MIPS: DS1286: New RTC driver

This driver replaces the broken DS1286 driver in drivers/char and gives back
RTC support for SGI IP22 and IP28 machines.

Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Acked-by: Alessandro Zummo <alessandro.zummo@towertech.it>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 409 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-ds1286.c b/drivers/rtc/rtc-ds1286.c
new file mode 100644
index 000000000000..4b4c1b6a4187
--- /dev/null
+++ b/drivers/rtc/rtc-ds1286.c
@@ -0,0 +1,409 @@
+/*
+ * DS1286 Real Time Clock interface for Linux
+ *
+ * Copyright (C) 1998, 1999, 2000 Ralf Baechle
+ * Copyright (C) 2008 Thomas Bogendoerfer
+ *
+ * Based on code written by Paul Gortmaker.
+ *
+ * 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/module.h>
+#include <linux/rtc.h>
+#include <linux/platform_device.h>
+#include <linux/bcd.h>
+#include <linux/ds1286.h>
+
+#define DRV_VERSION             "1.0"
+
+struct ds1286_priv {
+        struct rtc_device *rtc;
+        u32 __iomem *rtcregs;
+        size_t size;
+        unsigned long baseaddr;
+        spinlock_t lock;
+};
+
+static inline u8 ds1286_rtc_read(struct ds1286_priv *priv, int reg)
+{
+        return __raw_readl(&priv->rtcregs[reg]) & 0xff;
+}
+
+static inline void ds1286_rtc_write(struct ds1286_priv *priv, u8 data, int reg)
+{
+        __raw_writel(data, &priv->rtcregs[reg]);
+}
+
+#ifdef CONFIG_RTC_INTF_DEV
+
+static int ds1286_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
+{
+        struct ds1286_priv *priv = dev_get_drvdata(dev);
+        unsigned long flags;
+        unsigned char val;
+
+        switch (cmd) {
+        case RTC_AIE_OFF:
+                /* Mask alarm int. enab. bit    */
+                spin_lock_irqsave(&priv->lock, flags);
+                val = ds1286_rtc_read(priv, RTC_CMD);
+                val |=  RTC_TDM;
+                ds1286_rtc_write(priv, val, RTC_CMD);
+                spin_unlock_irqrestore(&priv->lock, flags);
+                break;
+        case RTC_AIE_ON:
+                /* Allow alarm interrupts.      */
+                spin_lock_irqsave(&priv->lock, flags);
+                val = ds1286_rtc_read(priv, RTC_CMD);
+                val &=  ~RTC_TDM;
+                ds1286_rtc_write(priv, val, RTC_CMD);
+                spin_unlock_irqrestore(&priv->lock, flags);
+                break;
+        case RTC_WIE_OFF:
+                /* Mask watchdog int. enab. bit */
+                spin_lock_irqsave(&priv->lock, flags);
+                val = ds1286_rtc_read(priv, RTC_CMD);
+                val |= RTC_WAM;
+                ds1286_rtc_write(priv, val, RTC_CMD);
+                spin_unlock_irqrestore(&priv->lock, flags);
+                break;
+        case RTC_WIE_ON:
+                /* Allow watchdog interrupts.   */
+                spin_lock_irqsave(&priv->lock, flags);
+                val = ds1286_rtc_read(priv, RTC_CMD);
+                val &= ~RTC_WAM;
+                ds1286_rtc_write(priv, val, RTC_CMD);
+                spin_unlock_irqrestore(&priv->lock, flags);
+                break;
+        default:
+                return -ENOIOCTLCMD;
+        }
+        return 0;
+}
+
+#else
+#define ds1286_ioctl    NULL
+#endif
+
+#ifdef CONFIG_PROC_FS
+
