rtc: driver for Marvell's SoCs 88F6281 and 88F6192

Driver for the on-chip RTC found in some of Marvell's SoCs such as the
Kirkwood 88F6281 and 88F6192 devices.

Signed-off-by: Saeed Bishara <saeed@marvell.com>
Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>
Signed-off-by: Nicolas Pitre <nico@marvell.com>
Signed-off-by: Alessandro Zummo <a.zummo@towertech.it>
Cc: David Brownell <david-b@pacbell.net>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 175 insertions, 0 deletions

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index e374bf03e4f..4ad831de41a 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -712,4 +712,15 @@ config RTC_DRV_TX4939
           Driver for the internal RTC (Realtime Clock) module found on
           Toshiba TX4939 SoC.
 
+config RTC_DRV_MV
+        tristate "Marvell SoC RTC"
+        depends on ARCH_KIRKWOOD
+        help
+          If you say yes here you will get support for the in-chip RTC
+          that can be found in some of Marvell's SoC devices, such as
+          the Kirkwood 88F6281 and 88F6192.
+
+          This driver can also be built as a module. If so, the module
+          will be called rtc-mv.
+
 endif # RTC_CLASS
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index b651fdd4881..9a4340d48f2 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -48,6 +48,7 @@ obj-$(CONFIG_RTC_DRV_SUN4V)	+= rtc-sun4v.o
 obj-$(CONFIG_RTC_DRV_STARFIRE)  += rtc-starfire.o
 obj-$(CONFIG_RTC_DRV_MAX6900)   += rtc-max6900.o
 obj-$(CONFIG_RTC_DRV_MAX6902)   += rtc-max6902.o
+obj-$(CONFIG_RTC_DRV_MV)        += rtc-mv.o
 obj-$(CONFIG_RTC_DRV_OMAP)      += rtc-omap.o
 obj-$(CONFIG_RTC_DRV_PCF8563)   += rtc-pcf8563.o
 obj-$(CONFIG_RTC_DRV_PCF8583)   += rtc-pcf8583.o
diff --git a/drivers/rtc/rtc-mv.c b/drivers/rtc/rtc-mv.c
new file mode 100644
index 00000000000..45f12dcd371
--- /dev/null
+++ b/drivers/rtc/rtc-mv.c
@@ -0,0 +1,163 @@
+/*
+ * Driver for the RTC in Marvell SoCs.
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2.  This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/rtc.h>
+#include <linux/bcd.h>
+#include <linux/io.h>
+#include <linux/platform_device.h>
+
+
+#define RTC_TIME_REG_OFFS       0
+#define RTC_SECONDS_OFFS        0
+#define RTC_MINUTES_OFFS        8
+#define RTC_HOURS_OFFS          16
+#define RTC_WDAY_OFFS           24
+#define RTC_HOURS_12H_MODE              (1 << 22) /* 12 hours mode */
+
+#define RTC_DATE_REG_OFFS       4
+#define RTC_MDAY_OFFS           0
+#define RTC_MONTH_OFFS          8
+#define RTC_YEAR_OFFS           16
+
+
+struct rtc_plat_data {
+        struct rtc_device *rtc;
+        void __iomem *ioaddr;
+};
+
+static int mv_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+        struct rtc_plat_data *pdata = dev_get_drvdata(dev);
+        void __iomem *ioaddr = pdata->ioaddr;
+        u32     rtc_reg;
+
+        rtc_reg = (bin2bcd(tm->tm_sec) << RTC_SECONDS_OFFS) |
+                (bin2bcd(tm->tm_min) << RTC_MINUTES_OFFS) |
+                (bin2bcd(tm->tm_hour) << RTC_HOURS_OFFS) |
+                (bin2bcd(tm->tm_wday) << RTC_WDAY_OFFS);
+        writel(rtc_reg, ioaddr + RTC_TIME_REG_OFFS);
+
+        rtc_reg = (bin2bcd(tm->tm_mday) << RTC_MDAY_OFFS) |
+                (bin2bcd(tm->tm_mon + 1) << RTC_MONTH_OFFS) |
+                (bin2bcd(tm->tm_year % 100) << RTC_YEAR_OFFS);
+        writel(rtc_reg, ioaddr + RTC_DATE_REG_OFFS);
+
+        return 0;
+}
+
