance:
... it is better to use a gptimer in a power domain that is
always-on for clocksource. Therefore we switch to use the first gptimer
for clocksource and the second for clockevents.

Yes exactly. Good point I can make that bit explicit.

quoted

Signed-off-by: Jon Hunter <redacted>

Apart from above,
Acked-by: Igor Grinberg <redacted>

Thanks
Jon