ARM: omap2+: am437x: rollback to use omap3_gptimer_timer_init()

commit f86a2c875fd146d9b82c8fdd86d31084507bcf4c upstream.

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>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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 bab814d2f37d..60f5e838a3bc 100644
--- a/arch/arm/mach-omap2/board-generic.c
+++ b/arch/arm/mach-omap2/board-generic.c
@@ -306,7 +306,7 @@ 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      = 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 5e2e2218a402..b2f2448bfa6d 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",