On Tue, 2017-08-01 at 12:15 -0500, David Lechner wrote: > On 08/01/2017 11:41 AM, Andy Shevchenko wrote: > > On Tue, 2017-08-01 at 11:21 -0500, David Lechner wrote: > > > On 08/01/2017 10:45 AM, Andy Shevchenko wrote: > > > > > > > > > > > + /* Use hard coded value for reference voltage in > > > > > > > ACPI > > > > > > > case */ > > > > > > > + if (ACPI_COMPANION(&spi->dev)) > > > > > > > + st->vref_mv = > > > > > > > TI_ADS7950_VA_MV_ACPI_DEFAULT; > > > > > > > > > > > > Instead of checking or ACPI, you could just say "if we have > > > > > > a > > > > > > dummy > > > > > > regulator, then use the default value". > > > > > > > > > > > > > Agreed. Sounds sensible to me. Hopefully in DT people will > > > > > provide the right regulator, but chances are this won't > > > > > always happen. > > > > > > > > There is no call like > > > > regulator_is_dummy() > > > > (and, looking into the code of regulator framework, can't be) > > > > > > > > Can you elaborate a bit, maybe I'm missing something obvious? > > > > > > > > > > I haven't tested this, but shouldn't regulator_get_voltage() > > > return > > > an > > > error for a dummy regulator? You could use this as your test. > > > > While it would work it's very fragile. > > > > _regulator_get_voltage() will return error code even for normal > > regulators if something happened there. And user gets an impression > > that > > everything is okay while it's not. > > > > So, I wouldn't go this way. > > In drivers/iio/adc/max11100.c:91. The solution was to only support > raw > value and not scaled if there is a dummy regulator. The comment there is just partially correct. While get_voltage() indeed returns -EINVAL for dummy it might return same or other error code for non-dummy regulator. So, by the fact the code there should be done like in the rest (the below is mangled, can't be used directly as a patch): --- a/drivers/iio/adc/max11100.c +++ b/drivers/iio/adc/max11100.c @@ -88,8 +88,7 @@ static int max11100_read_raw(struct iio_dev *indio_dev, case IIO_CHAN_INFO_SCALE: vref_uv = regulator_get_voltage(state->vref_reg); if (vref_uv < 0) - /* dummy regulator "get_voltage" returns -EINVAL */ - return -EINVAL; + return vref_uv; *val = vref_uv / 1000; *val2 = MAX11100_LSB_DIV; -- Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> Intel Finland Oy -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
