On 01/10/2013 10:37 PM, Bedia, Vaibhav wrote:

On Tue, Jan 08, 2013 at 20:45:10, Shilimkar, Santosh wrote:

quoted

On Monday 31 December 2012 06:37 PM, Vaibhav Bedia wrote:

quoted

The current OMAP timer code registers two timers -
one as clocksource and one as clockevent.
AM33XX has only one usable timer in the WKUP domain
so one of the timers needs suspend-resume support
to restore the configuration to pre-suspend state.

commit adc78e6 (timekeeping: Add suspend and resume
of clock event devices) introduced .suspend and .resume
callbacks for clock event devices. Leverages these
callbacks to have AM33XX clockevent timer which is
in not in WKUP domain to behave properly across system
suspend.

Signed-off-by: Vaibhav Bedia <redacted>
Cc: Santosh Shilimkar <redacted>
Cc: Benoit Cousson <redacted>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Kevin Hilman <redacted>
Cc: Vaibhav Hiremath <redacted>
Cc: Jon Hunter <redacted>
---
v1->v2:
	Get rid of harcoded timer id.
	Note: since a platform device is not created for these timer
	instances and because there's very minimal change needed for
	restarting the timer a full blown context save and restore
	has been skipped.

  arch/arm/mach-omap2/timer.c |   33 +++++++++++++++++++++++++++++++++
  1 files changed, 33 insertions(+), 0 deletions(-)

diff --git a/arch/arm/mach-omap2/timer.c b/arch/arm/mach-omap2/timer.c
index 691aa67..38f9cbc 100644
--- a/arch/arm/mach-omap2/timer.c
+++ b/arch/arm/mach-omap2/timer.c

@@ -128,6 +128,36 @@ static void omap2_gp_timer_set_mode(enum clock_event_mode mode,
  	}
  }

+static void omap_clkevt_suspend(struct clock_event_device *unused)
+{
+	char name[10];
+	struct omap_hwmod *oh;
+
+	sprintf(name, "timer%d", clkev.id);
+	oh = omap_hwmod_lookup(name);
+	if (!oh)
+		return;
+
+	__omap_dm_timer_stop(&clkev, 1, clkev.rate);
+	omap_hwmod_idle(oh);
+}
+
+static void omap_clkevt_resume(struct clock_event_device *unused)
+{
+	char name[10];
+	struct omap_hwmod *oh;
+
+	sprintf(name, "timer%d", clkev.id);
+	oh = omap_hwmod_lookup(name);
+	if (!oh)
+		return;
+
+	omap_hwmod_enable(oh);
+	__omap_dm_timer_load_start(&clkev,
+			OMAP_TIMER_CTRL_ST | OMAP_TIMER_CTRL_AR, 0, 1);
+	__omap_dm_timer_int_enable(&clkev, OMAP_TIMER_INT_OVERFLOW);
+}
+

Am still bit uncomfortable with direct hwmod usage in the suspend/resmue
hooks.

Jon, Any alternatives you can think of ?

Jon,

Any suggestions here?

Sorry completed this missed this!

Unfortunately, I don't have any good suggestions here. However, I am
wondering if the suspend/resume handlers can just be calls to
omap_hwmod_idle/enable and we can remove these __omap_dm_timer_xxxx
calls (I don't think they are needed). Furthermore, my understanding is
this is only needed for AM335x (per the changelog), and so we should not
add suspend/resume handlers for all OMAP2+ based devices.

Cheers
Jon