Re: [PATCH v3] hwmon/pmbus: use simple i2c probe function

[Stephen Kitt <steve@sk2.org>]

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On Fri, 7 Aug 2020 21:07:07 +0200, Stephen Kitt <steve@sk2.org> wrote:

> On Fri, 7 Aug 2020 10:32:31 -0700, Guenter Roeck <linux@roeck-us.net> wrote:
> > On Fri, Aug 07, 2020 at 06:28:01PM +0200, Stephen Kitt wrote:  
> > >  
> > > -static int ltc2978_probe(struct i2c_client *client,
> > > -			 const struct i2c_device_id *id)
> > > +static int ltc2978_probe(struct i2c_client *client)
> > >  {
> > >  	int i, chip_id;
> > >  	struct ltc2978_data *data;
> > > @@ -670,10 +669,10 @@ static int ltc2978_probe(struct i2c_client
> > > *client, return chip_id;
> > >  
> > >  	data->id = chip_id;
> > > -	if (data->id != id->driver_data)
> > > +	if (strcmp(client->name, ltc2978_id[data->id].name) != 0)    
> > 
> > I was about to apply this patch, but this is problematic: It assumes that
> > __stringify(id) == ltc2978_id[id].name and that ltc2978_id[id].driver_data
> > == id. While that is curently the case (as far as I can see), it is still
> > unsafe. I think it would be much safer to use i2c_match_id() here.  
> 
> I’m not following the __stringify assumption
[...]

I get it, the code assumes there’s a bijection between the set of names and
the set of driver_data values. So effectively we can’t log the detected name
based on the chip_id...

Regards,

Stephen

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