UPSTREAM Revert 3.9 "rtc: palmas: Add RTC driver Palmas series PMIC"
[linux-3.10.git] / drivers / rtc / rtc-cmos.c
index 6d0c353..f1cb706 100644 (file)
 #include <linux/spinlock.h>
 #include <linux/platform_device.h>
 #include <linux/mod_devicetable.h>
+#include <linux/log2.h>
+#include <linux/pm.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
 
 /* this is for "generic access to PC-style RTC" using CMOS_READ/CMOS_WRITE */
 #include <asm-generic/rtc.h>
 
-
 struct cmos_rtc {
        struct rtc_device       *rtc;
        struct device           *dev;
@@ -59,7 +62,7 @@ struct cmos_rtc {
 };
 
 /* both platform and pnp busses use negative numbers for invalid irqs */
-#define is_valid_irq(n)                ((n) >= 0)
+#define is_valid_irq(n)                ((n) > 0)
 
 static const char driver_name[] = "rtc_cmos";
 
@@ -78,6 +81,109 @@ static inline int is_intr(u8 rtc_intr)
 
 /*----------------------------------------------------------------*/
 
+/* Much modern x86 hardware has HPETs (10+ MHz timers) which, because
+ * many BIOS programmers don't set up "sane mode" IRQ routing, are mostly
+ * used in a broken "legacy replacement" mode.  The breakage includes
+ * HPET #1 hijacking the IRQ for this RTC, and being unavailable for
+ * other (better) use.
+ *
+ * When that broken mode is in use, platform glue provides a partial
+ * emulation of hardware RTC IRQ facilities using HPET #1.  We don't
+ * want to use HPET for anything except those IRQs though...
+ */
+#ifdef CONFIG_HPET_EMULATE_RTC
+#include <asm/hpet.h>
+#else
+
+static inline int is_hpet_enabled(void)
+{
+       return 0;
+}
+
+static inline int hpet_mask_rtc_irq_bit(unsigned long mask)
+{
+       return 0;
+}
+
+static inline int hpet_set_rtc_irq_bit(unsigned long mask)
+{
+       return 0;
+}
+
+static inline int
+hpet_set_alarm_time(unsigned char hrs, unsigned char min, unsigned char sec)
+{
+       return 0;
+}
+
+static inline int hpet_set_periodic_freq(unsigned long freq)
+{
+       return 0;
+}
+
+static inline int hpet_rtc_dropped_irq(void)
+{
+       return 0;
+}
+
+static inline int hpet_rtc_timer_init(void)
+{
+       return 0;
+}
+
+extern irq_handler_t hpet_rtc_interrupt;
+
+static inline int hpet_register_irq_handler(irq_handler_t handler)
+{
+       return 0;
+}
+
+static inline int hpet_unregister_irq_handler(irq_handler_t handler)
+{
+       return 0;
+}
+
+#endif
+
+/*----------------------------------------------------------------*/
+
+#ifdef RTC_PORT
+
+/* Most newer x86 systems have two register banks, the first used
+ * for RTC and NVRAM and the second only for NVRAM.  Caller must
+ * own rtc_lock ... and we won't worry about access during NMI.
+ */
+#define can_bank2      true
+
+static inline unsigned char cmos_read_bank2(unsigned char addr)
+{
+       outb(addr, RTC_PORT(2));
+       return inb(RTC_PORT(3));
+}
+
+static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
+{
+       outb(addr, RTC_PORT(2));
+       outb(val, RTC_PORT(3));
+}
+
+#else
+
+#define can_bank2      false
+
+static inline unsigned char cmos_read_bank2(unsigned char addr)
+{
+       return 0;
+}
+
+static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
+{
+}
+
+#endif
+
+/*----------------------------------------------------------------*/
+
 static int cmos_read_time(struct device *dev, struct rtc_time *t)
 {
        /* REVISIT:  if the clock has a "century" register, use
@@ -120,7 +226,8 @@ static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t)
        t->time.tm_hour = CMOS_READ(RTC_HOURS_ALARM);
 
        if (cmos->day_alrm) {
-               t->time.tm_mday = CMOS_READ(cmos->day_alrm);
+               /* ignore upper bits on readback per ACPI spec */
+               t->time.tm_mday = CMOS_READ(cmos->day_alrm) & 0x3f;
                if (!t->time.tm_mday)
                        t->time.tm_mday = -1;
 
@@ -134,31 +241,32 @@ static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t)
        rtc_control = CMOS_READ(RTC_CONTROL);
        spin_unlock_irq(&rtc_lock);
 
-       /* REVISIT this assumes PC style usage:  always BCD */
-
-       if (((unsigned)t->time.tm_sec) < 0x60)
-               t->time.tm_sec = BCD2BIN(t->time.tm_sec);
-       else
-               t->time.tm_sec = -1;
-       if (((unsigned)t->time.tm_min) < 0x60)
-               t->time.tm_min = BCD2BIN(t->time.tm_min);
-       else
-               t->time.tm_min = -1;
-       if (((unsigned)t->time.tm_hour) < 0x24)
-               t->time.tm_hour = BCD2BIN(t->time.tm_hour);
-       else
-               t->time.tm_hour = -1;
-
-       if (cmos->day_alrm) {
-               if (((unsigned)t->time.tm_mday) <= 0x31)
-                       t->time.tm_mday = BCD2BIN(t->time.tm_mday);
+       if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
+               if (((unsigned)t->time.tm_sec) < 0x60)
+                       t->time.tm_sec = bcd2bin(t->time.tm_sec);
                else
-                       t->time.tm_mday = -1;
-               if (cmos->mon_alrm) {
-                       if (((unsigned)t->time.tm_mon) <= 0x12)
-                               t->time.tm_mon = BCD2BIN(t->time.tm_mon) - 1;
+                       t->time.tm_sec = -1;
+               if (((unsigned)t->time.tm_min) < 0x60)
+                       t->time.tm_min = bcd2bin(t->time.tm_min);
+               else
+                       t->time.tm_min = -1;
+               if (((unsigned)t->time.tm_hour) < 0x24)
+                       t->time.tm_hour = bcd2bin(t->time.tm_hour);
+               else
+                       t->time.tm_hour = -1;
+
+               if (cmos->day_alrm) {
+                       if (((unsigned)t->time.tm_mday) <= 0x31)
+                               t->time.tm_mday = bcd2bin(t->time.tm_mday);
                        else
-                               t->time.tm_mon = -1;
+                               t->time.tm_mday = -1;
+
+                       if (cmos->mon_alrm) {
+                               if (((unsigned)t->time.tm_mon) <= 0x12)
+                                       t->time.tm_mon = bcd2bin(t->time.tm_mon)-1;
+                               else
+                                       t->time.tm_mon = -1;
+                       }
                }
        }
        t->time.tm_year = -1;
@@ -169,45 +277,80 @@ static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t)
        return 0;
 }
 
