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

From: Lee Jones
Date: Thu May 07 2015 - 09:41:24 EST


Signed-off-by: Lee Jones <lee.jones@xxxxxxxxxx>
---
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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