1 files changed, 91 insertions, 27 deletions

diff --git a/drivers/pinctrl/core.c b/drivers/pinctrl/core.c
index 59f5a965bdc4..b0de6e7f1fdb 100644
--- a/drivers/pinctrl/core.c
+++ b/drivers/pinctrl/core.c
@@ -14,6 +14,7 @@
 #define pr_fmt(fmt) "pinctrl core: " fmt
 
 #include <linux/kernel.h>
+#include <linux/kref.h>
 #include <linux/export.h>
 #include <linux/init.h>
 #include <linux/device.h>
@@ -31,17 +32,6 @@
 #include "pinmux.h"
 #include "pinconf.h"
 
-/**
- * struct pinctrl_maps - a list item containing part of the mapping table
- * @node: mapping table list node
- * @maps: array of mapping table entries
- * @num_maps: the number of entries in @maps
- */
-struct pinctrl_maps {
-	struct list_head node;
-	struct pinctrl_map const *maps;
-	unsigned num_maps;
-};
 
 static bool pinctrl_dummy_state;
 
@@ -55,13 +45,8 @@ LIST_HEAD(pinctrldev_list);
 static LIST_HEAD(pinctrl_list);
 
 /* List of pinctrl maps (struct pinctrl_maps) */
-static LIST_HEAD(pinctrl_maps);
+LIST_HEAD(pinctrl_maps);
 
-#define for_each_maps(_maps_node_, _i_, _map_) \
-	list_for_each_entry(_maps_node_, &pinctrl_maps, node) \
-		for (_i_ = 0, _map_ = &_maps_node_->maps[_i_]; \
-			_i_ < _maps_node_->num_maps; \
-			_i_++, _map_ = &_maps_node_->maps[_i_])
 
 /**
  * pinctrl_provide_dummies() - indicate if pinctrl provides dummy state support
@@ -83,6 +68,12 @@ const char *pinctrl_dev_get_name(struct pinctrl_dev *pctldev)
 }
 EXPORT_SYMBOL_GPL(pinctrl_dev_get_name);
 
+const char *pinctrl_dev_get_devname(struct pinctrl_dev *pctldev)
+{
+	return dev_name(pctldev->dev);
+}
+EXPORT_SYMBOL_GPL(pinctrl_dev_get_devname);
+
 void *pinctrl_dev_get_drvdata(struct pinctrl_dev *pctldev)
 {
 	return pctldev->driver_data;
@@ -609,13 +600,16 @@ static int add_setting(struct pinctrl *p, struct pinctrl_map const *map)
 
 	setting->pctldev = get_pinctrl_dev_from_devname(map->ctrl_dev_name);
 	if (setting->pctldev == NULL) {
-		dev_info(p->dev, "unknown pinctrl device %s in map entry, deferring probe",
-			map->ctrl_dev_name);
 		kfree(setting);
+		/* Do not defer probing of hogs (circular loop) */
+		if (!strcmp(map->ctrl_dev_name, map->dev_name))
+			return -ENODEV;
 		/*
 		 * OK let us guess that the driver is not there yet, and
 		 * let's defer obtaining this pinctrl handle to later...
 		 */
+		dev_info(p->dev, "unknown pinctrl device %s in map entry, deferring probe",
+			map->ctrl_dev_name);
 		return -EPROBE_DEFER;
 	}
 
@@ -694,11 +688,31 @@ static struct pinctrl *create_pinctrl(struct device *dev)
 			continue;
 
 		ret = add_setting(p, map);
-		if (ret < 0) {
+		/*
+		 * At this point the adding of a setting may:
+		 *
+		 * - Defer, if the pinctrl device is not yet available
+		 * - Fail, if the pinctrl device is not yet available,
+		 *   AND the setting is a hog. We cannot defer that, since
+		 *   the hog will kick in immediately after the device
+		 *   is registered.
+		 *
+		 * If the error returned was not -EPROBE_DEFER then we
+		 * accumulate the errors to see if we end up with
+		 * an -EPROBE_DEFER later, as that is the worst case.
+		 */
+		if (ret == -EPROBE_DEFER) {
 			pinctrl_put_locked(p, false);
 			return ERR_PTR(ret);
 		}
 	}
+	if (ret < 0) {
+		/* If some other error than deferral occured, return here */
+		pinctrl_put_locked(p, false);
+		return ERR_PTR(ret);
+	}
+
+	kref_init(&p->users);
 
