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authorDaniel Mack <daniel@caiaq.de>2009-06-17 16:28:15 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-06-18 13:03:58 -0700
commitc8a06c1ef0bc45915fc45a170c7c60426971304c (patch)
tree9e8f5d3890766bca481c15aac69ef96f52612874 /include/linux/w1-gpio.h
parent9916219579d078c80377dd3988c2cc213536d868 (diff)
w1-gpio: add external pull-up enable callback
On embedded devices, sleep mode conditions can be tricky to handle, Especially when processors tend to pull-down the w1 bus during sleep. Bus slaves (such as the ds2760) may interpret this as a reason for power-down conditions and entirely switch off the device. This patch adds a callback function pointer to let users switch on and off the external pull-up resistor. This lets the outside world know whether the processor is currently actively driving the bus or not. When this callback is not provided, the code behaviour won't change. Signed-off-by: Daniel Mack <daniel@caiaq.de> Acked-by: Ville Syrjala <syrjala@sci.fi> Acked-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/w1-gpio.h')
-rw-r--r--include/linux/w1-gpio.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/w1-gpio.h b/include/linux/w1-gpio.h
index 9797fec7748a..3adeff82212f 100644
--- a/include/linux/w1-gpio.h
+++ b/include/linux/w1-gpio.h
@@ -18,6 +18,7 @@
struct w1_gpio_platform_data {
unsigned int pin;
unsigned int is_open_drain:1;
+ void (*enable_external_pullup)(int enable);
};
#endif /* _LINUX_W1_GPIO_H */