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authorDaniel Vetter <daniel.vetter@ffwll.ch>2012-02-28 00:39:39 +0100
committerDaniel Vetter <daniel.vetter@ffwll.ch>2012-02-29 20:47:42 +0100
commitb0209b39951868069710c1e39ca14add9fa77ada (patch)
tree56f69726580d40ee2ea8004ee8387907dc291aa7 /include/linux/i2c-algo-bit.h
parent1298330bd6ab5ea7c9616a242a6f40ef4968521d (diff)
downloadop-kernel-dev-b0209b39951868069710c1e39ca14add9fa77ada.zip
op-kernel-dev-b0209b39951868069710c1e39ca14add9fa77ada.tar.gz
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>
Diffstat (limited to 'include/linux/i2c-algo-bit.h')
-rw-r--r--include/linux/i2c-algo-bit.h1
1 files changed, 1 insertions, 0 deletions
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 */
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