On Thu, Sep 12, 2019 at 03:45:29PM -0700, Nicolin Chen wrote: > On Thu, Sep 12, 2019 at 03:09:47PM -0700, Guenter Roeck wrote: > > On Thu, Sep 12, 2019 at 02:09:58PM -0700, Nicolin Chen wrote: > > > Hello Guenter, > > > > > > On Thu, Sep 12, 2019 at 11:32:18AM -0700, Guenter Roeck wrote: > > > > On Wed, Sep 11, 2019 at 05:28:14PM -0700, Nicolin Chen wrote: > > > > > Hello Guenter, > > > > > > > > > > Datasheet: http://www.ti.com/lit/ds/symlink/ina3221.pdf > > > > > (At page 32, chapter 8.6.2.14 and 8.6.2.15) > > > > > > > > > > I have two registers that I need to expose to user space: > > > > > Shunt-Voltage-Sum and Shunt-Voltage-Limit registers > > > > > > > > > > Right now in[123]_input of INA3221 are for voltage channels > > > > > while in[456]_input are for Shunt voltage channels. > > > > > > > > > > So can I just use in7_input and in7_crit for them? > > > > > > > > > Doesn't Shunt-Voltage-Limit apply to in[456]_input ? > > > > If so, the limit should be attached to those. > > > > > > The initial patch of ina3221 driver applied Shunt-Voltage-Limits, > > > being named as "Critical Alert Limit Registers" in the datasheet, > > > to curr[123]_crit, corresponding to curr[123] and in[456]_input. > > > > > > And this Shunt-Voltage-Limit-Sum is more related to the reading > > > from Shunt-Voltage-Sum, which we just agreed it to be in7_input. > > > > > You didn't say Shunt-Voltage-Limit-Sum earlier. You said > > Ah....right...it's my fault. Sorry. > > > Shunt-Voltage-Limit. I would agree that Shunt-Voltage-Limit-Sum is > > associated with Shunt-Voltage-Sum, but, again, that is not what you > > said earlier. Confused :-( > > So, those two should be in7_input and in7_crit? And a couple of more questions upon it: 1) There are 3 control bits for the summation of this shunt-voltage-sum register to enable corresponding input channels. But in7_enable only allows users to en/disable all three channels at the same time. So how should I attach three enable bits using ABI? Or should I create a device-specific sysfs node? 2) We have a requirement of providing current-sum and current-limit-sum nodes, for use cases where those enabled channels use same value shunt resistors. It's similar to provide curr[1-3]_crit by dividing shunt[123]_resistor from in[456]_input. So could I deploy curr4_input and curr4_crit nodes for this requirement? Thank you!
