[PATCH] RTC: class driver for Samsung S3C series SoC

This is a renamed and tested version of the previous S3C24XX RTC class
driver.

The driver has been renamed from the original s3c2410-rtc, which is now too
narrow for the range of devices supported.

The rtc-s3c has been chosen as there is the distinct possibility of this
driver being carried forward into newer Samsung SoC silicon.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Cc: 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, 607 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-s3c.c b/drivers/rtc/rtc-s3c.c
new file mode 100644
index 000000000000..d6d1bff52b8e
--- /dev/null
+++ b/drivers/rtc/rtc-s3c.c
@@ -0,0 +1,607 @@
+/* drivers/rtc/rtc-s3c.c
+ *
+ * Copyright (c) 2004,2006 Simtec Electronics
+ *      Ben Dooks, <ben@simtec.co.uk>
+ *      http://armlinux.simtec.co.uk/
+ *
+ * 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.
+ *
+ * S3C2410/S3C2440/S3C24XX Internal RTC Driver
+*/
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/string.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/interrupt.h>
+#include <linux/rtc.h>
+#include <linux/bcd.h>
+#include <linux/clk.h>
+
+#include <asm/hardware.h>
+#include <asm/uaccess.h>
+#include <asm/io.h>
+#include <asm/irq.h>
+#include <asm/rtc.h>
+
+#include <asm/mach/time.h>
+
+#include <asm/arch/regs-rtc.h>
+
+/* I have yet to find an S3C implementation with more than one
+ * of these rtc blocks in */
+
+static struct resource *s3c_rtc_mem;
+
+static void __iomem *s3c_rtc_base;
+static int s3c_rtc_alarmno = NO_IRQ;
+static int s3c_rtc_tickno  = NO_IRQ;
+static int s3c_rtc_freq    = 1;
+
+static DEFINE_SPINLOCK(s3c_rtc_pie_lock);
+static unsigned int tick_count;
+
+/* IRQ Handlers */
+
+static irqreturn_t s3c_rtc_alarmirq(int irq, void *id, struct pt_regs *r)
+{
+        struct rtc_device *rdev = id;
+
+        rtc_update_irq(&rdev->class_dev, 1, RTC_AF | RTC_IRQF);
+        return IRQ_HANDLED;
+}
+
+static irqreturn_t s3c_rtc_tickirq(int irq, void *id, struct pt_regs *r)
+{
+        struct rtc_device *rdev = id;
+
+        rtc_update_irq(&rdev->class_dev, tick_count++, RTC_PF | RTC_IRQF);
+        return IRQ_HANDLED;
+}
+
+/* Update control registers */
+static void s3c_rtc_setaie(int to)
+{
+        unsigned int tmp;
+
+        pr_debug("%s: aie=%d\n", __FUNCTION__, to);
+
+        tmp = readb(S3C2410_RTCALM) & ~S3C2410_RTCALM_ALMEN;
+
+        if (to)
+                tmp |= S3C2410_RTCALM_ALMEN;
+
+        writeb(tmp, S3C2410_RTCALM);
+}
+
+static void s3c_rtc_setpie(int to)
+{
+        unsigned int tmp;
+
+        pr_debug("%s: pie=%d\n", __FUNCTION__, to);
+
+        spin_lock_irq(&s3c_rtc_pie_lock);
+        tmp = readb(S3C2410_TICNT) & ~S3C2410_TICNT_ENABLE;
+
+        if (to)
+                tmp |= S3C2410_TICNT_ENABLE;
+
+        writeb(tmp, S3C2410_TICNT);
+        spin_unlock_irq(&s3c_rtc_pie_lock);
+}
+
+static void s3c_rtc_setfreq(int freq)
+{
+        unsigned int tmp;
+
+        spin_lock_irq(&s3c_rtc_pie_lock);
+        tmp = readb(S3C2410_TICNT) & S3C2410_TICNT_ENABLE;
+
+        s3c_rtc_freq = freq;
+
+        tmp |= (128 / freq)-1;
+
+        writeb(tmp, S3C2410_TICNT);
+        spin_unlock_irq(&s3c_rtc_pie_lock);
+}
+
+/* Time read/write */
+
+static int s3c_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
+{
+        unsigned int have_retried = 0;
+
+ retry_get_time:
+        rtc_tm->tm_min  = readb(S3C2410_RTCMIN);
+        rtc_tm->tm_hour = readb(S3C2410_RTCHOUR);
+        rtc_tm->tm_mday = readb(S3C2410_RTCDATE);
+        rtc_tm->tm_mon  = readb(S3C2410_RTCMON);
