On Sun, Nov 02, 2014 at 09:40:09PM +0100, Wolfram Sang wrote: > The current implementation creates muxed i2c-<n> busses as immediate > children of their i2c-<n> parent bus. In case of multiple muxes on one > bus, it is impossible to determine which muxed bus comes from which mux. > > Change the topology so that they are created under the corresponding mux > device. This way, multiple muxes on the same segment can coexist and > children busses are grouped accordingly. > > So for instance, by adding a pca9547 device with address 0x70 to > bus i2c-0, instead of: > > /sys/class/i2c-dev/i2c-0/device/i2c-1 > ... > /sys/class/i2c-dev/i2c-0/device/i2c-8 > > we get: > > /sys/class/i2c-dev/i2c-0/device/0-0070/i2c-1 > ... > /sys/class/i2c-dev/i2c-0/device/0-0070/i2c-8 > > Symlinks for backward compatibility are provided. > > Signed-off-by: Gerlando Falauto <gerlando.falauto@xxxxxxxxxxx> > > [wsa: Ported to top-of-tree (1 line left :)) and added the compatibility > links.] > Signed-off-by: Wolfram Sang <wsa@xxxxxxxxxxxxx> > Cc: Jean Delvare <jdelvare@xxxxxxx> > Cc: Guenter Roeck <linux@xxxxxxxxxxxx> > Cc: Martin Belanger <martin.belanger@xxxxxxxxxxx> > Cc: Rodolfo Giometti <giometti@xxxxxxxxxxxx> > Cc: Michael Lawnick <ml.lawnick@xxxxxx> > Cc: Jeroen De Wachter <jeroen.de.wachter@xxxxxxxxxx> > --- > > So, this is what I came up with to fix the mux-topology problem. Since I don't > really use muxes, please review/comment/test. And give Acks/Tested-by tags if > this works for you. > > drivers/i2c/i2c-mux.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/drivers/i2c/i2c-mux.c b/drivers/i2c/i2c-mux.c > index 2d0847b6be62..5b482ea32faf 100644 > --- a/drivers/i2c/i2c-mux.c > +++ b/drivers/i2c/i2c-mux.c > @@ -138,7 +138,7 @@ struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter *parent, > priv->adap.owner = THIS_MODULE; > priv->adap.algo = &priv->algo; > priv->adap.algo_data = priv; > - priv->adap.dev.parent = &parent->dev; > + priv->adap.dev.parent = mux_dev; > priv->adap.retries = parent->retries; > priv->adap.timeout = parent->timeout; > > @@ -183,6 +183,9 @@ struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter *parent, > return NULL; > } > > + WARN(sysfs_create_link(&parent->dev.kobj, &priv->adap.dev.kobj, priv->adap.dev.kobj.name), > + "can't create compatibility link for old mux name scheme\n"); > + Something seems to be wrong with the linking. I get lots of messages such as sysfs: cannot create duplicate filename '/devices/fff70a000.pcie/pci0000:00/0000:00:00.0/0000:01:00.0/0000:02:09.0/0000:10:00.0/i2c-sam.16/i2c-88/i2c-89' followed by "can't create compatibility link for old mux name scheme". Guenter -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
