regmap: When we sanity check during range adds say what errors we find

Rather than just returning a single error code for every possible thing we
can notice print an error message saying what the problem was. This makes
it very much easier to figure out what's wrong and fix it.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

drivers/base/regmap/regmap.c

@@ -524,11 +524,29 @@ struct regmap *regmap_init(struct device *dev,
 		struct regmap_range_node *new;
 
 		/* Sanity check */
-		if (range_cfg->range_max < range_cfg->range_min ||
-		    range_cfg->range_max > map->max_register ||
-		    range_cfg->selector_reg > map->max_register ||
-		    range_cfg->window_len == 0)
+		if (range_cfg->range_max < range_cfg->range_min) {
+			dev_err(map->dev, "Invalid range %d: %d < %d\n", i,
+				range_cfg->range_max, range_cfg->range_min);
 			goto err_range;
+		}
+
+		if (range_cfg->range_max > map->max_register) {
+			dev_err(map->dev, "Invalid range %d: %d > %d\n", i,
+				range_cfg->range_max, map->max_register);
+			goto err_range;
+		}
+
+		if (range_cfg->selector_reg > map->max_register) {
+			dev_err(map->dev,
+				"Invalid range %d: selector out of map\n", i);
+			goto err_range;
+		}
+
+		if (range_cfg->window_len == 0) {
+			dev_err(map->dev, "Invalid range %d: window_len 0\n",
+				i);
+			goto err_range;
+		}
 
 		/* Make sure, that this register range has no selector
 		   or data window within its boundary */
@@ -540,11 +558,17 @@ struct regmap *regmap_init(struct device *dev,
 
 			if (range_cfg->range_min <= sel_reg &&
 			    sel_reg <= range_cfg->range_max) {
+				dev_err(map->dev,
+					"Range %d: selector for %d in window\n",
+					i, j);
 				goto err_range;
 			}
 
 			if (!(win_max < range_cfg->range_min ||
 			      win_min > range_cfg->range_max)) {
+				dev_err(map->dev,
+					"Range %d: window for %d in window\n",
+					i, j);
 				goto err_range;
 			}
 		}
@@ -564,6 +588,7 @@ struct regmap *regmap_init(struct device *dev,
 		new->window_len = range_cfg->window_len;
 
 		if (_regmap_range_add(map, new) == false) {
+			dev_err(map->dev, "Failed to add range %d\n", i);
 			kfree(new);
 			goto err_range;
 		}