i2c: designware: always clear interrupts before enabling them
authorMika Westerberg <mika.westerberg@linux.intel.com>
Mon, 13 May 2013 00:54:30 +0000 (00:54 +0000)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Fri, 24 May 2013 18:14:22 +0000 (11:14 -0700)
commit1cd75cf191d5e3995e22d7bfc573939ffeebcc51
treed41278befa9396265c29e0c56d5b06c9a7a62041
parent0e293f095529e998677b7e5f4893ad8aec01ea6f
i2c: designware: always clear interrupts before enabling them

commit 2a2d95e9d6d29e726cc294b65391917ed2e32bf4 upstream.

If the I2C bus is put to a low power state by an ACPI method it might pull
the SDA line low (as its power is removed). Once the bus is put to full
power state again, the SDA line is pulled back to high. This transition
looks like a STOP condition from the controller point-of-view which sets
STOP detected bit in its status register causing the driver to fail
subsequent transfers.

Fix this by always clearing all interrupts before we start a transfer.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/i2c/busses/i2c-designware-core.c