On Mon, Jul 31, 2023 at 12:11:47AM +0200, Michał Mirosław wrote: > On Sun, Jul 30, 2023 at 10:25:07PM +0200, Andi Shyti wrote: > > On Sat, Jul 29, 2023 at 07:08:57PM +0300, Svyatoslav Ryhel wrote: > > > +static int i2c_hotplug_activate(struct i2c_hotplug_priv *priv) > [...] > > > +{ > > > + int ret; > > > + > > > + if (priv->adap.algo_data) > > > + return 0; > [...] > > > + ret = i2c_add_adapter(&priv->adap); > > > + if (!ret) > > > + priv->adap.algo_data = (void *)1; > > > > You want to set algo_data to "1" in order to keep the > > activate/deactivate ordering. > > > > But if we fail to add the adapter, what's the point to keep it > > active? > > The code above does "if we added the adapter, remember we did so". > IOW, if we failed to add the adapter we don't set the mark so that > the next interrupt edge can trigger another try. Also we prevent > trying to remove an adapter we didn't successfully add. Maybe the function's name is misleading? We could find a better one. Activation/deactivation in this driver means "initialize/shutdown the hotplugged bus" and is done in response to an edge (triggering an interrupt) of the hotplug-detect signal. Best Regards Michał Mirosław