drivers/clocksource/time-lpc32xx.c - arm/linux - Git at Google

 /*
  * Clocksource driver for NXP LPC32xx/18xx/43xx timer
  *
  * Copyright (C) 2015 Joachim Eastwood <manabian@gmail.com>
  *
  * Based on:
  * time-efm32 Copyright (C) 2013 Pengutronix
  * mach-lpc32xx/timer.c Copyright (C) 2009 - 2010 NXP Semiconductors
  *
  * This file is licensed under the terms of the GNU General Public
  * License version 2. This program is licensed "as is" without any
  * warranty of any kind, whether express or implied.
  *
  */

 #define pr_fmt(fmt) "%s: " fmt, __func__

 #include <linux/clk.h>
 #include <linux/clockchips.h>
 #include <linux/clocksource.h>
 #include <linux/delay.h>
 #include <linux/interrupt.h>
 #include <linux/irq.h>
 #include <linux/kernel.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
 #include <linux/sched_clock.h>

 #define LPC32XX_TIMER_IR		0x000
 #define  LPC32XX_TIMER_IR_MR0INT	BIT(0)
 #define LPC32XX_TIMER_TCR		0x004
 #define  LPC32XX_TIMER_TCR_CEN		BIT(0)
 #define  LPC32XX_TIMER_TCR_CRST		BIT(1)
 #define LPC32XX_TIMER_TC		0x008
 #define LPC32XX_TIMER_PR		0x00c
 #define LPC32XX_TIMER_MCR		0x014
 #define  LPC32XX_TIMER_MCR_MR0I		BIT(0)
 #define  LPC32XX_TIMER_MCR_MR0R		BIT(1)
 #define  LPC32XX_TIMER_MCR_MR0S		BIT(2)
 #define LPC32XX_TIMER_MR0		0x018
 #define LPC32XX_TIMER_CTCR		0x070

 struct lpc32xx_clock_event_ddata {
 	struct clock_event_device evtdev;
 	void __iomem *base;
 	u32 ticks_per_jiffy;
 };

 /* Needed for the sched clock */
 static void __iomem *clocksource_timer_counter;

 static u64 notrace lpc32xx_read_sched_clock(void)
 {
 	return readl(clocksource_timer_counter);
 }

 static unsigned long lpc32xx_delay_timer_read(void)
 {
 	return readl(clocksource_timer_counter);
 }

 static struct delay_timer lpc32xx_delay_timer = {
 	.read_current_timer = lpc32xx_delay_timer_read,
 };

 static int lpc32xx_clkevt_next_event(unsigned long delta,
 				     struct clock_event_device *evtdev)
 {
 	struct lpc32xx_clock_event_ddata *ddata =
 		container_of(evtdev, struct lpc32xx_clock_event_ddata, evtdev);

 	/*
 	 * Place timer in reset and program the delta in the match
 	 * channel 0 (MR0). When the timer counter matches the value
 	 * in MR0 register the match will trigger an interrupt.
 	 * After setup the timer is released from reset and enabled.
 	 */
 	writel_relaxed(LPC32XX_TIMER_TCR_CRST, ddata->base + LPC32XX_TIMER_TCR);
 	writel_relaxed(delta, ddata->base + LPC32XX_TIMER_MR0);
 	writel_relaxed(LPC32XX_TIMER_TCR_CEN, ddata->base + LPC32XX_TIMER_TCR);

 	return 0;
 }

 static int lpc32xx_clkevt_shutdown(struct clock_event_device *evtdev)
 {
 	struct lpc32xx_clock_event_ddata *ddata =
 		container_of(evtdev, struct lpc32xx_clock_event_ddata, evtdev);

 	/* Disable the timer */
 	writel_relaxed(0, ddata->base + LPC32XX_TIMER_TCR);

 	return 0;
 }

 static int lpc32xx_clkevt_oneshot(struct clock_event_device *evtdev)
 {
 	struct lpc32xx_clock_event_ddata *ddata =
 		container_of(evtdev, struct lpc32xx_clock_event_ddata, evtdev);