+static int mv_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+        struct rtc_plat_data *pdata = dev_get_drvdata(dev);
+        void __iomem *ioaddr = pdata->ioaddr;
+        u32     rtc_time, rtc_date;
+        unsigned int year, month, day, hour, minute, second, wday;
+
+        rtc_time = readl(ioaddr + RTC_TIME_REG_OFFS);
+        rtc_date = readl(ioaddr + RTC_DATE_REG_OFFS);
+
+        second = rtc_time & 0x7f;
+        minute = (rtc_time >> RTC_MINUTES_OFFS) & 0x7f;
+        hour = (rtc_time >> RTC_HOURS_OFFS) & 0x3f; /* assume 24 hours mode */
+        wday = (rtc_time >> RTC_WDAY_OFFS) & 0x7;
+
+        day = rtc_date & 0x3f;
+        month = (rtc_date >> RTC_MONTH_OFFS) & 0x3f;
+        year = (rtc_date >> RTC_YEAR_OFFS) & 0xff;
+
+        tm->tm_sec = bcd2bin(second);
+        tm->tm_min = bcd2bin(minute);
+        tm->tm_hour = bcd2bin(hour);
+        tm->tm_mday = bcd2bin(day);
+        tm->tm_wday = bcd2bin(wday);
+        tm->tm_mon = bcd2bin(month) - 1;
+        /* hw counts from year 2000, but tm_year is relative to 1900 */
+        tm->tm_year = bcd2bin(year) + 100;
+
+        return rtc_valid_tm(tm);
+}
+
+static const struct rtc_class_ops mv_rtc_ops = {
+        .read_time      = mv_rtc_read_time,
+        .set_time       = mv_rtc_set_time,
+};
+
+static int __init mv_rtc_probe(struct platform_device *pdev)
+{
+        struct resource *res;
+        struct rtc_plat_data *pdata;
+        resource_size_t size;
+        u32 rtc_time;
+
+        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        if (!res)
+                return -ENODEV;
+
+        pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
+        if (!pdata)
+                return -ENOMEM;
+
+        size = resource_size(res);
+        if (!devm_request_mem_region(&pdev->dev, res->start, size,
+                                     pdev->name))
+                return -EBUSY;
+
+        pdata->ioaddr = devm_ioremap(&pdev->dev, res->start, size);
+        if (!pdata->ioaddr)
+                return -ENOMEM;
+
+        /* make sure the 24 hours mode is enabled */
+        rtc_time = readl(pdata->ioaddr + RTC_TIME_REG_OFFS);
+        if (rtc_time & RTC_HOURS_12H_MODE) {
+                dev_err(&pdev->dev, "24 Hours mode not supported.\n");
+                return -EINVAL;
+        }
+
+        platform_set_drvdata(pdev, pdata);
+        pdata->rtc = rtc_device_register(pdev->name, &pdev->dev,
+                                         &mv_rtc_ops, THIS_MODULE);
+        if (IS_ERR(pdata->rtc))
+                return PTR_ERR(pdata->rtc);
+
+        return 0;
+}
+
+static int __exit mv_rtc_remove(struct platform_device *pdev)
+{
+        struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
+
+        rtc_device_unregister(pdata->rtc);
+        return 0;
+}
+
+static struct platform_driver mv_rtc_driver = {
+        .remove         = __exit_p(mv_rtc_remove),
+        .driver         = {
+                .name   = "rtc-mv",
+                .owner  = THIS_MODULE,
+        },
+};
+
+static __init int mv_init(void)
+{
+        return platform_driver_probe(&mv_rtc_driver, mv_rtc_probe);
+}
+
+static __exit void mv_exit(void)
+{
+        platform_driver_unregister(&mv_rtc_driver);
+}
+
+module_init(mv_init);
+module_exit(mv_exit);
+
+MODULE_AUTHOR("Saeed Bishara <saeed@marvell.com>");
+MODULE_DESCRIPTION("Marvell RTC driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:rtc-mv");