+        rtc_tm->tm_year = readb(S3C2410_RTCYEAR);
+        rtc_tm->tm_sec  = readb(S3C2410_RTCSEC);
+
+        /* the only way to work out wether the system was mid-update
+         * when we read it is to check the second counter, and if it
+         * is zero, then we re-try the entire read
+         */
+
+        if (rtc_tm->tm_sec == 0 && !have_retried) {
+                have_retried = 1;
+                goto retry_get_time;
+        }
+
+        pr_debug("read time %02x.%02x.%02x %02x/%02x/%02x\n",
+                 rtc_tm->tm_year, rtc_tm->tm_mon, rtc_tm->tm_mday,
+                 rtc_tm->tm_hour, rtc_tm->tm_min, rtc_tm->tm_sec);
+
+        BCD_TO_BIN(rtc_tm->tm_sec);
+        BCD_TO_BIN(rtc_tm->tm_min);
+        BCD_TO_BIN(rtc_tm->tm_hour);
+        BCD_TO_BIN(rtc_tm->tm_mday);
+        BCD_TO_BIN(rtc_tm->tm_mon);
+        BCD_TO_BIN(rtc_tm->tm_year);
+
+        rtc_tm->tm_year += 100;
+        rtc_tm->tm_mon -= 1;
+
+        return 0;
+}
+
+static int s3c_rtc_settime(struct device *dev, struct rtc_time *tm)
+{
+        /* the rtc gets round the y2k problem by just not supporting it */
+
+        if (tm->tm_year < 100)
+                return -EINVAL;
+
+        writeb(BIN2BCD(tm->tm_sec),  S3C2410_RTCSEC);
+        writeb(BIN2BCD(tm->tm_min),  S3C2410_RTCMIN);
+        writeb(BIN2BCD(tm->tm_hour), S3C2410_RTCHOUR);
+        writeb(BIN2BCD(tm->tm_mday), S3C2410_RTCDATE);
+        writeb(BIN2BCD(tm->tm_mon + 1), S3C2410_RTCMON);
+        writeb(BIN2BCD(tm->tm_year - 100), S3C2410_RTCYEAR);
+
+        return 0;
+}
+
+static int s3c_rtc_getalarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+        struct rtc_time *alm_tm = &alrm->time;
+        unsigned int alm_en;
+
+        alm_tm->tm_sec  = readb(S3C2410_ALMSEC);
+        alm_tm->tm_min  = readb(S3C2410_ALMMIN);
+        alm_tm->tm_hour = readb(S3C2410_ALMHOUR);
+        alm_tm->tm_mon  = readb(S3C2410_ALMMON);
+        alm_tm->tm_mday = readb(S3C2410_ALMDATE);
+        alm_tm->tm_year = readb(S3C2410_ALMYEAR);
+
+        alm_en = readb(S3C2410_RTCALM);
+
+        pr_debug("read alarm %02x %02x.%02x.%02x %02x/%02x/%02x\n",
+                 alm_en,
+                 alm_tm->tm_year, alm_tm->tm_mon, alm_tm->tm_mday,
+                 alm_tm->tm_hour, alm_tm->tm_min, alm_tm->tm_sec);
+
+
+        /* decode the alarm enable field */
+
+        if (alm_en & S3C2410_RTCALM_SECEN)
+                BCD_TO_BIN(alm_tm->tm_sec);
+        else
+                alm_tm->tm_sec = 0xff;
+
+        if (alm_en & S3C2410_RTCALM_MINEN)
+                BCD_TO_BIN(alm_tm->tm_min);
+        else
+                alm_tm->tm_min = 0xff;
+
+        if (alm_en & S3C2410_RTCALM_HOUREN)
+                BCD_TO_BIN(alm_tm->tm_hour);
+        else
+                alm_tm->tm_hour = 0xff;
+
+        if (alm_en & S3C2410_RTCALM_DAYEN)
+                BCD_TO_BIN(alm_tm->tm_mday);
+        else
+                alm_tm->tm_mday = 0xff;
+
+        if (alm_en & S3C2410_RTCALM_MONEN) {
+                BCD_TO_BIN(alm_tm->tm_mon);
+                alm_tm->tm_mon -= 1;
+        } else {
+                alm_tm->tm_mon = 0xff;
+        }
+
+        if (alm_en & S3C2410_RTCALM_YEAREN)
+                BCD_TO_BIN(alm_tm->tm_year);
+        else
+                alm_tm->tm_year = 0xffff;
+
+        return 0;
+}
+
+static int s3c_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+        struct rtc_time *tm = &alrm->time;
+        unsigned int alrm_en;
+
+        pr_debug("s3c_rtc_setalarm: %d, %02x/%02x/%02x %02x.%02x.%02x\n",
+                 alrm->enabled,
+                 tm->tm_mday & 0xff, tm->tm_mon & 0xff, tm->tm_year & 0xff,