+static int ds1286_proc(struct device *dev, struct seq_file *seq)
+{
+        struct ds1286_priv *priv = dev_get_drvdata(dev);
+        unsigned char month, cmd, amode;
+        const char *s;
+
+        month = ds1286_rtc_read(priv, RTC_MONTH);
+        seq_printf(seq,
+                   "oscillator\t: %s\n"
+                   "square_wave\t: %s\n",
+                   (month & RTC_EOSC) ? "disabled" : "enabled",
+                   (month & RTC_ESQW) ? "disabled" : "enabled");
+
+        amode = ((ds1286_rtc_read(priv, RTC_MINUTES_ALARM) & 0x80) >> 5) |
+                ((ds1286_rtc_read(priv, RTC_HOURS_ALARM) & 0x80) >> 6) |
+                ((ds1286_rtc_read(priv, RTC_DAY_ALARM) & 0x80) >> 7);
+        switch (amode) {
+        case 7:
+                s = "each minute";
+                break;
+        case 3:
+                s = "minutes match";
+                break;
+        case 1:
+                s = "hours and minutes match";
+                break;
+        case 0:
+                s = "days, hours and minutes match";
+                break;
+        default:
+                s = "invalid";
+                break;
+        }
+        seq_printf(seq, "alarm_mode\t: %s\n", s);
+
+        cmd = ds1286_rtc_read(priv, RTC_CMD);
+        seq_printf(seq,
+                   "alarm_enable\t: %s\n"
+                   "wdog_alarm\t: %s\n"
+                   "alarm_mask\t: %s\n"
+                   "wdog_alarm_mask\t: %s\n"
+                   "interrupt_mode\t: %s\n"
+                   "INTB_mode\t: %s_active\n"
+                   "interrupt_pins\t: %s\n",
+                   (cmd & RTC_TDF) ? "yes" : "no",
+                   (cmd & RTC_WAF) ? "yes" : "no",
+                   (cmd & RTC_TDM) ? "disabled" : "enabled",
+                   (cmd & RTC_WAM) ? "disabled" : "enabled",
+                   (cmd & RTC_PU_LVL) ? "pulse" : "level",
+                   (cmd & RTC_IBH_LO) ? "low" : "high",
+                   (cmd & RTC_IPSW) ? "unswapped" : "swapped");
+        return 0;
+}
+
+#else
+#define ds1286_proc     NULL
+#endif
+
+static int ds1286_read_time(struct device *dev, struct rtc_time *tm)
+{
+        struct ds1286_priv *priv = dev_get_drvdata(dev);
+        unsigned char save_control;
+        unsigned long flags;
+        unsigned long uip_watchdog = jiffies;
+
+        /*
+         * read RTC once any update in progress is done. The update
+         * can take just over 2ms. We wait 10 to 20ms. There is no need to
+         * to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP.
+         * If you need to know *exactly* when a second has started, enable
+         * periodic update complete interrupts, (via ioctl) and then
+         * immediately read /dev/rtc which will block until you get the IRQ.
+         * Once the read clears, read the RTC time (again via ioctl). Easy.
+         */
+
+        if (ds1286_rtc_read(priv, RTC_CMD) & RTC_TE)
+                while (time_before(jiffies, uip_watchdog + 2*HZ/100))
+                        barrier();
+
+        /*
+         * Only the values that we read from the RTC are set. We leave
+         * tm_wday, tm_yday and tm_isdst untouched. Even though the
+         * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated
+         * by the RTC when initially set to a non-zero value.
