irqchip/ls-extirq: Use for_each_of_imap_item iterator

The ls-extirq driver parses the interrupt-map property. It does it using
open code.

Recently for_each_of_imap_item iterator has been introduce to help
drivers in this parsing.

Convert the ls-extirq driver to use the for_each_of_imap_item
iterator instead of open code.

Signed-off-by: Herve Codina (Schneider Electric) <[e-mail]>
Reviewed-by: Linus Walleij <[e-mail]>
Reviewed-by: Thomas Gleixner <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Geert Uytterhoeven <[e-mail]>

drivers/irqchip/irq-ls-extirq.c

···
 static int
 ls_extirq_parse_map(struct ls_extirq_data *priv, struct device_node *node)
 {
-	const __be32 *map;
-	u32 mapsize;
+	struct of_imap_parser imap_parser;
+	struct of_imap_item imap_item;
 	int ret;
 
-	map = of_get_property(node, "interrupt-map", &mapsize);
-	if (!map)
-		return -ENOENT;
-	if (mapsize % sizeof(*map))
-		return -EINVAL;
-	mapsize /= sizeof(*map);
+	ret = of_imap_parser_init(&imap_parser, node, &imap_item);
+	if (ret)
+		return ret;
 
-	while (mapsize) {
+	for_each_of_imap_item(&imap_parser, &imap_item) {
 		struct device_node *ipar;
-		u32 hwirq, intsize, j;
+		u32 hwirq;
+		int i;
 
-		if (mapsize < 3)
+		hwirq = imap_item.child_imap[0];
+		if (hwirq >= MAXIRQ) {
+			of_node_put(imap_item.parent_args.np);
 			return -EINVAL;
-		hwirq = be32_to_cpup(map);
-		if (hwirq >= MAXIRQ)
-			return -EINVAL;
+		}
 		priv->nirq = max(priv->nirq, hwirq + 1);
 
-		ipar = of_find_node_by_phandle(be32_to_cpup(map + 2));
-		map += 3;
-		mapsize -= 3;
-		if (!ipar)
-			return -EINVAL;
-		priv->map[hwirq].fwnode = &ipar->fwnode;
-		ret = of_property_read_u32(ipar, "#interrupt-cells", &intsize);
-		if (ret)
-			return ret;
+		ipar = of_node_get(imap_item.parent_args.np);
+		priv->map[hwirq].fwnode = of_fwnode_handle(ipar);
 
-		if (intsize > mapsize)
-			return -EINVAL;
-
-		priv->map[hwirq].param_count = intsize;
-		for (j = 0; j < intsize; ++j)
-			priv->map[hwirq].param[j] = be32_to_cpup(map++);
-		mapsize -= intsize;
+		priv->map[hwirq].param_count = imap_item.parent_args.args_count;
+		for (i = 0; i < priv->map[hwirq].param_count; i++)
+			priv->map[hwirq].param[i] = imap_item.parent_args.args[i];
 	}
 	return 0;
 }