Re: [bug report] iio: dac: adding support for Microchip MCP47FEB02

Dan Carpenter
2026-02-06T14:33:31Z

On Fri, Feb 06, 2026 at 04:04:07PM +0200, Andy Shevchenko wrote:
> > drivers/iio/dac/mcp47feb02.c
> > 712 static int mcp47feb02_init_scales_avail(struct mcp47feb02_data *data, int vdd_mV,
> > 713 int vref_mV, int vref1_mV)
> > 714 {
> > 715 struct device *dev = regmap_get_device(data->regmap);
> > 716 int tmp_vref;
> > 717
> > 718 mcp47feb02_init_scale(data, MCP47FEB02_SCALE_VDD, vdd_mV, data->scale);
> > 719
> > 720 if (data->use_vref)
> > 721 tmp_vref = vref_mV;
> > 722 else
> > 723 tmp_vref = MCP47FEB02_INTERNAL_BAND_GAP_mV;
> > 724
> > 725 mcp47feb02_init_scale(data, MCP47FEB02_SCALE_GAIN_X1, tmp_vref, data->scale);
> > 726 mcp47feb02_init_scale(data, MCP47FEB02_SCALE_GAIN_X2, tmp_vref * 2, data->scale);
> > 727
> > 728 if (data->phys_channels >= 4) {
> > 729 mcp47feb02_init_scale(data, MCP47FEB02_SCALE_VDD, vdd_mV, data->scale_1);
> > 730
> > 731 if (data->use_vref1 && vref1_mV <= 0)
> > --> 732 return dev_err_probe(dev, vref1_mV, "Invalid voltage for Vref1\n");
> > ^^^^^^^^
> > vref1_mV is not a valid error code.
>
> Why not? When it's negative I believe the above statement is not true.
>

I saw this as just sanity checking the input. vref1_mV is never
actually negative. I don't know if devm_regulator_get_enable_read_voltage()
can return less than one millivolt.

regards,
dan carpenter