[PATCH] Add driver for ARM AMBA PL031 RTC

Add a driver for the ARM PL031 RTC found on some ARM SOCs.  The driver is
fairly trivial as the RTC only provides a read/write and alarm capability.

[akpm@osdl.org: compile fix]
Signed-off-by: Deepak <dsaxena@plexity.net>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 233 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-pl031.c b/drivers/rtc/rtc-pl031.c
new file mode 100644
index 000000000000..ee538632660b
--- /dev/null
+++ b/drivers/rtc/rtc-pl031.c
@@ -0,0 +1,233 @@
+/*
+ * drivers/rtc/rtc-pl031.c
+ *
+ * Real Time Clock interface for ARM AMBA PrimeCell 031 RTC
+ *
+ * Author: Deepak Saxena <dsaxena@plexity.net>
+ *
+ * Copyright 2006 (c) MontaVista Software, Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/rtc.h>
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/interrupt.h>
+#include <linux/string.h>
+#include <linux/pm.h>
+
+#include <linux/amba/bus.h>
+
+#include <asm/io.h>
+#include <asm/bitops.h>
+#include <asm/hardware.h>
+#include <asm/irq.h>
+#include <asm/rtc.h>
+
+/*
+ * Register definitions
+ */
+#define RTC_DR          0x00    /* Data read register */
+#define RTC_MR          0x04    /* Match register */
+#define RTC_LR          0x08    /* Data load register */
+#define RTC_CR          0x0c    /* Control register */
+#define RTC_IMSC        0x10    /* Interrupt mask and set register */
+#define RTC_RIS         0x14    /* Raw interrupt status register */
+#define RTC_MIS         0x18    /* Masked interrupt status register */
+#define RTC_ICR         0x1c    /* Interrupt clear register */
+
+struct pl031_local {
+        struct rtc_device *rtc;
+        void __iomem *base;
+};
+
+static irqreturn_t pl031_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+{
+        struct rtc_device *rtc = dev_id;
+
+        rtc_update_irq(&rtc->class_dev, 1, RTC_AF);
+
+        return IRQ_HANDLED;
+}
+
+static int pl031_open(struct device *dev)
+{
+        /*
+         * We request IRQ in pl031_probe, so nothing to do here...
+         */
+        return 0;
+}
+
+static void pl031_release(struct device *dev)
+{
+}
+
+static int pl031_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
+{
+        struct pl031_local *ldata = dev_get_drvdata(dev);
+
+        switch (cmd) {
+        case RTC_AIE_OFF:
+                __raw_writel(1, ldata->base + RTC_MIS);
+                return 0;
+        case RTC_AIE_ON:
+                __raw_writel(0, ldata->base + RTC_MIS);
+                return 0;
+        }
+
+        return -ENOIOCTLCMD;
+}
+
+static int pl031_read_time(struct device *dev, struct rtc_time *tm)
+{
+        struct pl031_local *ldata = dev_get_drvdata(dev);
+
+        rtc_time_to_tm(__raw_readl(ldata->base + RTC_DR), tm);
+
+        return 0;
+}
+
+static int pl031_set_time(struct device *dev, struct rtc_time *tm)
+{
+        unsigned long time;
+        struct pl031_local *ldata = dev_get_drvdata(dev);
+
+        rtc_tm_to_time(tm, &time);
+        __raw_writel(time, ldata->base + RTC_LR);
+
+        return 0;
+}
+
+static int pl031_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
+{
+        struct pl031_local *ldata = dev_get_drvdata(dev);
+
+        rtc_time_to_tm(__raw_readl(ldata->base + RTC_MR), &alarm->time);
+        alarm->pending = __raw_readl(ldata->base + RTC_RIS);
+        alarm->enabled = __raw_readl(ldata->base + RTC_IMSC);
+
+        return 0;
+}
+
+static int pl031_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
+{
+        struct pl031_local *ldata = dev_get_drvdata(dev);
+        unsigned long time;
+
+        rtc_tm_to_time(&alarm->time, &time);
+
+        __raw_writel(time, ldata->base + RTC_MR);
+        __raw_writel(!alarm->enabled, ldata->base + RTC_MIS);
+
+        return 0;
+}
+
+static struct rtc_class_ops pl031_ops = {
+        .open = pl031_open,
+        .release = pl031_release,
+        .ioctl = pl031_ioctl,
+        .read_time = pl031_read_time,
+        .set_time = pl031_set_time,
+        .read_alarm = pl031_read_alarm,
+        .set_alarm = pl031_set_alarm,
+};
+
+static int pl031_remove(struct amba_device *adev)
+{
+        struct pl031_local *ldata = dev_get_drvdata(&adev->dev);
+
+        if (ldata) {
+                dev_set_drvdata(&adev->dev, NULL);
+                free_irq(adev->irq[0], ldata->rtc);
+                rtc_device_unregister(ldata->rtc);
+                iounmap(ldata->base);
+                kfree(ldata);
+        }
+
+        return 0;
+}
+
+static int pl031_probe(struct amba_device *adev, void *id)
+{
+        int ret;
+        struct pl031_local *ldata;
+
+
+        ldata = kmalloc(sizeof(struct pl031_local), GFP_KERNEL);
+        if (!ldata) {
+                ret = -ENOMEM;
+                goto out;
+        }
+        dev_set_drvdata(&adev->dev, ldata);
+
+        ldata->base = ioremap(adev->res.start,
+                              adev->res.end - adev->res.start + 1);
+        if (!ldata->base) {
+                ret = -ENOMEM;
+                goto out_no_remap;
+        }
+
+        if (request_irq(adev->irq[0], pl031_interrupt, SA_INTERRUPT,
+                        "rtc-pl031", ldata->rtc)) {
+                ret = -EIO;
+                goto out_no_irq;
+        }
+
+        ldata->rtc = rtc_device_register("pl031", &adev->dev, &pl031_ops,
+                                         THIS_MODULE);
+        if (IS_ERR(ldata->rtc)) {
+                ret = PTR_ERR(ldata->rtc);
+                goto out_no_rtc;
+        }
+
+        return 0;
+
+out_no_rtc:
+        free_irq(adev->irq[0], ldata->rtc);
+out_no_irq:
+        iounmap(ldata->base);
+out_no_remap:
+        dev_set_drvdata(&adev->dev, NULL);
+        kfree(ldata);
+out:
+        return ret;
+}
+
+static struct amba_id pl031_ids[] __initdata = {
+        {
+                 .id = 0x00041031,
+                .mask = 0x000fffff, },
+        {0, 0},
+};
+
+static struct amba_driver pl031_driver = {
+        .drv = {
+                .name = "rtc-pl031",
+        },
+        .id_table = pl031_ids,
+        .probe = pl031_probe,
+        .remove = pl031_remove,
+};
+
+static int __init pl031_init(void)
+{
+        return amba_driver_register(&pl031_driver);
+}
+
+static void __exit pl031_exit(void)
+{
+        amba_driver_unregister(&pl031_driver);
+}
+
+module_init(pl031_init);
+module_exit(pl031_exit);
+
+MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net");
+MODULE_DESCRIPTION("ARM AMBA PL031 RTC Driver");
+MODULE_LICENSE("GPL");