[PATCH] RTC subsystem: M48T86 driver
Add a driver for the ST M48T86 / Dallas DS12887 RTC.
This is a platform driver. The platform device must provide I/O routines to
access the RTC.
Signed-off-by: Alessandro Zummo <a.zummo@towertech.it>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/rtc/rtc-m48t86.c b/drivers/rtc/rtc-m48t86.c
new file mode 100644
index 0000000..db445c8
--- /dev/null
+++ b/drivers/rtc/rtc-m48t86.c
@@ -0,0 +1,209 @@
+/*
+ * ST M48T86 / Dallas DS12887 RTC driver
+ * Copyright (c) 2006 Tower Technologies
+ *
+ * Author: Alessandro Zummo <a.zummo@towertech.it>
+ *
+ * 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.
+ *
+ * This drivers only supports the clock running in BCD and 24H mode.
+ * If it will be ever adapted to binary and 12H mode, care must be taken
+ * to not introduce bugs.
+ */
+
+#include <linux/module.h>
+#include <linux/rtc.h>
+#include <linux/platform_device.h>
+#include <linux/m48t86.h>
+#include <linux/bcd.h>
+
+#define M48T86_REG_SEC 0x00
+#define M48T86_REG_SECALRM 0x01
+#define M48T86_REG_MIN 0x02
+#define M48T86_REG_MINALRM 0x03
+#define M48T86_REG_HOUR 0x04
+#define M48T86_REG_HOURALRM 0x05
+#define M48T86_REG_DOW 0x06 /* 1 = sunday */
+#define M48T86_REG_DOM 0x07
+#define M48T86_REG_MONTH 0x08 /* 1 - 12 */
+#define M48T86_REG_YEAR 0x09 /* 0 - 99 */
+#define M48T86_REG_A 0x0A
+#define M48T86_REG_B 0x0B
+#define M48T86_REG_C 0x0C
+#define M48T86_REG_D 0x0D
+
+#define M48T86_REG_B_H24 (1 << 1)
+#define M48T86_REG_B_DM (1 << 2)
+#define M48T86_REG_B_SET (1 << 7)
+#define M48T86_REG_D_VRT (1 << 7)
+
+#define DRV_VERSION "0.1"
+
+
+static int m48t86_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ unsigned char reg;
+ struct platform_device *pdev = to_platform_device(dev);
+ struct m48t86_ops *ops = pdev->dev.platform_data;
+
+ reg = ops->readb(M48T86_REG_B);
+
+ if (reg & M48T86_REG_B_DM) {
+ /* data (binary) mode */
+ tm->tm_sec = ops->readb(M48T86_REG_SEC);
+ tm->tm_min = ops->readb(M48T86_REG_MIN);
+ tm->tm_hour = ops->readb(M48T86_REG_HOUR) & 0x3F;
+ tm->tm_mday = ops->readb(M48T86_REG_DOM);
+ /* tm_mon is 0-11 */
+ tm->tm_mon = ops->readb(M48T86_REG_MONTH) - 1;
+ tm->tm_year = ops->readb(M48T86_REG_YEAR) + 100;
+ tm->tm_wday = ops->readb(M48T86_REG_DOW);
+ } else {
+ /* bcd mode */
+ tm->tm_sec = BCD2BIN(ops->readb(M48T86_REG_SEC));
+ tm->tm_min = BCD2BIN(ops->readb(M48T86_REG_MIN));
+ tm->tm_hour = BCD2BIN(ops->readb(M48T86_REG_HOUR) & 0x3F);
+ tm->tm_mday = BCD2BIN(ops->readb(M48T86_REG_DOM));
+ /* tm_mon is 0-11 */
+ tm->tm_mon = BCD2BIN(ops->readb(M48T86_REG_MONTH)) - 1;
+ tm->tm_year = BCD2BIN(ops->readb(M48T86_REG_YEAR)) + 100;
+ tm->tm_wday = BCD2BIN(ops->readb(M48T86_REG_DOW));
+ }
+
+ /* correct the hour if the clock is in 12h mode */
+ if (!(reg & M48T86_REG_B_H24))
+ if (ops->readb(M48T86_REG_HOUR) & 0x80)
+ tm->tm_hour += 12;
+
+ return 0;
+}
+
+static int m48t86_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+ unsigned char reg;
+ struct platform_device *pdev = to_platform_device(dev);
+ struct m48t86_ops *ops = pdev->dev.platform_data;
+
+ reg = ops->readb(M48T86_REG_B);
+
