RTC: M48T35: new RTC driver
This driver replaces the broken ip27-rtc driver in drivers/char and
gives back RTC support for SGI IP27 machines.
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Acked-by: Alessandro Zummo <alessandro.zummo@towertech.it>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/drivers/rtc/rtc-m48t35.c b/drivers/rtc/rtc-m48t35.c
new file mode 100644
index 0000000..b9c1fe4
--- /dev/null
+++ b/drivers/rtc/rtc-m48t35.c
@@ -0,0 +1,234 @@
+/*
+ * Driver for the SGS-Thomson M48T35 Timekeeper RAM chip
+ *
+ * Copyright (C) 2000 Silicon Graphics, Inc.
+ * Written by Ulf Carlsson (ulfc@engr.sgi.com)
+ *
+ * Copyright (C) 2008 Thomas Bogendoerfer
+ *
+ * Based on code written by Paul Gortmaker.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/rtc.h>
+#include <linux/platform_device.h>
+#include <linux/bcd.h>
+
+#define DRV_VERSION "1.0"
+
+struct m48t35_rtc {
+ u8 pad[0x7ff8]; /* starts at 0x7ff8 */
+ u8 control;
+ u8 sec;
+ u8 min;
+ u8 hour;
+ u8 day;
+ u8 date;
+ u8 month;
+ u8 year;
+};
+
+#define M48T35_RTC_SET 0x80
+#define M48T35_RTC_READ 0x40
+
+struct m48t35_priv {
+ struct rtc_device *rtc;
+ struct m48t35_rtc __iomem *reg;
+ size_t size;
+ unsigned long baseaddr;
+ spinlock_t lock;
+};
+
+static int m48t35_read_time(struct device *dev, struct rtc_time *tm)
+{
+ struct m48t35_priv *priv = dev_get_drvdata(dev);
+ u8 control;
+
+ /*
+ * Only the values that we read from the RTC are set. We leave
+ * tm_wday, tm_yday and tm_isdst untouched. Even though the
+ * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated
+ * by the RTC when initially set to a non-zero value.
+ */
+ spin_lock_irq(&priv->lock);
+ control = readb(&priv->reg->control);
+ writeb(control | M48T35_RTC_READ, &priv->reg->control);
+ tm->tm_sec = readb(&priv->reg->sec);
+ tm->tm_min = readb(&priv->reg->min);
+ tm->tm_hour = readb(&priv->reg->hour);
+ tm->tm_mday = readb(&priv->reg->date);
+ tm->tm_mon = readb(&priv->reg->month);
+ tm->tm_year = readb(&priv->reg->year);
+ writeb(control, &priv->reg->control);
+ spin_unlock_irq(&priv->lock);
+
+ tm->tm_sec = bcd2bin(tm->tm_sec);
+ tm->tm_min = bcd2bin(tm->tm_min);
+ tm->tm_hour = bcd2bin(tm->tm_hour);
+ tm->tm_mday = bcd2bin(tm->tm_mday);
+ tm->tm_mon = bcd2bin(tm->tm_mon);
+ tm->tm_year = bcd2bin(tm->tm_year);
+
+ /*
+ * Account for differences between how the RTC uses the values
+ * and how they are defined in a struct rtc_time;
+ */
+ tm->tm_year += 70;
+ if (tm->tm_year <= 69)
+ tm->tm_year += 100;
+
+ tm->tm_mon--;
+ return rtc_valid_tm(tm);
+}
+
+static int m48t35_set_time(struct device *dev, struct rtc_time *tm)
+{
+ struct m48t35_priv *priv = dev_get_drvdata(dev);
+ unsigned char mon, day, hrs, min, sec;
+ unsigned int yrs;
+ u8 control;
+
+ yrs = tm->tm_year + 1900;
+ mon = tm->tm_mon + 1; /* tm_mon starts at zero */
+ day = tm->tm_mday;
+ hrs = tm->tm_hour;
+ min = tm->tm_min;
+ sec = tm->tm_sec;
+
+ if (yrs < 1970)
+ return -EINVAL;
+
