linux-kernel - [PATCHv2 1/3] plat-nomadik: MTU sched

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Date:	Thu, 2 Jun 2011 11:35:14 +0200
From:	Mattias Wallin <mattias.wallin@...ricsson.com>
To:	Thomas Gleixner <tglx@...utronix.de>,
	<linux-kernel@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>
Cc:	Lee Jones <lee.jones@...aro.org>,
	Mattias Wallin <mattias.wallin@...ricsson.com>
Subject: [PATCHv2 1/3] plat-nomadik: MTU sched_clock as a config option

To make room for another sched_clk implementation a config
option is added around the sched_clk part of the MTU timer.
This makes it possible to configure away the sched_clk part.
An alternate sched_clk and clocksource is needed for the db8500
chip because the MTU is placed in a none always on power domain and will loose
power in some cpuidle sleep states.

Signed-off-by: Mattias Wallin <mattias.wallin@...ricsson.com>
Acked-by: Linus Walleij <linus.walleij@...aro.org>
---
 arch/arm/plat-nomadik/Kconfig |    8 +++++++-
 arch/arm/plat-nomadik/timer.c |    4 ++++
 2 files changed, 11 insertions(+), 1 deletions(-)

diff --git a/arch/arm/plat-nomadik/Kconfig b/arch/arm/plat-nomadik/Kconfig
index ce65901..bca4914 100644
--- a/arch/arm/plat-nomadik/Kconfig
+++ b/arch/arm/plat-nomadik/Kconfig
@@ -15,10 +15,16 @@ if PLAT_NOMADIK
 
 config HAS_MTU
 	bool
-	select HAVE_SCHED_CLOCK
 	help
 	  Support for Multi Timer Unit. MTU provides access
 	  to multiple interrupt generating programmable
 	  32-bit free running decrementing counters.
 
+config NOMADIK_MTU_SCHED_CLOCK
+	bool
+	depends on HAS_MTU
+	select HAVE_SCHED_CLOCK
+	help
+	  Use the Multi Timer Unit as the sched_clock.
+
 endif
diff --git a/arch/arm/plat-nomadik/timer.c b/arch/arm/plat-nomadik/timer.c
index ef74e15..b55c4ec 100644
--- a/arch/arm/plat-nomadik/timer.c
+++ b/arch/arm/plat-nomadik/timer.c
@@ -25,6 +25,7 @@
 
 void __iomem *mtu_base; /* Assigned by machine code */
 
+#ifdef CONFIG_NOMADIK_MTU_SCHED_CLOCK
 /*
  * Override the global weak sched_clock symbol with this
  * local implementation which uses the clocksource to get some
@@ -48,6 +49,7 @@ static void notrace nomadik_update_sched_clock(void)
 	u32 cyc = -readl(mtu_base + MTU_VAL(0));
 	update_sched_clock(&cd, cyc, (u32)~0);
 }
+#endif
 
 /* Clockevent device: use one-shot mode */
 static void nmdk_clkevt_mode(enum clock_event_mode mode,
@@ -154,7 +156,9 @@ void __init nmdk_timer_init(void)
 		pr_err("timer: failed to initialize clock source %s\n",
 		       "mtu_0");
 
+#ifdef CONFIG_NOMADIK_MTU_SCHED_CLOCK
 	init_sched_clock(&cd, nomadik_update_sched_clock, 32, rate);
+#endif
 
 	/* Timer 1 is used for events */
 
-- 
1.7.4.3

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