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Subject[PATCH v2] ARM: omap2: am437x: rollback to use omap3_gptimer_timer_init()
Date
From: Grygorii Strashko <grygorii.strashko@ti.com>

The commit 55ee7017ee31 ("arm: omap2: board-generic: use
omap4_local_timer_init for AM437x") unintentionally changes the
clocksource devices for AM437x from OMAP GP Timer to SyncTimer32K.

Unfortunately, the SyncTimer32K is starving from frequency deviation
as mentioned in commit 5b5c01359152 ("ARM: OMAP2+: AM43x: Use gptimer
as clocksource") and, as reported by Franklin [1], even its monotonic
nature is under question (most probably there is a HW issue, but it's
still under investigation).

Taking into account above facts It's reasonable to rollback to the use
of omap3_gptimer_timer_init().

[1] http://www.spinics.net/lists/linux-omap/msg127425.html

Fixes: 55ee7017ee31 ("arm: omap2: board-generic: use
omap4_local_timer_init for AM437x")
Reported-by: Cooper Jr., Franklin <fcooper@ti.com>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Signed-off-by: Keerthy <j-keerthy@ti.com>
---

Changes in v2:

* Added a proper Fixes tag with the commit ID.

arch/arm/mach-omap2/board-generic.c | 2 +-
arch/arm/mach-omap2/timer.c | 9 +++++----
2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/arch/arm/mach-omap2/board-generic.c b/arch/arm/mach-omap2/board-generic.c
index 36d9943..dc9e34e 100644
--- a/arch/arm/mach-omap2/board-generic.c
+++ b/arch/arm/mach-omap2/board-generic.c
@@ -304,7 +304,7 @@ static void __init rx51_reserve(void)
.init_late = am43xx_init_late,
.init_irq = omap_gic_of_init,
.init_machine = omap_generic_init,
- .init_time = omap4_local_timer_init,
+ .init_time = omap3_gptimer_timer_init,
.dt_compat = am43_boards_compat,
.restart = omap44xx_restart,
MACHINE_END
diff --git a/arch/arm/mach-omap2/timer.c b/arch/arm/mach-omap2/timer.c
index 5e2e221..b2f2448 100644
--- a/arch/arm/mach-omap2/timer.c
+++ b/arch/arm/mach-omap2/timer.c
@@ -510,18 +510,19 @@ void __init omap3_secure_sync32k_timer_init(void)
}
#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)
void __init omap3_gptimer_timer_init(void)
{
__omap_sync32k_timer_init(2, "timer_sys_ck", NULL,
1, "timer_sys_ck", "ti,timer-alwon", true);
-
- clocksource_probe();
+ if (of_have_populated_dt())
+ clocksource_probe();
}
#endif

#if defined(CONFIG_ARCH_OMAP4) || defined(CONFIG_SOC_OMAP5) || \
- defined(CONFIG_SOC_DRA7XX) || defined(CONFIG_SOC_AM43XX)
+ defined(CONFIG_SOC_DRA7XX)
static void __init omap4_sync32k_timer_init(void)
{
__omap_sync32k_timer_init(1, "timer_32k_ck", "ti,timer-alwon",
--
1.9.1
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