344 lines
9.4 KiB
C
344 lines
9.4 KiB
C
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/*
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* A RTC driver for the Simtek STK17TA8
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*
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* By Thomas Hommel <thomas.hommel@ge.com>
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*
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* Based on the DS1553 driver from
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* Atsushi Nemoto <anemo@mba.ocn.ne.jp>
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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 version 2 as
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* published by the Free Software Foundation.
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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 0x20000
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#define RTC_OFFSET 0x1fff0
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#define RTC_FLAGS (RTC_OFFSET + 0)
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#define RTC_CENTURY (RTC_OFFSET + 1)
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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_CALIBRATION (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_SECONDS_MASK 0x7f
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#define RTC_DAY_MASK 0x07
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#define RTC_CAL_MASK 0x3f
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/* Bits in the Calibration 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_PF 0x20
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#define RTC_WRITE 0x02
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#define RTC_READ 0x01
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/* Bits in the Interrupts register */
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#define RTC_INTS_AIE 0x40
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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 stk17ta8_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 flags;
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flags = readb(pdata->ioaddr + RTC_FLAGS);
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writeb(flags | RTC_WRITE, pdata->ioaddr + RTC_FLAGS);
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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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writeb(bin2bcd((tm->tm_year + 1900) / 100), ioaddr + RTC_CENTURY);
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writeb(flags & ~RTC_WRITE, pdata->ioaddr + RTC_FLAGS);
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return 0;
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}
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static int stk17ta8_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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u8 flags;
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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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flags = readb(pdata->ioaddr + RTC_FLAGS);
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writeb(flags | RTC_READ, ioaddr + RTC_FLAGS);
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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);
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writeb(flags & ~RTC_READ, ioaddr + RTC_FLAGS);
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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 stk17ta8_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 irqflags;
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u8 flags;
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spin_lock_irqsave(&pdata->lock, irqflags);
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flags = readb(ioaddr + RTC_FLAGS);
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writeb(flags | RTC_WRITE, ioaddr + RTC_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_AIE : 0, ioaddr + RTC_INTERRUPTS);
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readb(ioaddr + RTC_FLAGS); /* clear interrupts */
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writeb(flags & ~RTC_WRITE, ioaddr + RTC_FLAGS);
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spin_unlock_irqrestore(&pdata->lock, irqflags);
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}
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static int stk17ta8_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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stk17ta8_rtc_update_alarm(pdata);
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return 0;
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}
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static int stk17ta8_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 stk17ta8_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 stk17ta8_rtc_alarm_irq_enable(struct device *dev,
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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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stk17ta8_rtc_update_alarm(pdata);
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return 0;
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}
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static const struct rtc_class_ops stk17ta8_rtc_ops = {
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.read_time = stk17ta8_rtc_read_time,
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.set_time = stk17ta8_rtc_set_time,
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.read_alarm = stk17ta8_rtc_read_alarm,
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.set_alarm = stk17ta8_rtc_set_alarm,
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.alarm_irq_enable = stk17ta8_rtc_alarm_irq_enable,
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};
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static int stk17ta8_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 rtc_plat_data *pdata = priv;
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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 stk17ta8_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 rtc_plat_data *pdata = priv;
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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 stk17ta8_rtc_probe(struct platform_device *pdev)
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{
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struct resource *res;
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unsigned int cal;
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unsigned int flags;
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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 = "stk17ta8_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 = stk17ta8_nvram_read,
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.reg_write = stk17ta8_nvram_write,
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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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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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ioaddr = devm_ioremap_resource(&pdev->dev, res);
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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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cal = readb(ioaddr + RTC_CALIBRATION);
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if (cal & RTC_STOP) {
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cal &= RTC_CAL_MASK;
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flags = readb(ioaddr + RTC_FLAGS);
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writeb(flags | RTC_WRITE, ioaddr + RTC_FLAGS);
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writeb(cal, ioaddr + RTC_CALIBRATION);
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writeb(flags & ~RTC_WRITE, ioaddr + RTC_FLAGS);
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}
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if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_PF)
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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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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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stk17ta8_rtc_interrupt,
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IRQF_SHARED,
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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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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 = &stk17ta8_rtc_ops;
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pdata->rtc->nvram_old_abi = true;
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nvmem_cfg.priv = pdata;
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ret = rtc_nvmem_register(pdata->rtc, &nvmem_cfg);
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if (ret)
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return ret;
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return rtc_register_device(pdata->rtc);
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}
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/* work with hotplug and coldplug */
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MODULE_ALIAS("platform:stk17ta8");
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static struct platform_driver stk17ta8_rtc_driver = {
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.probe = stk17ta8_rtc_probe,
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.driver = {
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.name = "stk17ta8",
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},
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};
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module_platform_driver(stk17ta8_rtc_driver);
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MODULE_AUTHOR("Thomas Hommel <thomas.hommel@ge.com>");
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MODULE_DESCRIPTION("Simtek STK17TA8 RTC driver");
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MODULE_LICENSE("GPL");
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