 	/*
 	 * When using oneshot, we must also disable the timer
 	 * to wait for the first call to set_next_event().
 	 */
 	writel_relaxed(0, ddata->base + LPC32XX_TIMER_TCR);

 	/* Enable interrupt, reset on match and stop on match (MCR). */
 	writel_relaxed(LPC32XX_TIMER_MCR_MR0I | LPC32XX_TIMER_MCR_MR0R |
 		       LPC32XX_TIMER_MCR_MR0S, ddata->base + LPC32XX_TIMER_MCR);
 	return 0;
 }

 static int lpc32xx_clkevt_periodic(struct clock_event_device *evtdev)
 {
 	struct lpc32xx_clock_event_ddata *ddata =
 		container_of(evtdev, struct lpc32xx_clock_event_ddata, evtdev);

 	/* Enable interrupt and reset on match. */
 	writel_relaxed(LPC32XX_TIMER_MCR_MR0I | LPC32XX_TIMER_MCR_MR0R,
 		       ddata->base + LPC32XX_TIMER_MCR);

 	/*
 	 * Place timer in reset and program the delta in the match
 	 * channel 0 (MR0).
 	 */
 	writel_relaxed(LPC32XX_TIMER_TCR_CRST, ddata->base + LPC32XX_TIMER_TCR);
 	writel_relaxed(ddata->ticks_per_jiffy, ddata->base + LPC32XX_TIMER_MR0);
 	writel_relaxed(LPC32XX_TIMER_TCR_CEN, ddata->base + LPC32XX_TIMER_TCR);

 	return 0;
 }

 static irqreturn_t lpc32xx_clock_event_handler(int irq, void *dev_id)
 {
 	struct lpc32xx_clock_event_ddata *ddata = dev_id;

 	/* Clear match on channel 0 */
 	writel_relaxed(LPC32XX_TIMER_IR_MR0INT, ddata->base + LPC32XX_TIMER_IR);

 	ddata->evtdev.event_handler(&ddata->evtdev);

 	return IRQ_HANDLED;
 }

 static struct lpc32xx_clock_event_ddata lpc32xx_clk_event_ddata = {
 	.evtdev = {
 		.name			= "lpc3220 clockevent",
 		.features		= CLOCK_EVT_FEAT_ONESHOT |
 					  CLOCK_EVT_FEAT_PERIODIC,
 		.rating			= 300,
 		.set_next_event		= lpc32xx_clkevt_next_event,
 		.set_state_shutdown	= lpc32xx_clkevt_shutdown,
 		.set_state_oneshot	= lpc32xx_clkevt_oneshot,
 		.set_state_periodic	= lpc32xx_clkevt_periodic,
 	},
 };

 static int __init lpc32xx_clocksource_init(struct device_node *np)
 {
 	void __iomem *base;
 	unsigned long rate;
 	struct clk *clk;
 	int ret;

 	clk = of_clk_get_by_name(np, "timerclk");
 	if (IS_ERR(clk)) {
 		pr_err("clock get failed (%ld)\n", PTR_ERR(clk));
 		return PTR_ERR(clk);
 	}

 	ret = clk_prepare_enable(clk);
 	if (ret) {
 		pr_err("clock enable failed (%d)\n", ret);
 		goto err_clk_enable;
 	}

 	base = of_iomap(np, 0);
 	if (!base) {
 		pr_err("unable to map registers\n");
 		ret = -EADDRNOTAVAIL;
 		goto err_iomap;
 	}

