[PATCH] I2C: i2c-algo-pca -- gracefully handle a busy bus

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>

diff --git a/drivers/i2c/algos/i2c-algo-pca.c b/drivers/i2c/algos/i2c-algo-pca.c
index cc3a952..ff2db0d 100644 (file)
--- a/drivers/i2c/algos/i2c-algo-pca.c
+++ b/drivers/i2c/algos/i2c-algo-pca.c
@@ -187,12 +187,14 @@ static int pca_xfer(struct i2c_adapter *i2c_adap,
        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);