[PATCH v2 4/9] lpc2k: generic time and clockevents

[Ithamar R. Adema]

This code was mostly "borrowed" form the lpc32xx implementation.

Signed-off-by: Ithamar R. Adema <ithamar.adema at team-embedded.nl>
---
changes since v1:
	* make use of clockevents_calc_mult_shift.
---
 arch/arm/mach-lpc2k/Makefile |    2 +-
 arch/arm/mach-lpc2k/time.c   |  173 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 174 insertions(+), 1 deletions(-)
 create mode 100644 arch/arm/mach-lpc2k/time.c

diff --git a/arch/arm/mach-lpc2k/Makefile b/arch/arm/mach-lpc2k/Makefile
index 9eb0a6a..267432c 100644
--- a/arch/arm/mach-lpc2k/Makefile
+++ b/arch/arm/mach-lpc2k/Makefile
@@ -1 +1 @@
-obj-y	:= clock.o irq.o
+obj-y	:= clock.o irq.o time.o
diff --git a/arch/arm/mach-lpc2k/time.c b/arch/arm/mach-lpc2k/time.c
new file mode 100644
index 0000000..67abf2b
--- /dev/null
+++ b/arch/arm/mach-lpc2k/time.c
@@ -0,0 +1,173 @@
+/*
+ * Copyright (C) 2011 Team Embeded VOF
+ *                    Ithamar R. Adema <ihamar.adema at team-embedded.nl>
+ * Copyright (C) 2009 - 2010 NXP Semiconductors
+ * Copyright (C) 2009 Fontys University of Applied Sciences, Eindhoven
+ *                    Ed Schouten <e.schouten at fontys.nl>
+ *                    Laurens Timmermans <l.timmermans at fontys.nl>
+ *
+ * Based on timer code from plat-lpc32xx.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/time.h>
+#include <linux/err.h>
+#include <linux/clockchips.h>
+#include <linux/clk.h>
+
+#include <asm/mach/time.h>
+
+#include <mach/hardware.h>
+
+#define IR		0x00
+#define TCR		0x04
+#define TC		0x08
+#define PR		0x0c
+#define PC		0x10
+#define MCR		0x14
+#define MR0		0x18
+#define MR1		0x1c
+#define MR2		0x20
+#define CCR		0x28
+#define CR0		0x2c
+#define CR1		0x30
+#define CR2		0x34
+#define CR3		0x38
+#define EMR		0x3c
+#define CTCR		0x70
+
+#define IR_MR_SHIFT	0
+#define IR_CR_SHIFT	4
+
+#define TCR_EN		(1 << 0)
+#define TCR_RESET	(1 << 1)
+
+
+static void __iomem *timer0 = (void __iomem *)APB_TIMER0_BASE;
+static void __iomem *timer1 = (void __iomem *)APB_TIMER1_BASE;
+
+static cycle_t lpc2k_clksrc_read(struct clocksource *cs)
+{
+	return __raw_readl(timer1 + TC);
+}
+
+static struct clocksource lpc2k_clksrc = {
+	.name	= "lpc2k_clksrc",
+	.rating	= 300,
+	.read	= lpc2k_clksrc_read,
+	.mask	= CLOCKSOURCE_MASK(32),
+	.flags	= CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+static int lpc2k_clkevt_next_event(unsigned long delta,
+	struct clock_event_device *dev)
+{
+	__raw_writel(TCR_RESET, timer0 + TCR);
+	__raw_writel(delta, timer0 + PR);
+	__raw_writel(TCR_EN, timer0 + TCR);
+
+	return 0;
+}
+
+static void lpc2k_clkevt_mode(enum clock_event_mode mode,
+	struct clock_event_device *dev)
+{
+	switch (mode) {
+	case CLOCK_EVT_MODE_PERIODIC:
+		BUG();
+		break;
+
+	case CLOCK_EVT_MODE_ONESHOT:
+	case CLOCK_EVT_MODE_SHUTDOWN:
+		/*
+		 * Disable the timer. When using oneshot, we must also
+		 * disable the timer to wait for the first call to
+		 * set_next_event().
+		 */
+		__raw_writel(0, timer0 + TCR);
+		break;
+
+	case CLOCK_EVT_MODE_UNUSED:
+	case CLOCK_EVT_MODE_RESUME:
+		break;
+	}
+}
+
+static struct clock_event_device lpc2k_clkevt = {
+	.name		= "lpc2k_clkevt",
+	.features	= CLOCK_EVT_FEAT_ONESHOT,
+	.rating		= 300,
+	.set_next_event	= lpc2k_clkevt_next_event,
+	.set_mode	= lpc2k_clkevt_mode,
+};
+
+static irqreturn_t lpc2k_timer_interrupt(int irq, void *dev_id)
+{
+	struct clock_event_device *evt = &lpc2k_clkevt;
+
+	/* Clear match */
+	__raw_writel((1 << IR_MR_SHIFT), timer0 + IR);
+
+	evt->event_handler(evt);
+
+	return IRQ_HANDLED;
+}
+
+static struct irqaction lpc2k_timer_irq = {
+	.name		= "LPC2K Timer Tick",
+	.flags		= IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
+	.handler	= lpc2k_timer_interrupt,
+};
+
+/*
+ * The clock management driver isn't initialized at this point, so the
+ * clocks need to be enabled here manually and then tagged as used in
+ * the clock driver initialization
+ */
+static void __init lpc2k_timer_init(void)
+{
+	unsigned long rate;
+	struct clk *clk;
+
+	clk = clk_get(NULL, "timer1");
+	BUG_ON(IS_ERR(clk));
+
+	clk_enable(clk);
+	rate = clk_get_rate(clk);
+	clk_put(clk);
+
+	/* Initial timer setup */
+	__raw_writel(0, timer0 + TCR);
+	__raw_writel(1 << IR_MR_SHIFT, timer0 + IR);
+	__raw_writel(1, timer0 + MR0);
+	__raw_writel(3 << 0, timer0 + MCR);
+
+	/* Setup tick interrupt */
+	setup_irq(IRQ_LPC2K_TIMER0, &lpc2k_timer_irq);
+
+	/* Setup the clockevent structure. */
+	clockevents_calc_mult_shift(&lpc2k_clkevt, rate, 5);
+	lpc2k_clkevt.max_delta_ns = clockevent_delta2ns(-1,
+		&lpc2k_clkevt);
+	lpc2k_clkevt.min_delta_ns = clockevent_delta2ns(1,
+		&lpc2k_clkevt) + 1;
+	lpc2k_clkevt.cpumask = cpumask_of(0);
+	clockevents_register_device(&lpc2k_clkevt);
+
+	/* Use timer1 as clock source. */
+	__raw_writel(TCR_RESET, timer1 + TCR);
+	__raw_writel(0, timer1 + PR);
+	__raw_writel(0, timer1 + MCR);
+	__raw_writel(TCR_EN, timer1 + TCR);
+	clocksource_register_hz(&lpc2k_clksrc, rate);
+}
+
+struct sys_timer lpc2k_timer = {
+	.init		= &lpc2k_timer_init,
+};
-- 
1.7.1