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331 lines
9.1 KiB
331 lines
9.1 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* An rtc driver for the Dallas DS1553 |
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* |
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* Copyright (C) 2006 Atsushi Nemoto <[email protected]> |
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*/ |
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#include <linux/bcd.h> |
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#include <linux/init.h> |
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#include <linux/kernel.h> |
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#include <linux/gfp.h> |
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#include <linux/delay.h> |
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#include <linux/jiffies.h> |
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#include <linux/interrupt.h> |
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#include <linux/rtc.h> |
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#include <linux/platform_device.h> |
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#include <linux/io.h> |
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#include <linux/module.h> |
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#define RTC_REG_SIZE 0x2000 |
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#define RTC_OFFSET 0x1ff0 |
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#define RTC_FLAGS (RTC_OFFSET + 0) |
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#define RTC_SECONDS_ALARM (RTC_OFFSET + 2) |
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#define RTC_MINUTES_ALARM (RTC_OFFSET + 3) |
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#define RTC_HOURS_ALARM (RTC_OFFSET + 4) |
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#define RTC_DATE_ALARM (RTC_OFFSET + 5) |
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#define RTC_INTERRUPTS (RTC_OFFSET + 6) |
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#define RTC_WATCHDOG (RTC_OFFSET + 7) |
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#define RTC_CONTROL (RTC_OFFSET + 8) |
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#define RTC_CENTURY (RTC_OFFSET + 8) |
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#define RTC_SECONDS (RTC_OFFSET + 9) |
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#define RTC_MINUTES (RTC_OFFSET + 10) |
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#define RTC_HOURS (RTC_OFFSET + 11) |
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#define RTC_DAY (RTC_OFFSET + 12) |
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#define RTC_DATE (RTC_OFFSET + 13) |
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#define RTC_MONTH (RTC_OFFSET + 14) |
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#define RTC_YEAR (RTC_OFFSET + 15) |
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#define RTC_CENTURY_MASK 0x3f |
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#define RTC_SECONDS_MASK 0x7f |
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#define RTC_DAY_MASK 0x07 |
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/* Bits in the Control/Century register */ |
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#define RTC_WRITE 0x80 |
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#define RTC_READ 0x40 |
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/* Bits in the Seconds register */ |
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#define RTC_STOP 0x80 |
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/* Bits in the Flags register */ |
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#define RTC_FLAGS_AF 0x40 |
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#define RTC_FLAGS_BLF 0x10 |
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/* Bits in the Interrupts register */ |
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#define RTC_INTS_AE 0x80 |
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struct rtc_plat_data { |
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struct rtc_device *rtc; |
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void __iomem *ioaddr; |
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unsigned long last_jiffies; |
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int irq; |
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unsigned int irqen; |
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int alrm_sec; |
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int alrm_min; |
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int alrm_hour; |
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int alrm_mday; |
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spinlock_t lock; |
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}; |
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static int ds1553_rtc_set_time(struct device *dev, struct rtc_time *tm) |
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{ |
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struct rtc_plat_data *pdata = dev_get_drvdata(dev); |
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void __iomem *ioaddr = pdata->ioaddr; |
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u8 century; |
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century = bin2bcd((tm->tm_year + 1900) / 100); |
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writeb(RTC_WRITE, pdata->ioaddr + RTC_CONTROL); |
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writeb(bin2bcd(tm->tm_year % 100), ioaddr + RTC_YEAR); |
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writeb(bin2bcd(tm->tm_mon + 1), ioaddr + RTC_MONTH); |
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writeb(bin2bcd(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY); |
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writeb(bin2bcd(tm->tm_mday), ioaddr + RTC_DATE); |
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writeb(bin2bcd(tm->tm_hour), ioaddr + RTC_HOURS); |
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writeb(bin2bcd(tm->tm_min), ioaddr + RTC_MINUTES); |
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writeb(bin2bcd(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS); |
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/* RTC_CENTURY and RTC_CONTROL share same register */ |
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writeb(RTC_WRITE | (century & RTC_CENTURY_MASK), ioaddr + RTC_CENTURY); |
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writeb(century & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL); |
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return 0; |
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} |
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static int ds1553_rtc_read_time(struct device *dev, struct rtc_time *tm) |
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{ |
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struct rtc_plat_data *pdata = dev_get_drvdata(dev); |
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void __iomem *ioaddr = pdata->ioaddr; |
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unsigned int year, month, day, hour, minute, second, week; |
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unsigned int century; |
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/* give enough time to update RTC in case of continuous read */ |
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if (pdata->last_jiffies == jiffies) |
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msleep(1); |
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pdata->last_jiffies = jiffies; |
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writeb(RTC_READ, ioaddr + RTC_CONTROL); |
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second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK; |
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minute = readb(ioaddr + RTC_MINUTES); |
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hour = readb(ioaddr + RTC_HOURS); |
