rtc-v3020: add ability to access v3020 chip with GPIOs

The v3020 RTC can be connected to GPIOs as well as to memory-like
interface.  Add ability to use GPIO bit-bang for v3020 read-write access.

[akpm@linux-foundation.org: fix off-by-one in error path]
Signed-off-by: Mike Rapoport <mike@compulab.co.il>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/rtc-v3020.h b/include/linux/rtc-v3020.h
index bf74e63..8ba646e 100644
--- a/include/linux/rtc-v3020.h
+++ b/include/linux/rtc-v3020.h
@@ -14,6 +14,12 @@
  * is used depends on the board. */
 struct v3020_platform_data {
 	int leftshift; /* (1<<(leftshift)) & readl() */
+
+	int use_gpio:1;
+	unsigned int gpio_cs;
+	unsigned int gpio_wr;
+	unsigned int gpio_rd;
+	unsigned int gpio_io;
 };
 
 #define V3020_STATUS_0	0x00