[PATCH] RTC subsystem: M48T86 driver
authorAlessandro Zummo <a.zummo@towertech.it>
Mon, 27 Mar 2006 09:16:47 +0000 (01:16 -0800)
committerLinus Torvalds <torvalds@g5.osdl.org>
Mon, 27 Mar 2006 16:44:52 +0000 (08:44 -0800)
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>
drivers/rtc/Kconfig
drivers/rtc/Makefile
drivers/rtc/rtc-m48t86.c [new file with mode: 0644]
include/linux/m48t86.h [new file with mode: 0644]

index 166232a3f56bf18cf9287d9057a04f1f91ab46a2..929dd8090578b07213ddb22733d585ab0f2d0668 100644 (file)
@@ -117,6 +117,16 @@ config RTC_DRV_RS5C372
          This driver can also be built as a module. If so, the module
          will be called rtc-rs5c372.
 
+config RTC_DRV_M48T86
+       tristate "ST M48T86/Dallas DS12887"
+       depends on RTC_CLASS
+       help
+         If you say Y here you will get support for the
+         ST M48T86 and Dallas DS12887 RTC chips.
+
+         This driver can also be built as a module. If so, the module
+         will be called rtc-m48t86.
+
 config RTC_DRV_EP93XX
        tristate "Cirrus Logic EP93XX"
        depends on RTC_CLASS && ARCH_EP93XX
index 56820d18161e275921582b0a9cb808f04d3f40a9..8d4c7fe88d58538bf66f3af267542e62cd889725 100644 (file)
@@ -16,5 +16,6 @@ obj-$(CONFIG_RTC_DRV_TEST)    += rtc-test.o
 obj-$(CONFIG_RTC_DRV_DS1672)   += rtc-ds1672.o
 obj-$(CONFIG_RTC_DRV_PCF8563)  += rtc-pcf8563.o
 obj-$(CONFIG_RTC_DRV_RS5C372)  += rtc-rs5c372.o
+obj-$(CONFIG_RTC_DRV_M48T86)   += rtc-m48t86.o
 obj-$(CONFIG_RTC_DRV_EP93XX)   += rtc-ep93xx.o
 obj-$(CONFIG_RTC_DRV_SA1100)   += rtc-sa1100.o
diff --git a/drivers/rtc/rtc-m48t86.c b/drivers/rtc/rtc-m48t86.c
new file mode 100644 (file)
index 0000000..db445c8
--- /dev/null
@@ -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);
diff --git a/include/linux/m48t86.h b/include/linux/m48t86.h
new file mode 100644 (file)
index 0000000..9065199
--- /dev/null
@@ -0,0 +1,16 @@
+/*
+ * 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.
+*/
+
+struct m48t86_ops
+{
+       void (*writeb)(unsigned char value, unsigned long addr);
+       unsigned char (*readb)(unsigned long addr);
+};