--- /dev/null
+/*
+ * An rtc driver for the Dallas DS1742
+ *
+ * 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/rtc.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+
+#define DRV_VERSION "0.1"
+
+#define RTC_REG_SIZE 0x800
+#define RTC_OFFSET 0x7f8
+
+#define RTC_CONTROL (RTC_OFFSET + 0)
+#define RTC_CENTURY (RTC_OFFSET + 0)
+#define RTC_SECONDS (RTC_OFFSET + 1)
+#define RTC_MINUTES (RTC_OFFSET + 2)
+#define RTC_HOURS (RTC_OFFSET + 3)
+#define RTC_DAY (RTC_OFFSET + 4)
+#define RTC_DATE (RTC_OFFSET + 5)
+#define RTC_MONTH (RTC_OFFSET + 6)
+#define RTC_YEAR (RTC_OFFSET + 7)
+
+#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 Day register */
+#define RTC_BATT_FLAG 0x80
+
+struct rtc_plat_data {
+ struct rtc_device *rtc;
+ void __iomem *ioaddr;
+ unsigned long baseaddr;
+ unsigned long last_jiffies;
+};
+
+static int ds1742_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, 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 ds1742_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 struct rtc_class_ops ds1742_rtc_ops = {
+ .read_time = ds1742_rtc_read_time,
+ .set_time = ds1742_rtc_set_time,
+};
+
+static ssize_t ds1742_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 ds1742_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 ds1742_nvram_attr = {
+ .attr = {
+ .name = "nvram",
+ .mode = S_IRUGO | S_IWUGO,
+ .owner = THIS_MODULE,
+ },
+ .size = RTC_OFFSET,
+ .read = ds1742_nvram_read,
+ .write = ds1742_nvram_write,
+};
+
+static int __init ds1742_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;
+ 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;
+
+ /* 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_DAY) & RTC_BATT_FLAG)
+ dev_warn(&pdev->dev, "voltage-low detected.\n");
+
+ rtc = rtc_device_register(pdev->name, &pdev->dev,
+ &ds1742_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, &ds1742_nvram_attr);
+ return 0;
+ out:
+ if (ioaddr)
+ iounmap(ioaddr);
+ if (pdata->baseaddr)
+ release_mem_region(pdata->baseaddr, RTC_REG_SIZE);
+ kfree(pdata);
+ return ret;
+}
+
+static int __devexit ds1742_rtc_remove(struct platform_device *pdev)
+{
+ struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
+
+ sysfs_remove_bin_file(&pdev->dev.kobj, &ds1742_nvram_attr);
+ rtc_device_unregister(pdata->rtc);
+ iounmap(pdata->ioaddr);
+ release_mem_region(pdata->baseaddr, RTC_REG_SIZE);
+ kfree(pdata);
+ return 0;
+}
+
+static struct platform_driver ds1742_rtc_driver = {
+ .probe = ds1742_rtc_probe,
+ .remove = __devexit_p(ds1742_rtc_remove),
+ .driver = {
+ .name = "ds1742",
+ .owner = THIS_MODULE,
+ },
+};
+
+static __init int ds1742_init(void)
+{
+ return platform_driver_register(&ds1742_rtc_driver);
+}
+
+static __exit void ds1742_exit(void)
+{
+ return platform_driver_unregister(&ds1742_rtc_driver);
+}
+
+module_init(ds1742_init);
+module_exit(ds1742_exit);
+
+MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
+MODULE_DESCRIPTION("Dallas DS1742 RTC driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_VERSION);
projects / linux-2.6 / commitdiff