+                 tm->tm_hour & 0xff, tm->tm_min & 0xff, tm->tm_sec);
+
+
+        alrm_en = readb(S3C2410_RTCALM) & S3C2410_RTCALM_ALMEN;
+        writeb(0x00, S3C2410_RTCALM);
+
+        if (tm->tm_sec < 60 && tm->tm_sec >= 0) {
+                alrm_en |= S3C2410_RTCALM_SECEN;
+                writeb(BIN2BCD(tm->tm_sec), S3C2410_ALMSEC);
+        }
+
+        if (tm->tm_min < 60 && tm->tm_min >= 0) {
+                alrm_en |= S3C2410_RTCALM_MINEN;
+                writeb(BIN2BCD(tm->tm_min), S3C2410_ALMMIN);
+        }
+
+        if (tm->tm_hour < 24 && tm->tm_hour >= 0) {
+                alrm_en |= S3C2410_RTCALM_HOUREN;
+                writeb(BIN2BCD(tm->tm_hour), S3C2410_ALMHOUR);
+        }
+
+        pr_debug("setting S3C2410_RTCALM to %08x\n", alrm_en);
+
+        writeb(alrm_en, S3C2410_RTCALM);
+
+        if (0) {
+                alrm_en = readb(S3C2410_RTCALM);
+                alrm_en &= ~S3C2410_RTCALM_ALMEN;
+                writeb(alrm_en, S3C2410_RTCALM);
+                disable_irq_wake(s3c_rtc_alarmno);
+        }
+
+        if (alrm->enabled)
+                enable_irq_wake(s3c_rtc_alarmno);
+        else
+                disable_irq_wake(s3c_rtc_alarmno);
+
+        return 0;
+}
+
+static int s3c_rtc_ioctl(struct device *dev,
+                         unsigned int cmd, unsigned long arg)
+{
+        unsigned int ret = -ENOIOCTLCMD;
+
+        switch (cmd) {
+        case RTC_AIE_OFF:
+        case RTC_AIE_ON:
+                s3c_rtc_setaie((cmd == RTC_AIE_ON) ? 1 : 0);
+                ret = 0;
+                break;
+
+        case RTC_PIE_OFF:
+        case RTC_PIE_ON:
+                tick_count = 0;
+                s3c_rtc_setpie((cmd == RTC_PIE_ON) ? 1 : 0);
+                ret = 0;
+                break;
+
+        case RTC_IRQP_READ:
+                ret = put_user(s3c_rtc_freq, (unsigned long __user *)arg);
+                break;
+
+        case RTC_IRQP_SET:
+                /* check for power of 2 */
+
+                if ((arg & (arg-1)) != 0 || arg < 1) {
+                        ret = -EINVAL;
+                        goto exit;
+                }
+
+                pr_debug("s3c2410_rtc: setting frequency %ld\n", arg);
+
+                s3c_rtc_setfreq(arg);
+                ret = 0;
+                break;
+
+        case RTC_UIE_ON:
+        case RTC_UIE_OFF:
+                ret = -EINVAL;
+        }
+
+ exit:
+        return ret;
+}
+
+static int s3c_rtc_proc(struct device *dev, struct seq_file *seq)
+{
+        unsigned int rtcalm = readb(S3C2410_RTCALM);
+        unsigned int ticnt = readb (S3C2410_TICNT);
+
+        seq_printf(seq, "alarm_IRQ\t: %s\n",
+                   (rtcalm & S3C2410_RTCALM_ALMEN) ? "yes" : "no" );
+
+        seq_printf(seq, "periodic_IRQ\t: %s\n",
+                     (ticnt & S3C2410_TICNT_ENABLE) ? "yes" : "no" );
+
+        seq_printf(seq, "periodic_freq\t: %d\n", s3c_rtc_freq);
+
+        return 0;
+}
+
+static int s3c_rtc_open(struct device *dev)
+{
+        struct platform_device *pdev = to_platform_device(dev);
+        struct rtc_device *rtc_dev = platform_get_drvdata(pdev);
+        int ret;
+
+        ret = request_irq(s3c_rtc_alarmno, s3c_rtc_alarmirq,
+                          SA_INTERRUPT,  "s3c2410-rtc alarm", rtc_dev);
+
+        if (ret) {
+                dev_err(dev, "IRQ%d error %d\n", s3c_rtc_alarmno, ret);
+                return ret;
+        }
+
+        ret = request_irq(s3c_rtc_tickno, s3c_rtc_tickirq,
+                          SA_INTERRUPT,  "s3c2410-rtc tick", rtc_dev);
+
+        if (ret) {
