onewire: w1-gpio: add ext_pullup_enable pin in platform data

In the process of porting boards to devicetree implemenation, we should
keep information about external circuitry where they belong - the
individual drivers.

This patch adds a way to specify a GPIO to drive the (optional) external
pull-up logic, rather than using a function pointer for that.

Signed-off-by: Daniel Mack <zonque@gmail.com>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Acked-by: Ville Syrjälä <syrjala@sci.fi>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/include/linux/w1-gpio.h b/include/linux/w1-gpio.h
index 3adeff8..065e3ae 100644
--- a/include/linux/w1-gpio.h
+++ b/include/linux/w1-gpio.h
@@ -19,6 +19,7 @@
 	unsigned int pin;
 	unsigned int is_open_drain:1;
 	void (*enable_external_pullup)(int enable);
+	unsigned int ext_pullup_enable_pin;
 };
 
 #endif /* _LINUX_W1_GPIO_H */