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| author | Mike Ditto <mditto@consentry.com> | 2008-12-16 20:17:09 +0000 |
|---|---|---|
| committer | Ben Dooks <ben-linux@fluff.org> | 2008-12-16 20:17:09 +0000 |
| commit | a804644a1a31a0b85e4c7d3c49f30419513cb6c1 (patch) | |
| tree | 31ee129f4590b3f99e69e78fe50ce5f503bc4a19 /drivers/i2c | |
| parent | 1bda71282ded6a2e09a2db7c8884542fb46bfd4f (diff) | |
| download | lwn-a804644a1a31a0b85e4c7d3c49f30419513cb6c1.tar.gz lwn-a804644a1a31a0b85e4c7d3c49f30419513cb6c1.zip | |
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 <mditto@consentry.com>
Acked-by: Jochen Friedrich <jochen@scram.de>
[ben-linux@fluff.org: reordered description text]
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Diffstat (limited to 'drivers/i2c')
| -rw-r--r-- | drivers/i2c/busses/i2c-cpm.c | 1 |
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); else |