127 строки
2.4 KiB
C
127 строки
2.4 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* DS1287 clockevent driver
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*
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* Copyright (C) 2008 Yoichi Yuasa <yuasa@linux-mips.org>
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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 int ds1287_shutdown(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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val &= ~RTC_PIE;
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CMOS_WRITE(val, RTC_REG_B);
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spin_unlock(&rtc_lock);
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return 0;
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}
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static int ds1287_set_periodic(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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val |= RTC_PIE;
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CMOS_WRITE(val, RTC_REG_B);
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spin_unlock(&rtc_lock);
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return 0;
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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_state_shutdown = ds1287_shutdown,
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.set_state_periodic = ds1287_set_periodic,
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.tick_resume = ds1287_shutdown,
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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_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->max_delta_ticks = 0x7fffffff;
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cd->min_delta_ns = clockevent_delta2ns(0x300, cd);
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cd->min_delta_ticks = 0x300;
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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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