pinctrl: core: Fix pinctrl_register_and_init() with pinctrl_enable()

Recent pinctrl changes to allow dynamic allocation of pins exposed one
more issue with the pinctrl pins claimed early by the controller itself.
This caused a regression for IMX6 pinctrl hogs.

Before enabling the pin controller driver we need to wait until it has
been properly initialized, then claim the hogs, and only then enable it.

To fix the regression, split the code into pinctrl_claim_hogs() and
pinctrl_enable(). And then let's require that pinctrl_enable() is always
called by the pin controller driver when ready after calling
pinctrl_register_and_init().

Depends-on: 950b0d91dc ("pinctrl: core: Fix regression caused by delayed
work for hogs")
Fixes: df61b366af26 ("pinctrl: core: Use delayed work for hogs")
Fixes: e566fc11ea ("pinctrl: imx: use generic pinctrl helpers for
managing groups")
Cc: Haojian Zhuang <haojian.zhuang@linaro.org>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Mika Penttilä <mika.penttila@nextfour.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Nishanth Menon <nm@ti.com>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Stefan Agner <stefan@agner.ch>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Gary Bisson <gary.bisson@boundarydevices.com>
Tested-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Documentation/pinctrl.txt

@@ -77,9 +77,15 @@ static struct pinctrl_desc foo_desc = {
 
 int __init foo_probe(void)
 {
+	int error;
+
 	struct pinctrl_dev *pctl;
 
-	return pinctrl_register_and_init(&foo_desc, <PARENT>, NULL, &pctl);
+	error = pinctrl_register_and_init(&foo_desc, <PARENT>, NULL, &pctl);
+	if (error)
+		return error;
+
+	return pinctrl_enable(pctl);
 }
 
 To enable the pinctrl subsystem and the subgroups for PINMUX and PINCONF and

drivers/pinctrl/core.c

@@ -2010,29 +2010,57 @@ out_err:
 	return ERR_PTR(ret);
 }
 
-static int pinctrl_create_and_start(struct pinctrl_dev *pctldev)
+static int pinctrl_claim_hogs(struct pinctrl_dev *pctldev)
 {
 	pctldev->p = create_pinctrl(pctldev->dev, pctldev);
-	if (!IS_ERR(pctldev->p)) {
-		kref_get(&pctldev->p->users);
-		pctldev->hog_default =
-			pinctrl_lookup_state(pctldev->p, PINCTRL_STATE_DEFAULT);
-		if (IS_ERR(pctldev->hog_default)) {
-			dev_dbg(pctldev->dev,
-				"failed to lookup the default state\n");
-		} else {
-			if (pinctrl_select_state(pctldev->p,
-						pctldev->hog_default))
-				dev_err(pctldev->dev,
-					"failed to select default state\n");
-		}
+	if (PTR_ERR(pctldev->p) == -ENODEV) {
+		dev_dbg(pctldev->dev, "no hogs found\n");
 
-		pctldev->hog_sleep =
-			pinctrl_lookup_state(pctldev->p,
-						    PINCTRL_STATE_SLEEP);
-		if (IS_ERR(pctldev->hog_sleep))
-			dev_dbg(pctldev->dev,
-				"failed to lookup the sleep state\n");
+		return 0;
+	}
+
+	if (IS_ERR(pctldev->p)) {
+		dev_err(pctldev->dev, "error claiming hogs: %li\n",
+			PTR_ERR(pctldev->p));
+
+		return PTR_ERR(pctldev->p);
+	}
+
+	kref_get(&pctldev->p->users);
+	pctldev->hog_default =
+		pinctrl_lookup_state(pctldev->p, PINCTRL_STATE_DEFAULT);
+	if (IS_ERR(pctldev->hog_default)) {
+		dev_dbg(pctldev->dev,
+			"failed to lookup the default state\n");
+	} else {
+		if (pinctrl_select_state(pctldev->p,
+					 pctldev->hog_default))
+			dev_err(pctldev->dev,
+				"failed to select default state\n");
+	}
+
+	pctldev->hog_sleep =
+		pinctrl_lookup_state(pctldev->p,
+				     PINCTRL_STATE_SLEEP);
+	if (IS_ERR(pctldev->hog_sleep))
+		dev_dbg(pctldev->dev,
+			"failed to lookup the sleep state\n");
+
+	return 0;
+}
+
+int pinctrl_enable(struct pinctrl_dev *pctldev)
+{
+	int error;
+
+	error = pinctrl_claim_hogs(pctldev);
+	if (error) {
+		dev_err(pctldev->dev, "could not claim hogs: %i\n",
+			error);
+		mutex_destroy(&pctldev->mutex);
+		kfree(pctldev);
+
+		return error;
 	}
 
 	mutex_lock(&pinctrldev_list_mutex);
@@ -2043,6 +2071,7 @@ static int pinctrl_create_and_start(struct pinctrl_dev *pctldev)
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(pinctrl_enable);
 
