rtc: Add MPC5121 Real time clock driver

Add support for MPC5121 real time clock module.

Signed-off-by: John Rigby <jcrigby@gmail.com>
Signed-off-by: Piotr Ziecik <kosmo@semihalf.com>
Signed-off-by: Wolfgang Denk <wd@denx.de>
Signed-off-by: Anatolij Gustschin <agust@denx.de>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

3 files changed, 398 insertions, 0 deletions

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 8167e9e6827a..2bb8a8b7ffaf 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -868,4 +868,14 @@ config RTC_DRV_MC13783
         help
           This enables support for the Freescale MC13783 PMIC RTC
 
+config RTC_DRV_MPC5121
+        tristate "Freescale MPC5121 built-in RTC"
+        depends on PPC_MPC512x && RTC_CLASS
+        help
+          If you say yes here you will get support for the
+          built-in RTC MPC5121.
+
+          This driver can also be built as a module. If so, the module
+          will be called rtc-mpc5121.
+
 endif # RTC_CLASS
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index e5160fddc446..b7148afb8f55 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -55,6 +55,7 @@ obj-$(CONFIG_RTC_DRV_MAX6900)	+= rtc-max6900.o
 obj-$(CONFIG_RTC_DRV_MAX6902)   += rtc-max6902.o
 obj-$(CONFIG_RTC_DRV_MC13783)   += rtc-mc13783.o
 obj-$(CONFIG_RTC_DRV_MSM6242)   += rtc-msm6242.o
+obj-$(CONFIG_RTC_DRV_MPC5121)   += rtc-mpc5121.o
 obj-$(CONFIG_RTC_DRV_MV)        += rtc-mv.o
 obj-$(CONFIG_RTC_DRV_NUC900)    += rtc-nuc900.o
 obj-$(CONFIG_RTC_DRV_OMAP)      += rtc-omap.o
diff --git a/drivers/rtc/rtc-mpc5121.c b/drivers/rtc/rtc-mpc5121.c
new file mode 100644
index 000000000000..4313ca03a96d
--- /dev/null
+++ b/drivers/rtc/rtc-mpc5121.c
@@ -0,0 +1,387 @@
+/*
+ * Real-time clock driver for MPC5121
+ *
+ * Copyright 2007, Domen Puncer <domen.puncer@telargo.com>
+ * Copyright 2008, Freescale Semiconductor, Inc. All rights reserved.
+ *
+ * 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.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/rtc.h>
+#include <linux/of_device.h>
+#include <linux/of_platform.h>
+#include <linux/io.h>
+
+struct mpc5121_rtc_regs {
+        u8 set_time;            /* RTC + 0x00 */
+        u8 hour_set;            /* RTC + 0x01 */
+        u8 minute_set;          /* RTC + 0x02 */
+        u8 second_set;          /* RTC + 0x03 */
+
+        u8 set_date;            /* RTC + 0x04 */
+        u8 month_set;           /* RTC + 0x05 */
+        u8 weekday_set;         /* RTC + 0x06 */
+        u8 date_set;            /* RTC + 0x07 */
+
+        u8 write_sw;            /* RTC + 0x08 */
+        u8 sw_set;              /* RTC + 0x09 */
+        u16 year_set;           /* RTC + 0x0a */
+
+        u8 alm_enable;          /* RTC + 0x0c */
+        u8 alm_hour_set;        /* RTC + 0x0d */
+        u8 alm_min_set;         /* RTC + 0x0e */
+        u8 int_enable;          /* RTC + 0x0f */
+
+        u8 reserved1;
+        u8 hour;                /* RTC + 0x11 */
+        u8 minute;              /* RTC + 0x12 */
+        u8 second;              /* RTC + 0x13 */
+
+        u8 month;               /* RTC + 0x14 */
+        u8 wday_mday;           /* RTC + 0x15 */
+        u16 year;               /* RTC + 0x16 */
+
+        u8 int_alm;             /* RTC + 0x18 */
+        u8 int_sw;              /* RTC + 0x19 */
+        u8 alm_status;          /* RTC + 0x1a */
+        u8 sw_minute;           /* RTC + 0x1b */
+
+        u8 bus_error_1;         /* RTC + 0x1c */
+        u8 int_day;             /* RTC + 0x1d */
+        u8 int_min;             /* RTC + 0x1e */
+        u8 int_sec;             /* RTC + 0x1f */
+
+        /*
+         * target_time:
+         *      intended to be used for hibernation but hibernation
+         *      does not work on silicon rev 1.5 so use it for non-volatile
+         *      storage of offset between the actual_time register and linux
+         *      time
+         */
+        u32 target_time;        /* RTC + 0x20 */
+        /*
+         * actual_time:
+         *      readonly time since VBAT_RTC was last connected
+         */
+        u32 actual_time;        /* RTC + 0x24 */
+        u32 keep_alive;         /* RTC + 0x28 */
+};
+
+struct mpc5121_rtc_data {
+        unsigned irq;
+        unsigned irq_periodic;
+        struct mpc5121_rtc_regs __iomem *regs;
+        struct rtc_device *rtc;
+        struct rtc_wkalrm wkalarm;
+};
+
+/*
+ * Update second/minute/hour registers.
+ *
+ * This is just so alarm will work.
+ */
+static void mpc5121_rtc_update_smh(struct mpc5121_rtc_regs __iomem *regs,
+                                   struct rtc_time *tm)
+{