 	/*
 	 * Disable and reset timer then set it to free running timer
 	 * mode (CTCR) with no prescaler (PR) or match operations (MCR).
 	 * After setup the timer is released from reset and enabled.
 	 */
 	writel_relaxed(LPC32XX_TIMER_TCR_CRST, base + LPC32XX_TIMER_TCR);
 	writel_relaxed(0, base + LPC32XX_TIMER_PR);
 	writel_relaxed(0, base + LPC32XX_TIMER_MCR);
 	writel_relaxed(0, base + LPC32XX_TIMER_CTCR);
 	writel_relaxed(LPC32XX_TIMER_TCR_CEN, base + LPC32XX_TIMER_TCR);

 	rate = clk_get_rate(clk);
 	ret = clocksource_mmio_init(base + LPC32XX_TIMER_TC, "lpc3220 timer",
 				    rate, 300, 32, clocksource_mmio_readl_up);
 	if (ret) {
 		pr_err("failed to init clocksource (%d)\n", ret);
 		goto err_clocksource_init;
 	}

 	clocksource_timer_counter = base + LPC32XX_TIMER_TC;
 	lpc32xx_delay_timer.freq = rate;
 	register_current_timer_delay(&lpc32xx_delay_timer);
 	sched_clock_register(lpc32xx_read_sched_clock, 32, rate);

 	return 0;

 err_clocksource_init:
 	iounmap(base);
 err_iomap:
 	clk_disable_unprepare(clk);
 err_clk_enable:
 	clk_put(clk);
 	return ret;
 }

 static int __init lpc32xx_clockevent_init(struct device_node *np)
 {
 	void __iomem *base;
 	unsigned long rate;
 	struct clk *clk;
 	int ret, irq;

 	clk = of_clk_get_by_name(np, "timerclk");
 	if (IS_ERR(clk)) {
 		pr_err("clock get failed (%ld)\n", PTR_ERR(clk));
 		return PTR_ERR(clk);
 	}

 	ret = clk_prepare_enable(clk);
 	if (ret) {
 		pr_err("clock enable failed (%d)\n", ret);
 		goto err_clk_enable;
 	}

 	base = of_iomap(np, 0);
 	if (!base) {
 		pr_err("unable to map registers\n");
 		ret = -EADDRNOTAVAIL;
 		goto err_iomap;
 	}

 	irq = irq_of_parse_and_map(np, 0);
 	if (!irq) {
 		pr_err("get irq failed\n");
 		ret = -ENOENT;
 		goto err_irq;
 	}

 	/*
 	 * Disable timer and clear any pending interrupt (IR) on match
 	 * channel 0 (MR0). Clear the prescaler as it's not used.
 	 */
 	writel_relaxed(0, base + LPC32XX_TIMER_TCR);
 	writel_relaxed(0, base + LPC32XX_TIMER_PR);
 	writel_relaxed(0, base + LPC32XX_TIMER_CTCR);
 	writel_relaxed(LPC32XX_TIMER_IR_MR0INT, base + LPC32XX_TIMER_IR);

 	rate = clk_get_rate(clk);
 	lpc32xx_clk_event_ddata.base = base;
 	lpc32xx_clk_event_ddata.ticks_per_jiffy = DIV_ROUND_CLOSEST(rate, HZ);
 	clockevents_config_and_register(&lpc32xx_clk_event_ddata.evtdev,
 					rate, 1, -1);

 	ret = request_irq(irq, lpc32xx_clock_event_handler,
 			  IRQF_TIMER | IRQF_IRQPOLL, "lpc3220 clockevent",
 			  &lpc32xx_clk_event_ddata);
 	if (ret) {
 		pr_err("request irq failed\n");
 		goto err_irq;
 	}

 	return 0;

 err_irq:
 	iounmap(base);
 err_iomap:
 	clk_disable_unprepare(clk);
 err_clk_enable:
 	clk_put(clk);
 	return ret;
 }