+static void cmos_checkintr(struct cmos_rtc *cmos, unsigned char rtc_control)
+{
+       unsigned char   rtc_intr;
+
+       /* NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
+        * allegedly some older rtcs need that to handle irqs properly
+        */
+       rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
+
+       if (is_hpet_enabled())
+               return;
+
+       rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
+       if (is_intr(rtc_intr))
+               rtc_update_irq(cmos->rtc, 1, rtc_intr);
+}
+
+static void cmos_irq_enable(struct cmos_rtc *cmos, unsigned char mask)
+{
+       unsigned char   rtc_control;
+
+       /* flush any pending IRQ status, notably for update irqs,
+        * before we enable new IRQs
+        */
+       rtc_control = CMOS_READ(RTC_CONTROL);
+       cmos_checkintr(cmos, rtc_control);
+
+       rtc_control |= mask;
+       CMOS_WRITE(rtc_control, RTC_CONTROL);
+       hpet_set_rtc_irq_bit(mask);
+
+       cmos_checkintr(cmos, rtc_control);
+}
+
+static void cmos_irq_disable(struct cmos_rtc *cmos, unsigned char mask)
+{
+       unsigned char   rtc_control;
+
+       rtc_control = CMOS_READ(RTC_CONTROL);
+       rtc_control &= ~mask;
+       CMOS_WRITE(rtc_control, RTC_CONTROL);
+       hpet_mask_rtc_irq_bit(mask);
+
+       cmos_checkintr(cmos, rtc_control);
+}
+
 static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 {
        struct cmos_rtc *cmos = dev_get_drvdata(dev);
-       unsigned char   mon, mday, hrs, min, sec;
-       unsigned char   rtc_control, rtc_intr;
+       unsigned char   mon, mday, hrs, min, sec, rtc_control;
 
        if (!is_valid_irq(cmos->irq))
                return -EIO;
 
-       /* REVISIT this assumes PC style usage:  always BCD */
-
-       /* Writing 0xff means "don't care" or "match all".  */
-
-       mon = t->time.tm_mon;
-       mon = (mon < 12) ? BIN2BCD(mon) : 0xff;
-       mon++;
-
+       mon = t->time.tm_mon + 1;
        mday = t->time.tm_mday;
-       mday = (mday >= 1 && mday <= 31) ? BIN2BCD(mday) : 0xff;
-
        hrs = t->time.tm_hour;
-       hrs = (hrs < 24) ? BIN2BCD(hrs) : 0xff;
-
        min = t->time.tm_min;
-       min = (min < 60) ? BIN2BCD(min) : 0xff;
-
        sec = t->time.tm_sec;
-       sec = (sec < 60) ? BIN2BCD(sec) : 0xff;
+
+       rtc_control = CMOS_READ(RTC_CONTROL);
+       if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
+               /* Writing 0xff means "don't care" or "match all".  */
+               mon = (mon <= 12) ? bin2bcd(mon) : 0xff;
+               mday = (mday >= 1 && mday <= 31) ? bin2bcd(mday) : 0xff;
+               hrs = (hrs < 24) ? bin2bcd(hrs) : 0xff;
+               min = (min < 60) ? bin2bcd(min) : 0xff;
+               sec = (sec < 60) ? bin2bcd(sec) : 0xff;
+       }
 
        spin_lock_irq(&rtc_lock);
 
        /* next rtc irq must not be from previous alarm setting */
-       rtc_control = CMOS_READ(RTC_CONTROL);
-       rtc_control &= ~RTC_AIE;
-       CMOS_WRITE(rtc_control, RTC_CONTROL);
-       rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
-       rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
-       if (is_intr(rtc_intr))
-               rtc_update_irq(cmos->rtc, 1, rtc_intr);
+       cmos_irq_disable(cmos, RTC_AIE);
 
        /* update alarm */
        CMOS_WRITE(hrs, RTC_HOURS_ALARM);
@@ -221,128 +364,38 @@ static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
                        CMOS_WRITE(mon, cmos->mon_alrm);
        }
 
-       if (t->enabled) {
-               rtc_control |= RTC_AIE;
-               CMOS_WRITE(rtc_control, RTC_CONTROL);
-               rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
-               rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
-               if (is_intr(rtc_intr))
-                       rtc_update_irq(cmos->rtc, 1, rtc_intr);
-       }
+       /* FIXME the HPET alarm glue currently ignores day_alrm
+        * and mon_alrm ...
+        */
+       hpet_set_alarm_time(t->time.tm_hour, t->time.tm_min, t->time.tm_sec);
+
+       if (t->enabled)
+               cmos_irq_enable(cmos, RTC_AIE);
 
        spin_unlock_irq(&rtc_lock);
 
        return 0;
 }
 
-static int cmos_irq_set_freq(struct device *dev, int freq)
+static int cmos_alarm_irq_enable(struct device *dev, unsigned int enabled)
 {
        struct cmos_rtc *cmos = dev_get_drvdata(dev);
-       int             f;
        unsigned long   flags;
 
        if (!is_valid_irq(cmos->irq))
-               return -ENXIO;
-
-       /* 0 = no irqs; 1 = 2^15 Hz ... 15 = 2^0 Hz */
-       f = ffs(freq);
-       if (f-- > 16)
                return -EINVAL;
-       f = 16 - f;
 
