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authorMika Westerberg <mika.westerberg@linux.intel.com>2013-05-13 00:54:30 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-05-24 11:14:22 -0700
commit1cd75cf191d5e3995e22d7bfc573939ffeebcc51 (patch)
treed41278befa9396265c29e0c56d5b06c9a7a62041
parent0e293f095529e998677b7e5f4893ad8aec01ea6f (diff)
downloadvexpress-lsk-1cd75cf191d5e3995e22d7bfc573939ffeebcc51.tar.gz
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>
-rw-r--r--drivers/i2c/busses/i2c-designware-core.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c
index 619334994df..3c2812f13d9 100644
--- a/drivers/i2c/busses/i2c-designware-core.c
+++ b/drivers/i2c/busses/i2c-designware-core.c
@@ -349,7 +349,8 @@ static void i2c_dw_xfer_init(struct dw_i2c_dev *dev)
/* Enable the adapter */
dw_writel(dev, 1, DW_IC_ENABLE);
- /* Enable interrupts */
+ /* Clear and enable interrupts */
+ i2c_dw_clear_int(dev);
dw_writel(dev, DW_IC_INTR_DEFAULT_MASK, DW_IC_INTR_MASK);
}