On 4/7/21 12:41 AM, Quan Nguyen wrote: [ ... ] >> >> But then why don't you just use reg_ext to store SOC_VR_HOT_THRESHOLD_REG >> or MEM_HOT_THRESHOLD_REG ? It is already available, after all, and with it >> the code could be simplified to >> >> ret = regmap_read(hwmon->regmap, temperature[channel].reg_ext, &value); >> if (ret) >> return ret; >> > Thank you for the comment. > > Will change code follow this suggestion, will include in next version > >> I don't have a datasheet, but I do wonder what is in bit 9..15. Any idea ? >> Main question is if there is a sign bit, as theoretic as it may be. >> > The original intention was to use this as 9-bit 2-complement value follow LM75, but the fact is that the operation temperature is 0-125 C degree, so we simply use it as-is. > The operational temperature is not the question here. The question is if the chip _reports_ a sign. If it does, it should be handled, even if it is outside the operational range. The reported range is relevant here, not the operational range. After all, the chip won't really blow apart at -1 degrees C. Thanks, Guenter