[PATCH] RTC: add rtc-ds1553 driver

Add an RTC driver for the Dallas DS1553 RTC chip.

[akpm@osdl.org: cleanups, compile fix]
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 425 insertions, 0 deletions

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 0bfd3aad6179..40e3d9c3da84 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -111,6 +111,16 @@ config RTC_DRV_DS1307
           This driver can also be built as a module. If so, the module
           will be called rtc-ds1307.
 
+config RTC_DRV_DS1553
+        tristate "Dallas DS1553"
+        depends on RTC_CLASS
+        help
+          If you say yes here you get support for the
+          Dallas DS1553 timekeeping chip.
+
+          This driver can also be built as a module. If so, the module
+          will be called rtc-ds1553.
+
 config RTC_DRV_DS1672
         tristate "Dallas/Maxim DS1672"
         depends on RTC_CLASS && I2C
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index f39992b865ce..1c50687fa4f3 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -19,6 +19,7 @@ obj-$(CONFIG_RTC_DRV_PCF8563)	+= rtc-pcf8563.o
 obj-$(CONFIG_RTC_DRV_PCF8583)   += rtc-pcf8583.o
 obj-$(CONFIG_RTC_DRV_RS5C372)   += rtc-rs5c372.o
 obj-$(CONFIG_RTC_DRV_M48T86)    += rtc-m48t86.o
+obj-$(CONFIG_RTC_DRV_DS1553)    += rtc-ds1553.o
 obj-$(CONFIG_RTC_DRV_EP93XX)    += rtc-ep93xx.o
 obj-$(CONFIG_RTC_DRV_SA1100)    += rtc-sa1100.o
 obj-$(CONFIG_RTC_DRV_VR41XX)    += rtc-vr41xx.o
diff --git a/drivers/rtc/rtc-ds1553.c b/drivers/rtc/rtc-ds1553.c
new file mode 100644
index 000000000000..ecafbad41a24
--- /dev/null
+++ b/drivers/rtc/rtc-ds1553.c
@@ -0,0 +1,414 @@
+/*
+ * An rtc driver for the Dallas DS1553
+ *
+ * Copyright (C) 2006 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/delay.h>
+#include <linux/jiffies.h>
+#include <linux/interrupt.h>
+#include <linux/rtc.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+
+#define DRV_VERSION "0.1"
+
+#define RTC_REG_SIZE            0x2000
+#define RTC_OFFSET              0x1ff0
+
+#define RTC_FLAGS               (RTC_OFFSET + 0)
+#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_CONTROL             (RTC_OFFSET + 8)
+#define RTC_CENTURY             (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_CENTURY_MASK        0x3f
+#define RTC_SECONDS_MASK        0x7f
+#define RTC_DAY_MASK            0x07
+
+/* Bits in the Control/Century register */
+#define RTC_WRITE               0x80
+#define RTC_READ                0x40
+
+/* Bits in the Seconds register */
+#define RTC_STOP                0x80
+
+/* Bits in the Flags register */
+#define RTC_FLAGS_AF            0x40
+#define RTC_FLAGS_BLF           0x10
+
+/* Bits in the Interrupts register */
+#define RTC_INTS_AE             0x80
+
+struct rtc_plat_data {
+        struct rtc_device *rtc;
+        void __iomem *ioaddr;
+        unsigned long baseaddr;
+        unsigned long last_jiffies;
+        int irq;
+        unsigned int irqen;
+        int alrm_sec;
+        int alrm_min;
+        int alrm_hour;
+        int alrm_mday;
+};
+
+static int ds1553_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+        struct platform_device *pdev = to_platform_device(dev);
+        struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
+        void __iomem *ioaddr = pdata->ioaddr;
+        u8 century;
+
+        century = BIN2BCD((tm->tm_year + 1900) / 100);
+
+        writeb(RTC_WRITE, pdata->ioaddr + RTC_CONTROL);
+
+        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);
+
+        /* RTC_CENTURY and RTC_CONTROL share same register */
+        writeb(RTC_WRITE | (century & RTC_CENTURY_MASK), ioaddr + RTC_CENTURY);
+        writeb(century & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
+        return 0;
+}
+
+static int ds1553_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+        struct platform_device *pdev = to_platform_device(dev);
+        struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
+        void __iomem *ioaddr = pdata->ioaddr;
+        unsigned int year, month, day, hour, minute, second, week;
+        unsigned int century;
+
+        /* give enough time to update RTC in case of continuous read */
+        if (pdata->last_jiffies == jiffies)
+                msleep(1);
+        pdata->last_jiffies = jiffies;
+        writeb(RTC_READ, ioaddr + RTC_CONTROL);
+        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) & RTC_CENTURY_MASK;
+        writeb(0, ioaddr + RTC_CONTROL);
