[MIPS] DS1287: Add clockevent driver

Signed-off-by: Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/kernel/Makefile

@@ -10,6 +10,7 @@ obj-y		+= cpu-probe.o branch.o entry.o genex.o irq.o process.o \
 
 obj-$(CONFIG_CEVT_BCM1480)	+= cevt-bcm1480.o
 obj-$(CONFIG_CEVT_R4K)		+= cevt-r4k.o
+obj-$(CONFIG_CEVT_DS1287)	+= cevt-ds1287.o
 obj-$(CONFIG_CEVT_GT641XX)	+= cevt-gt641xx.o
 obj-$(CONFIG_CEVT_SB1250)	+= cevt-sb1250.o
 obj-$(CONFIG_CEVT_TXX9)		+= cevt-txx9.o

arch/mips/kernel/cevt-ds1287.c

@@ -0,0 +1,129 @@
+/*
+ *  DS1287 clockevent driver
+ *
+ *  Copyright (C) 2008  Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+#include <linux/clockchips.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/mc146818rtc.h>
+
+#include <asm/time.h>
+
+int ds1287_timer_state(void)
+{
+	return (CMOS_READ(RTC_REG_C) & RTC_PF) != 0;
+}
+
+int ds1287_set_base_clock(unsigned int hz)
+{
+	u8 rate;
+
+	switch (hz) {
+	case 128:
+		rate = 0x9;
+		break;
+	case 256:
+		rate = 0x8;
+		break;
+	case 1024:
+		rate = 0x6;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	CMOS_WRITE(RTC_REF_CLCK_32KHZ | rate, RTC_REG_A);
+
+	return 0;
+}
+
+static int ds1287_set_next_event(unsigned long delta,
+				 struct clock_event_device *evt)
+{
+	return -EINVAL;
+}
+
+static void ds1287_set_mode(enum clock_event_mode mode,
+			    struct clock_event_device *evt)
+{
+	u8 val;
+
+	spin_lock(&rtc_lock);
+
+	val = CMOS_READ(RTC_REG_B);
+
+	switch (mode) {
+	case CLOCK_EVT_MODE_PERIODIC:
+		val |= RTC_PIE;
+		break;
+	default:
+		val &= ~RTC_PIE;
+		break;
+	}
+
+	CMOS_WRITE(val, RTC_REG_B);
+
+	spin_unlock(&rtc_lock);
+}
+
+static void ds1287_event_handler(struct clock_event_device *dev)
+{
+}
+
+static struct clock_event_device ds1287_clockevent = {
+	.name		= "ds1287",
+	.features	= CLOCK_EVT_FEAT_PERIODIC,
+	.cpumask	= CPU_MASK_CPU0,
+	.set_next_event	= ds1287_set_next_event,
+	.set_mode	= ds1287_set_mode,
+	.event_handler	= ds1287_event_handler,
+};
+
+static irqreturn_t ds1287_interrupt(int irq, void *dev_id)
+{
+	struct clock_event_device *cd = &ds1287_clockevent;
+
+	/* Ack the RTC interrupt. */
+	CMOS_READ(RTC_REG_C);
+
+	cd->event_handler(cd);
+
+	return IRQ_HANDLED;
+}
+
+static struct irqaction ds1287_irqaction = {
+	.handler	= ds1287_interrupt,
+	.flags		= IRQF_DISABLED | IRQF_PERCPU,
+	.name		= "ds1287",
+};
+
+int __init ds1287_clockevent_init(int irq)
+{
+	struct clock_event_device *cd;
+
+	cd = &ds1287_clockevent;
+	cd->rating = 100;
+	cd->irq = irq;
+	clockevent_set_clock(cd, 32768);
+	cd->max_delta_ns = clockevent_delta2ns(0x7fffffff, cd);
+	cd->min_delta_ns = clockevent_delta2ns(0x300, cd);
+
+	clockevents_register_device(&ds1287_clockevent);
+
+	return setup_irq(irq, &ds1287_irqaction);
+}