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

[Guenter Roeck]

On 8/7/20 11:53 PM, Stephen Kitt wrote:
> On Fri, 7 Aug 2020 21:07:07 +0200, Stephen Kitt <steve@xxxxxxx> wrote:
> 
>> On Fri, 7 Aug 2020 10:32:31 -0700, Guenter Roeck <linux@xxxxxxxxxxxx> 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...

Exactly.

Thanks,
Guenter

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