 /*
  * This function asserts that we have exactly one clocksource and one
  * clock_event_device in the end.
  */
 static int __init lpc32xx_timer_init(struct device_node *np)
 {
 	static int has_clocksource, has_clockevent;
 	int ret = 0;

 	if (!has_clocksource) {
 		ret = lpc32xx_clocksource_init(np);
 		if (!ret) {
 			has_clocksource = 1;
 			return 0;
 		}
 	}

 	if (!has_clockevent) {
 		ret = lpc32xx_clockevent_init(np);
 		if (!ret) {
 			has_clockevent = 1;
 			return 0;
 		}
 	}

 	return ret;
 }
 TIMER_OF_DECLARE(lpc32xx_timer, "nxp,lpc3220-timer", lpc32xx_timer_init);
	/*
	* Clocksource driver for NXP LPC32xx/18xx/43xx timer
	*
	* Copyright (C) 2015 Joachim Eastwood <manabian@gmail.com>
	*
	* Based on:
	* time-efm32 Copyright (C) 2013 Pengutronix
	* mach-lpc32xx/timer.c Copyright (C) 2009 - 2010 NXP Semiconductors
	*
	* This file is licensed under the terms of the GNU General Public
	* License version 2. This program is licensed "as is" without any
	* warranty of any kind, whether express or implied.
	*
	*/

	#define pr_fmt(fmt) "%s: " fmt, __func__

	#include <linux/clk.h>
	#include <linux/clockchips.h>
	#include <linux/clocksource.h>
	#include <linux/delay.h>
	#include <linux/interrupt.h>
	#include <linux/irq.h>
	#include <linux/kernel.h>
	#include <linux/of.h>
	#include <linux/of_address.h>
	#include <linux/of_irq.h>
	#include <linux/sched_clock.h>

	#define LPC32XX_TIMER_IR 0x000
	#define LPC32XX_TIMER_IR_MR0INT BIT(0)
	#define LPC32XX_TIMER_TCR 0x004
	#define LPC32XX_TIMER_TCR_CEN BIT(0)
	#define LPC32XX_TIMER_TCR_CRST BIT(1)
	#define LPC32XX_TIMER_TC 0x008
	#define LPC32XX_TIMER_PR 0x00c
	#define LPC32XX_TIMER_MCR 0x014
	#define LPC32XX_TIMER_MCR_MR0I BIT(0)
	#define LPC32XX_TIMER_MCR_MR0R BIT(1)
	#define LPC32XX_TIMER_MCR_MR0S BIT(2)
	#define LPC32XX_TIMER_MR0 0x018
	#define LPC32XX_TIMER_CTCR 0x070

	struct lpc32xx_clock_event_ddata {
	struct clock_event_device evtdev;
	void __iomem *base;
	u32 ticks_per_jiffy;
	};

	/* Needed for the sched clock */
	static void __iomem *clocksource_timer_counter;

	static u64 notrace lpc32xx_read_sched_clock(void)
	{
	return readl(clocksource_timer_counter);
	}

	static unsigned long lpc32xx_delay_timer_read(void)
	{
	return readl(clocksource_timer_counter);
	}

	static struct delay_timer lpc32xx_delay_timer = {
	.read_current_timer = lpc32xx_delay_timer_read,
	};

	static int lpc32xx_clkevt_next_event(unsigned long delta,
	struct clock_event_device *evtdev)
	{
	struct lpc32xx_clock_event_ddata *ddata =
	container_of(evtdev, struct lpc32xx_clock_event_ddata, evtdev);

	/*
	* Place timer in reset and program the delta in the match
	* channel 0 (MR0). When the timer counter matches the value
	* in MR0 register the match will trigger an interrupt.
	* After setup the timer is released from reset and enabled.
	*/
	writel_relaxed(LPC32XX_TIMER_TCR_CRST, ddata->base + LPC32XX_TIMER_TCR);
	writel_relaxed(delta, ddata->base + LPC32XX_TIMER_MR0);
	writel_relaxed(LPC32XX_TIMER_TCR_CEN, ddata->base + LPC32XX_TIMER_TCR);

	return 0;
	}

	static int lpc32xx_clkevt_shutdown(struct clock_event_device *evtdev)
	{
	struct lpc32xx_clock_event_ddata *ddata =
	container_of(evtdev, struct lpc32xx_clock_event_ddata, evtdev);

