p54usb: Add device ID for Dell WLA3310 USB
[safe/jmp/linux-2.6] / drivers / rtc / rtc-cmos.c
index 6ea349a..e9aa814 100644 (file)
@@ -35,6 +35,7 @@
 #include <linux/spinlock.h>
 #include <linux/platform_device.h>
 #include <linux/mod_devicetable.h>
+#include <linux/log2.h>
 
 /* this is for "generic access to PC-style RTC" using CMOS_READ/CMOS_WRITE */
 #include <asm-generic/rtc.h>
@@ -58,7 +59,7 @@ 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";
 
@@ -143,6 +144,43 @@ static inline int hpet_unregister_irq_handler(irq_handler_t handler)
 
 /*----------------------------------------------------------------*/
 
+#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(2));
+}
+
+#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
@@ -203,26 +241,26 @@ static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t)
        /* REVISIT this assumes PC style usage:  always BCD */
 
        if (((unsigned)t->time.tm_sec) < 0x60)
-               t->time.tm_sec = BCD2BIN(t->time.tm_sec);
+               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);
+               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);
+               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);
+                       t->time.tm_mday = bcd2bin(t->time.tm_mday);
                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_mon = bcd2bin(t->time.tm_mon) - 1;
                        else
                                t->time.tm_mon = -1;
                }
@@ -294,19 +332,19 @@ static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
        /* Writing 0xff means "don't care" or "match all".  */
 
        mon = t->time.tm_mon + 1;
-       mon = (mon <= 12) ? BIN2BCD(mon) : 0xff;
+       mon = (mon <= 12) ? bin2bcd(mon) : 0xff;
 
        mday = t->time.tm_mday;
-       mday = (mday >= 1 && mday <= 31) ? BIN2BCD(mday) : 0xff;
+       mday = (mday >= 1 && mday <= 31) ? bin2bcd(mday) : 0xff;
 
        hrs = t->time.tm_hour;
-       hrs = (hrs < 24) ? BIN2BCD(hrs) : 0xff;
+       hrs = (hrs < 24) ? bin2bcd(hrs) : 0xff;
 
        min = t->time.tm_min;
-       min = (min < 60) ? BIN2BCD(min) : 0xff;
+       min = (min < 60) ? bin2bcd(min) : 0xff;
 
        sec = t->time.tm_sec;
-       sec = (sec < 60) ? BIN2BCD(sec) : 0xff;
+       sec = (sec < 60) ? bin2bcd(sec) : 0xff;
 
        spin_lock_irq(&rtc_lock);
 
@@ -347,6 +385,8 @@ static int cmos_irq_set_freq(struct device *dev, int freq)
        if (!is_valid_irq(cmos->irq))
                return -ENXIO;
 
+       if (!is_power_of_2(freq))
+               return -EINVAL;
        /* 0 = no irqs; 1 = 2^15 Hz ... 15 = 2^0 Hz */
        f = ffs(freq);
        if (f-- > 16)
@@ -380,49 +420,43 @@ static int cmos_irq_set_state(struct device *dev, int enabled)
        return 0;
 }
 
-#if defined(CONFIG_RTC_INTF_DEV) || defined(CONFIG_RTC_INTF_DEV_MODULE)
-
-static int
-cmos_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
+static int cmos_alarm_irq_enable(struct device *dev, unsigned int enabled)
 {
        struct cmos_rtc *cmos = dev_get_drvdata(dev);
        unsigned long   flags;
 
-       switch (cmd) {
-       case RTC_AIE_OFF:
-       case RTC_AIE_ON:
-       case RTC_UIE_OFF:
-       case RTC_UIE_ON:
-               if (!is_valid_irq(cmos->irq))
-                       return -EINVAL;
-               break;
-       /* PIE ON/OFF is handled by cmos_irq_set_state() */
-       default:
-               return -ENOIOCTLCMD;
-       }
+       if (!is_valid_irq(cmos->irq))
+               return -EINVAL;
 
        spin_lock_irqsave(&rtc_lock, flags);
-       switch (cmd) {
-       case RTC_AIE_OFF:       /* alarm off */
-               cmos_irq_disable(cmos, RTC_AIE);
-               break;
-       case RTC_AIE_ON:        /* alarm on */
+
+       if (enabled)
                cmos_irq_enable(cmos, RTC_AIE);
-               break;
-       case RTC_UIE_OFF:       /* update off */
-               cmos_irq_disable(cmos, RTC_UIE);
-               break;
-       case RTC_UIE_ON:        /* update on */
-               cmos_irq_enable(cmos, RTC_UIE);
-               break;
-       }
+       else
+               cmos_irq_disable(cmos, RTC_AIE);
+
        spin_unlock_irqrestore(&rtc_lock, flags);
        return 0;
 }
 