        spin_lock_irqsave(&rtc_lock, flags);
-       CMOS_WRITE(RTC_REF_CLCK_32KHZ | f, RTC_FREQ_SELECT);
-       spin_unlock_irqrestore(&rtc_lock, flags);
-
-       return 0;
-}
-
-static int cmos_irq_set_state(struct device *dev, int enabled)
-{
-       struct cmos_rtc *cmos = dev_get_drvdata(dev);
-       unsigned char   rtc_control, rtc_intr;
-       unsigned long   flags;
-
-       if (!is_valid_irq(cmos->irq))
-               return -ENXIO;
-
-       spin_lock_irqsave(&rtc_lock, flags);
-       rtc_control = CMOS_READ(RTC_CONTROL);
 
        if (enabled)
-               rtc_control |= RTC_PIE;
+               cmos_irq_enable(cmos, RTC_AIE);
        else
-               rtc_control &= ~RTC_PIE;
-
-       CMOS_WRITE(rtc_control, RTC_CONTROL);
-
-       rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
-       rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
-       if (is_intr(rtc_intr))
-               rtc_update_irq(cmos->rtc, 1, rtc_intr);
-
-       spin_unlock_irqrestore(&rtc_lock, flags);
-       return 0;
-}
-
-#if defined(CONFIG_RTC_INTF_DEV) || defined(CONFIG_RTC_INTF_DEV_MODULE)
+               cmos_irq_disable(cmos, RTC_AIE);
 
-static int
-cmos_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
-{
-       struct cmos_rtc *cmos = dev_get_drvdata(dev);
-       unsigned char   rtc_control, rtc_intr;
-       unsigned long   flags;
-
-       switch (cmd) {
-       case RTC_AIE_OFF:
-       case RTC_AIE_ON:
-       case RTC_UIE_OFF:
-       case RTC_UIE_ON:
-       case RTC_PIE_OFF:
-       case RTC_PIE_ON:
-               if (!is_valid_irq(cmos->irq))
-                       return -EINVAL;
-               break;
-       default:
-               return -ENOIOCTLCMD;
-       }
-
-       spin_lock_irqsave(&rtc_lock, flags);
-       rtc_control = CMOS_READ(RTC_CONTROL);
-       switch (cmd) {
-       case RTC_AIE_OFF:       /* alarm off */
-               rtc_control &= ~RTC_AIE;
-               break;
-       case RTC_AIE_ON:        /* alarm on */
-               rtc_control |= RTC_AIE;
-               break;
-       case RTC_UIE_OFF:       /* update off */
-               rtc_control &= ~RTC_UIE;
-               break;
-       case RTC_UIE_ON:        /* update on */
-               rtc_control |= RTC_UIE;
-               break;
-       case RTC_PIE_OFF:       /* periodic off */
-               rtc_control &= ~RTC_PIE;
-               break;
-       case RTC_PIE_ON:        /* periodic on */
-               rtc_control |= RTC_PIE;
-               break;
-       }
-       CMOS_WRITE(rtc_control, RTC_CONTROL);
-       rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
-       rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
-       if (is_intr(rtc_intr))
-               rtc_update_irq(cmos->rtc, 1, rtc_intr);
        spin_unlock_irqrestore(&rtc_lock, flags);
        return 0;
 }
 
-#else
-#define        cmos_rtc_ioctl  NULL
-#endif
-
 #if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
 
 static int cmos_procfs(struct device *dev, struct seq_file *seq)
@@ -361,15 +414,17 @@ static int cmos_procfs(struct device *dev, struct seq_file *seq)
        return seq_printf(seq,
                        "periodic_IRQ\t: %s\n"
                        "update_IRQ\t: %s\n"
+                       "HPET_emulated\t: %s\n"
                        // "square_wave\t: %s\n"
-                       // "BCD\t\t: %s\n"
+                       "BCD\t\t: %s\n"
                        "DST_enable\t: %s\n"
                        "periodic_freq\t: %d\n"
                        "batt_status\t: %s\n",
                        (rtc_control & RTC_PIE) ? "yes" : "no",
                        (rtc_control & RTC_UIE) ? "yes" : "no",
+                       is_hpet_enabled() ? "yes" : "no",
                        // (rtc_control & RTC_SQWE) ? "yes" : "no",
-                       // (rtc_control & RTC_DM_BINARY) ? "no" : "yes",
+                       (rtc_control & RTC_DM_BINARY) ? "no" : "yes",
                        (rtc_control & RTC_DST_EN) ? "yes" : "no",
                        cmos->rtc->irq_freq,
                        (valid & RTC_VRT) ? "okay" : "dead");
@@ -380,14 +435,103 @@ static int cmos_procfs(struct device *dev, struct seq_file *seq)
 #endif
 