+ yrs -= 1970;
+ if (yrs > 255) /* They are unsigned */
+ return -EINVAL;
+
+ if (yrs > 169)
+ return -EINVAL;
+
+ if (yrs >= 100)
+ yrs -= 100;
+
+ sec = bin2bcd(sec);
+ min = bin2bcd(min);
+ hrs = bin2bcd(hrs);
+ day = bin2bcd(day);
+ mon = bin2bcd(mon);
+ yrs = bin2bcd(yrs);
+
+ spin_lock_irq(&priv->lock);
+ control = readb(&priv->reg->control);
+ writeb(control | M48T35_RTC_SET, &priv->reg->control);
+ writeb(yrs, &priv->reg->year);
+ writeb(mon, &priv->reg->month);
+ writeb(day, &priv->reg->date);
+ writeb(hrs, &priv->reg->hour);
+ writeb(min, &priv->reg->min);
+ writeb(sec, &priv->reg->sec);
+ writeb(control, &priv->reg->control);
+ spin_unlock_irq(&priv->lock);
+ return 0;
+}
+
+static const struct rtc_class_ops m48t35_ops = {
+ .read_time = m48t35_read_time,
+ .set_time = m48t35_set_time,
+};
+
+static int __devinit m48t35_probe(struct platform_device *pdev)
+{
+ struct rtc_device *rtc;
+ struct resource *res;
+ struct m48t35_priv *priv;
+ int ret = 0;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res)
+ return -ENODEV;
+ priv = kzalloc(sizeof(struct m48t35_priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->size = res->end - res->start + 1;
+ /*
+ * kludge: remove the #ifndef after ioc3 resource
+ * conflicts are resolved
+ */
+#ifndef CONFIG_SGI_IP27
+ if (!request_mem_region(res->start, priv->size, pdev->name)) {
+ ret = -EBUSY;
+ goto out;
+ }
+#endif
+ priv->baseaddr = res->start;
+ priv->reg = ioremap(priv->baseaddr, priv->size);
+ if (!priv->reg) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ spin_lock_init(&priv->lock);
+ rtc = rtc_device_register("m48t35", &pdev->dev,
+ &m48t35_ops, THIS_MODULE);
+ if (IS_ERR(rtc)) {
+ ret = PTR_ERR(rtc);
+ goto out;
+ }
+ priv->rtc = rtc;
+ platform_set_drvdata(pdev, priv);
+ return 0;
+
+out:
+ if (priv->rtc)
+ rtc_device_unregister(priv->rtc);
+ if (priv->reg)
+ iounmap(priv->reg);
+ if (priv->baseaddr)
+ release_mem_region(priv->baseaddr, priv->size);
+ kfree(priv);
+ return ret;
+}
+
+static int __devexit m48t35_remove(struct platform_device *pdev)
+{
+ struct m48t35_priv *priv = platform_get_drvdata(pdev);
+
+ rtc_device_unregister(priv->rtc);
+ iounmap(priv->reg);
+#ifndef CONFIG_SGI_IP27
+ release_mem_region(priv->baseaddr, priv->size);
+#endif
+ kfree(priv);
+ return 0;
+}
+
+static struct platform_driver m48t35_platform_driver = {
+ .driver = {
+ .name = "rtc-m48t35",
+ .owner = THIS_MODULE,
+ },
+ .probe = m48t35_probe,
+ .remove = __devexit_p(m48t35_remove),
+};
+
+static int __init m48t35_init(void)
+{
+ return platform_driver_register(&m48t35_platform_driver);
+}
+
+static void __exit m48t35_exit(void)
+{
+ platform_driver_unregister(&m48t35_platform_driver);
+}
+
+MODULE_AUTHOR("Thomas Bogendoerfer <tsbogend@alpha.franken.de>");
+MODULE_DESCRIPTION("M48T35 RTC driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_VERSION);
+MODULE_ALIAS("platform:rtc-m48t35");
+
+module_init(m48t35_init);
+module_exit(m48t35_exit);
