mfd: Deny ab8500 suspend if i2c transfer is ongoing

If we are in the middle of an I2C transfer we need to deny suspend
of the AB8500 core. Implement an atomic reference counter for the
I2C operations to make sure we don't do this.

Signed-off-by: Jonas Aaberg <jonas.aberg@stericsson.com>
Reviewed-by: Mattias Wallin <mattias.wallin@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/include/linux/mfd/abx500/ab8500.h b/include/linux/mfd/abx500/ab8500.h
index d798f5b..91dd3ef 100644
--- a/include/linux/mfd/abx500/ab8500.h
+++ b/include/linux/mfd/abx500/ab8500.h
@@ -7,6 +7,7 @@
 #ifndef MFD_AB8500_H
 #define MFD_AB8500_H
 
+#include <linux/atomic.h>
 #include <linux/mutex.h>
 
 struct device;
@@ -224,6 +225,7 @@
  * @dev: parent device
  * @lock: read/write operations lock
  * @irq_lock: genirq bus lock
+ * @transfer_ongoing: 0 if no transfer ongoing
  * @irq: irq line
  * @version: chip version id (e.g. ab8500 or ab9540)
  * @chip_id: chip revision id
@@ -242,7 +244,7 @@
 	struct device	*dev;
 	struct mutex	lock;
 	struct mutex	irq_lock;
-
+	atomic_t	transfer_ongoing;
 	int		irq_base;
 	int		irq;
 	enum ab8500_version version;
@@ -288,6 +290,8 @@
 				 enum ab8500_version version);
 extern int __devexit ab8500_exit(struct ab8500 *ab8500);
 
+extern int ab8500_suspend(struct ab8500 *ab8500);
+
 static inline int is_ab8500(struct ab8500 *ab)
 {
 	return ab->version == AB8500_VERSION_AB8500;