-#else
-#define        cmos_rtc_ioctl  NULL
-#endif
+static int cmos_update_irq_enable(struct device *dev, unsigned int enabled)
+{
+       struct cmos_rtc *cmos = dev_get_drvdata(dev);
+       unsigned long   flags;
+
+       if (!is_valid_irq(cmos->irq))
+               return -EINVAL;
+
+       spin_lock_irqsave(&rtc_lock, flags);
+
+       if (enabled)
+               cmos_irq_enable(cmos, RTC_UIE);
+       else
+               cmos_irq_disable(cmos, RTC_UIE);
+
+       spin_unlock_irqrestore(&rtc_lock, flags);
+       return 0;
+}
 
 #if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
 
@@ -463,14 +497,15 @@ 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,
+       .irq_set_freq           = cmos_irq_set_freq,
+       .irq_set_state          = cmos_irq_set_state,
+       .alarm_irq_enable       = cmos_alarm_irq_enable,
+       .update_irq_enable      = cmos_update_irq_enable,
 };
 
 /*----------------------------------------------------------------*/
@@ -491,12 +526,21 @@ cmos_nvram_read(struct kobject *kobj, struct bin_attribute *attr,
 
        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, off += NVRAM_OFFSET; count--; retval++, off++)
-               *buf++ = CMOS_READ(off);
+       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;
@@ -512,6 +556,8 @@ cmos_nvram_write(struct kobject *kobj, struct bin_attribute *attr,
        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;
 
@@ -520,15 +566,20 @@ cmos_nvram_write(struct kobject *kobj, struct bin_attribute *attr,
         * 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, off += NVRAM_OFFSET; count--; retval++, off++) {
+       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
+               else if (off < 128)
                        CMOS_WRITE(*buf++, off);
+               else if (can_bank2)
+                       cmos_write_bank2(*buf++, off);
+               else
+                       break;
        }
        spin_unlock_irq(&rtc_lock);
 
@@ -539,7 +590,6 @@ static struct bin_attribute nvram = {
        .attr = {
                .name   = "nvram",
                .mode   = S_IRUGO | S_IWUSR,
-               .owner  = THIS_MODULE,
        },
 
        .read   = cmos_nvram_read,
@@ -631,17 +681,20 @@ cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
 
        /* 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, and for now we ignore the way newer
-        * chips can address 256 bytes (using two more i/o ports).
+        * 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__)
+#elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) \
+                       || defined(__sparc__) || defined(__mips__)
        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
@@ -675,7 +728,7 @@ cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
 
        cmos_rtc.dev = dev;
        dev_set_drvdata(dev, &cmos_rtc);
-       rename_region(ports, cmos_rtc.rtc->dev.bus_id);
+       rename_region(ports, dev_name(&cmos_rtc.rtc->dev));
 
        spin_lock_irq(&rtc_lock);
 
@@ -699,7 +752,8 @@ cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
        /* FIXME teach the alarm code how to handle binary mode;
         * <asm-generic/rtc.h> doesn't know 12-hour mode either.
         */
-       if (!(rtc_control & RTC_24H) || (rtc_control & (RTC_DM_BINARY))) {
+       if (is_valid_irq(rtc_irq) &&
+           (!(rtc_control & RTC_24H) || (rtc_control & (RTC_DM_BINARY)))) {
                dev_dbg(dev, "only 24-hr BCD mode supported\n");
                retval = -ENXIO;
                goto cleanup1;
@@ -722,7 +776,7 @@ cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
                        rtc_cmos_int_handler = cmos_interrupt;
 
                retval = request_irq(rtc_irq, rtc_cmos_int_handler,
-                               IRQF_DISABLED, cmos_rtc.rtc->dev.bus_id,
+                               IRQF_DISABLED, dev_name(&cmos_rtc.rtc->dev),
                                cmos_rtc.rtc);
                if (retval < 0) {
                        dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq);
@@ -739,16 +793,15 @@ cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
                goto cleanup2;
        }
 
-       pr_info("%s: alarms up to one %s%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" : "",
-                       is_hpet_enabled() ? ", hpet irqs" : "");
+       pr_info("%s: %s%s, %zd bytes nvram%s\n",
+               dev_name(&cmos_rtc.rtc->dev),
+               !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;
 
@@ -800,7 +853,6 @@ static void __exit cmos_do_remove(struct device *dev)
 static int cmos_suspend(struct device *dev, pm_message_t mesg)
 {
        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 */
@@ -809,14 +861,15 @@ static int cmos_suspend(struct device *dev, pm_message_t mesg)
        if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
                unsigned char   mask;
 
