Re: [PATCH 2/2] hwmon: (pmbus): Add driver for BluTek BPA-RS600

[Guenter Roeck]

On 3/15/21 9:21 PM, Chris Packham wrote:
> 
> On 16/03/21 4:43 pm, Guenter Roeck wrote:
>> On 3/15/21 7:35 PM, Chris Packham wrote:
>>> The BPA-RS600 is a compact 600W AC to DC removable power supply module.
>>>
>>> Signed-off-by: Chris Packham <chris.packham@xxxxxxxxxxxxxxxxxxx>
>>> ---
> <snip>
>>> +
>>> +static int bpa_rs600_read_word_data(struct i2c_client *client, int page,
>>> +		int phase, int reg)+{
>>> +	int ret;
>>> +
>>> +	if (page > 0)
>>> +		return -ENXIO;
>>> +
>>> +	switch (reg) {
>>> +	case PMBUS_VIN_UV_FAULT_LIMIT:
>>> +	case PMBUS_VIN_OV_FAULT_LIMIT:
>>> +	case PMBUS_VOUT_UV_FAULT_LIMIT:
>>> +	case PMBUS_VOUT_OV_FAULT_LIMIT:
>>> +		ret = -ENXIO;
>> Is that needed ? Why not -ENODATA ?
> 
> Basically these commands get responses on the bus but they don't have 
> valid data (nor are they documented in the datasheet). I'll add a 
> comment to that effect.
> 
> If I'm reading things correctly -ENODATA is a signal to 
> _pmbus_read_word_data use the "normal" read operation. So I need to 

Correct.

> return something other than that. I found another driver (mp2975.c) 
> doing the same thing for what I assume are similar reasons so I went 
> with -ENXIO.
> 
-ENXIO is ok, but please document it.

Thanks,
Guenter