+        out_8(&regs->second_set, tm->tm_sec);
+        out_8(&regs->minute_set, tm->tm_min);
+        out_8(&regs->hour_set, tm->tm_hour);
+
+        /* set time sequence */
+        out_8(&regs->set_time, 0x1);
+        out_8(&regs->set_time, 0x3);
+        out_8(&regs->set_time, 0x1);
+        out_8(&regs->set_time, 0x0);
+}
+
+static int mpc5121_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+        struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
+        struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
+        unsigned long now;
+
+        /*
+         * linux time is actual_time plus the offset saved in target_time
+         */
+        now = in_be32(&regs->actual_time) + in_be32(&regs->target_time);
+
+        rtc_time_to_tm(now, tm);
+
+        /*
+         * update second minute hour registers
+         * so alarms will work
+         */
+        mpc5121_rtc_update_smh(regs, tm);
+
+        return rtc_valid_tm(tm);
+}
+
+static int mpc5121_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+        struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
+        struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
+        int ret;
+        unsigned long now;
+
+        /*
+         * The actual_time register is read only so we write the offset
+         * between it and linux time to the target_time register.
+         */
+        ret = rtc_tm_to_time(tm, &now);
+        if (ret == 0)
+                out_be32(&regs->target_time, now - in_be32(&regs->actual_time));
+
+        /*
+         * update second minute hour registers
+         * so alarms will work
+         */
+        mpc5121_rtc_update_smh(regs, tm);
+
+        return 0;
+}
+
+static int mpc5121_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
+{
+        struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
+        struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
+
+        *alarm = rtc->wkalarm;
+
+        alarm->pending = in_8(&regs->alm_status);
+
+        return 0;
+}
+
+static int mpc5121_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
+{
+        struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
+        struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
+
+        /*
+         * the alarm has no seconds so deal with it
+         */
+        if (alarm->time.tm_sec) {
+                alarm->time.tm_sec = 0;
+                alarm->time.tm_min++;
+                if (alarm->time.tm_min >= 60) {
+                        alarm->time.tm_min = 0;
+                        alarm->time.tm_hour++;
+                        if (alarm->time.tm_hour >= 24)
+                                alarm->time.tm_hour = 0;
+                }
+        }
+
+        alarm->time.tm_mday = -1;
+        alarm->time.tm_mon = -1;
+        alarm->time.tm_year = -1;
+
+        out_8(&regs->alm_min_set, alarm->time.tm_min);
+        out_8(&regs->alm_hour_set, alarm->time.tm_hour);
+
+        out_8(&regs->alm_enable, alarm->enabled);
+
+        rtc->wkalarm = *alarm;
+        return 0;
+}
+
+static irqreturn_t mpc5121_rtc_handler(int irq, void *dev)
+{
+        struct mpc5121_rtc_data *rtc = dev_get_drvdata((struct device *)dev);
+        struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
+
+        if (in_8(&regs->int_alm)) {
+                /* acknowledge and clear status */
+                out_8(&regs->int_alm, 1);
+                out_8(&regs->alm_status, 1);
+
+                rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_AF);
+                return IRQ_HANDLED;
+        }
+
+        return IRQ_NONE;
+}
+
+static irqreturn_t mpc5121_rtc_handler_upd(int irq, void *dev)
+{
+        struct mpc5121_rtc_data *rtc = dev_get_drvdata((struct device *)dev);
+        struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
+
+        if (in_8(&regs->int_sec) && (in_8(&regs->int_enable) & 0x1)) {
+                /* acknowledge */
+                out_8(&regs->int_sec, 1);
+
+                rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_UF);
+                return IRQ_HANDLED;
+        }
+
+        return IRQ_NONE;
+}
+
+static int mpc5121_rtc_alarm_irq_enable(struct device *dev,
+                                        unsigned int enabled)
+{
+        struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
+        struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
+        int val;
+
+        if (enabled)
+                val = 1;
+        else
+                val = 0;
+
+        out_8(&regs->alm_enable, val);
+        rtc->wkalarm.enabled = val;
+
+        return 0;
+}
+
