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

[Dan Carpenter <dan.carpenter@linaro.org>]

[ 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'

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.  Return -EINVAL.

    733 
    734                 if (data->use_vref1)
    735                         tmp_vref = vref1_mV;
    736                 else
    737                         tmp_vref = MCP47FEB02_INTERNAL_BAND_GAP_mV;
    738 
    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 }

regards,
dan carpenter