regulator: rohm-regulator: warn if unsupported voltage is set

A few of the ROHM PMICs allow setting low-power state specific voltages
for regulators. These voltages are then taken in use (by the hardware)
when the PMIC state is changed.

The voltages for these states can be given via device-tree. If
unsupported voltage has been given, the users have only seen print:
"driver callback failed to parse DT for regulator <name>". This does
help to pinpoint the problem to some extent, but there may be several
properties in device-tree so it should help if we can be a bit more
specific.

Print the voltage value and the run-state property if voltage can not be
supported.

Signed-off-by: Matti Vaittinen <[email protected]>
Link: https://msgid.link/r/0937411855967cbefd9ff2d6045a52ca26712c4a.1715848512.git.mazziesaccount@gmail.com
Signed-off-by: Mark Brown <[email protected]>

Author: M-Vaittinen

drivers/regulator/rohm-regulator.c

@@ -46,13 +46,17 @@ static int set_dvs_level(const struct regulator_desc *desc,
 			continue;
 		if (ret == uv) {
 			i <<= ffs(desc->vsel_mask) - 1;
+
 			ret = regmap_update_bits(regmap, reg, mask, i);
 			if (omask && !ret)
 				ret = regmap_update_bits(regmap, oreg, omask,
 							 omask);
 			break;
 		}
 	}
+	if (i == desc->n_voltages)
+		pr_warn("Unsupported %s voltage %u\n", prop, uv);
+
 	return ret;
 }