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day = readb(ioaddr + RTC_DATE); |
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week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK; |
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month = readb(ioaddr + RTC_MONTH); |
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year = readb(ioaddr + RTC_YEAR); |
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century = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK; |
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writeb(0, ioaddr + RTC_CONTROL); |
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tm->tm_sec = bcd2bin(second); |
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tm->tm_min = bcd2bin(minute); |
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tm->tm_hour = bcd2bin(hour); |
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tm->tm_mday = bcd2bin(day); |
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tm->tm_wday = bcd2bin(week); |
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tm->tm_mon = bcd2bin(month) - 1; |
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/* year is 1900 + tm->tm_year */ |
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tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900; |
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return 0; |
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} |
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static void ds1553_rtc_update_alarm(struct rtc_plat_data *pdata) |
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{ |
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void __iomem *ioaddr = pdata->ioaddr; |
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unsigned long flags; |
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spin_lock_irqsave(&pdata->lock, flags); |
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writeb(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ? |
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0x80 : bin2bcd(pdata->alrm_mday), |
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ioaddr + RTC_DATE_ALARM); |
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writeb(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ? |
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0x80 : bin2bcd(pdata->alrm_hour), |
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ioaddr + RTC_HOURS_ALARM); |
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writeb(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ? |
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0x80 : bin2bcd(pdata->alrm_min), |
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ioaddr + RTC_MINUTES_ALARM); |
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writeb(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ? |
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0x80 : bin2bcd(pdata->alrm_sec), |
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ioaddr + RTC_SECONDS_ALARM); |
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writeb(pdata->irqen ? RTC_INTS_AE : 0, ioaddr + RTC_INTERRUPTS); |
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readb(ioaddr + RTC_FLAGS); /* clear interrupts */ |
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spin_unlock_irqrestore(&pdata->lock, flags); |
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} |
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static int ds1553_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) |
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{ |
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struct rtc_plat_data *pdata = dev_get_drvdata(dev); |
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if (pdata->irq <= 0) |
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return -EINVAL; |
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pdata->alrm_mday = alrm->time.tm_mday; |
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pdata->alrm_hour = alrm->time.tm_hour; |
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pdata->alrm_min = alrm->time.tm_min; |
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pdata->alrm_sec = alrm->time.tm_sec; |
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if (alrm->enabled) |
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pdata->irqen |= RTC_AF; |
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ds1553_rtc_update_alarm(pdata); |
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return 0; |
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} |
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static int ds1553_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) |
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{ |
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struct rtc_plat_data *pdata = dev_get_drvdata(dev); |
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if (pdata->irq <= 0) |
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return -EINVAL; |
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alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday; |
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alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour; |
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alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min; |
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alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec; |
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alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0; |
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return 0; |
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} |
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static irqreturn_t ds1553_rtc_interrupt(int irq, void *dev_id) |
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{ |
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struct platform_device *pdev = dev_id; |
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struct rtc_plat_data *pdata = platform_get_drvdata(pdev); |
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void __iomem *ioaddr = pdata->ioaddr; |
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unsigned long events = 0; |
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spin_lock(&pdata->lock); |
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/* read and clear interrupt */ |
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if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF) { |
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events = RTC_IRQF; |
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if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80) |
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events |= RTC_UF; |
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else |
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events |= RTC_AF; |
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rtc_update_irq(pdata->rtc, 1, events); |
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} |
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spin_unlock(&pdata->lock); |
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return events ? IRQ_HANDLED : IRQ_NONE; |
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} |
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static int ds1553_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) |
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{ |
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struct rtc_plat_data *pdata = dev_get_drvdata(dev); |
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if (pdata->irq <= 0) |
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return -EINVAL; |
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if (enabled) |
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pdata->irqen |= RTC_AF; |
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else |
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pdata->irqen &= ~RTC_AF; |
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ds1553_rtc_update_alarm(pdata); |
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return 0; |
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} |
