linux-kernel - [PATCH 03/12] clocksource: sti: Provide 'use timer as sched clock' capability

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Date:	Thu,  7 May 2015 14:38:35 +0100
From:	Lee Jones <lee.jones@...aro.org>
To:	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Cc:	kernel@...inux.com, devicetree@...r.kernel.org,
	daniel.lezcano@...aro.org, tglx@...utronix.de, wim@...ana.be,
	a.zummo@...ertech.it, linux-watchdog@...r.kernel.org,
	rtc-linux@...glegroups.com, linux@...ck-us.net,
	Lee Jones <lee.jones@...aro.org>
Subject: [PATCH 03/12] clocksource: sti: Provide 'use timer as sched clock' capability

Signed-off-by: Lee Jones <lee.jones@...aro.org>
---
 drivers/clocksource/Kconfig         |  8 ++++++++
 drivers/clocksource/clksrc_st_lpc.c | 11 +++++++++++
 2 files changed, 19 insertions(+)

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index ac424cf..218daf8 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -258,4 +258,12 @@ config CLKSRC_ST_LPC
 	help
 	  Enable this option to use the Low Power controller timer
 	  as clocksource.
+
+config CLKSRC_ST_LPC_TIMER_SCHED_CLOCK
+	bool
+	depends on CLKSRC_ST_LPC
+	default y
+	help
+	  Use Low Power controller timer clock source as sched_clock
+
 endmenu
diff --git a/drivers/clocksource/clksrc_st_lpc.c b/drivers/clocksource/clksrc_st_lpc.c
index 18a7dcd0..3d92b26 100644
--- a/drivers/clocksource/clksrc_st_lpc.c
+++ b/drivers/clocksource/clksrc_st_lpc.c
@@ -16,6 +16,7 @@
 #include <linux/clocksource.h>
 #include <linux/init.h>
 #include <linux/of_address.h>
+#include <linux/sched_clock.h>
 #include <linux/slab.h>
 
 #include <dt-bindings/mfd/st-lpc.h>
@@ -38,6 +39,13 @@ static void st_clksrc_reset(void)
 	writel_relaxed(1, ddata.base + LPC_LPT_START_OFF);
 }
 
+#ifdef CONFIG_CLKSRC_ST_LPC_TIMER_SCHED_CLOCK
+static u64 notrace st_clksrc_sched_clock_read(void)
+{
+	return (u64)readl_relaxed(ddata.base + LPC_LPT_LSB_OFF);
+}
+#endif
+
 static int __init st_clksrc_init(void)
 {
 	unsigned long rate;
@@ -47,6 +55,9 @@ static int __init st_clksrc_init(void)
 
 	rate = clk_get_rate(ddata.clk);
 
+#ifdef CONFIG_CLKSRC_ST_LPC_TIMER_SCHED_CLOCK
+	sched_clock_register(st_clksrc_sched_clock_read, 32, rate);
+#endif
 	ret = clocksource_mmio_init(ddata.base + LPC_LPT_LSB_OFF,
 				    "clksrc-st-lpc", rate, 300, 32,
 				    clocksource_mmio_readl_up);
-- 
1.9.1

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