/* * A RTC driver for the Simtek STK17TA8 * * By Thomas Hommel <thomas.hommel@ge.com> * * Based on the DS1553 driver from * Atsushi Nemoto <anemo@mba.ocn.ne.jp> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include <linux/bcd.h> #include <linux/init.h> #include <linux/kernel.h> #include <linux/gfp.h> #include <linux/delay.h> #include <linux/jiffies.h> #include <linux/interrupt.h> #include <linux/rtc.h> #include <linux/platform_device.h> #include <linux/io.h> #include <linux/module.h> #define RTC_REG_SIZE 0x20000 #define RTC_OFFSET 0x1fff0 #define RTC_FLAGS (RTC_OFFSET + 0) #define RTC_CENTURY (RTC_OFFSET + 1) #define RTC_SECONDS_ALARM (RTC_OFFSET + 2) #define RTC_MINUTES_ALARM (RTC_OFFSET + 3) #define RTC_HOURS_ALARM (RTC_OFFSET + 4) #define RTC_DATE_ALARM (RTC_OFFSET + 5) #define RTC_INTERRUPTS (RTC_OFFSET + 6) #define RTC_WATCHDOG (RTC_OFFSET + 7) #define RTC_CALIBRATION (RTC_OFFSET + 8) #define RTC_SECONDS (RTC_OFFSET + 9) #define RTC_MINUTES (RTC_OFFSET + 10) #define RTC_HOURS (RTC_OFFSET + 11) #define RTC_DAY (RTC_OFFSET + 12) #define RTC_DATE (RTC_OFFSET + 13) #define RTC_MONTH (RTC_OFFSET + 14) #define RTC_YEAR (RTC_OFFSET + 15) #define RTC_SECONDS_MASK 0x7f #define RTC_DAY_MASK 0x07 #define RTC_CAL_MASK 0x3f /* Bits in the Calibration register */ #define RTC_STOP 0x80 /* Bits in the Flags register */ #define RTC_FLAGS_AF 0x40 #define RTC_FLAGS_PF 0x20 #define RTC_WRITE 0x02 #define RTC_READ 0x01 /* Bits in the Interrupts register */ #define RTC_INTS_AIE 0x40 struct rtc_plat_data { struct rtc_device *rtc; void __iomem *ioaddr; unsigned long last_jiffies; int irq; unsigned int irqen; int alrm_sec; int alrm_min; int alrm_hour; int alrm_mday; spinlock_t lock; }; static int stk17ta8_rtc_set_time(struct device *dev, struct rtc_time *tm) { struct rtc_plat_data *pdata = dev_get_drvdata(dev); void __iomem *ioaddr = pdata->ioaddr; u8 flags; flags = readb(pdata->ioaddr + RTC_FLAGS); writeb(flags | RTC_WRITE, pdata->ioaddr + RTC_FLAGS); writeb(bin2bcd(tm->tm_year % 100), ioaddr + RTC_YEAR); writeb(bin2bcd(tm->tm_mon + 1), ioaddr + RTC_MONTH); writeb(bin2bcd(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY); writeb(bin2bcd(tm->tm_mday), ioaddr + RTC_DATE); writeb(bin2bcd(tm->tm_hour), ioaddr + RTC_HOURS); writeb(bin2bcd(tm->tm_min), ioaddr + RTC_MINUTES); writeb(bin2bcd(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS); writeb(bin2bcd((tm->tm_year + 1900) / 100), ioaddr + RTC_CENTURY); writeb(flags & ~RTC_WRITE, pdata->ioaddr + RTC_FLAGS); return 0; } static int stk17ta8_rtc_read_time(struct device *dev, struct rtc_time *tm) { struct rtc_plat_data *pdata = dev_get_drvdata(dev); void __iomem *ioaddr = pdata->ioaddr; unsigned int year, month, day, hour, minute, second, week; unsigned int century; u8 flags; /* give enough time to update RTC in case of continuous read */ if (pdata->last_jiffies == jiffies) msleep(1); pdata->last_jiffies = jiffies; flags = readb(pdata->ioaddr + RTC_FLAGS); writeb(flags | RTC_READ, ioaddr + RTC_FLAGS); second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK; minute = readb(ioaddr + RTC_MINUTES); hour = readb(ioaddr + RTC_HOURS); day = readb(ioaddr + RTC_DATE); week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK; month = readb(ioaddr + RTC_MONTH); year = readb(ioaddr + RTC_YEAR); century = readb(ioaddr + RTC_CENTURY); writeb(flags & ~RTC_READ, ioaddr + RTC_FLAGS); tm->tm_sec = bcd2bin(second); tm->tm_min = bcd2bin(minute); tm->tm_hour = bcd2bin(hour); tm->tm_mday = bcd2bin(day); tm->tm_wday = bcd2bin(week); tm->tm_mon = bcd2bin(month) - 1; /* year is 1900 + tm->tm_year */ tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900; return 0; } static void stk17ta8_rtc_update_alarm(struct rtc_plat_data *pdata) { void __iomem *ioaddr = pdata->ioaddr; unsigned long irqflags; u8 flags; spin_lock_irqsave(&pdata->lock, irqflags); flags = readb(ioaddr + RTC_FLAGS); writeb(flags | RTC_WRITE, ioaddr + RTC_FLAGS); writeb(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ? 0x80 : bin2bcd(pdata->alrm_mday), ioaddr + RTC_DATE_ALARM); writeb(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ? 0x80 : bin2bcd(pdata->alrm_hour), ioaddr + RTC_HOURS_ALARM); writeb(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ? 0x80 : bin2bcd(pdata->alrm_min), ioaddr + RTC_MINUTES_ALARM); writeb(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ? 