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static const struct rtc_class_ops ds1553_rtc_ops = { |
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.read_time = ds1553_rtc_read_time, |
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.set_time = ds1553_rtc_set_time, |
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.read_alarm = ds1553_rtc_read_alarm, |
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.set_alarm = ds1553_rtc_set_alarm, |
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.alarm_irq_enable = ds1553_rtc_alarm_irq_enable, |
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}; |
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static int ds1553_nvram_read(void *priv, unsigned int pos, void *val, |
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size_t bytes) |
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{ |
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struct platform_device *pdev = priv; |
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struct rtc_plat_data *pdata = platform_get_drvdata(pdev); |
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void __iomem *ioaddr = pdata->ioaddr; |
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u8 *buf = val; |
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for (; bytes; bytes--) |
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*buf++ = readb(ioaddr + pos++); |
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return 0; |
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} |
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static int ds1553_nvram_write(void *priv, unsigned int pos, void *val, |
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size_t bytes) |
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{ |
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struct platform_device *pdev = priv; |
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struct rtc_plat_data *pdata = platform_get_drvdata(pdev); |
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void __iomem *ioaddr = pdata->ioaddr; |
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u8 *buf = val; |
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for (; bytes; bytes--) |
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writeb(*buf++, ioaddr + pos++); |
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return 0; |
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} |
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static int ds1553_rtc_probe(struct platform_device *pdev) |
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{ |
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unsigned int cen, sec; |
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struct rtc_plat_data *pdata; |
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void __iomem *ioaddr; |
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int ret = 0; |
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struct nvmem_config nvmem_cfg = { |
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.name = "ds1553_nvram", |
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.word_size = 1, |
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.stride = 1, |
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.size = RTC_OFFSET, |
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.reg_read = ds1553_nvram_read, |
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.reg_write = ds1553_nvram_write, |
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.priv = pdev, |
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}; |
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pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); |
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if (!pdata) |
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return -ENOMEM; |
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ioaddr = devm_platform_ioremap_resource(pdev, 0); |
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if (IS_ERR(ioaddr)) |
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return PTR_ERR(ioaddr); |
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pdata->ioaddr = ioaddr; |
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pdata->irq = platform_get_irq(pdev, 0); |
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/* turn RTC on if it was not on */ |
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sec = readb(ioaddr + RTC_SECONDS); |
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if (sec & RTC_STOP) { |
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sec &= RTC_SECONDS_MASK; |
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cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK; |
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writeb(RTC_WRITE, ioaddr + RTC_CONTROL); |
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writeb(sec, ioaddr + RTC_SECONDS); |
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writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL); |
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} |
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if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_BLF) |
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dev_warn(&pdev->dev, "voltage-low detected.\n"); |
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spin_lock_init(&pdata->lock); |
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pdata->last_jiffies = jiffies; |
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platform_set_drvdata(pdev, pdata); |
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pdata->rtc = devm_rtc_allocate_device(&pdev->dev); |
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if (IS_ERR(pdata->rtc)) |
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return PTR_ERR(pdata->rtc); |
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pdata->rtc->ops = &ds1553_rtc_ops; |
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ret = devm_rtc_register_device(pdata->rtc); |
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if (ret) |
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return ret; |
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if (pdata->irq > 0) { |
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writeb(0, ioaddr + RTC_INTERRUPTS); |
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if (devm_request_irq(&pdev->dev, pdata->irq, |
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ds1553_rtc_interrupt, |
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0, pdev->name, pdev) < 0) { |
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dev_warn(&pdev->dev, "interrupt not available.\n"); |
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pdata->irq = 0; |
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} |
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} |
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devm_rtc_nvmem_register(pdata->rtc, &nvmem_cfg); |
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return 0; |
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} |
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/* work with hotplug and coldplug */ |
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MODULE_ALIAS("platform:rtc-ds1553"); |
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static struct platform_driver ds1553_rtc_driver = { |
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.probe = ds1553_rtc_probe, |
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.driver = { |
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.name = "rtc-ds1553", |
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}, |
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}; |
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module_platform_driver(ds1553_rtc_driver); |
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MODULE_AUTHOR("Atsushi Nemoto <[email protected]>"); |
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MODULE_DESCRIPTION("Dallas DS1553 RTC driver"); |
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MODULE_LICENSE("GPL");
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