Re: [PATCH v2 2/4] soundwire: core: add device tree support for slave devices

[Srinivas Kandagatla]

On 09/08/2019 06:46, Vinod Koul wrote:
> > > > +int sdw_of_find_slaves(struct sdw_bus *bus)
> > > > +{
> > > > +ÂÂÂ struct device *dev = bus->dev;
> > > > +ÂÂÂ struct device_node *node;
> > > > +
> > > > +ÂÂÂ for_each_child_of_node(bus->dev->of_node, node) {
> > > > +ÂÂÂÂÂÂÂ struct sdw_slave_id id;
> > > > +ÂÂÂÂÂÂÂ const char *compat = NULL;
> > > > +ÂÂÂÂÂÂÂ int unique_id, ret;
> > > > +ÂÂÂÂÂÂÂ int ver, mfg_id, part_id, class_id;
> > > > +
> > > > +ÂÂÂÂÂÂÂ compat = of_get_property(node, "compatible", NULL);
> > > > +ÂÂÂÂÂÂÂ if (!compat)
> > > > +ÂÂÂÂÂÂÂÂÂÂÂ continue;
> > > > +
> > > > +ÂÂÂÂÂÂÂ ret = sscanf(compat, "sdw%x,%x,%x,%x",
> > > > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ &ver, &mfg_id, &part_id, &class_id);
> > > > +ÂÂÂÂÂÂÂ if (ret != 4) {
> > > > +ÂÂÂÂÂÂÂÂÂÂÂ dev_err(dev, "Manf ID & Product code not found %s\n",
> > > > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ compat);
> > > > +ÂÂÂÂÂÂÂÂÂÂÂ continue;
> > > > +ÂÂÂÂÂÂÂ }
> > > > +
> > > > +ÂÂÂÂÂÂÂ ret = of_property_read_u32(node, "sdw-instance-id", &unique_id);
> > > > +ÂÂÂÂÂÂÂ if (ret) {
> > > > +ÂÂÂÂÂÂÂÂÂÂÂ dev_err(dev, "Instance id not found:%d\n", ret);
> > > > +ÂÂÂÂÂÂÂÂÂÂÂ continue;
> > > I am confused here.
> > > If you have two identical devices on the same link, isn't this property
> > > required and that should be a real error instead of a continue?
> > Yes, I agree it will be mandatory in such cases.
> >
> > Am okay either way, I dont mind changing it to returning EINVAL in all the
> > cases.
> Do we want to abort? We are in loop scanning for devices so makes sense
> if we do not do that and continue to check next one..

That was my inital plan.
Pierre suggested a better compatible to include instance ID and LinkID 
so this check would be part of the check one before this line.

--srini