[PATCH] pinctrl: core: Use delayed work for hogs

[Tony Lindgren]

Having the pin control framework call pin controller functions
before it's probe has finished is not nice as the pin controller
device driver does not yet have struct pinctrl_dev handle.

Let's fix this issue by adding deferred work for late init. This is
needed to be able to add pinctrl generic helper functions that expect
to know struct pinctrl_dev handle. Note that we now need to call
create_pinctrl() directly as we don't want to add the pin controller
to the list of controllers until the hogs are claimed.

Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx>
---
 drivers/pinctrl/core.c | 66 ++++++++++++++++++++++++++++++--------------------
 drivers/pinctrl/core.h |  2 ++
 2 files changed, 42 insertions(+), 26 deletions(-)

diff --git a/drivers/pinctrl/core.c b/drivers/pinctrl/core.c
--- a/drivers/pinctrl/core.c
+++ b/drivers/pinctrl/core.c
@@ -1911,6 +1911,43 @@ static int pinctrl_check_ops(struct pinctrl_dev *pctldev)
 }
 
 /**
+ * pinctrl_late_init() - finish pin controller device registration
+ * @work: work struct
+ */
+static void pinctrl_late_init(struct work_struct *work)
+{
+	struct pinctrl_dev *pctldev;
+
+	pctldev = container_of(work, struct pinctrl_dev, late_init.work);
+
+	pctldev->p = create_pinctrl(pctldev->dev);
+	if (IS_ERR(pctldev->p))
+		return;
+
+	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");
+
+	mutex_lock(&pinctrldev_list_mutex);
+	list_add_tail(&pctldev->node, &pinctrldev_list);
+	mutex_unlock(&pinctrldev_list_mutex);
+
+	pinctrl_init_device_debugfs(pctldev);
+}
+
+/**
  * pinctrl_register() - register a pin controller device
  * @pctldesc: descriptor for this pin controller
  * @dev: parent device for this pin controller
@@ -1941,6 +1978,7 @@ struct pinctrl_dev *pinctrl_register(struct pinctrl_desc *pctldesc,
 	INIT_RADIX_TREE(&pctldev->pin_group_tree, GFP_KERNEL);
 	INIT_RADIX_TREE(&pctldev->pin_function_tree, GFP_KERNEL);
 	INIT_LIST_HEAD(&pctldev->gpio_ranges);
+	INIT_DELAYED_WORK(&pctldev->late_init, pinctrl_late_init);
 	pctldev->dev = dev;
 	mutex_init(&pctldev->mutex);
 
@@ -1975,32 +2013,7 @@ struct pinctrl_dev *pinctrl_register(struct pinctrl_desc *pctldesc,
 		goto out_err;
 	}
 
-	mutex_lock(&pinctrldev_list_mutex);
-	list_add_tail(&pctldev->node, &pinctrldev_list);
-	mutex_unlock(&pinctrldev_list_mutex);
-
-	pctldev->p = pinctrl_get(pctldev->dev);
-
-	if (!IS_ERR(pctldev->p)) {
-		pctldev->hog_default =
-			pinctrl_lookup_state(pctldev->p, PINCTRL_STATE_DEFAULT);
-		if (IS_ERR(pctldev->hog_default)) {
-			dev_dbg(dev, "failed to lookup the default state\n");
-		} else {
-			if (pinctrl_select_state(pctldev->p,
-						pctldev->hog_default))
-				dev_err(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(dev, "failed to lookup the sleep state\n");
-	}
-
-	pinctrl_init_device_debugfs(pctldev);
+	schedule_delayed_work(&pctldev->late_init, 0);
 
 	return pctldev;
 
@@ -2023,6 +2036,7 @@ void pinctrl_unregister(struct pinctrl_dev *pctldev)
 	if (pctldev == NULL)
 		return;
 
+	cancel_delayed_work_sync(&pctldev->late_init);
 	mutex_lock(&pctldev->mutex);
 	pinctrl_remove_device_debugfs(pctldev);
 	mutex_unlock(&pctldev->mutex);
diff --git a/drivers/pinctrl/core.h b/drivers/pinctrl/core.h
--- a/drivers/pinctrl/core.h
+++ b/drivers/pinctrl/core.h
@@ -37,6 +37,7 @@ struct pinctrl_gpio_range;
  * @p: result of pinctrl_get() for this device
  * @hog_default: default state for pins hogged by this device
  * @hog_sleep: sleep state for pins hogged by this device
+ * @late_init: delayed work for pin controller to finish registration
  * @mutex: mutex taken on each pin controller specific action
  * @device_root: debugfs root for this device
  */
@@ -55,6 +56,7 @@ struct pinctrl_dev {
 	struct pinctrl *p;
 	struct pinctrl_state *hog_default;
 	struct pinctrl_state *hog_sleep;
+	struct delayed_work late_init;
 	struct mutex mutex;
 #ifdef CONFIG_DEBUG_FS
 	struct dentry *device_root;
-- 
2.10.2