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.
Signed-off-by: Daniel Vetter daniel.vetter@ffwll.ch --- drivers/i2c/algos/i2c-algo-bit.c | 12 +++++++----- include/linux/i2c-algo-bit.h | 4 ++++ 2 files changed, 11 insertions(+), 5 deletions(-)
diff --git a/drivers/i2c/algos/i2c-algo-bit.c b/drivers/i2c/algos/i2c-algo-bit.c index 525c734..ec1651a 100644 --- a/drivers/i2c/algos/i2c-algo-bit.c +++ b/drivers/i2c/algos/i2c-algo-bit.c @@ -531,8 +531,8 @@ static int bit_doAddress(struct i2c_adapter *i2c_adap, struct i2c_msg *msg) return 0; }
-static int bit_xfer(struct i2c_adapter *i2c_adap, - struct i2c_msg msgs[], int num) +int i2c_bit_xfer(struct i2c_adapter *i2c_adap, + struct i2c_msg msgs[], int num) { struct i2c_msg *pmsg; struct i2c_algo_bit_data *adap = i2c_adap->algo_data; @@ -598,21 +598,23 @@ bailout: adap->post_xfer(i2c_adap); return ret; } +EXPORT_SYMBOL(i2c_bit_xfer);
-static u32 bit_func(struct i2c_adapter *adap) +u32 i2c_bit_func(struct i2c_adapter *adap) { return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SMBUS_READ_BLOCK_DATA | I2C_FUNC_SMBUS_BLOCK_PROC_CALL | I2C_FUNC_10BIT_ADDR | I2C_FUNC_PROTOCOL_MANGLING; } +EXPORT_SYMBOL(i2c_bit_func);
/* -----exported algorithm data: ------------------------------------- */
static const struct i2c_algorithm i2c_bit_algo = { - .master_xfer = bit_xfer, - .functionality = bit_func, + .master_xfer = i2c_bit_xfer, + .functionality = i2c_bit_func, };
/* diff --git a/include/linux/i2c-algo-bit.h b/include/linux/i2c-algo-bit.h index 4f98148..cdd6336 100644 --- a/include/linux/i2c-algo-bit.h +++ b/include/linux/i2c-algo-bit.h @@ -47,6 +47,10 @@ struct i2c_algo_bit_data { int timeout; /* in jiffies */ };
+int i2c_bit_xfer(struct i2c_adapter *i2c_adap, + struct i2c_msg msgs[], int num); +u32 i2c_bit_func(struct i2c_adapter *adap); + int i2c_bit_add_bus(struct i2c_adapter *); int i2c_bit_add_numbered_bus(struct i2c_adapter *);