RTC driver for DS1216 chips

RTC driver for Dallas/Maxim DS126 chips used in SNI RM200/RM400

[akpm@linux-foundation.org: cleanups]
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index bcd18765a4add3c03871777333b9c7a731bfb6b6..6210280135c88bc2656f566a84085075fd111b4d 100644 (file)
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -280,6 +280,12 @@ config RTC_DRV_CMOS
          This driver can also be built as a module. If so, the module
          will be called rtc-cmos.
 
+config RTC_DRV_DS1216
+       tristate "Dallas DS1216"
+       depends on RTC_CLASS && SNI_RM
+       help
+         If you say yes here you get support for the Dallas DS1216 RTC chips.
+
 config RTC_DRV_DS1553
        tristate "Dallas DS1553"
        depends on RTC_CLASS

diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index ca9166d319b8d9b6ef284e0b39073eb0605afa73..3109af9a16517706750e5b8732ed3333e3aef7c7 100644 (file)
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -44,3 +44,4 @@ obj-$(CONFIG_RTC_DRV_AT91RM9200)+= rtc-at91rm9200.o
 obj-$(CONFIG_RTC_DRV_SH)       += rtc-sh.o
 obj-$(CONFIG_RTC_DRV_BFIN)     += rtc-bfin.o
 obj-$(CONFIG_RTC_DRV_M48T59)   += rtc-m48t59.o
+obj-$(CONFIG_RTC_DRV_DS1216)   += rtc-ds1216.o

