summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorDaniel Vetter <daniel.vetter@ffwll.ch>2012-02-28 03:39:39 +0400
committerDaniel Vetter <daniel.vetter@ffwll.ch>2012-02-29 23:47:42 +0400
commitb0209b39951868069710c1e39ca14add9fa77ada (patch)
tree56f69726580d40ee2ea8004ee8387907dc291aa7
parent1298330bd6ab5ea7c9616a242a6f40ef4968521d (diff)
downloadlinux-b0209b39951868069710c1e39ca14add9fa77ada.tar.xz
i2c: export bit-banging algo functions
i915 has a hw i2c controller (gmbus) but for a bunch of stupid reasons we need to be able to fall back to the bit-banging algo on gpio pins. The current code sets up a 2nd i2c controller for the same i2c bus using the bit-banging algo. This has a bunch of issues, the major one being that userspace can directly access this fallback i2c adaptor behind the drivers back. But we need to frob a few registers before and after using fallback gpio bit-banging, so this horribly fails. The new plan is to only set up one i2c adaptor and transparently fall back to bit-banging by directly calling the xfer function of the bit- banging algo in the i2c core. To make that possible, export the 2 i2c algo functions. v2: As suggested by Jean Delvare, simply export the i2c_bit_algo vtable instead of the individual functions. Acked-by: Jean Delvare <khali@linux-fr.org> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
-rw-r--r--drivers/i2c/algos/i2c-algo-bit.c3
-rw-r--r--include/linux/i2c-algo-bit.h1
2 files changed, 3 insertions, 1 deletions
diff --git a/drivers/i2c/algos/i2c-algo-bit.c b/drivers/i2c/algos/i2c-algo-bit.c
index 525c7345fa0b..ad0459c4c1cf 100644
--- a/drivers/i2c/algos/i2c-algo-bit.c
+++ b/drivers/i2c/algos/i2c-algo-bit.c
@@ -610,10 +610,11 @@ static u32 bit_func(struct i2c_adapter *adap)
/* -----exported algorithm data: ------------------------------------- */
-static const struct i2c_algorithm i2c_bit_algo = {
+const struct i2c_algorithm i2c_bit_algo = {
.master_xfer = bit_xfer,
.functionality = bit_func,
};
+EXPORT_SYMBOL(i2c_bit_algo);
/*
* registering functions to load algorithms at runtime
diff --git a/include/linux/i2c-algo-bit.h b/include/linux/i2c-algo-bit.h
index 4f98148c11c3..584ffa0f3282 100644
--- a/include/linux/i2c-algo-bit.h
+++ b/include/linux/i2c-algo-bit.h
@@ -49,5 +49,6 @@ struct i2c_algo_bit_data {
int i2c_bit_add_bus(struct i2c_adapter *);
int i2c_bit_add_numbered_bus(struct i2c_adapter *);
+extern const struct i2c_algorithm i2c_bit_algo;
#endif /* _LINUX_I2C_ALGO_BIT_H */