+        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;
+
+        if (rtc_valid_tm(tm) < 0) {
+                dev_err(dev, "retrieved date/time is not valid.\n");
+                rtc_time_to_tm(0, tm);
+        }
+        return 0;
+}
+
+static void ds1553_rtc_update_alarm(struct rtc_plat_data *pdata)
+{
+        void __iomem *ioaddr = pdata->ioaddr;
+        unsigned long flags;
+
+        spin_lock_irqsave(&pdata->rtc->irq_lock, 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_AE : 0, ioaddr + RTC_INTERRUPTS);
+        readb(ioaddr + RTC_FLAGS);      /* clear interrupts */
+        spin_unlock_irqrestore(&pdata->rtc->irq_lock, flags);
+}
+
+static int ds1553_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+        struct platform_device *pdev = to_platform_device(dev);
+        struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
+
+        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;
+        ds1553_rtc_update_alarm(pdata);
+        return 0;
+}
+
+static int ds1553_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+        struct platform_device *pdev = to_platform_device(dev);
+        struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
+
+        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 ds1553_rtc_interrupt(int irq, void *dev_id,
+                                        struct pt_regs *regs)
+{
+        struct platform_device *pdev = dev_id;
+        struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
+        void __iomem *ioaddr = pdata->ioaddr;
+        unsigned long events = RTC_IRQF;
+
+        /* read and clear interrupt */
+        if (!(readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF))
+                return IRQ_NONE;
+        if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80)
+                events |= RTC_UF;
+        else
+                events |= RTC_AF;
+        rtc_update_irq(&pdata->rtc->class_dev, 1, events);
+        return IRQ_HANDLED;
+}
+
+static void ds1553_rtc_release(struct device *dev)
+{
+        struct platform_device *pdev = to_platform_device(dev);
+        struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
+
+        if (pdata->irq >= 0) {
+                pdata->irqen = 0;
+                ds1553_rtc_update_alarm(pdata);
+        }
+}
+
+static int ds1553_rtc_ioctl(struct device *dev, unsigned int cmd,
+                            unsigned long arg)
+{
+        struct platform_device *pdev = to_platform_device(dev);
+        struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
+
+        if (pdata->irq < 0)
+                return -ENOIOCTLCMD;
+        switch (cmd) {
+        case RTC_AIE_OFF:
+                pdata->irqen &= ~RTC_AF;
+                ds1553_rtc_update_alarm(pdata);
+                break;
+        case RTC_AIE_ON:
+                pdata->irqen |= RTC_AF;
+                ds1553_rtc_update_alarm(pdata);
+                break;
+        case RTC_UIE_OFF:
+                pdata->irqen &= ~RTC_UF;
+                ds1553_rtc_update_alarm(pdata);
+                break;
+        case RTC_UIE_ON:
+                pdata->irqen |= RTC_UF;
+                ds1553_rtc_update_alarm(pdata);
+                break;
+        default:
+                return -ENOIOCTLCMD;
+        }
+        return 0;
+}
+
+static struct rtc_class_ops ds1553_rtc_ops = {
+        .read_time      = ds1553_rtc_read_time,
+        .set_time       = ds1553_rtc_set_time,
+        .read_alarm     = ds1553_rtc_read_alarm,
+        .set_alarm      = ds1553_rtc_set_alarm,
+        .release        = ds1553_rtc_release,
+        .ioctl          = ds1553_rtc_ioctl,
+};
+
+static ssize_t ds1553_nvram_read(struct kobject *kobj, char *buf,
+                                 loff_t pos, size_t size)
+{
+        struct platform_device *pdev =
+                to_platform_device(container_of(kobj, struct device, kobj));
+        struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
+        void __iomem *ioaddr = pdata->ioaddr;
+        ssize_t count;
+
+        for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--)
+                *buf++ = readb(ioaddr + pos++);
+        return count;
+}
+
+static ssize_t ds1553_nvram_write(struct kobject *kobj, char *buf,
+                                  loff_t pos, size_t size)
+{
+        struct platform_device *pdev =
+                to_platform_device(container_of(kobj, struct device, kobj));
