--- /dev/null
+/*
+ * 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 DRV_VERSION "0.1"
+
+#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 platform_device *pdev = to_platform_device(dev);
+ struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
+ 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 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;
+ 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;
+
+ 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 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 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;
+ stk17ta8_rtc_update_alarm(pdata);
+ return 0;
+}
+
+static int stk17ta8_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 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 platform_device *pdev = to_platform_device(dev);
+ struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
+
+ 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 ssize_t stk17ta8_nvram_read(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *attr, char *buf,
+ loff_t pos, size_t size)
+{
+ struct device *dev = container_of(kobj, struct device, kobj);
+ struct platform_device *pdev = to_platform_device(dev);
+ 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 stk17ta8_nvram_write(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *attr, char *buf,
+ loff_t pos, size_t size)
+{
+ struct device *dev = container_of(kobj, struct device, kobj);
+ struct platform_device *pdev = to_platform_device(dev);
+ 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 stk17ta8_nvram_attr = {
+ .attr = {
+ .name = "nvram",
+ .mode = S_IRUGO | S_IWUSR,
+ },
+ .size = RTC_OFFSET,
+ .read = stk17ta8_nvram_read,
+ .write = stk17ta8_nvram_write,
+};
+
+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;
+
+ 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_device_register(&pdev->dev, pdev->name,
+ &stk17ta8_rtc_ops, THIS_MODULE);
+ if (IS_ERR(pdata->rtc))
+ return PTR_ERR(pdata->rtc);
+
+ ret = sysfs_create_bin_file(&pdev->dev.kobj, &stk17ta8_nvram_attr);
+
+ return ret;
+}
+
+static int stk17ta8_rtc_remove(struct platform_device *pdev)
+{
+ struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
+
+ sysfs_remove_bin_file(&pdev->dev.kobj, &stk17ta8_nvram_attr);
+ if (pdata->irq > 0)
+ writeb(0, pdata->ioaddr + RTC_INTERRUPTS);
+ return 0;
+}
+
+/* work with hotplug and coldplug */
+MODULE_ALIAS("platform:stk17ta8");
+
+static struct platform_driver stk17ta8_rtc_driver = {
+ .probe = stk17ta8_rtc_probe,
+ .remove = stk17ta8_rtc_remove,
+ .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");
+MODULE_VERSION(DRV_VERSION);
Code Review / kvmfornfv.git / blobdiff