 static const struct rtc_class_ops cmos_rtc_ops = {
-       .ioctl          = cmos_rtc_ioctl,
-       .read_time      = cmos_read_time,
-       .set_time       = cmos_set_time,
-       .read_alarm     = cmos_read_alarm,
-       .set_alarm      = cmos_set_alarm,
-       .proc           = cmos_procfs,
-       .irq_set_freq   = cmos_irq_set_freq,
-       .irq_set_state  = cmos_irq_set_state,
+       .read_time              = cmos_read_time,
+       .set_time               = cmos_set_time,
+       .read_alarm             = cmos_read_alarm,
+       .set_alarm              = cmos_set_alarm,
+       .proc                   = cmos_procfs,
+       .alarm_irq_enable       = cmos_alarm_irq_enable,
+};
+
+/*----------------------------------------------------------------*/
+
+/*
+ * All these chips have at least 64 bytes of address space, shared by
+ * RTC registers and NVRAM.  Most of those bytes of NVRAM are used
+ * by boot firmware.  Modern chips have 128 or 256 bytes.
+ */
+
+#define NVRAM_OFFSET   (RTC_REG_D + 1)
+
+static ssize_t
+cmos_nvram_read(struct file *filp, struct kobject *kobj,
+               struct bin_attribute *attr,
+               char *buf, loff_t off, size_t count)
+{
+       int     retval;
+
+       if (unlikely(off >= attr->size))
+               return 0;
+       if (unlikely(off < 0))
+               return -EINVAL;
+       if ((off + count) > attr->size)
+               count = attr->size - off;
+
+       off += NVRAM_OFFSET;
+       spin_lock_irq(&rtc_lock);
+       for (retval = 0; count; count--, off++, retval++) {
+               if (off < 128)
+                       *buf++ = CMOS_READ(off);
+               else if (can_bank2)
+                       *buf++ = cmos_read_bank2(off);
+               else
+                       break;
+       }
+       spin_unlock_irq(&rtc_lock);
+
+       return retval;
+}
+
+static ssize_t
+cmos_nvram_write(struct file *filp, struct kobject *kobj,
+               struct bin_attribute *attr,
+               char *buf, loff_t off, size_t count)
+{
+       struct cmos_rtc *cmos;
+       int             retval;
+
+       cmos = dev_get_drvdata(container_of(kobj, struct device, kobj));
+       if (unlikely(off >= attr->size))
+               return -EFBIG;
+       if (unlikely(off < 0))
+               return -EINVAL;
+       if ((off + count) > attr->size)
+               count = attr->size - off;
+
+       /* NOTE:  on at least PCs and Ataris, the boot firmware uses a
+        * checksum on part of the NVRAM data.  That's currently ignored
+        * here.  If userspace is smart enough to know what fields of
+        * NVRAM to update, updating checksums is also part of its job.
+        */
+       off += NVRAM_OFFSET;
+       spin_lock_irq(&rtc_lock);
+       for (retval = 0; count; count--, off++, retval++) {
+               /* don't trash RTC registers */
+               if (off == cmos->day_alrm
+                               || off == cmos->mon_alrm
+                               || off == cmos->century)
+                       buf++;
+               else if (off < 128)
+                       CMOS_WRITE(*buf++, off);
+               else if (can_bank2)
+                       cmos_write_bank2(*buf++, off);
+               else
+                       break;
+       }
+       spin_unlock_irq(&rtc_lock);
+
+       return retval;
+}
+
+static struct bin_attribute nvram = {
+       .attr = {
+               .name   = "nvram",
+               .mode   = S_IRUGO | S_IWUSR,
+       },
+
+       .read   = cmos_nvram_read,
+       .write  = cmos_nvram_write,
+       /* size gets set up later */
 };
 
 /*----------------------------------------------------------------*/
@@ -397,10 +541,34 @@ static struct cmos_rtc    cmos_rtc;
 static irqreturn_t cmos_interrupt(int irq, void *p)
 {
        u8              irqstat;
+       u8              rtc_control;
 
        spin_lock(&rtc_lock);
+
+       /* When the HPET interrupt handler calls us, the interrupt
+        * status is passed as arg1 instead of the irq number.  But
+        * always clear irq status, even when HPET is in the way.
+        *
+        * Note that HPET and RTC are almost certainly out of phase,
+        * giving different IRQ status ...
+        */
        irqstat = CMOS_READ(RTC_INTR_FLAGS);
-       irqstat &= (CMOS_READ(RTC_CONTROL) & RTC_IRQMASK) | RTC_IRQF;
+       rtc_control = CMOS_READ(RTC_CONTROL);
+       if (is_hpet_enabled())
+               irqstat = (unsigned long)irq & 0xF0;
+       irqstat &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
+
+       /* All Linux RTC alarms should be treated as if they were oneshot.
+        * Similar code may be needed in system wakeup paths, in case the
+        * alarm woke the system.
+        */
+       if (irqstat & RTC_AIE) {
+               rtc_control &= ~RTC_AIE;
+               CMOS_WRITE(rtc_control, RTC_CONTROL);
+               hpet_mask_rtc_irq_bit(RTC_AIE);
+
+               CMOS_READ(RTC_INTR_FLAGS);
+       }
        spin_unlock(&rtc_lock);
 
        if (is_intr(irqstat)) {
@@ -411,11 +579,9 @@ static irqreturn_t cmos_interrupt(int irq, void *p)
 }
 
 #ifdef CONFIG_PNP
-#define        is_pnp()        1
 #define        INITSECTION
 
 #else
-#define        is_pnp()        0
 #define        INITSECTION     __init
 #endif
 
@@ -425,6 +591,7 @@ cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
        struct cmos_rtc_board_info      *info = dev->platform_data;
        int                             retval = 0;
        unsigned char                   rtc_control;
+       unsigned                        address_space;
 
        /* there can be only one ... */
        if (cmos_rtc.dev)
@@ -433,18 +600,56 @@ cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
        if (!ports)
                return -ENODEV;
 
+       /* Claim I/O ports ASAP, minimizing conflict with legacy driver.
+        *
+        * REVISIT non-x86 systems may instead use memory space resources
+        * (needing ioremap etc), not i/o space resources like this ...
+        */
+       ports = request_region(ports->start,
+                       resource_size(ports),
+                       driver_name);
+       if (!ports) {
+               dev_dbg(dev, "i/o registers already in use\n");
+               return -EBUSY;
+       }
+
        cmos_rtc.irq = rtc_irq;
        cmos_rtc.iomem = ports;
 
+       /* Heuristic to deduce NVRAM size ... do what the legacy NVRAM
+        * driver did, but don't reject unknown configs.   Old hardware
+        * won't address 128 bytes.  Newer chips have multiple banks,
+        * though they may not be listed in one I/O resource.
+        */
+#if    defined(CONFIG_ATARI)
+       address_space = 64;
+#elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) \
+                       || defined(__sparc__) || defined(__mips__) \
+                       || defined(__powerpc__)
+       address_space = 128;
+#else
+#warning Assuming 128 bytes of RTC+NVRAM address space, not 64 bytes.
+       address_space = 128;
+#endif
+       if (can_bank2 && ports->end > (ports->start + 1))
+               address_space = 256;
+
        /* For ACPI systems extension info comes from the FADT.  On others,
         * board specific setup provides it as appropriate.  Systems where
         * the alarm IRQ isn't automatically a wakeup IRQ (like ACPI, and
         * some almost-clones) can provide hooks to make that behave.
+        *
+        * Note that ACPI doesn't preclude putting these registers into
+        * "extended" areas of the chip, including some that we won't yet
+        * expect CMOS_READ and friends to handle.
         */
        if (info) {
-               cmos_rtc.day_alrm = info->rtc_day_alarm;
-               cmos_rtc.mon_alrm = info->rtc_mon_alarm;
-               cmos_rtc.century = info->rtc_century;
+               if (info->rtc_day_alarm && info->rtc_day_alarm < 128)
+                       cmos_rtc.day_alrm = info->rtc_day_alarm;
+               if (info->rtc_mon_alarm && info->rtc_mon_alarm < 128)
+                       cmos_rtc.mon_alrm = info->rtc_mon_alarm;
+               if (info->rtc_century && info->rtc_century < 128)
+                       cmos_rtc.century = info->rtc_century;
 
