On Tue, 28 Feb 2012 00:39:39 +0100, Daniel Vetter wrote:
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@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 */
Acked-by: Jean Delvare khali@linux-fr.org