diff options
authorMike Ditto <>2008-12-16 20:17:09 +0000
committerBen Dooks <>2008-12-16 20:17:09 +0000
commita804644a1a31a0b85e4c7d3c49f30419513cb6c1 (patch)
parent1bda71282ded6a2e09a2db7c8884542fb46bfd4f (diff)
i2c-cpm: Detect and report NAK right away instead of timing out
Make the driver report an ENXIO error immediately upon NAK instead of waiting for another interrupt and getting a timeout. When reading from a device that is not present or declines to respond to, e.g., a non-existent register address, CPM immediately reports a NAK condition in the TxBD, but the driver kept waiting until a timeout, which takes 1 second and causes an ugly console error message. Signed-off-by: Mike Ditto <> Acked-by: Jochen Friedrich <> [ reordered description text] Signed-off-by: Ben Dooks <>
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-cpm.c b/drivers/i2c/busses/i2c-cpm.c
index 228f75723063..3fcf78e906db 100644
--- a/drivers/i2c/busses/i2c-cpm.c
+++ b/drivers/i2c/busses/i2c-cpm.c
@@ -365,6 +365,7 @@ static int cpm_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
pmsg = &msgs[tptr];
if (pmsg->flags & I2C_M_RD)
ret = wait_event_interruptible_timeout(cpm->i2c_wait,
+ (in_be16(&tbdf[tptr].cbd_sc) & BD_SC_NAK) ||
!(in_be16(&rbdf[rptr].cbd_sc) & BD_SC_EMPTY),
1 * HZ);