omap: consolidate touch screen initialization among different boards

Add common-board-devices.c that will contain the code for peripheral
devices initializatoin shared between multiple boards.
Start small with touchscreen initialization.

Signed-off-by: Mike Rapoport <mike@compulab.co.il>
Signed-off-by: Tony Lindgren <tony@atomide.com>
diff --git a/arch/arm/mach-omap2/common-board-devices.h b/arch/arm/mach-omap2/common-board-devices.h
new file mode 100644
index 0000000..75f9248d
--- /dev/null
+++ b/arch/arm/mach-omap2/common-board-devices.h
@@ -0,0 +1,18 @@
+#ifndef __OMAP_COMMON_BOARD_DEVICES__
+#define __OMAP_COMMON_BOARD_DEVICES__
+
+#if defined(CONFIG_TOUCHSCREEN_ADS7846) || \
+	defined(CONFIG_TOUCHSCREEN_ADS7846_MODULE)
+struct ads7846_platform_data;
+
+void omap_ads7846_init(int bus_num, int gpio_pendown, int gpio_debounce,
+		       struct ads7846_platform_data *board_pdata);
+#else
+static inline void omap_ads7846_init(int bus_num,
+				     int gpio_pendown, int gpio_debounce,
+				     struct ads7846_platform_data *board_data)
+{
+}
+#endif
+
+#endif /* __OMAP_COMMON_BOARD_DEVICES__ */