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

Andy Shevchenko
2026-02-06T14:04:12Z

On Fri, Feb 06, 2026 at 04:40:15PM +0300, Dan Carpenter wrote:
> [ Smatch checking is paused while we raise funding. #SadFace
> https://lore.kernel.org/all/aTaiGSbWZ9DJaGo7@stanley.mountain/ -dan ]
>
> Hello Ariana Lazar,
>
> Commit bf394cc80369 ("iio: dac: adding support for Microchip
> MCP47FEB02") from Dec 16, 2025 (linux-next), leads to the following
> Smatch static checker warning:
>
> drivers/iio/dac/mcp47feb02.c:732 mcp47feb02_init_scales_avail()
> warn: passing zero to 'dev_err_probe'

Btw, why the bot mangles the patch, please?
Adding leading information (line number and some other markings) should not
mangle the code (tab-based indentation).

> 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.

> Return -EINVAL.

Probably true for the == 0 case.

With the above, this probably should be

> 734 if (data->use_vref1)
> 735 tmp_vref = vref1_mV;
> 736 else
> 737 tmp_vref = MCP47FEB02_INTERNAL_BAND_GAP_mV;

if (data->use_vref1) {
if (vref1_mV < 0)
return dev_err_probe(dev, vref1_mV, "Can't get voltage for Vref1\n");
if (vref1_mV == 0)
return dev_err_probe(dev, -ERANGE, "Invalid voltage for Vref1\n");
// or -EINVAL?
tmp_vref = vref1_mV;
} else {
tmp_vref = MCP47FEB02_INTERNAL_BAND_GAP_mV;
}

> 739 mcp47feb02_init_scale(data, MCP47FEB02_SCALE_GAIN_X1,
> 740 tmp_vref, data->scale_1);
> 741 mcp47feb02_init_scale(data, MCP47FEB02_SCALE_GAIN_X2,
> 742 tmp_vref * 2, data->scale_1);
> 743 }
> 744
> 745 return 0;
> 746 }

--
With Best Regards,
Andy Shevchenko