                if (info->wake_on && info->wake_off) {
                        cmos_rtc.wake_on = info->wake_on;
@@ -452,27 +657,17 @@ cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
                }
        }
 
-       cmos_rtc.rtc = rtc_device_register(driver_name, dev,
-                               &cmos_rtc_ops, THIS_MODULE);
-       if (IS_ERR(cmos_rtc.rtc))
-               return PTR_ERR(cmos_rtc.rtc);
-
        cmos_rtc.dev = dev;
        dev_set_drvdata(dev, &cmos_rtc);
 
-       /* platform and pnp busses handle resources incompatibly.
-        *
-        * REVISIT for non-x86 systems we may need to handle io memory
-        * resources: ioremap them, and request_mem_region().
-        */
-       if (is_pnp()) {
-               retval = request_resource(&ioport_resource, ports);
-               if (retval < 0) {
-                       dev_dbg(dev, "i/o registers already in use\n");
-                       goto cleanup0;
-               }
+       cmos_rtc.rtc = rtc_device_register(driver_name, dev,
+                               &cmos_rtc_ops, THIS_MODULE);
+       if (IS_ERR(cmos_rtc.rtc)) {
+               retval = PTR_ERR(cmos_rtc.rtc);
+               goto cleanup0;
        }
-       rename_region(ports, cmos_rtc.rtc->dev.bus_id);
+
+       rename_region(ports, dev_name(&cmos_rtc.rtc->dev));
 
        spin_lock_irq(&rtc_lock);
 
@@ -482,118 +677,136 @@ cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
         * doesn't use 32KHz here ... for portability we might need to
         * do something about other clock frequencies.
         */
-       CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT);
        cmos_rtc.rtc->irq_freq = 1024;
+       hpet_set_periodic_freq(cmos_rtc.rtc->irq_freq);
+       CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT);
+
+       /* disable irqs */
+       cmos_irq_disable(&cmos_rtc, RTC_PIE | RTC_AIE | RTC_UIE);
 
-       /* disable irqs.
-        *
-        * NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
-        * allegedly some older rtcs need that to handle irqs properly
-        */
        rtc_control = CMOS_READ(RTC_CONTROL);
-       rtc_control &= ~(RTC_PIE | RTC_AIE | RTC_UIE);
-       CMOS_WRITE(rtc_control, RTC_CONTROL);
-       CMOS_READ(RTC_INTR_FLAGS);
 
        spin_unlock_irq(&rtc_lock);
 
-       /* FIXME teach the alarm code how to handle binary mode;
+       /* FIXME:
         * <asm-generic/rtc.h> doesn't know 12-hour mode either.
         */
-       if (!(rtc_control & RTC_24H) || (rtc_control & (RTC_DM_BINARY))) {
-               dev_dbg(dev, "only 24-hr BCD mode supported\n");
+       if (is_valid_irq(rtc_irq) && !(rtc_control & RTC_24H)) {
+               dev_warn(dev, "only 24-hr supported\n");
                retval = -ENXIO;
                goto cleanup1;
        }
 
-       if (is_valid_irq(rtc_irq))
-               retval = request_irq(rtc_irq, cmos_interrupt, IRQF_DISABLED,
-                               cmos_rtc.rtc->dev.bus_id,
+       if (is_valid_irq(rtc_irq)) {
+               irq_handler_t rtc_cmos_int_handler;
+
+               if (is_hpet_enabled()) {
+                       int err;
+
+                       rtc_cmos_int_handler = hpet_rtc_interrupt;
+                       err = hpet_register_irq_handler(cmos_interrupt);
+                       if (err != 0) {
+                               dev_warn(dev, "hpet_register_irq_handler "
+                                               " failed in rtc_init().");
+                               goto cleanup1;
+                       }
+               } else
+                       rtc_cmos_int_handler = cmos_interrupt;
+
+               retval = request_irq(rtc_irq, rtc_cmos_int_handler,
+                               0, dev_name(&cmos_rtc.rtc->dev),
                                cmos_rtc.rtc);
-       if (retval < 0) {
-               dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq);
-               goto cleanup1;
+               if (retval < 0) {
+                       dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq);
+                       goto cleanup1;
+               }
        }
+       hpet_rtc_timer_init();
 
-       /* REVISIT optionally make 50 or 114 bytes NVRAM available,
-        * like rtc-ds1553, rtc-ds1742 ... this will often include
-        * registers for century, and day/month alarm.
-        */
+       /* export at least the first block of NVRAM */
+       nvram.size = address_space - NVRAM_OFFSET;
+       retval = sysfs_create_bin_file(&dev->kobj, &nvram);
+       if (retval < 0) {
+               dev_dbg(dev, "can't create nvram file? %d\n", retval);
+               goto cleanup2;
+       }
 
-       pr_info("%s: alarms up to one %s%s\n",
-                       cmos_rtc.rtc->dev.bus_id,
-                       is_valid_irq(rtc_irq)
-                               ?  (cmos_rtc.mon_alrm
-                                       ? "year"
-                                       : (cmos_rtc.day_alrm
-                                               ? "month" : "day"))
-                               : "no",
-                       cmos_rtc.century ? ", y3k" : ""
-                       );
+       dev_info(dev, "%s%s, %zd bytes nvram%s\n",
+               !is_valid_irq(rtc_irq) ? "no alarms" :
+                       cmos_rtc.mon_alrm ? "alarms up to one year" :
+                       cmos_rtc.day_alrm ? "alarms up to one month" :
+                       "alarms up to one day",
+               cmos_rtc.century ? ", y3k" : "",
+               nvram.size,
+               is_hpet_enabled() ? ", hpet irqs" : "");
 
        return 0;
 
