i2c: piix4: Add support for multiplexed main adapter in SB800
The SB800 chipset supports a multiplexed main SMBus controller with four ports. The multiplexed ports share the same SMBus address and register set. The port is selected by bits 2:1 of the smb_en register (0x2C). Only one port can be active at any point in time therefore a mutex is needed in order to synchronize access. Additionally, the commit avoids requesting and releasing the SMBus base address index region on every multiplexed transfer by moving the request_region call into piix4_probe. Tested on HP ProLiant MicroServer G7 N54L (where this patch adds support to access sensor data from the w83795adg). Cc: Thomas Brandon <tbrandonau@gmail.com> Cc: Eddi De Pieri <eddi@depieri.net> Signed-off-by: NChristian Fetzer <fetzer.ch@gmail.com> Reviewed-by: NMika Westerberg <mika.westerberg@linux.intel.com> Reviewed-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: NWolfram Sang <wsa@the-dreams.de>
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