[I2C] i2c-elektor: getting rid of cli()/sti() usage

Signed-off-by: Aristeu Sergio Rozanski Filho <aris@cathedrallabs.org>

--- x25/drivers/i2c/busses/i2c-elektor.c.old	2004-11-24 08:23:07.000000000 -0200
+++ x25/drivers/i2c/busses/i2c-elektor.c	2004-11-24 13:16:44.000000000 -0200
@@ -59,6 +59,7 @@ static int mmapped;
 
 static wait_queue_head_t pcf_wait;
 static int pcf_pending;
+static spinlock_t lock;
 
 /* ----- local functions ----------------------------------------------	*/
 
@@ -111,14 +112,24 @@ static int pcf_isa_getclock(void *data)
 static void pcf_isa_waitforpin(void) {
 
 	int timeout = 2;
+	long flags;
 
 	if (irq > 0) {
-		cli();
+		spin_lock_irqsave(&lock, flags);
 		if (pcf_pending == 0) {
-			interruptible_sleep_on_timeout(&pcf_wait, timeout*HZ );
-		} else
+			spin_unlock_irqrestore(&lock, flags);
+			if (interruptible_sleep_on_timeout(&pcf_wait,
+								timeout*HZ)) {
+				spin_lock_irqsave(&lock, flags);
+				if (pcf_pending == 1) {
+					pcf_pending = 0;
+				}
+				spin_unlock_irqrestore(&lock, flags);
+			}
+		} else {
 			pcf_pending = 0;
-		sti();
+			spin_unlock_irqrestore(&lock, flags);
+		}
 	} else {
 		udelay(100);
 	}
@@ -126,7 +137,9 @@ static void pcf_isa_waitforpin(void) {
 
 
 static irqreturn_t pcf_isa_handler(int this_irq, void *dev_id, struct pt_regs *regs) {
+	spin_lock(&lock);
 	pcf_pending = 1;
+	spin_unlock(&lock);
 	wake_up_interruptible(&pcf_wait);
 	return IRQ_HANDLED;
 }
@@ -134,6 +147,7 @@ static irqreturn_t pcf_isa_handler(int t
 
 static int pcf_isa_init(void)
 {
+	spin_lock_init(&lock);
 	if (!mmapped) {
 		if (!request_region(base, 2, "i2c (isa bus adapter)")) {
 			printk(KERN_ERR