+cleanup2:
+       if (is_valid_irq(rtc_irq))
+               free_irq(rtc_irq, cmos_rtc.rtc);
 cleanup1:
-       rename_region(ports, NULL);
-cleanup0:
+       cmos_rtc.dev = NULL;
        rtc_device_unregister(cmos_rtc.rtc);
+cleanup0:
+       release_region(ports->start, resource_size(ports));
        return retval;
 }
 
 static void cmos_do_shutdown(void)
 {
-       unsigned char   rtc_control;
-
        spin_lock_irq(&rtc_lock);
-       rtc_control = CMOS_READ(RTC_CONTROL);
-       rtc_control &= ~(RTC_PIE|RTC_AIE|RTC_UIE);
-       CMOS_WRITE(rtc_control, RTC_CONTROL);
-       CMOS_READ(RTC_INTR_FLAGS);
+       cmos_irq_disable(&cmos_rtc, RTC_IRQMASK);
        spin_unlock_irq(&rtc_lock);
 }
 
 static void __exit cmos_do_remove(struct device *dev)
 {
        struct cmos_rtc *cmos = dev_get_drvdata(dev);
+       struct resource *ports;
 
        cmos_do_shutdown();
 
-       if (is_pnp())
-               release_resource(cmos->iomem);
-       rename_region(cmos->iomem, NULL);
+       sysfs_remove_bin_file(&dev->kobj, &nvram);
 
-       if (is_valid_irq(cmos->irq))
-               free_irq(cmos->irq, cmos_rtc.rtc);
+       if (is_valid_irq(cmos->irq)) {
+               free_irq(cmos->irq, cmos->rtc);
+               hpet_unregister_irq_handler(cmos_interrupt);
+       }
 
-       rtc_device_unregister(cmos_rtc.rtc);
+       rtc_device_unregister(cmos->rtc);
+       cmos->rtc = NULL;
 
-       cmos_rtc.dev = NULL;
+       ports = cmos->iomem;
+       release_region(ports->start, resource_size(ports));
+       cmos->iomem = NULL;
+
+       cmos->dev = NULL;
        dev_set_drvdata(dev, NULL);
 }
 
 #ifdef CONFIG_PM
 
-static int cmos_suspend(struct device *dev, pm_message_t mesg)
+static int cmos_suspend(struct device *dev)
 {
        struct cmos_rtc *cmos = dev_get_drvdata(dev);
-       int             do_wake = device_may_wakeup(dev);
        unsigned char   tmp;
 
        /* only the alarm might be a wakeup event source */
        spin_lock_irq(&rtc_lock);
        cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);
        if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
-               unsigned char   irqstat;
+               unsigned char   mask;
 
-               if (do_wake)
-                       tmp &= ~(RTC_PIE|RTC_UIE);
+               if (device_may_wakeup(dev))
+                       mask = RTC_IRQMASK & ~RTC_AIE;
                else
-                       tmp &= ~(RTC_PIE|RTC_AIE|RTC_UIE);
+                       mask = RTC_IRQMASK;
+               tmp &= ~mask;
                CMOS_WRITE(tmp, RTC_CONTROL);
-               irqstat = CMOS_READ(RTC_INTR_FLAGS);
-               irqstat &= (tmp & RTC_IRQMASK) | RTC_IRQF;
-               if (is_intr(irqstat))
-                       rtc_update_irq(cmos->rtc, 1, irqstat);
+               hpet_mask_rtc_irq_bit(mask);
+
+               cmos_checkintr(cmos, tmp);
        }
        spin_unlock_irq(&rtc_lock);
 
@@ -605,21 +818,32 @@ static int cmos_suspend(struct device *dev, pm_message_t mesg)
                        enable_irq_wake(cmos->irq);
        }
 
-       pr_debug("%s: suspend%s, ctrl %02x\n",
-                       cmos_rtc.rtc->dev.bus_id,
+       dev_dbg(dev, "suspend%s, ctrl %02x\n",
                        (tmp & RTC_AIE) ? ", alarm may wake" : "",
                        tmp);
 
        return 0;
 }
 
+/* We want RTC alarms to wake us from e.g. ACPI G2/S5 "soft off", even
+ * after a detour through G3 "mechanical off", although the ACPI spec
+ * says wakeup should only work from G1/S4 "hibernate".  To most users,
+ * distinctions between S4 and S5 are pointless.  So when the hardware
+ * allows, don't draw that distinction.
+ */
+static inline int cmos_poweroff(struct device *dev)
+{
+       return cmos_suspend(dev);
+}
+
 static int cmos_resume(struct device *dev)
 {
        struct cmos_rtc *cmos = dev_get_drvdata(dev);
        unsigned char   tmp = cmos->suspend_ctrl;
 
        /* re-enable any irqs previously active */
-       if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
+       if (tmp & RTC_IRQMASK) {
+               unsigned char   mask;
 
                if (cmos->enabled_wake) {
                        if (cmos->wake_off)
@@ -630,54 +854,154 @@ static int cmos_resume(struct device *dev)
                }
 
                spin_lock_irq(&rtc_lock);
-               CMOS_WRITE(tmp, RTC_CONTROL);
-               tmp = CMOS_READ(RTC_INTR_FLAGS);
-               tmp &= (cmos->suspend_ctrl & RTC_IRQMASK) | RTC_IRQF;
-               if (is_intr(tmp))
-                       rtc_update_irq(cmos->rtc, 1, tmp);
+               if (device_may_wakeup(dev))
+                       hpet_rtc_timer_init();
+
+               do {
+                       CMOS_WRITE(tmp, RTC_CONTROL);
+                       hpet_set_rtc_irq_bit(tmp & RTC_IRQMASK);
+
+                       mask = CMOS_READ(RTC_INTR_FLAGS);
+                       mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
+                       if (!is_hpet_enabled() || !is_intr(mask))
+                               break;
+
+                       /* force one-shot behavior if HPET blocked
+                        * the wake alarm's irq
+                        */
+                       rtc_update_irq(cmos->rtc, 1, mask);
+                       tmp &= ~RTC_AIE;
+                       hpet_mask_rtc_irq_bit(RTC_AIE);
+               } while (mask & RTC_AIE);
                spin_unlock_irq(&rtc_lock);
        }
 