 	/* Add the pinctrl handle to the global list */
 	list_add_tail(&p->node, &pinctrl_list);
@@ -713,9 +727,17 @@ static struct pinctrl *pinctrl_get_locked(struct device *dev)
 	if (WARN_ON(!dev))
 		return ERR_PTR(-EINVAL);
 
+	/*
+	 * See if somebody else (such as the device core) has already
+	 * obtained a handle to the pinctrl for this device. In that case,
+	 * return another pointer to it.
+	 */
 	p = find_pinctrl(dev);
-	if (p != NULL)
-		return ERR_PTR(-EBUSY);
+	if (p != NULL) {
+		dev_dbg(dev, "obtain a copy of previously claimed pinctrl\n");
+		kref_get(&p->users);
+		return p;
+	}
 
 	return create_pinctrl(dev);
 }
@@ -771,13 +793,24 @@ static void pinctrl_put_locked(struct pinctrl *p, bool inlist)
 }
 
 /**
- * pinctrl_put() - release a previously claimed pinctrl handle
+ * pinctrl_release() - release the pinctrl handle
+ * @kref: the kref in the pinctrl being released
+ */
+static void pinctrl_release(struct kref *kref)
+{
+	struct pinctrl *p = container_of(kref, struct pinctrl, users);
+
+	pinctrl_put_locked(p, true);
+}
+
+/**
+ * pinctrl_put() - decrease use count on a previously claimed pinctrl handle
  * @p: the pinctrl handle to release
  */
 void pinctrl_put(struct pinctrl *p)
 {
 	mutex_lock(&pinctrl_mutex);
-	pinctrl_put_locked(p, true);
+	kref_put(&p->users, pinctrl_release);
 	mutex_unlock(&pinctrl_mutex);
 }
 EXPORT_SYMBOL_GPL(pinctrl_put);
@@ -1055,6 +1088,30 @@ void pinctrl_unregister_map(struct pinctrl_map const *map)
 	}
 }
 
+/**
+ * pinctrl_force_sleep() - turn a given controller device into sleep state
+ * @pctldev: pin controller device
+ */
+int pinctrl_force_sleep(struct pinctrl_dev *pctldev)
+{
+	if (!IS_ERR(pctldev->p) && !IS_ERR(pctldev->hog_sleep))
+		return pinctrl_select_state(pctldev->p, pctldev->hog_sleep);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(pinctrl_force_sleep);
+
+/**
+ * pinctrl_force_default() - turn a given controller device into default state
+ * @pctldev: pin controller device
+ */
+int pinctrl_force_default(struct pinctrl_dev *pctldev)
+{
+	if (!IS_ERR(pctldev->p) && !IS_ERR(pctldev->hog_default))
+		return pinctrl_select_state(pctldev->p, pctldev->hog_default);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(pinctrl_force_default);
+
 #ifdef CONFIG_DEBUG_FS
 
 static int pinctrl_pins_show(struct seq_file *s, void *what)
@@ -1500,16 +1557,23 @@ struct pinctrl_dev *pinctrl_register(struct pinctrl_desc *pctldesc,
 
 	pctldev->p = pinctrl_get_locked(pctldev->dev);
 	if (!IS_ERR(pctldev->p)) {
-		struct pinctrl_state *s =
+		pctldev->hog_default =
 			pinctrl_lookup_state_locked(pctldev->p,
 						    PINCTRL_STATE_DEFAULT);
-		if (IS_ERR(s)) {
+		if (IS_ERR(pctldev->hog_default)) {
 			dev_dbg(dev, "failed to lookup the default state\n");
 		} else {
-			if (pinctrl_select_state_locked(pctldev->p, s))
+			if (pinctrl_select_state_locked(pctldev->p,
+						pctldev->hog_default))
 				dev_err(dev,
 					"failed to select default state\n");
 		}
+
+		pctldev->hog_sleep =
+			pinctrl_lookup_state_locked(pctldev->p,
+						    PINCTRL_STATE_SLEEP);
+		if (IS_ERR(pctldev->hog_sleep))
+			dev_dbg(dev, "failed to lookup the sleep state\n");
 	}
 
 	mutex_unlock(&pinctrl_mutex);