diff --git a/drivers/rtc/rtc-ds1216.c b/drivers/rtc/rtc-ds1216.c
new file mode 100644 (file)
index 0000000..83efb88
--- /dev/null
+++ b/drivers/rtc/rtc-ds1216.c
@@ -0,0 +1,226 @@
+/*
+ * Dallas DS1216 RTC driver
+ *
+ * Copyright (c) 2007 Thomas Bogendoerfer
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/rtc.h>
+#include <linux/platform_device.h>
+#include <linux/bcd.h>
+
+#define DRV_VERSION "0.1"
+
+struct ds1216_regs {
+       u8 tsec;
+       u8 sec;
+       u8 min;
+       u8 hour;
+       u8 wday;
+       u8 mday;
+       u8 month;
+       u8 year;
+};
+
+#define DS1216_HOUR_1224       (1 << 7)
+#define DS1216_HOUR_AMPM       (1 << 5)
+
+struct ds1216_priv {
+       struct rtc_device *rtc;
+       void __iomem *ioaddr;
+       size_t size;
+       unsigned long baseaddr;
+};
+
+static const u8 magic[] = {
+       0xc5, 0x3a, 0xa3, 0x5c, 0xc5, 0x3a, 0xa3, 0x5c
+};
+
+/*
+ * Read the 64 bit we'd like to have - It a series
+ * of 64 bits showing up in the LSB of the base register.
+ *
+ */
+static void ds1216_read(u8 __iomem *ioaddr, u8 *buf)
+{
+       unsigned char c;
+       int i, j;
+
+       for (i = 0; i < 8; i++) {
+               c = 0;
+               for (j = 0; j < 8; j++)
+                       c |= (readb(ioaddr) & 0x1) << j;
+               buf[i] = c;
+       }
+}
+
+static void ds1216_write(u8 __iomem *ioaddr, const u8 *buf)
+{
+       unsigned char c;
+       int i, j;
+
+       for (i = 0; i < 8; i++) {
+               c = buf[i];
+               for (j = 0; j < 8; j++) {
+                       writeb(c, ioaddr);
+                       c = c >> 1;
+               }
+       }
+}
+
+static void ds1216_switch_ds_to_clock(u8 __iomem *ioaddr)
+{
+       /* Reset magic pointer */
+       readb(ioaddr);
+       /* Write 64 bit magic to DS1216 */
+       ds1216_write(ioaddr, magic);
+}
+
+static int ds1216_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+       struct platform_device *pdev = to_platform_device(dev);
+       struct ds1216_priv *priv = platform_get_drvdata(pdev);
+       struct ds1216_regs regs;
+
+       ds1216_switch_ds_to_clock(priv->ioaddr);
+       ds1216_read(priv->ioaddr, (u8 *)&regs);
+
+       tm->tm_sec = BCD2BIN(regs.sec);
+       tm->tm_min = BCD2BIN(regs.min);
+       if (regs.hour & DS1216_HOUR_1224) {
+               /* AM/PM mode */
+               tm->tm_hour = BCD2BIN(regs.hour & 0x1f);
+               if (regs.hour & DS1216_HOUR_AMPM)
+                       tm->tm_hour += 12;
+       } else
+               tm->tm_hour = BCD2BIN(regs.hour & 0x3f);
+       tm->tm_wday = (regs.wday & 7) - 1;
+       tm->tm_mday = BCD2BIN(regs.mday & 0x3f);
+       tm->tm_mon = BCD2BIN(regs.month & 0x1f);
+       tm->tm_year = BCD2BIN(regs.year);
+       if (tm->tm_year < 70)
+               tm->tm_year += 100;
+       return 0;
+}
+
+static int ds1216_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+       struct platform_device *pdev = to_platform_device(dev);
+       struct ds1216_priv *priv = platform_get_drvdata(pdev);
+       struct ds1216_regs regs;
+
+       ds1216_switch_ds_to_clock(priv->ioaddr);
+       ds1216_read(priv->ioaddr, (u8 *)&regs);
+
+       regs.tsec = 0; /* clear 0.1 and 0.01 seconds */
+       regs.sec = BIN2BCD(tm->tm_sec);
+       regs.min = BIN2BCD(tm->tm_min);
+       regs.hour &= DS1216_HOUR_1224;
+       if (regs.hour && tm->tm_hour > 12) {
+               regs.hour |= DS1216_HOUR_AMPM;
+               tm->tm_hour -= 12;
+       }
+       regs.hour |= BIN2BCD(tm->tm_hour);
+       regs.wday &= ~7;
+       regs.wday |= tm->tm_wday;
+       regs.mday = BIN2BCD(tm->tm_mday);
+       regs.month = BIN2BCD(tm->tm_mon);
+       regs.year = BIN2BCD(tm->tm_year % 100);
+
+       ds1216_switch_ds_to_clock(priv->ioaddr);
+       ds1216_write(priv->ioaddr, (u8 *)&regs);
+       return 0;
+}
+
+static const struct rtc_class_ops ds1216_rtc_ops = {
+       .read_time      = ds1216_rtc_read_time,
+       .set_time       = ds1216_rtc_set_time,
+};
+
+static int __devinit ds1216_rtc_probe(struct platform_device *pdev)
+{
+       struct rtc_device *rtc;
+       struct resource *res;
+       struct ds1216_priv *priv;
+       int ret = 0;
+       u8 dummy[8];
+
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       if (!res)
+               return -ENODEV;
+       priv = kzalloc(sizeof *priv, GFP_KERNEL);
+       if (!priv)
+               return -ENOMEM;
+       priv->size = res->end - res->start + 1;
+       if (!request_mem_region(res->start, priv->size, pdev->name)) {
+               ret = -EBUSY;
+               goto out;
+       }
+       priv->baseaddr = res->start;
+       priv->ioaddr = ioremap(priv->baseaddr, priv->size);
+       if (!priv->ioaddr) {
+               ret = -ENOMEM;
+               goto out;
+       }
+       rtc = rtc_device_register("ds1216", &pdev->dev,
+                                 &ds1216_rtc_ops, THIS_MODULE);
+       if (IS_ERR(rtc)) {
+               ret = PTR_ERR(rtc);
+               goto out;
+       }
+       priv->rtc = rtc;
+       platform_set_drvdata(pdev, priv);
+
+       /* dummy read to get clock into a known state */
+       ds1216_read(priv->ioaddr, dummy);
+       return 0;
+
+out:
+       if (priv->rtc)
+               rtc_device_unregister(priv->rtc);
+       if (priv->ioaddr)
+               iounmap(priv->ioaddr);
+       if (priv->baseaddr)
+               release_mem_region(priv->baseaddr, priv->size);
+       kfree(priv);
+       return ret;
+}
+
+static int __devexit ds1216_rtc_remove(struct platform_device *pdev)
+{
+       struct ds1216_priv *priv = platform_get_drvdata(pdev);
+
+       rtc_device_unregister(priv->rtc);
+       iounmap(priv->ioaddr);
+       release_mem_region(priv->baseaddr, priv->size);
+       kfree(priv);
+       return 0;
+}
+
+static struct platform_driver ds1216_rtc_platform_driver = {
+       .driver         = {
+               .name   = "rtc-ds1216",
+               .owner  = THIS_MODULE,
+       },
+       .probe          = ds1216_rtc_probe,
+       .remove         = __devexit_p(ds1216_rtc_remove),
+};
+
+static int __init ds1216_rtc_init(void)
+{
+       return platform_driver_register(&ds1216_rtc_platform_driver);
+}
+
+static void __exit ds1216_rtc_exit(void)
+{
+       platform_driver_unregister(&ds1216_rtc_platform_driver);
+}
+
+MODULE_AUTHOR("Thomas Bogendoerfer <tsbogend@alpha.franken.de>");
+MODULE_DESCRIPTION("DS1216 RTC driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_VERSION);
+
+module_init(ds1216_rtc_init);
+module_exit(ds1216_rtc_exit);