]> git.karo-electronics.de Git - linux-beck.git/commit
i2c: mux: pca954x: fix i2c mux selection caching
authorRussell King <rmk+kernel@armlinux.org.uk>
Sat, 17 Dec 2016 12:10:56 +0000 (12:10 +0000)
committerWolfram Sang <wsa@the-dreams.de>
Sat, 17 Dec 2016 18:29:44 +0000 (19:29 +0100)
commit7f638c1cb0a1112dbe0b682a42db30521646686b
treec745c75df0389c0c779c71d0906169469b1a26c2
parent493ff7e2cdda9182fb709d3681315180d9165bd8
i2c: mux: pca954x: fix i2c mux selection caching

smbus functions return -ve on error, 0 on success.  However,
__i2c_transfer() have a different return signature - -ve on error, or
number of buffers transferred (which may be zero or greater.)

The upshot of this is that the sense of the test is reversed when using
the mux on a bus supporting the master_xfer method: we cache the value
and never retry if we fail to transfer any buffers, but if we succeed,
we clear the cached value.

Fix this by making pca954x_reg_write() return a negative error code for
all failure cases.

Fixes: 463e8f845cbf ("i2c: mux: pca954x: retry updating the mux selection on failure")
Acked-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
drivers/i2c/muxes/i2c-mux-pca954x.c