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.
Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
---
drivers/i2c/algos/i2c-algo-bit.c | 3 ++-
include/linux/i2c-algo-bit.h | 1 +
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 525c734..ad0459c 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 4f98148..584ffa0 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 */
--
1.7.7.5