	/* Disable the timer */
	writel_relaxed(0, ddata->base + LPC32XX_TIMER_TCR);

	return 0;
	}

	static int lpc32xx_clkevt_oneshot(struct clock_event_device *evtdev)
	{
	struct lpc32xx_clock_event_ddata *ddata =
	container_of(evtdev, struct lpc32xx_clock_event_ddata, evtdev);

	/*
	* When using oneshot, we must also disable the timer
	* to wait for the first call to set_next_event().
	*/
	writel_relaxed(0, ddata->base + LPC32XX_TIMER_TCR);

	/* Enable interrupt, reset on match and stop on match (MCR). */
	writel_relaxed(LPC32XX_TIMER_MCR_MR0I \| LPC32XX_TIMER_MCR_MR0R \|
	LPC32XX_TIMER_MCR_MR0S, ddata->base + LPC32XX_TIMER_MCR);
	return 0;
	}

	static int lpc32xx_clkevt_periodic(struct clock_event_device *evtdev)
	{
	struct lpc32xx_clock_event_ddata *ddata =
	container_of(evtdev, struct lpc32xx_clock_event_ddata, evtdev);

	/* Enable interrupt and reset on match. */
	writel_relaxed(LPC32XX_TIMER_MCR_MR0I \| LPC32XX_TIMER_MCR_MR0R,
	ddata->base + LPC32XX_TIMER_MCR);

	/*
	* Place timer in reset and program the delta in the match
	* channel 0 (MR0).
	*/
	writel_relaxed(LPC32XX_TIMER_TCR_CRST, ddata->base + LPC32XX_TIMER_TCR);
	writel_relaxed(ddata->ticks_per_jiffy, ddata->base + LPC32XX_TIMER_MR0);
	writel_relaxed(LPC32XX_TIMER_TCR_CEN, ddata->base + LPC32XX_TIMER_TCR);

	return 0;
	}

	static irqreturn_t lpc32xx_clock_event_handler(int irq, void *dev_id)
	{
	struct lpc32xx_clock_event_ddata *ddata = dev_id;

	/* Clear match on channel 0 */
	writel_relaxed(LPC32XX_TIMER_IR_MR0INT, ddata->base + LPC32XX_TIMER_IR);

	ddata->evtdev.event_handler(&ddata->evtdev);

	return IRQ_HANDLED;
	}

	static struct lpc32xx_clock_event_ddata lpc32xx_clk_event_ddata = {
	.evtdev = {
	.name = "lpc3220 clockevent",
	.features = CLOCK_EVT_FEAT_ONESHOT \|
	CLOCK_EVT_FEAT_PERIODIC,
	.rating = 300,
	.set_next_event = lpc32xx_clkevt_next_event,
	.set_state_shutdown = lpc32xx_clkevt_shutdown,
	.set_state_oneshot = lpc32xx_clkevt_oneshot,
	.set_state_periodic = lpc32xx_clkevt_periodic,
	},
	};

	static int __init lpc32xx_clocksource_init(struct device_node *np)
	{
	void __iomem *base;
	unsigned long rate;
	struct clk *clk;
	int ret;

	clk = of_clk_get_by_name(np, "timerclk");
	if (IS_ERR(clk)) {
	pr_err("clock get failed (%ld)\n", PTR_ERR(clk));
	return PTR_ERR(clk);
	}

	ret = clk_prepare_enable(clk);
	if (ret) {
	pr_err("clock enable failed (%d)\n", ret);
	goto err_clk_enable;
	}

	base = of_iomap(np, 0);
	if (!base) {
	pr_err("unable to map registers\n");
	ret = -EADDRNOTAVAIL;
	goto err_iomap;
	}