-       pr_debug("%s: resume, ctrl %02x\n",
-                       cmos_rtc.rtc->dev.bus_id,
-                       cmos->suspend_ctrl);
-
+       dev_dbg(dev, "resume, ctrl %02x\n", tmp);
 
        return 0;
 }
 
+static SIMPLE_DEV_PM_OPS(cmos_pm_ops, cmos_suspend, cmos_resume);
+
 #else
-#define        cmos_suspend    NULL
-#define        cmos_resume     NULL
+
+static inline int cmos_poweroff(struct device *dev)
+{
+       return -ENOSYS;
+}
+
 #endif
 
 /*----------------------------------------------------------------*/
 
-/* The "CMOS" RTC normally lives on the platform_bus.  On ACPI systems,
- * the device node will always be created as a PNPACPI device.
+/* On non-x86 systems, a "CMOS" RTC lives most naturally on platform_bus.
+ * ACPI systems always list these as PNPACPI devices, and pre-ACPI PCs
+ * probably list them in similar PNPBIOS tables; so PNP is more common.
+ *
+ * We don't use legacy "poke at the hardware" probing.  Ancient PCs that
+ * predate even PNPBIOS should set up platform_bus devices.
  */
 
+#ifdef CONFIG_ACPI
+
+#include <linux/acpi.h>
+
+static u32 rtc_handler(void *context)
+{
+       struct device *dev = context;
+
+       pm_wakeup_event(dev, 0);
+       acpi_clear_event(ACPI_EVENT_RTC);
+       acpi_disable_event(ACPI_EVENT_RTC, 0);
+       return ACPI_INTERRUPT_HANDLED;
+}
+
+static inline void rtc_wake_setup(struct device *dev)
+{
+       acpi_install_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler, dev);
+       /*
+        * After the RTC handler is installed, the Fixed_RTC event should
+        * be disabled. Only when the RTC alarm is set will it be enabled.
+        */
+       acpi_clear_event(ACPI_EVENT_RTC);
+       acpi_disable_event(ACPI_EVENT_RTC, 0);
+}
+
+static void rtc_wake_on(struct device *dev)
+{
+       acpi_clear_event(ACPI_EVENT_RTC);
+       acpi_enable_event(ACPI_EVENT_RTC, 0);
+}
+
+static void rtc_wake_off(struct device *dev)
+{
+       acpi_disable_event(ACPI_EVENT_RTC, 0);
+}
+
+/* Every ACPI platform has a mc146818 compatible "cmos rtc".  Here we find
+ * its device node and pass extra config data.  This helps its driver use
+ * capabilities that the now-obsolete mc146818 didn't have, and informs it
+ * that this board's RTC is wakeup-capable (per ACPI spec).
+ */
+static struct cmos_rtc_board_info acpi_rtc_info;
+
+static void cmos_wake_setup(struct device *dev)
+{
+       if (acpi_disabled)
+               return;
+
+       rtc_wake_setup(dev);
+       acpi_rtc_info.wake_on = rtc_wake_on;
+       acpi_rtc_info.wake_off = rtc_wake_off;
+
+       /* workaround bug in some ACPI tables */
+       if (acpi_gbl_FADT.month_alarm && !acpi_gbl_FADT.day_alarm) {
+               dev_dbg(dev, "bogus FADT month_alarm (%d)\n",
+                       acpi_gbl_FADT.month_alarm);
+               acpi_gbl_FADT.month_alarm = 0;
+       }
+
+       acpi_rtc_info.rtc_day_alarm = acpi_gbl_FADT.day_alarm;
+       acpi_rtc_info.rtc_mon_alarm = acpi_gbl_FADT.month_alarm;
+       acpi_rtc_info.rtc_century = acpi_gbl_FADT.century;
+
+       /* NOTE:  S4_RTC_WAKE is NOT currently useful to Linux */
+       if (acpi_gbl_FADT.flags & ACPI_FADT_S4_RTC_WAKE)
+               dev_info(dev, "RTC can wake from S4\n");
+
+       dev->platform_data = &acpi_rtc_info;
+
+       /* RTC always wakes from S1/S2/S3, and often S4/STD */
+       device_init_wakeup(dev, 1);
+}
+
+#else
+
+static void cmos_wake_setup(struct device *dev)
+{
+}
+
+#endif
+
 #ifdef CONFIG_PNP
 
 #include <linux/pnp.h>
 
-static int __devinit
-cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
+static int cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
 {
-       /* REVISIT paranoia argues for a shutdown notifier, since PNP
-        * drivers can't provide shutdown() methods to disable IRQs.
-        * Or better yet, fix PNP to allow those methods...
-        */
+       cmos_wake_setup(&pnp->dev);
+
        if (pnp_port_start(pnp,0) == 0x70 && !pnp_irq_valid(pnp,0))
                /* Some machines contain a PNP entry for the RTC, but
                 * don't define the IRQ. It should always be safe to
                 * hardcode it in these cases
                 */
-               return cmos_do_probe(&pnp->dev, &pnp->res.port_resource[0], 8);
+               return cmos_do_probe(&pnp->dev,
+                               pnp_get_resource(pnp, IORESOURCE_IO, 0), 8);
        else
                return cmos_do_probe(&pnp->dev,
-                                    &pnp->res.port_resource[0],
-                                    pnp->res.irq_resource[0].start);
+                               pnp_get_resource(pnp, IORESOURCE_IO, 0),
+                               pnp_irq(pnp, 0));
 }
 
 static void __exit cmos_pnp_remove(struct pnp_dev *pnp)
@@ -689,7 +1013,7 @@ static void __exit cmos_pnp_remove(struct pnp_dev *pnp)
 
 static int cmos_pnp_suspend(struct pnp_dev *pnp, pm_message_t mesg)
 {
-       return cmos_suspend(&pnp->dev, mesg);
+       return cmos_suspend(&pnp->dev);
 }
 
 static int cmos_pnp_resume(struct pnp_dev *pnp)
@@ -702,6 +1026,13 @@ static int cmos_pnp_resume(struct pnp_dev *pnp)
 #define        cmos_pnp_resume         NULL
 #endif
 