 /**
  * pinctrl_register() - register a pin controller device
@@ -2065,25 +2094,30 @@ struct pinctrl_dev *pinctrl_register(struct pinctrl_desc *pctldesc,
 	if (IS_ERR(pctldev))
 		return pctldev;
 
-	error = pinctrl_create_and_start(pctldev);
-	if (error) {
-		mutex_destroy(&pctldev->mutex);
-		kfree(pctldev);
-
+	error = pinctrl_enable(pctldev);
+	if (error)
 		return ERR_PTR(error);
-	}
 
 	return pctldev;
 
 }
 EXPORT_SYMBOL_GPL(pinctrl_register);
 
+/**
+ * pinctrl_register_and_init() - register and init pin controller device
+ * @pctldesc: descriptor for this pin controller
+ * @dev: parent device for this pin controller
+ * @driver_data: private pin controller data for this pin controller
+ * @pctldev: pin controller device
+ *
+ * Note that pinctrl_enable() still needs to be manually called after
+ * this once the driver is ready.
+ */
 int pinctrl_register_and_init(struct pinctrl_desc *pctldesc,
 			      struct device *dev, void *driver_data,
 			      struct pinctrl_dev **pctldev)
 {
 	struct pinctrl_dev *p;
-	int error;
 
 	p = pinctrl_init_controller(pctldesc, dev, driver_data);
 	if (IS_ERR(p))
@@ -2097,15 +2131,6 @@ int pinctrl_register_and_init(struct pinctrl_desc *pctldesc,
 	 */
 	*pctldev = p;
 
-	error = pinctrl_create_and_start(p);
-	if (error) {
-		mutex_destroy(&p->mutex);
-		kfree(p);
-		*pctldev = NULL;
-
-		return error;
-	}
-
 	return 0;
 }
 EXPORT_SYMBOL_GPL(pinctrl_register_and_init);

drivers/pinctrl/freescale/pinctrl-imx.c

@@ -790,7 +790,7 @@ int imx_pinctrl_probe(struct platform_device *pdev,
 
 	dev_info(&pdev->dev, "initialized IMX pinctrl driver\n");
 
-	return 0;
+	return pinctrl_enable(ipctl->pctl);
 
 free:
 	imx_free_resources(ipctl);

drivers/pinctrl/pinctrl-single.c

@@ -1781,7 +1781,7 @@ static int pcs_probe(struct platform_device *pdev)
 	dev_info(pcs->dev, "%i pins at pa %p size %u\n",
 		 pcs->desc.npins, pcs->base, pcs->size);
 
-	return 0;
+	return pinctrl_enable(pcs->pctl);
 
 free:
 	pcs_free_resources(pcs);

drivers/pinctrl/sh-pfc/pinctrl.c

@@ -816,6 +816,13 @@ int sh_pfc_register_pinctrl(struct sh_pfc *pfc)
 	pmx->pctl_desc.pins = pmx->pins;
 	pmx->pctl_desc.npins = pfc->info->nr_pins;
 
-	return devm_pinctrl_register_and_init(pfc->dev, &pmx->pctl_desc, pmx,
-					      &pmx->pctl);
+	ret = devm_pinctrl_register_and_init(pfc->dev, &pmx->pctl_desc, pmx,
+					     &pmx->pctl);
+	if (ret) {
+		dev_err(pfc->dev, "could not register: %i\n", ret);
+
+		return ret;
+	}
+
+	return pinctrl_enable(pmx->pctl);
 }

drivers/pinctrl/ti/pinctrl-ti-iodelay.c

@@ -893,6 +893,8 @@ static int ti_iodelay_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, iod);
 
+	return pinctrl_enable(iod->pctl);
+
 exit_out:
 	of_node_put(np);
 	return ret;

include/linux/pinctrl/pinctrl.h

@@ -145,8 +145,9 @@ struct pinctrl_desc {
 extern int pinctrl_register_and_init(struct pinctrl_desc *pctldesc,
 				     struct device *dev, void *driver_data,
 				     struct pinctrl_dev **pctldev);
+extern int pinctrl_enable(struct pinctrl_dev *pctldev);
 
-/* Please use pinctrl_register_and_init() instead */
+/* Please use pinctrl_register_and_init() and pinctrl_enable() instead */
 extern struct pinctrl_dev *pinctrl_register(struct pinctrl_desc *pctldesc,
 				struct device *dev, void *driver_data);