Hi Adam, > Am 10.09.2019 um 20:51 schrieb H. Nikolaus Schaller <hns@xxxxxxxxxxxxx>: > > Hi, > >> Am 10.09.2019 um 20:30 schrieb Adam Ford <aford173@xxxxxxxxx>: >> >> On Tue, Sep 10, 2019 at 11:59 AM H. Nikolaus Schaller <hns@xxxxxxxxxxxxx> wrote: >>> >> >> I assumed this to be -EINVAL, but I'd be happy to be wrong. > > It seems that cat microvolts stringifies the int returned from reading > the regulator voltage. > > Since it is initialized to -EINVAL it returns "-22" as string instead of > converting into an errno return when reading /sys... So one step is > missing a proper error check. Ok, found it in regulator_uV_show(). ret = sprintf(buf, "%d\n", regulator_get_voltage_rdev(rdev)); simply prints the result into a string. But regulator_get_voltage_rdev() (or _regulator_get_voltage() before v5.3-rc1) may return errors like -EPROBE_DEFER or -EINVAL or whatever rdev->desc->ops->get_voltage_sel(rdev) returns. So this is clearly a bug in regulator_uV_show(). > But that is just a symptom that there is no call to set a good voltage. That is the next issue to find... BR, Nikolaus