+        struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
+        void __iomem *ioaddr = pdata->ioaddr;
+        ssize_t count;
+
+        for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--)
+                writeb(*buf++, ioaddr + pos++);
+        return count;
+}
+
+static struct bin_attribute ds1553_nvram_attr = {
+        .attr = {
+                .name = "nvram",
+                .mode = S_IRUGO | S_IWUGO,
+                .owner = THIS_MODULE,
+        },
+        .size = RTC_OFFSET,
+        .read = ds1553_nvram_read,
+        .write = ds1553_nvram_write,
+};
+
+static int __init ds1553_rtc_probe(struct platform_device *pdev)
+{
+        struct rtc_device *rtc;
+        struct resource *res;
+        unsigned int cen, sec;
+        struct rtc_plat_data *pdata = NULL;
+        void __iomem *ioaddr = NULL;
+        int ret = 0;
+
+        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        if (!res)
+                return -ENODEV;
+        pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
+        if (!pdata)
+                return -ENOMEM;
+        pdata->irq = -1;
+        if (!request_mem_region(res->start, RTC_REG_SIZE, pdev->name)) {
+                ret = -EBUSY;
+                goto out;
+        }
+        pdata->baseaddr = res->start;
+        ioaddr = ioremap(pdata->baseaddr, RTC_REG_SIZE);
+        if (!ioaddr) {
+                ret = -ENOMEM;
+                goto out;
+        }
+        pdata->ioaddr = ioaddr;
+        pdata->irq = platform_get_irq(pdev, 0);
+
+        /* turn RTC on if it was not on */
+        sec = readb(ioaddr + RTC_SECONDS);
+        if (sec & RTC_STOP) {
+                sec &= RTC_SECONDS_MASK;
+                cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
+                writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
+                writeb(sec, ioaddr + RTC_SECONDS);
+                writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
+        }
+        if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_BLF)
+                dev_warn(&pdev->dev, "voltage-low detected.\n");
+
+        if (pdata->irq >= 0) {
+                writeb(0, ioaddr + RTC_INTERRUPTS);
+                if (request_irq(pdata->irq, ds1553_rtc_interrupt, SA_SHIRQ,
+                                pdev->name, pdev) < 0) {
+                        dev_warn(&pdev->dev, "interrupt not available.\n");
+                        pdata->irq = -1;
+                }
+        }
+
+        rtc = rtc_device_register(pdev->name, &pdev->dev,
+                                  &ds1553_rtc_ops, THIS_MODULE);
+        if (IS_ERR(rtc)) {
+                ret = PTR_ERR(rtc);
+                goto out;
+        }
+        pdata->rtc = rtc;
+        pdata->last_jiffies = jiffies;
+        platform_set_drvdata(pdev, pdata);
+        sysfs_create_bin_file(&pdev->dev.kobj, &ds1553_nvram_attr);
+        return 0;
+ out:
+        if (pdata->irq >= 0)
+                free_irq(pdata->irq, pdev);
+        if (ioaddr)
+                iounmap(ioaddr);
+        if (pdata->baseaddr)
+                release_mem_region(pdata->baseaddr, RTC_REG_SIZE);
+        kfree(pdata);
+        return ret;
+}
+
+static int __devexit ds1553_rtc_remove(struct platform_device *pdev)
+{
+        struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
+
+        sysfs_remove_bin_file(&pdev->dev.kobj, &ds1553_nvram_attr);
+        rtc_device_unregister(pdata->rtc);
+        if (pdata->irq >= 0) {
+                writeb(0, pdata->ioaddr + RTC_INTERRUPTS);
+                free_irq(pdata->irq, pdev);
+        }
+        iounmap(pdata->ioaddr);
+        release_mem_region(pdata->baseaddr, RTC_REG_SIZE);
+        kfree(pdata);
+        return 0;
+}
+
+static struct platform_driver ds1553_rtc_driver = {
+        .probe          = ds1553_rtc_probe,
+        .remove         = __devexit_p(ds1553_rtc_remove),
+        .driver         = {
+                .name   = "ds1553",
+                .owner  = THIS_MODULE,
+        },
+};
+
+static __init int ds1553_init(void)
+{
+        return platform_driver_register(&ds1553_rtc_driver);
+}
+
+static __exit void ds1553_exit(void)
+{
+        return platform_driver_unregister(&ds1553_rtc_driver);
+}
+
+module_init(ds1553_init);
+module_exit(ds1553_exit);
+
+MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
+MODULE_DESCRIPTION("Dallas DS1553 RTC driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_VERSION);