From 6fddcaed97292f001589c2c12878c76a394a52a4 Mon Sep 17 00:00:00 2001 From: Mika Westerberg Date: Mon, 13 May 2013 00:54:30 +0000 Subject: 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 Signed-off-by: Wolfram Sang Signed-off-by: Greg Kroah-Hartman --- drivers/i2c/busses/i2c-designware-core.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) 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); } -- cgit v1.2.3-18-g5258