From icampbell@arcom.com Wed Aug 10 08:05:05 2005
Subject: I2C: i2c-algo-pca -- gracefully handle a busy bus
From: Ian Campbell <icampbell@arcom.com>
To: Greg KH <gregkh@suse.de>
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 <icampbell@arcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
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);