mfd: MAX77693: Fix NULL pointer error when initializing irqs

This patch initialize register map of MUIC device because mfd driver
of Maxim MAX77693 use regmap-muic instance of MUIC device when irqs of
Maxim MAX77693 is initialized before call max77693-muic probe() function.

Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Myungjoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Reported-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/drivers/extcon/extcon-max77693.c b/drivers/extcon/extcon-max77693.c
index 920a609..38f9e52 100644
--- a/drivers/extcon/extcon-max77693.c
+++ b/drivers/extcon/extcon-max77693.c
@@ -669,13 +669,18 @@
 	}
 	info->dev = &pdev->dev;
 	info->max77693 = max77693;
-	info->max77693->regmap_muic = regmap_init_i2c(info->max77693->muic,
-					 &max77693_muic_regmap_config);
-	if (IS_ERR(info->max77693->regmap_muic)) {
-		ret = PTR_ERR(info->max77693->regmap_muic);
-		dev_err(max77693->dev,
-			"failed to allocate register map: %d\n", ret);
-		goto err_regmap;
+	if (info->max77693->regmap_muic)
+		dev_dbg(&pdev->dev, "allocate register map\n");
+	else {
+		info->max77693->regmap_muic = devm_regmap_init_i2c(
+						info->max77693->muic,
+						&max77693_muic_regmap_config);
+		if (IS_ERR(info->max77693->regmap_muic)) {
+			ret = PTR_ERR(info->max77693->regmap_muic);
+			dev_err(max77693->dev,
+				"failed to allocate register map: %d\n", ret);
+			goto err_regmap;
+		}
 	}
 	platform_set_drvdata(pdev, info);
 	mutex_init(&info->mutex);