0x80 : bin2bcd(pdata->alrm_sec), ioaddr + RTC_SECONDS_ALARM); writeb(pdata->irqen ? RTC_INTS_AIE : 0, ioaddr + RTC_INTERRUPTS); readb(ioaddr + RTC_FLAGS); /* clear interrupts */ writeb(flags & ~RTC_WRITE, ioaddr + RTC_FLAGS); spin_unlock_irqrestore(&pdata->lock, irqflags); } static int stk17ta8_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) { struct rtc_plat_data *pdata = dev_get_drvdata(dev); if (pdata->irq <= 0) return -EINVAL; pdata->alrm_mday = alrm->time.tm_mday; pdata->alrm_hour = alrm->time.tm_hour; pdata->alrm_min = alrm->time.tm_min; pdata->alrm_sec = alrm->time.tm_sec; if (alrm->enabled) pdata->irqen |= RTC_AF; stk17ta8_rtc_update_alarm(pdata); return 0; } static int stk17ta8_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) { struct rtc_plat_data *pdata = dev_get_drvdata(dev); if (pdata->irq <= 0) return -EINVAL; alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday; alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour; alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min; alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec; alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0; return 0; } static irqreturn_t stk17ta8_rtc_interrupt(int irq, void *dev_id) { struct platform_device *pdev = dev_id; struct rtc_plat_data *pdata = platform_get_drvdata(pdev); void __iomem *ioaddr = pdata->ioaddr; unsigned long events = 0; spin_lock(&pdata->lock); /* read and clear interrupt */ if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF) { events = RTC_IRQF; if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80) events |= RTC_UF; else events |= RTC_AF; rtc_update_irq(pdata->rtc, 1, events); } spin_unlock(&pdata->lock); return events ? IRQ_HANDLED : IRQ_NONE; } static int stk17ta8_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) { struct rtc_plat_data *pdata = dev_get_drvdata(dev); if (pdata->irq <= 0) return -EINVAL; if (enabled) pdata->irqen |= RTC_AF; else pdata->irqen &= ~RTC_AF; stk17ta8_rtc_update_alarm(pdata); return 0; } static const struct rtc_class_ops stk17ta8_rtc_ops = { .read_time = stk17ta8_rtc_read_time, .set_time = stk17ta8_rtc_set_time, .read_alarm = stk17ta8_rtc_read_alarm, .set_alarm = stk17ta8_rtc_set_alarm, .alarm_irq_enable = stk17ta8_rtc_alarm_irq_enable, }; static int stk17ta8_nvram_read(void *priv, unsigned int pos, void *val, size_t bytes) { struct rtc_plat_data *pdata = priv; void __iomem *ioaddr = pdata->ioaddr; u8 *buf = val; for (; bytes; bytes--) *buf++ = readb(ioaddr + pos++); return 0; } static int stk17ta8_nvram_write(void *priv, unsigned int pos, void *val, size_t bytes) { struct rtc_plat_data *pdata = priv; void __iomem *ioaddr = pdata->ioaddr; u8 *buf = val; for (; bytes; bytes--) writeb(*buf++, ioaddr + pos++); return 0; } static int stk17ta8_rtc_probe(struct platform_device *pdev) { struct resource *res; unsigned int cal; unsigned int flags; struct rtc_plat_data *pdata; void __iomem *ioaddr; int ret = 0; struct nvmem_config nvmem_cfg = { .name = "stk17ta8_nvram", .word_size = 1, .stride = 1, .size = RTC_OFFSET, .reg_read = stk17ta8_nvram_read, .reg_write = stk17ta8_nvram_write, }; pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); if (!pdata) return -ENOMEM; res = platform_get_resource(pdev, IORESOURCE_MEM, 0); ioaddr = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(ioaddr)) return PTR_ERR(ioaddr); pdata->ioaddr = ioaddr; pdata->irq = platform_get_irq(pdev, 0); /* turn RTC on if it was not on */ cal = readb(ioaddr + RTC_CALIBRATION); if (cal & RTC_STOP) { cal &= RTC_CAL_MASK; flags = readb(ioaddr + RTC_FLAGS); writeb(flags | RTC_WRITE, ioaddr + RTC_FLAGS); writeb(cal, ioaddr + RTC_CALIBRATION); writeb(flags & ~RTC_WRITE, ioaddr + RTC_FLAGS); } if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_PF) dev_warn(&pdev->dev, "voltage-low detected.\n"); spin_lock_init(&pdata->lock); pdata->last_jiffies = jiffies; platform_set_drvdata(pdev, pdata); if (pdata->irq > 0) { writeb(0, ioaddr + RTC_INTERRUPTS); if (devm_request_irq(&pdev->dev, pdata->irq, stk17ta8_rtc_interrupt, IRQF_SHARED, pdev->name, pdev) < 0) { dev_warn(&pdev->dev, "interrupt not available.\n"); pdata->irq = 0; } } pdata->rtc = devm_rtc_allocate_device(&pdev->dev); if (IS_ERR(pdata->rtc)) return PTR_ERR(pdata->rtc); pdata->rtc->ops = &stk17ta8_rtc_ops; pdata->rtc->nvram_old_abi = true; nvmem_cfg.priv = pdata; ret = rtc_nvmem_register(pdata->rtc, &nvmem_cfg); if (ret) return ret; return rtc_register_device(pdata->rtc); } /* work with hotplug and coldplug */ MODULE_ALIAS("platform:stk17ta8"); static struct platform_driver stk17ta8_rtc_driver = { .probe = stk17ta8_rtc_probe, .driver = { .name = "stk17ta8", }, }; module_platform_driver(stk17ta8_rtc_driver); MODULE_AUTHOR("Thomas Hommel <thomas.hommel@ge.com>"); MODULE_DESCRIPTION("Simtek STK17TA8 RTC driver"); MODULE_LICENSE("GPL");