From icampbell@arcom.com Wed Aug 10 08:05:05 2005 Subject: I2C: i2c-algo-pca -- gracefully handle a busy bus From: Ian Campbell To: Greg KH Date: Wed, 10 Aug 2005 08:51:16 +0100 Message-Id: <1123660276.13258.28.camel@icampbell-debian> I've been running with this patch for a while now, and while I've never seen it trigger except with buggy hardware I think it is a cleaner way to handle a busy bus. I had -EBUSY until about 10 minutes ago but -EIO seems to be what most of the existing algo drivers will return in the same circumstances. Signed-off-by: Ian Campbell Signed-off-by: Greg Kroah-Hartman --- drivers/i2c/algos/i2c-algo-pca.c | 12 +++++++----- 1 files changed, 7 insertions(+), 5 deletions(-) --- gregkh-2.6.orig/drivers/i2c/algos/i2c-algo-pca.c 2005-08-10 14:40:03.000000000 -0700 +++ gregkh-2.6/drivers/i2c/algos/i2c-algo-pca.c 2005-08-10 14:40:08.000000000 -0700 @@ -187,12 +187,14 @@ int numbytes = 0; int state; int ret; + int timeout = 100; - state = pca_status(adap); - if ( state != 0xF8 ) { - dev_dbg(&i2c_adap->dev, "bus is not idle. status is %#04x\n", state ); - /* FIXME: what to do. Force stop ? */ - return -EREMOTEIO; + while ((state = pca_status(adap)) != 0xf8 && timeout--) { + msleep(10); + } + if (state != 0xf8) { + dev_dbg(&i2c_adap->dev, "bus is not idle. status is %#04x\n", state); + return -EIO; } DEB1("{{{ XFER %d messages\n", num);