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>

3 files changed, 233 insertions, 0 deletions

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index bcd18765a4ad..6210280135c8 100644
--- 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 ca9166d319b8..3109af9a1651 100644
--- 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
index 000000000000..83efb88f8f23
--- /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);