+ /* update flag and 24h mode */
+ reg |= M48T86_REG_B_SET | M48T86_REG_B_H24;
+ ops->writeb(reg, M48T86_REG_B);
+
+ if (reg & M48T86_REG_B_DM) {
+ /* data (binary) mode */
+ ops->writeb(tm->tm_sec, M48T86_REG_SEC);
+ ops->writeb(tm->tm_min, M48T86_REG_MIN);
+ ops->writeb(tm->tm_hour, M48T86_REG_HOUR);
+ ops->writeb(tm->tm_mday, M48T86_REG_DOM);
+ ops->writeb(tm->tm_mon + 1, M48T86_REG_MONTH);
+ ops->writeb(tm->tm_year % 100, M48T86_REG_YEAR);
+ ops->writeb(tm->tm_wday, M48T86_REG_DOW);
+ } else {
+ /* bcd mode */
+ ops->writeb(BIN2BCD(tm->tm_sec), M48T86_REG_SEC);
+ ops->writeb(BIN2BCD(tm->tm_min), M48T86_REG_MIN);
+ ops->writeb(BIN2BCD(tm->tm_hour), M48T86_REG_HOUR);
+ ops->writeb(BIN2BCD(tm->tm_mday), M48T86_REG_DOM);
+ ops->writeb(BIN2BCD(tm->tm_mon + 1), M48T86_REG_MONTH);
+ ops->writeb(BIN2BCD(tm->tm_year % 100), M48T86_REG_YEAR);
+ ops->writeb(BIN2BCD(tm->tm_wday), M48T86_REG_DOW);
+ }
+
+ /* update ended */
+ reg &= ~M48T86_REG_B_SET;
+ ops->writeb(reg, M48T86_REG_B);
+
+ return 0;
+}
+
+static int m48t86_rtc_proc(struct device *dev, struct seq_file *seq)
+{
+ unsigned char reg;
+ struct platform_device *pdev = to_platform_device(dev);
+ struct m48t86_ops *ops = pdev->dev.platform_data;
+
+ reg = ops->readb(M48T86_REG_B);
+
+ seq_printf(seq, "24hr\t\t: %s\n",
+ (reg & M48T86_REG_B_H24) ? "yes" : "no");
+
+ seq_printf(seq, "mode\t\t: %s\n",
+ (reg & M48T86_REG_B_DM) ? "binary" : "bcd");
+
+ reg = ops->readb(M48T86_REG_D);
+
+ seq_printf(seq, "battery\t\t: %s\n",
+ (reg & M48T86_REG_D_VRT) ? "ok" : "exhausted");
+
+ return 0;
+}
+
+static struct rtc_class_ops m48t86_rtc_ops = {
+ .read_time = m48t86_rtc_read_time,
+ .set_time = m48t86_rtc_set_time,
+ .proc = m48t86_rtc_proc,
+};
+
+static int __devinit m48t86_rtc_probe(struct platform_device *dev)
+{
+ unsigned char reg;
+ struct m48t86_ops *ops = dev->dev.platform_data;
+ struct rtc_device *rtc = rtc_device_register("m48t86",
+ &dev->dev, &m48t86_rtc_ops, THIS_MODULE);
+
+ if (IS_ERR(rtc)) {
+ dev_err(&dev->dev, "unable to register\n");
+ return PTR_ERR(rtc);
+ }
+
+ platform_set_drvdata(dev, rtc);
+
+ /* read battery status */
+ reg = ops->readb(M48T86_REG_D);
+ dev_info(&dev->dev, "battery %s\n",
+ (reg & M48T86_REG_D_VRT) ? "ok" : "exhausted");
+
+ return 0;
+}
+
+static int __devexit m48t86_rtc_remove(struct platform_device *dev)
+{
+ struct rtc_device *rtc = platform_get_drvdata(dev);
+
+ if (rtc)
+ rtc_device_unregister(rtc);
+
+ platform_set_drvdata(dev, NULL);
+
+ return 0;
+}
+
+static struct platform_driver m48t86_rtc_platform_driver = {
+ .driver = {
+ .name = "rtc-m48t86",
+ .owner = THIS_MODULE,
+ },
+ .probe = m48t86_rtc_probe,
+ .remove = __devexit_p(m48t86_rtc_remove),
+};
+
+static int __init m48t86_rtc_init(void)
+{
+ return platform_driver_register(&m48t86_rtc_platform_driver);
+}
+
+static void __exit m48t86_rtc_exit(void)
+{
+ platform_driver_unregister(&m48t86_rtc_platform_driver);
+}
+
+MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
+MODULE_DESCRIPTION("M48T86 RTC driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_VERSION);
+
+module_init(m48t86_rtc_init);
+module_exit(m48t86_rtc_exit);