+         */
+        spin_lock_irqsave(&priv->lock, flags);
+        save_control = ds1286_rtc_read(priv, RTC_CMD);
+        ds1286_rtc_write(priv, (save_control|RTC_TE), RTC_CMD);
+
+        tm->tm_sec = ds1286_rtc_read(priv, RTC_SECONDS);
+        tm->tm_min = ds1286_rtc_read(priv, RTC_MINUTES);
+        tm->tm_hour = ds1286_rtc_read(priv, RTC_HOURS) & 0x3f;
+        tm->tm_mday = ds1286_rtc_read(priv, RTC_DATE);
+        tm->tm_mon = ds1286_rtc_read(priv, RTC_MONTH) & 0x1f;
+        tm->tm_year = ds1286_rtc_read(priv, RTC_YEAR);
+
+        ds1286_rtc_write(priv, save_control, RTC_CMD);
+        spin_unlock_irqrestore(&priv->lock, flags);
+
+        tm->tm_sec = bcd2bin(tm->tm_sec);
+        tm->tm_min = bcd2bin(tm->tm_min);
+        tm->tm_hour = bcd2bin(tm->tm_hour);
+        tm->tm_mday = bcd2bin(tm->tm_mday);
+        tm->tm_mon = bcd2bin(tm->tm_mon);
+        tm->tm_year = bcd2bin(tm->tm_year);
+
+        /*
+         * Account for differences between how the RTC uses the values
+         * and how they are defined in a struct rtc_time;
+         */
+        if (tm->tm_year < 45)
+                tm->tm_year += 30;
+        tm->tm_year += 40;
+        if (tm->tm_year < 70)
+                tm->tm_year += 100;
+
+        tm->tm_mon--;
+
+        return rtc_valid_tm(tm);
+}
+
+static int ds1286_set_time(struct device *dev, struct rtc_time *tm)
+{
+        struct ds1286_priv *priv = dev_get_drvdata(dev);
+        unsigned char mon, day, hrs, min, sec;
+        unsigned char save_control;
+        unsigned int yrs;
+        unsigned long flags;
+
+        yrs = tm->tm_year + 1900;
+        mon = tm->tm_mon + 1;   /* tm_mon starts at zero */
+        day = tm->tm_mday;
+        hrs = tm->tm_hour;
+        min = tm->tm_min;
+        sec = tm->tm_sec;
+
+        if (yrs < 1970)
+                return -EINVAL;
+
+        yrs -= 1940;
+        if (yrs > 255)    /* They are unsigned */
+                return -EINVAL;
+
+        if (yrs >= 100)
+                yrs -= 100;
+
+        sec = bin2bcd(sec);
+        min = bin2bcd(min);
+        hrs = bin2bcd(hrs);
+        day = bin2bcd(day);
+        mon = bin2bcd(mon);
+        yrs = bin2bcd(yrs);
+
+        spin_lock_irqsave(&priv->lock, flags);
+        save_control = ds1286_rtc_read(priv, RTC_CMD);
+        ds1286_rtc_write(priv, (save_control|RTC_TE), RTC_CMD);
+
+        ds1286_rtc_write(priv, yrs, RTC_YEAR);
+        ds1286_rtc_write(priv, mon, RTC_MONTH);
+        ds1286_rtc_write(priv, day, RTC_DATE);
+        ds1286_rtc_write(priv, hrs, RTC_HOURS);
+        ds1286_rtc_write(priv, min, RTC_MINUTES);
+        ds1286_rtc_write(priv, sec, RTC_SECONDS);
+        ds1286_rtc_write(priv, 0, RTC_HUNDREDTH_SECOND);
+
+        ds1286_rtc_write(priv, save_control, RTC_CMD);
+        spin_unlock_irqrestore(&priv->lock, flags);
+        return 0;
+}
+
+static int ds1286_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
+{
+        struct ds1286_priv *priv = dev_get_drvdata(dev);
+        unsigned char cmd;
+        unsigned long flags;
+
+        /*
+         * Only the values that we read from the RTC are set. That
+         * means only tm_wday, tm_hour, tm_min.
