Hi Lucas, On 02/17/2017 08:07 AM, Lucas Tanure wrote:
Hi, We have here in our company an internal hardware platform for our linux development that can measure current in a few circuits with nanoamps precision. The measured values are exposed by a 32bit register that must read as a 32bit float. If we follow the hwmon sysfs interface we loss precision converting to milliamps, where the final value exposed is zero. Example : Measure 291nA becomes 0mA under sysfs curr1_input The best solution for me would be a file in sysfs that I could just expose the float from my register (like curr1_input_float), this solution has two benefits for me: - I wouldn't need to convert my internal float to int - This would give the best precision that I can have from my hardware The value could be exposed as a 32bit hex string, like 0x349c3abc. So, how should I proceed with this ?
A hex string would be really bad; userspace (generic) would not know what to do with it. You could on purpose violate the ABI and report the current in nano-Amps with currX_input (properly documented). This way the sensors command would still work after proper adjustments in /etc/sensors3.conf. If the current sense resistor is configurable, you could also not tell me at all and assume a current sense resistor which is 1,000,000 times larger than the one you actually use (after all, currency is usually measured as voltage loss over a current sense resistor). Another possibility would be to add a curr1_input_na attribute, but I would prefer the above mechanism. Guenter -- To unsubscribe from this list: send the line "unsubscribe linux-hwmon" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
