Re: [PATCH v2 2/6] hwmon: (max6697) Drop platform data support

[Guenter Roeck <linux@roeck-us.net>]

On 7/24/24 06:03, Tzung-Bi Shih wrote:
> On Tue, Jul 23, 2024 at 08:44:43AM -0700, Guenter Roeck wrote:
>> +	if (data->type != max6581) {
>> +		if (of_property_read_bool(node, "resistance-cancellation") &&
>> +		    chip->valid_conf & MAX6697_CONF_RESISTANCE) {
>> +			confreg |= MAX6697_CONF_RESISTANCE;
>> +			factor = 1;
>> +		}
>> +	} else {
>> +		if (of_property_read_u32(node, "resistance-cancellation", &vals[0])) {
>> +			if (of_property_read_bool(node, "resistance-cancellation"))
>> +				vals[0] = 0xfe;
>> +			else
>> +				vals[0] = 0;
>> +		}
>> +
>> +		factor = hweight8(vals[0] & 0xfe);
> 
> It doesn't AND with 0xfe originally.
> 

Yes, but the original code uses the value in
	factor += hweight8(pdata->resistance_cancellation >> 1);
	ret = i2c_smbus_write_byte_data(client, MAX6581_REG_RESISTANCE,
                                         pdata->resistance_cancellation >> 1);
which is effectively the same. I can't just use
	factor = hweight8(vals[0] >> 1);
because, unlike resistance_cancellation, val[] is an u32 array which would
not auto-mask the upper bits.

Thanks,
Guenter