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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 11:35:47 -0700
commit6fddcaed97292f001589c2c12878c76a394a52a4 (patch)
tree4333f27d725fba7ac2785cdb4dfe4655782b246d
parentd66affca2391a38a0fdfea47d263da089ab23d2f (diff)
downloadvexpress-lsk-6fddcaed97292f001589c2c12878c76a394a52a4.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 8dbeef117ff..2db362854d7 100644
--- a/drivers/i2c/busses/i2c-designware-core.c
+++ b/drivers/i2c/busses/i2c-designware-core.c
@@ -361,7 +361,8 @@ 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);
}