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awilliam
GitHub Repository: awilliam/linux-vfio
 Path: blob/master/arch/mips/kernel/cevt-ds1287.c
10817 views
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/*

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 *  DS1287 clockevent driver

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 *

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 *  Copyright (C) 2008  Yoichi Yuasa <[email protected]>

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 *

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 *  This program is free software; you can redistribute it and/or modify

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 *  it under the terms of the GNU General Public License as published by

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 *  the Free Software Foundation; either version 2 of the License, or

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 *  (at your option) any later version.

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 *

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 *  This program is distributed in the hope that it will be useful,

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 *  but WITHOUT ANY WARRANTY; without even the implied warranty of

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 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

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 *  GNU General Public License for more details.

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 *

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 *  You should have received a copy of the GNU General Public License

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 *  along with this program; if not, write to the Free Software

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 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

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 */

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#include <linux/clockchips.h>

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#include <linux/init.h>

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#include <linux/interrupt.h>

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#include <linux/mc146818rtc.h>

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#include <linux/irq.h>

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#include <asm/time.h>

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int ds1287_timer_state(void)

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{

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	return (CMOS_READ(RTC_REG_C) & RTC_PF) != 0;

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}

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int ds1287_set_base_clock(unsigned int hz)

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{

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	u8 rate;

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	switch (hz) {

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	case 128:

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		rate = 0x9;

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		break;

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	case 256:

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		rate = 0x8;

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		break;

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	case 1024:

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		rate = 0x6;

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		break;

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	default:

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		return -EINVAL;

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	}

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	CMOS_WRITE(RTC_REF_CLCK_32KHZ | rate, RTC_REG_A);

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	return 0;

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}

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static int ds1287_set_next_event(unsigned long delta,

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				 struct clock_event_device *evt)

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{

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	return -EINVAL;

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}

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static void ds1287_set_mode(enum clock_event_mode mode,

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			    struct clock_event_device *evt)

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{

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	u8 val;

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	spin_lock(&rtc_lock);

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	val = CMOS_READ(RTC_REG_B);

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	switch (mode) {

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	case CLOCK_EVT_MODE_PERIODIC:

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		val |= RTC_PIE;

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		break;

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	default:

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		val &= ~RTC_PIE;

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		break;

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	}

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	CMOS_WRITE(val, RTC_REG_B);

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	spin_unlock(&rtc_lock);

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}

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static void ds1287_event_handler(struct clock_event_device *dev)

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{

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}

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static struct clock_event_device ds1287_clockevent = {

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	.name		= "ds1287",

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	.features	= CLOCK_EVT_FEAT_PERIODIC,

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	.set_next_event	= ds1287_set_next_event,

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	.set_mode	= ds1287_set_mode,

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	.event_handler	= ds1287_event_handler,

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};

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static irqreturn_t ds1287_interrupt(int irq, void *dev_id)

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{

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	struct clock_event_device *cd = &ds1287_clockevent;

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	/* Ack the RTC interrupt. */

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	CMOS_READ(RTC_REG_C);

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	cd->event_handler(cd);

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	return IRQ_HANDLED;

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}

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static struct irqaction ds1287_irqaction = {

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	.handler	= ds1287_interrupt,

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	.flags		= IRQF_DISABLED | IRQF_PERCPU | IRQF_TIMER,

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	.name		= "ds1287",

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};

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int __init ds1287_clockevent_init(int irq)

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{

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	struct clock_event_device *cd;

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	cd = &ds1287_clockevent;

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	cd->rating = 100;

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	cd->irq = irq;

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	clockevent_set_clock(cd, 32768);

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	cd->max_delta_ns = clockevent_delta2ns(0x7fffffff, cd);

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	cd->min_delta_ns = clockevent_delta2ns(0x300, cd);

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	cd->cpumask = cpumask_of(0);

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	clockevents_register_device(&ds1287_clockevent);

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	return setup_irq(irq, &ds1287_irqaction);

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}

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