pinctrl: mvebu: identify generic controls by name

We treat unnamed controls as generic mvebu mpp register controls but
we identify them by not being special controls. Flip the logic and
use the name pointer as identification instead. While at it, add some
comments explaining the not so obvious treatment.
Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Tested-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

drivers/pinctrl/mvebu/pinctrl-mvebu.c

@@ -638,23 +638,21 @@ int mvebu_pinctrl_probe(struct platform_device *pdev)
 		struct mvebu_mpp_ctrl *ctrl = &soc->controls[n];
 
 		pctl->desc.npins += ctrl->npins;
-		/* initial control pins */
+		/* initialize control's pins[] array */
 		for (k = 0; k < ctrl->npins; k++)
 			ctrl->pins[k] = ctrl->pid + k;
 
-		/* special soc specific control */
-		if (ctrl->mpp_get || ctrl->mpp_set) {
-			if (!ctrl->name || !ctrl->mpp_get || !ctrl->mpp_set) {
-				dev_err(&pdev->dev, "wrong soc control info\n");
-				return -EINVAL;
-			}
+		/*
+		 * We allow to pass controls with NULL name that we treat
+		 * as a range of one-pin groups with generic mvebu register
+		 * controls.
+		 */
+		if (!ctrl->name) {
+			pctl->num_groups += ctrl->npins;
+			noname += ctrl->npins;
+		} else {
 			pctl->num_groups += 1;
-			continue;
 		}
-
-		/* generic mvebu register control */
-		pctl->num_groups += ctrl->npins;
-		noname += ctrl->npins;
 	}
 
 	pdesc = devm_kzalloc(&pdev->dev, pctl->desc.npins *
@@ -690,8 +688,12 @@ int mvebu_pinctrl_probe(struct platform_device *pdev)
 		pctl->groups[gid].pins = ctrl->pins;
 		pctl->groups[gid].npins = ctrl->npins;
 
-		/* generic mvebu register control maps to a number of groups */
-		if (!ctrl->mpp_get && !ctrl->mpp_set) {
+		/*
+		 * We treat unnamed controls as a range of one-pin groups
+		 * with generic mvebu register controls. Use one group for
+		 * each in this range and assign a default group name.
+		 */
+		if (!ctrl->name) {
 			pctl->groups[gid].name = noname_buf;
 			pctl->groups[gid].npins = 1;
 			sprintf(noname_buf, "mpp%d", ctrl->pid+0);