+         */
+        spin_lock_irqsave(&priv->lock, flags);
+        alm->time.tm_min = ds1286_rtc_read(priv, RTC_MINUTES_ALARM) & 0x7f;
+        alm->time.tm_hour = ds1286_rtc_read(priv, RTC_HOURS_ALARM)  & 0x1f;
+        alm->time.tm_wday = ds1286_rtc_read(priv, RTC_DAY_ALARM)    & 0x07;
+        cmd = ds1286_rtc_read(priv, RTC_CMD);
+        spin_unlock_irqrestore(&priv->lock, flags);
+
+        alm->time.tm_min = bcd2bin(alm->time.tm_min);
+        alm->time.tm_hour = bcd2bin(alm->time.tm_hour);
+        alm->time.tm_sec = 0;
+        return 0;
+}
+
+static int ds1286_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
+{
+        struct ds1286_priv *priv = dev_get_drvdata(dev);
+        unsigned char hrs, min, sec;
+
+        hrs = alm->time.tm_hour;
+        min = alm->time.tm_min;
+        sec = alm->time.tm_sec;
+
+        if (hrs >= 24)
+                hrs = 0xff;
+
+        if (min >= 60)
+                min = 0xff;
+
+        if (sec != 0)
+                return -EINVAL;
+
+        min = bin2bcd(min);
+        hrs = bin2bcd(hrs);
+
+        spin_lock(&priv->lock);
+        ds1286_rtc_write(priv, hrs, RTC_HOURS_ALARM);
+        ds1286_rtc_write(priv, min, RTC_MINUTES_ALARM);
+        spin_unlock(&priv->lock);
+
+        return 0;
+}
+
+static const struct rtc_class_ops ds1286_ops = {
+        .ioctl          = ds1286_ioctl,
+        .proc           = ds1286_proc,
+        .read_time      = ds1286_read_time,
+        .set_time       = ds1286_set_time,
+        .read_alarm     = ds1286_read_alarm,
+        .set_alarm      = ds1286_set_alarm,
+};
+
+static int __devinit ds1286_probe(struct platform_device *pdev)
+{
+        struct rtc_device *rtc;
+        struct resource *res;
+        struct ds1286_priv *priv;
+        int ret = 0;
+
+        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        if (!res)
+                return -ENODEV;
+        priv = kzalloc(sizeof(struct ds1286_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->rtcregs = ioremap(priv->baseaddr, priv->size);
+        if (!priv->rtcregs) {
+                ret = -ENOMEM;
+                goto out;
+        }
+        spin_lock_init(&priv->lock);
+        rtc = rtc_device_register("ds1286", &pdev->dev,
+                                  &ds1286_ops, THIS_MODULE);
+        if (IS_ERR(rtc)) {
+                ret = PTR_ERR(rtc);
+                goto out;
+        }
+        priv->rtc = rtc;
+        platform_set_drvdata(pdev, priv);
+        return 0;
+
+out:
+        if (priv->rtc)
+                rtc_device_unregister(priv->rtc);
+        if (priv->rtcregs)
+                iounmap(priv->rtcregs);
+        if (priv->baseaddr)
+                release_mem_region(priv->baseaddr, priv->size);
+        kfree(priv);
+        return ret;
+}
+
+static int __devexit ds1286_remove(struct platform_device *pdev)
+{
+        struct ds1286_priv *priv = platform_get_drvdata(pdev);
+
+        rtc_device_unregister(priv->rtc);
+        iounmap(priv->rtcregs);
+        release_mem_region(priv->baseaddr, priv->size);
+        kfree(priv);
+        return 0;
+}
+
+static struct platform_driver ds1286_platform_driver = {
+        .driver         = {
+                .name   = "rtc-ds1286",
+                .owner  = THIS_MODULE,
+        },
+        .probe          = ds1286_probe,
+        .remove         = __devexit_p(ds1286_remove),
+};
+
+static int __init ds1286_init(void)
+{
+        return platform_driver_register(&ds1286_platform_driver);
+}
+
+static void __exit ds1286_exit(void)
+{
+        platform_driver_unregister(&ds1286_platform_driver);
+}
+
+MODULE_AUTHOR("Thomas Bogendoerfer <tsbogend@alpha.franken.de>");
+MODULE_DESCRIPTION("DS1286 RTC driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_VERSION);
+MODULE_ALIAS("platform:rtc-ds1286");
+
+module_init(ds1286_init);
+module_exit(ds1286_exit);