+                dev_err(dev, "IRQ%d error %d\n", s3c_rtc_tickno, ret);
+                goto tick_err;
+        }
+
+        return ret;
+
+ tick_err:
+        free_irq(s3c_rtc_alarmno, rtc_dev);
+        return ret;
+}
+
+static void s3c_rtc_release(struct device *dev)
+{
+        struct platform_device *pdev = to_platform_device(dev);
+        struct rtc_device *rtc_dev = platform_get_drvdata(pdev);
+
+        /* do not clear AIE here, it may be needed for wake */
+
+        s3c_rtc_setpie(0);
+        free_irq(s3c_rtc_alarmno, rtc_dev);
+        free_irq(s3c_rtc_tickno, rtc_dev);
+}
+
+static struct rtc_class_ops s3c_rtcops = {
+        .open           = s3c_rtc_open,
+        .release        = s3c_rtc_release,
+        .ioctl          = s3c_rtc_ioctl,
+        .read_time      = s3c_rtc_gettime,
+        .set_time       = s3c_rtc_settime,
+        .read_alarm     = s3c_rtc_getalarm,
+        .set_alarm      = s3c_rtc_setalarm,
+        .proc           = s3c_rtc_proc,
+};
+
+static void s3c_rtc_enable(struct platform_device *pdev, int en)
+{
+        unsigned int tmp;
+
+        if (s3c_rtc_base == NULL)
+                return;
+
+        if (!en) {
+                tmp = readb(S3C2410_RTCCON);
+                writeb(tmp & ~S3C2410_RTCCON_RTCEN, S3C2410_RTCCON);
+
+                tmp = readb(S3C2410_TICNT);
+                writeb(tmp & ~S3C2410_TICNT_ENABLE, S3C2410_TICNT);
+        } else {
+                /* re-enable the device, and check it is ok */
+
+                if ((readb(S3C2410_RTCCON) & S3C2410_RTCCON_RTCEN) == 0){
+                        dev_info(&pdev->dev, "rtc disabled, re-enabling\n");
+
+                        tmp = readb(S3C2410_RTCCON);
+                        writeb(tmp | S3C2410_RTCCON_RTCEN , S3C2410_RTCCON);
+                }
+
+                if ((readb(S3C2410_RTCCON) & S3C2410_RTCCON_CNTSEL)){
+                        dev_info(&pdev->dev, "removing RTCCON_CNTSEL\n");
+
+                        tmp = readb(S3C2410_RTCCON);
+                        writeb(tmp& ~S3C2410_RTCCON_CNTSEL , S3C2410_RTCCON);
+                }
+
+                if ((readb(S3C2410_RTCCON) & S3C2410_RTCCON_CLKRST)){
+                        dev_info(&pdev->dev, "removing RTCCON_CLKRST\n");
+
+                        tmp = readb(S3C2410_RTCCON);
+                        writeb(tmp & ~S3C2410_RTCCON_CLKRST, S3C2410_RTCCON);
+                }
+        }
+}
+
+static int s3c_rtc_remove(struct platform_device *dev)
+{
+        struct rtc_device *rtc = platform_get_drvdata(dev);
+
+        platform_set_drvdata(dev, NULL);
+        rtc_device_unregister(rtc);
+
+        s3c_rtc_setpie(0);
+        s3c_rtc_setaie(0);
+
+        iounmap(s3c_rtc_base);
+        release_resource(s3c_rtc_mem);
+        kfree(s3c_rtc_mem);
+
+        return 0;
+}
+
+static int s3c_rtc_probe(struct platform_device *pdev)
+{
+        struct rtc_device *rtc;
+        struct resource *res;
+        int ret;
+
+        pr_debug("%s: probe=%p\n", __FUNCTION__, pdev);
+
+        /* find the IRQs */
+
+        s3c_rtc_tickno = platform_get_irq(pdev, 1);
+        if (s3c_rtc_tickno < 0) {
+                dev_err(&pdev->dev, "no irq for rtc tick\n");
+                return -ENOENT;
+        }
+
+        s3c_rtc_alarmno = platform_get_irq(pdev, 0);
+        if (s3c_rtc_alarmno < 0) {
+                dev_err(&pdev->dev, "no irq for alarm\n");
+                return -ENOENT;
+        }
+
+        pr_debug("s3c2410_rtc: tick irq %d, alarm irq %d\n",
+                 s3c_rtc_tickno, s3c_rtc_alarmno);
+
+        /* get the memory region */
+