+static void cmos_pnp_shutdown(struct pnp_dev *pnp)
+{
+       if (system_state == SYSTEM_POWER_OFF && !cmos_poweroff(&pnp->dev))
+               return;
+
+       cmos_do_shutdown();
+}
 
 static const struct pnp_device_id rtc_ids[] = {
        { .id = "PNP0b00", },
@@ -716,6 +1047,7 @@ static struct pnp_driver cmos_pnp_driver = {
        .id_table       = rtc_ids,
        .probe          = cmos_pnp_probe,
        .remove         = __exit_p(cmos_pnp_remove),
+       .shutdown       = cmos_pnp_shutdown,
 
        /* flag ensures resume() gets called, and stops syslog spam */
        .flags          = PNP_DRIVER_RES_DO_NOT_CHANGE,
@@ -723,20 +1055,48 @@ static struct pnp_driver cmos_pnp_driver = {
        .resume         = cmos_pnp_resume,
 };
 
-static int __init cmos_init(void)
-{
-       return pnp_register_driver(&cmos_pnp_driver);
-}
-module_init(cmos_init);
+#endif /* CONFIG_PNP */
 
-static void __exit cmos_exit(void)
+#ifdef CONFIG_OF
+static const struct of_device_id of_cmos_match[] = {
+       {
+               .compatible = "motorola,mc146818",
+       },
+       { },
+};
+MODULE_DEVICE_TABLE(of, of_cmos_match);
+
+static __init void cmos_of_init(struct platform_device *pdev)
 {
-       pnp_unregister_driver(&cmos_pnp_driver);
+       struct device_node *node = pdev->dev.of_node;
+       struct rtc_time time;
+       int ret;
+       const __be32 *val;
+
+       if (!node)
+               return;
+
+       val = of_get_property(node, "ctrl-reg", NULL);
+       if (val)
+               CMOS_WRITE(be32_to_cpup(val), RTC_CONTROL);
+
+       val = of_get_property(node, "freq-reg", NULL);
+       if (val)
+               CMOS_WRITE(be32_to_cpup(val), RTC_FREQ_SELECT);
+
+       get_rtc_time(&time);
+       ret = rtc_valid_tm(&time);
+       if (ret) {
+               struct rtc_time def_time = {
+                       .tm_year = 1,
+                       .tm_mday = 1,
+               };
+               set_rtc_time(&def_time);
+       }
 }
-module_exit(cmos_exit);
-
-#else  /* no PNP */
-
+#else
+static inline void cmos_of_init(struct platform_device *pdev) {}
+#endif
 /*----------------------------------------------------------------*/
 
 /* Platform setup should have set up an RTC device, when PNP is
@@ -745,6 +1105,8 @@ module_exit(cmos_exit);
 
 static int __init cmos_platform_probe(struct platform_device *pdev)
 {
+       cmos_of_init(pdev);
+       cmos_wake_setup(&pdev->dev);
        return cmos_do_probe(&pdev->dev,
                        platform_get_resource(pdev, IORESOURCE_IO, 0),
                        platform_get_irq(pdev, 0));
@@ -758,35 +1120,72 @@ static int __exit cmos_platform_remove(struct platform_device *pdev)
 
 static void cmos_platform_shutdown(struct platform_device *pdev)
 {
+       if (system_state == SYSTEM_POWER_OFF && !cmos_poweroff(&pdev->dev))
+               return;
+
        cmos_do_shutdown();
 }
 
+/* work with hotplug and coldplug */
+MODULE_ALIAS("platform:rtc_cmos");
+
 static struct platform_driver cmos_platform_driver = {
        .remove         = __exit_p(cmos_platform_remove),
        .shutdown       = cmos_platform_shutdown,
        .driver = {
                .name           = (char *) driver_name,
-               .suspend        = cmos_suspend,
-               .resume         = cmos_resume,
+#ifdef CONFIG_PM
+               .pm             = &cmos_pm_ops,
+#endif
+               .of_match_table = of_match_ptr(of_cmos_match),
        }
 };
 
+#ifdef CONFIG_PNP
+static bool pnp_driver_registered;
+#endif
+static bool platform_driver_registered;
+
 static int __init cmos_init(void)
 {
-       return platform_driver_probe(&cmos_platform_driver,
-                       cmos_platform_probe);
+       int retval = 0;
+
+#ifdef CONFIG_PNP
+       retval = pnp_register_driver(&cmos_pnp_driver);
+       if (retval == 0)
+               pnp_driver_registered = true;
+#endif
+
+       if (!cmos_rtc.dev) {
+               retval = platform_driver_probe(&cmos_platform_driver,
+                                              cmos_platform_probe);
+               if (retval == 0)
+                       platform_driver_registered = true;
+       }
+
+       if (retval == 0)
+               return 0;
+
+#ifdef CONFIG_PNP
+       if (pnp_driver_registered)
+               pnp_unregister_driver(&cmos_pnp_driver);
+#endif
+       return retval;
 }
 module_init(cmos_init);
 
 static void __exit cmos_exit(void)
 {
-       platform_driver_unregister(&cmos_platform_driver);
+#ifdef CONFIG_PNP
+       if (pnp_driver_registered)
+               pnp_unregister_driver(&cmos_pnp_driver);
+#endif
+       if (platform_driver_registered)
+               platform_driver_unregister(&cmos_platform_driver);
 }
 module_exit(cmos_exit);
 
 
-#endif /* !PNP */
-
 MODULE_AUTHOR("David Brownell");
 MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");
 MODULE_LICENSE("GPL");