driver-core: Add attribute argument to class_attribute show/store

Passing the attribute to the low level IO functions allows all kinds
of cleanups, by sharing low level IO code without requiring
an own function for every piece of data.

Also drivers can extend the attributes with own data fields
and use that in the low level function.

This makes the class attributes the same as sysdev_class attributes
and plain attributes.

This will allow further cleanups in drivers.

Full tree sweep converting all users.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 9006fdb..6d1b866 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -623,7 +623,9 @@
  * /sys/class/gpio/unexport ... write-only
  *	integer N ... number of GPIO to unexport
  */
-static ssize_t export_store(struct class *class, const char *buf, size_t len)
+static ssize_t export_store(struct class *class,
+				struct class_attribute *attr,
+				const char *buf, size_t len)
 {
 	long	gpio;
 	int	status;
@@ -653,7 +655,9 @@
 	return status ? : len;
 }
 
-static ssize_t unexport_store(struct class *class, const char *buf, size_t len)
+static ssize_t unexport_store(struct class *class,
+				struct class_attribute *attr,
+				const char *buf, size_t len)
 {
 	long	gpio;
 	int	status;