+static int mpc5121_rtc_update_irq_enable(struct device *dev,
+                                         unsigned int enabled)
+{
+        struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
+        struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
+        int val;
+
+        val = in_8(&regs->int_enable);
+
+        if (enabled)
+                val = (val & ~0x8) | 0x1;
+        else
+                val &= ~0x1;
+
+        out_8(&regs->int_enable, val);
+
+        return 0;
+}
+
+static const struct rtc_class_ops mpc5121_rtc_ops = {
+        .read_time = mpc5121_rtc_read_time,
+        .set_time = mpc5121_rtc_set_time,
+        .read_alarm = mpc5121_rtc_read_alarm,
+        .set_alarm = mpc5121_rtc_set_alarm,
+        .alarm_irq_enable = mpc5121_rtc_alarm_irq_enable,
+        .update_irq_enable = mpc5121_rtc_update_irq_enable,
+};
+
+static int __devinit mpc5121_rtc_probe(struct of_device *op,
+                                        const struct of_device_id *match)
+{
+        struct mpc5121_rtc_data *rtc;
+        int err = 0;
+        u32 ka;
+
+        rtc = kzalloc(sizeof(*rtc), GFP_KERNEL);
+        if (!rtc)
+                return -ENOMEM;
+
+        rtc->regs = of_iomap(op->node, 0);
+        if (!rtc->regs) {
+                dev_err(&op->dev, "%s: couldn't map io space\n", __func__);
+                err = -ENOSYS;
+                goto out_free;
+        }
+
+        device_init_wakeup(&op->dev, 1);
+
+        dev_set_drvdata(&op->dev, rtc);
+
+        rtc->irq = irq_of_parse_and_map(op->node, 1);
+        err = request_irq(rtc->irq, mpc5121_rtc_handler, IRQF_DISABLED,
+                                                "mpc5121-rtc", &op->dev);
+        if (err) {
+                dev_err(&op->dev, "%s: could not request irq: %i\n",
+                                                        __func__, rtc->irq);
+                goto out_dispose;
+        }
+
+        rtc->irq_periodic = irq_of_parse_and_map(op->node, 0);
+        err = request_irq(rtc->irq_periodic, mpc5121_rtc_handler_upd,
+                                IRQF_DISABLED, "mpc5121-rtc_upd", &op->dev);
+        if (err) {
+                dev_err(&op->dev, "%s: could not request irq: %i\n",
+                                                __func__, rtc->irq_periodic);
+                goto out_dispose2;
+        }
+
+        ka = in_be32(&rtc->regs->keep_alive);
+        if (ka & 0x02) {
+                dev_warn(&op->dev,
+                        "mpc5121-rtc: Battery or oscillator failure!\n");
+                out_be32(&rtc->regs->keep_alive, ka);
+        }
+
+        rtc->rtc = rtc_device_register("mpc5121-rtc", &op->dev,
+                                        &mpc5121_rtc_ops, THIS_MODULE);
+        if (IS_ERR(rtc->rtc)) {
+                err = PTR_ERR(rtc->rtc);
+                goto out_free_irq;
+        }
+
+        return 0;
+
+out_free_irq:
+        free_irq(rtc->irq_periodic, &op->dev);
+out_dispose2:
+        irq_dispose_mapping(rtc->irq_periodic);
+        free_irq(rtc->irq, &op->dev);
+out_dispose:
+        irq_dispose_mapping(rtc->irq);
+        iounmap(rtc->regs);
+out_free:
+        kfree(rtc);
+
+        return err;
+}
+
+static int __devexit mpc5121_rtc_remove(struct of_device *op)
+{
+        struct mpc5121_rtc_data *rtc = dev_get_drvdata(&op->dev);
+        struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
+
+        /* disable interrupt, so there are no nasty surprises */
+        out_8(&regs->alm_enable, 0);
+        out_8(&regs->int_enable, in_8(&regs->int_enable) & ~0x1);
+
+        rtc_device_unregister(rtc->rtc);
+        iounmap(rtc->regs);
+        free_irq(rtc->irq, &op->dev);
+        free_irq(rtc->irq_periodic, &op->dev);
+        irq_dispose_mapping(rtc->irq);
+        irq_dispose_mapping(rtc->irq_periodic);
+        dev_set_drvdata(&op->dev, NULL);
+        kfree(rtc);
+
+        return 0;
+}
+
+static struct of_device_id mpc5121_rtc_match[] __devinitdata = {
+        { .compatible = "fsl,mpc5121-rtc", },
+        {},
+};
+
+static struct of_platform_driver mpc5121_rtc_driver = {
+        .owner = THIS_MODULE,
+        .name = "mpc5121-rtc",
+        .match_table = mpc5121_rtc_match,
+        .probe = mpc5121_rtc_probe,
+        .remove = __devexit_p(mpc5121_rtc_remove),
+};
+
+static int __init mpc5121_rtc_init(void)
+{
+        return of_register_platform_driver(&mpc5121_rtc_driver);
+}
+module_init(mpc5121_rtc_init);
+
+static void __exit mpc5121_rtc_exit(void)
+{
+        of_unregister_platform_driver(&mpc5121_rtc_driver);
+}
+module_exit(mpc5121_rtc_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("John Rigby <jcrigby@gmail.com>");