tree c7e8173bb0828777b70ba05d0e0442b9ac24c6a4
parent 69d02547cbdf3d571f0aba394ce4b90b5daf6b71
author Edward A. James <eajames@us.ibm.com> 1509123305 -0500
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1512909640 +0100

hwmon: (pmbus/core) Prevent unintentional setting of page to 0xFF


[ Upstream commit 6dcf2fb5e8db3704f50af1f198256cb4e2453f8b ]

The pmbus core may call read/write word data functions with a page value
of -1, intending to perform the operation without setting the page.
However, the read/write word data functions accept only unsigned 8-bit
page numbers, and therefore cannot check for negative page number to
avoid setting the page. This results in setting the page number to 0xFF.
This may result in errors or undefined behavior of some devices
(specifically the ir35221, which allows the page to be set to 0xFF,
but some subsequent operations to read registers may fail).

Switch the pmbus_set_page page parameter to an integer and perform the
check for negative page there. Make read/write functions consistent in
accepting an integer page number parameter.

Signed-off-by: Edward A. James <eajames@us.ibm.com>
Fixes: cbcdec6202c9 ("hwmon: (pmbus): Access word data for STATUS_WORD")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>