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@xxxxxxxx>
---
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 *);
--
1.7.7.5
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