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Commit f5ef02bd authored by Benjamin Gaignard's avatar Benjamin Gaignard Committed by Ingo Molnar
Browse files

clocksource/drivers/stm32: Add clocksource functionality 



The scene is set for the clocksource functionality, let's add it for this driver.

Tested-by: default avatarBenjamin Gaignard <benjamin.gaignard@st.com>
Signed-off-by: default avatarBenjamin Gaignard <benjamin.gaignard@st.com>
Signed-off-by: default avatarDaniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: default avatarBenjamin Gaignard <benjamin.gaignard@st.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1515418139-23276-18-git-send-email-daniel.lezcano@linaro.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 3c84e75b

drivers/clocksource/timer-stm32.c

+37 −0
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ 
#include <linux/of_irq.h>

#include <linux/clk.h>

#include <linux/reset.h>

#include <linux/sched_clock.h>

#include <linux/slab.h>



#include "timer-of.h"
@@ -80,6 +81,13 @@ static int stm32_timer_of_bits_get(struct timer_of *to) 
	return pd->bits;

}



static void __iomem *stm32_timer_cnt __read_mostly;



static u64 notrace stm32_read_sched_clock(void)

{

	return readl_relaxed(stm32_timer_cnt);

}



static void stm32_clock_event_disable(struct timer_of *to)

{

	writel_relaxed(0, timer_of_base(to) + TIM_DIER);
@@ -204,6 +212,31 @@ static void __init stm32_timer_set_prescaler(struct timer_of *to) 
	to->of_clk.period = DIV_ROUND_UP(to->of_clk.rate, HZ);

}



static int __init stm32_clocksource_init(struct timer_of *to)

{

        u32 bits = stm32_timer_of_bits_get(to);

	const char *name = to->np->full_name;



	/*

	 * This driver allows to register several timers and relies on

	 * the generic time framework to select the right one.

	 * However, nothing allows to do the same for the

	 * sched_clock. We are not interested in a sched_clock for the

	 * 16-bit timers but only for the 32-bit one, so if no 32-bit

	 * timer is registered yet, we select this 32-bit timer as a

	 * sched_clock.

	 */

	if (bits == 32 && !stm32_timer_cnt) {

		stm32_timer_cnt = timer_of_base(to) + TIM_CNT;

		sched_clock_register(stm32_read_sched_clock, bits, timer_of_rate(to));

		pr_info("%s: STM32 sched_clock registered\n", name);

	}



	return clocksource_mmio_init(timer_of_base(to) + TIM_CNT, name,

				     timer_of_rate(to), bits == 32 ? 250 : 100,

				     bits, clocksource_mmio_readl_up);

}



static void __init stm32_clockevent_init(struct timer_of *to)

{

	u32 bits = stm32_timer_of_bits_get(to);
@@ -256,6 +289,10 @@ static int __init stm32_timer_init(struct device_node *node) 


	stm32_timer_set_prescaler(to);



	ret = stm32_clocksource_init(to);

	if (ret)

		goto deinit;



	stm32_clockevent_init(to);

	return 0;