From mboxrd@z Thu Jan  1 00:00:00 1970
From: Wolfram Sang <wsa@the-dreams.de>
Subject: Re: [PATCH] i2c: mux: pca954x: fix i2c mux selection caching
Date: Sat, 17 Dec 2016 19:30:34 +0100
Message-ID: <20161217183034.GC27020@katana>
References: <E1cIDpI-0005y4-SW@rmk-PC.armlinux.org.uk>
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To: Russell King <rmk+kernel@armlinux.org.uk>
Cc: Peter Rosin <peda@axentia.se>, linux-i2c@vger.kernel.org


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On Sat, Dec 17, 2016 at 12:10:56PM +0000, Russell King wrote:
> 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.)
>=20
> 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.
>=20
> Fix this by making pca954x_reg_write() return a negative error code for
> all failure cases.
>=20
> 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>

Applied to for-current, thanks!


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