-               if (do_wake)
+               if (device_may_wakeup(dev))
                        mask = RTC_IRQMASK & ~RTC_AIE;
                else
                        mask = RTC_IRQMASK;
                tmp &= ~mask;
                CMOS_WRITE(tmp, RTC_CONTROL);
-               hpet_mask_rtc_irq_bit(mask);
 
+               /* shut down hpet emulation - we don't need it for alarm */
+               hpet_mask_rtc_irq_bit(RTC_PIE|RTC_AIE|RTC_UIE);
                cmos_checkintr(cmos, tmp);
        }
        spin_unlock_irq(&rtc_lock);
@@ -830,13 +883,24 @@ static int cmos_suspend(struct device *dev, pm_message_t mesg)
        }
 
        pr_debug("%s: suspend%s, ctrl %02x\n",
-                       cmos_rtc.rtc->dev.bus_id,
+                       dev_name(&cmos_rtc.rtc->dev),
                        (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, PMSG_HIBERNATE);
+}
+
 static int cmos_resume(struct device *dev)
 {
        struct cmos_rtc *cmos = dev_get_drvdata(dev);
@@ -875,7 +939,7 @@ static int cmos_resume(struct device *dev)
        }
 
        pr_debug("%s: resume, ctrl %02x\n",
-                       cmos_rtc.rtc->dev.bus_id,
+                       dev_name(&cmos_rtc.rtc->dev),
                        tmp);
 
        return 0;
@@ -884,6 +948,12 @@ static int cmos_resume(struct device *dev)
 #else
 #define        cmos_suspend    NULL
 #define        cmos_resume     NULL
+
+static inline int cmos_poweroff(struct device *dev)
+{
+       return -ENOSYS;
+}
+
 #endif
 
 /*----------------------------------------------------------------*/
@@ -896,6 +966,92 @@ static int cmos_resume(struct device *dev)
  * predate even PNPBIOS should set up platform_bus devices.
  */
 
+#ifdef CONFIG_ACPI
+
+#include <linux/acpi.h>
+
+#ifdef CONFIG_PM
+static u32 rtc_handler(void *context)
+{
+       acpi_clear_event(ACPI_EVENT_RTC);
+       acpi_disable_event(ACPI_EVENT_RTC, 0);
+       return ACPI_INTERRUPT_HANDLED;
+}
+
+static inline void rtc_wake_setup(void)
+{
+       acpi_install_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler, NULL);
+       /*
+        * 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);
+}
+#else
+#define rtc_wake_setup()       do{}while(0)
+#define rtc_wake_on            NULL
+#define rtc_wake_off           NULL
+#endif
+
+/* 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 __devinit
+cmos_wake_setup(struct device *dev)
+{
+       if (acpi_disabled)
+               return;
+
+       rtc_wake_setup();
+       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 __devinit
+cmos_wake_setup(struct device *dev)
+{
+}
+
+#endif
+
 #ifdef CONFIG_PNP
 
 #include <linux/pnp.h>
@@ -903,10 +1059,8 @@ static int cmos_resume(struct device *dev)
 static int __devinit
 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
@@ -942,6 +1096,13 @@ 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", },
@@ -956,6 +1117,7 @@ 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,
@@ -973,6 +1135,7 @@ static struct pnp_driver cmos_pnp_driver = {
 
 static int __init cmos_platform_probe(struct platform_device *pdev)
 {
+       cmos_wake_setup(&pdev->dev);
        return cmos_do_probe(&pdev->dev,
                        platform_get_resource(pdev, IORESOURCE_IO, 0),
                        platform_get_irq(pdev, 0));
@@ -986,6 +1149,9 @@ 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();
 }
 
@@ -1002,31 +1168,47 @@ static struct platform_driver cmos_platform_driver = {
        }
 };
 
+#ifdef CONFIG_PNP
+static bool pnp_driver_registered;
+#endif
+static bool platform_driver_registered;
+
 static int __init cmos_init(void)
 {
+       int retval = 0;
+
 #ifdef CONFIG_PNP
-       if (pnp_platform_devices)
-               return pnp_register_driver(&cmos_pnp_driver);
-       else
-               return platform_driver_probe(&cmos_platform_driver,
-                       cmos_platform_probe);
-#else
-       return platform_driver_probe(&cmos_platform_driver,
-                       cmos_platform_probe);
-#endif /* 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)
 {
 #ifdef CONFIG_PNP
-       if (pnp_platform_devices)
+       if (pnp_driver_registered)
                pnp_unregister_driver(&cmos_pnp_driver);
-       else
+#endif
+       if (platform_driver_registered)
                platform_driver_unregister(&cmos_platform_driver);
-#else
-       platform_driver_unregister(&cmos_platform_driver);
-#endif /* CONFIG_PNP */
 }
 module_exit(cmos_exit);