+        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        if (res == NULL) {
+                dev_err(&pdev->dev, "failed to get memory region resource\n");
+                return -ENOENT;
+        }
+
+        s3c_rtc_mem = request_mem_region(res->start,
+                                             res->end-res->start+1,
+                                             pdev->name);
+
+        if (s3c_rtc_mem == NULL) {
+                dev_err(&pdev->dev, "failed to reserve memory region\n");
+                ret = -ENOENT;
+                goto err_nores;
+        }
+
+        s3c_rtc_base = ioremap(res->start, res->end - res->start + 1);
+        if (s3c_rtc_base == NULL) {
+                dev_err(&pdev->dev, "failed ioremap()\n");
+                ret = -EINVAL;
+                goto err_nomap;
+        }
+
+        /* check to see if everything is setup correctly */
+
+        s3c_rtc_enable(pdev, 1);
+
+        pr_debug("s3c2410_rtc: RTCCON=%02x\n", readb(S3C2410_RTCCON));
+
+        s3c_rtc_setfreq(s3c_rtc_freq);
+
+        /* register RTC and exit */
+
+        rtc = rtc_device_register("s3c", &pdev->dev, &s3c_rtcops,
+                                  THIS_MODULE);
+
+        if (IS_ERR(rtc)) {
+                dev_err(&pdev->dev, "cannot attach rtc\n");
+                ret = PTR_ERR(rtc);
+                goto err_nortc;
+        }
+
+        rtc->max_user_freq = 128;
+
+        platform_set_drvdata(pdev, rtc);
+        return 0;
+
+ err_nortc:
+        s3c_rtc_enable(pdev, 0);
+        iounmap(s3c_rtc_base);
+
+ err_nomap:
+        release_resource(s3c_rtc_mem);
+
+ err_nores:
+        return ret;
+}
+
+#ifdef CONFIG_PM
+
+/* RTC Power management control */
+
+static struct timespec s3c_rtc_delta;
+
+static int ticnt_save;
+
+static int s3c_rtc_suspend(struct platform_device *pdev, pm_message_t state)
+{
+        struct rtc_time tm;
+        struct timespec time;
+
+        time.tv_nsec = 0;
+
+        /* save TICNT for anyone using periodic interrupts */
+
+        ticnt_save = readb(S3C2410_TICNT);
+
+        /* calculate time delta for suspend */
+
+        s3c_rtc_gettime(&pdev->dev, &tm);
+        rtc_tm_to_time(&tm, &time.tv_sec);
+        save_time_delta(&s3c_rtc_delta, &time);
+        s3c_rtc_enable(pdev, 0);
+
+        return 0;
+}
+
+static int s3c_rtc_resume(struct platform_device *pdev)
+{
+        struct rtc_time tm;
+        struct timespec time;
+
+        time.tv_nsec = 0;
+
+        s3c_rtc_enable(pdev, 1);
+        s3c_rtc_gettime(&pdev->dev, &tm);
+        rtc_tm_to_time(&tm, &time.tv_sec);
+        restore_time_delta(&s3c_rtc_delta, &time);
+
+        writeb(ticnt_save, S3C2410_TICNT);
+        return 0;
+}
+#else
+#define s3c_rtc_suspend NULL
+#define s3c_rtc_resume  NULL
+#endif
+
+static struct platform_driver s3c2410_rtcdrv = {
+        .probe          = s3c_rtc_probe,
+        .remove         = s3c_rtc_remove,
+        .suspend        = s3c_rtc_suspend,
+        .resume         = s3c_rtc_resume,
+        .driver         = {
+                .name   = "s3c2410-rtc",
+                .owner  = THIS_MODULE,
+        },
+};
+
+static char __initdata banner[] = "S3C24XX RTC, (c) 2004,2006 Simtec Electronics\n";
+
+static int __init s3c_rtc_init(void)
+{
+        printk(banner);
+        return platform_driver_register(&s3c2410_rtcdrv);
+}
+
+static void __exit s3c_rtc_exit(void)
+{
+        platform_driver_unregister(&s3c2410_rtcdrv);
+}
+
+module_init(s3c_rtc_init);
+module_exit(s3c_rtc_exit);
+
+MODULE_DESCRIPTION("Samsung S3C RTC Driver");
+MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
+MODULE_LICENSE("GPL");