Initial import

1 files changed, 182 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-m48t86.c b/drivers/rtc/rtc-m48t86.c
new file mode 100644
index 000000000..a17b7a3ce
--- /dev/null
+++ b/drivers/rtc/rtc-m48t86.c
@@ -0,0 +1,182 @@
+/*
+ * 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 = dev_get_platdata(&pdev->dev);
+
+	reg = ops->readbyte(M48T86_REG_B);
+
+	if (reg & M48T86_REG_B_DM) {
+		/* data (binary) mode */
+		tm->tm_sec	= ops->readbyte(M48T86_REG_SEC);
+		tm->tm_min	= ops->readbyte(M48T86_REG_MIN);
+		tm->tm_hour	= ops->readbyte(M48T86_REG_HOUR) & 0x3F;
+		tm->tm_mday	= ops->readbyte(M48T86_REG_DOM);
+		/* tm_mon is 0-11 */
+		tm->tm_mon	= ops->readbyte(M48T86_REG_MONTH) - 1;
+		tm->tm_year	= ops->readbyte(M48T86_REG_YEAR) + 100;
+		tm->tm_wday	= ops->readbyte(M48T86_REG_DOW);
+	} else {
+		/* bcd mode */
+		tm->tm_sec	= bcd2bin(ops->readbyte(M48T86_REG_SEC));
+		tm->tm_min	= bcd2bin(ops->readbyte(M48T86_REG_MIN));
+		tm->tm_hour	= bcd2bin(ops->readbyte(M48T86_REG_HOUR) & 0x3F);
+		tm->tm_mday	= bcd2bin(ops->readbyte(M48T86_REG_DOM));
+		/* tm_mon is 0-11 */
+		tm->tm_mon	= bcd2bin(ops->readbyte(M48T86_REG_MONTH)) - 1;
+		tm->tm_year	= bcd2bin(ops->readbyte(M48T86_REG_YEAR)) + 100;
+		tm->tm_wday	= bcd2bin(ops->readbyte(M48T86_REG_DOW));
+	}
+
+	/* correct the hour if the clock is in 12h mode */
+	if (!(reg & M48T86_REG_B_H24))
+		if (ops->readbyte(M48T86_REG_HOUR) & 0x80)
+			tm->tm_hour += 12;
+
+	return rtc_valid_tm(tm);
+}
+
+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 = dev_get_platdata(&pdev->dev);
+
+	reg = ops->readbyte(M48T86_REG_B);
+
+	/* update flag and 24h mode */
+	reg |= M48T86_REG_B_SET | M48T86_REG_B_H24;
+	ops->writebyte(reg, M48T86_REG_B);
+
+	if (reg & M48T86_REG_B_DM) {
+		/* data (binary) mode */
+		ops->writebyte(tm->tm_sec, M48T86_REG_SEC);
+		ops->writebyte(tm->tm_min, M48T86_REG_MIN);
+		ops->writebyte(tm->tm_hour, M48T86_REG_HOUR);
+		ops->writebyte(tm->tm_mday, M48T86_REG_DOM);
+		ops->writebyte(tm->tm_mon + 1, M48T86_REG_MONTH);
+		ops->writebyte(tm->tm_year % 100, M48T86_REG_YEAR);
+		ops->writebyte(tm->tm_wday, M48T86_REG_DOW);
+	} else {
+		/* bcd mode */
+		ops->writebyte(bin2bcd(tm->tm_sec), M48T86_REG_SEC);
+		ops->writebyte(bin2bcd(tm->tm_min), M48T86_REG_MIN);
+		ops->writebyte(bin2bcd(tm->tm_hour), M48T86_REG_HOUR);
+		ops->writebyte(bin2bcd(tm->tm_mday), M48T86_REG_DOM);
+		ops->writebyte(bin2bcd(tm->tm_mon + 1), M48T86_REG_MONTH);
+		ops->writebyte(bin2bcd(tm->tm_year % 100), M48T86_REG_YEAR);
+		ops->writebyte(bin2bcd(tm->tm_wday), M48T86_REG_DOW);
+	}
+
+	/* update ended */
+	reg &= ~M48T86_REG_B_SET;
+	ops->writebyte(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 = dev_get_platdata(&pdev->dev);
+
+	reg = ops->readbyte(M48T86_REG_B);
+
+	seq_printf(seq, "mode\t\t: %s\n",
+		 (reg & M48T86_REG_B_DM) ? "binary" : "bcd");
+
+	reg = ops->readbyte(M48T86_REG_D);
+
+	seq_printf(seq, "battery\t\t: %s\n",
+		 (reg & M48T86_REG_D_VRT) ? "ok" : "exhausted");
+
+	return 0;
+}
+
+static const 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 m48t86_rtc_probe(struct platform_device *dev)
+{
+	unsigned char reg;
+	struct m48t86_ops *ops = dev_get_platdata(&dev->dev);
+	struct rtc_device *rtc;
+
+	rtc = devm_rtc_device_register(&dev->dev, "m48t86",
+				&m48t86_rtc_ops, THIS_MODULE);
+
+	if (IS_ERR(rtc))
+		return PTR_ERR(rtc);
+
+	platform_set_drvdata(dev, rtc);
+
+	/* read battery status */
+	reg = ops->readbyte(M48T86_REG_D);
+	dev_info(&dev->dev, "battery %s\n",
+		(reg & M48T86_REG_D_VRT) ? "ok" : "exhausted");
+
+	return 0;
+}
+
+static struct platform_driver m48t86_rtc_platform_driver = {
+	.driver		= {
+		.name	= "rtc-m48t86",
+	},
+	.probe		= m48t86_rtc_probe,
+};
+
+module_platform_driver(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_ALIAS("platform:rtc-m48t86");