	/*
	* Disable and reset timer then set it to free running timer
	* mode (CTCR) with no prescaler (PR) or match operations (MCR).
	* After setup the timer is released from reset and enabled.
	*/
	writel_relaxed(LPC32XX_TIMER_TCR_CRST, base + LPC32XX_TIMER_TCR);
	writel_relaxed(0, base + LPC32XX_TIMER_PR);
	writel_relaxed(0, base + LPC32XX_TIMER_MCR);
	writel_relaxed(0, base + LPC32XX_TIMER_CTCR);
	writel_relaxed(LPC32XX_TIMER_TCR_CEN, base + LPC32XX_TIMER_TCR);

	rate = clk_get_rate(clk);
	ret = clocksource_mmio_init(base + LPC32XX_TIMER_TC, "lpc3220 timer",
	rate, 300, 32, clocksource_mmio_readl_up);
	if (ret) {
	pr_err("failed to init clocksource (%d)\n", ret);
	goto err_clocksource_init;
	}

	clocksource_timer_counter = base + LPC32XX_TIMER_TC;
	lpc32xx_delay_timer.freq = rate;
	register_current_timer_delay(&lpc32xx_delay_timer);
	sched_clock_register(lpc32xx_read_sched_clock, 32, rate);

	return 0;

	err_clocksource_init:
	iounmap(base);
	err_iomap:
	clk_disable_unprepare(clk);
	err_clk_enable:
	clk_put(clk);
	return ret;
	}

	static int __init lpc32xx_clockevent_init(struct device_node *np)
	{
	void __iomem *base;
	unsigned long rate;
	struct clk *clk;
	int ret, irq;

	clk = of_clk_get_by_name(np, "timerclk");
	if (IS_ERR(clk)) {
	pr_err("clock get failed (%ld)\n", PTR_ERR(clk));
	return PTR_ERR(clk);
	}

	ret = clk_prepare_enable(clk);
	if (ret) {
	pr_err("clock enable failed (%d)\n", ret);
	goto err_clk_enable;
	}

	base = of_iomap(np, 0);
	if (!base) {
	pr_err("unable to map registers\n");
	ret = -EADDRNOTAVAIL;
	goto err_iomap;
	}

	irq = irq_of_parse_and_map(np, 0);
	if (!irq) {
	pr_err("get irq failed\n");
	ret = -ENOENT;
	goto err_irq;
	}

	/*
	* Disable timer and clear any pending interrupt (IR) on match
	* channel 0 (MR0). Clear the prescaler as it's not used.
	*/
	writel_relaxed(0, base + LPC32XX_TIMER_TCR);
	writel_relaxed(0, base + LPC32XX_TIMER_PR);
	writel_relaxed(0, base + LPC32XX_TIMER_CTCR);
	writel_relaxed(LPC32XX_TIMER_IR_MR0INT, base + LPC32XX_TIMER_IR);

	rate = clk_get_rate(clk);
	lpc32xx_clk_event_ddata.base = base;
	lpc32xx_clk_event_ddata.ticks_per_jiffy = DIV_ROUND_CLOSEST(rate, HZ);
	clockevents_config_and_register(&lpc32xx_clk_event_ddata.evtdev,
	rate, 1, -1);

	ret = request_irq(irq, lpc32xx_clock_event_handler,
	IRQF_TIMER \| IRQF_IRQPOLL, "lpc3220 clockevent",
	&lpc32xx_clk_event_ddata);
	if (ret) {
	pr_err("request irq failed\n");
	goto err_irq;
	}

	return 0;

	err_irq:
	iounmap(base);
	err_iomap:
	clk_disable_unprepare(clk);
	err_clk_enable:
	clk_put(clk);
	return ret;
	}

	/*
	* This function asserts that we have exactly one clocksource and one
	* clock_event_device in the end.
	*/
	static int __init lpc32xx_timer_init(struct device_node *np)
	{
	static int has_clocksource, has_clockevent;
	int ret = 0;

	if (!has_clocksource) {
	ret = lpc32xx_clocksource_init(np);
	if (!ret) {
	has_clocksource = 1;
	return 0;
	}
	}

	if (!has_clockevent) {
	ret = lpc32xx_clockevent_init(np);
	if (!ret) {
	has_clockevent = 1;
	return 0;
	}
	}

	return ret;
	}
	TIMER_OF_DECLARE(lpc32xx_timer, "nxp,lpc3220-timer", lpc32xx_timer_init);