1 files changed, 292 insertions, 46 deletions

diff --git a/drivers/reset/core.c b/drivers/reset/core.c
index 4d5a78d3c085..22f67fc77ae5 100644
--- a/drivers/reset/core.c
+++ b/drivers/reset/core.c
@@ -5,14 +5,19 @@
  * Copyright 2013 Philipp Zabel, Pengutronix
  */
 #include <linux/atomic.h>
+#include <linux/cleanup.h>
 #include <linux/device.h>
 #include <linux/err.h>
 #include <linux/export.h>
 #include <linux/kernel.h>
 #include <linux/kref.h>
+#include <linux/gpio/driver.h>
+#include <linux/gpio/machine.h>
+#include <linux/idr.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/acpi.h>
+#include <linux/platform_device.h>
 #include <linux/reset.h>
 #include <linux/reset-controller.h>
 #include <linux/slab.h>
@@ -23,6 +28,11 @@ static LIST_HEAD(reset_controller_list);
 static DEFINE_MUTEX(reset_lookup_mutex);
 static LIST_HEAD(reset_lookup_list);
 
+/* Protects reset_gpio_lookup_list */
+static DEFINE_MUTEX(reset_gpio_lookup_mutex);
+static LIST_HEAD(reset_gpio_lookup_list);
+static DEFINE_IDA(reset_gpio_ida);
+
 /**
  * struct reset_control - a reset control
  * @rcdev: a pointer to the reset controller device
@@ -63,6 +73,16 @@ struct reset_control_array {
 	struct reset_control *rstc[] __counted_by(num_rstcs);
 };
 
+/**
+ * struct reset_gpio_lookup - lookup key for ad-hoc created reset-gpio devices
+ * @of_args: phandle to the reset controller with all the args like GPIO number
+ * @list: list entry for the reset_gpio_lookup_list
+ */
+struct reset_gpio_lookup {
+	struct of_phandle_args of_args;
+	struct list_head list;
+};
+
 static const char *rcdev_name(struct reset_controller_dev *rcdev)
 {
 	if (rcdev->dev)
@@ -71,6 +91,9 @@ static const char *rcdev_name(struct reset_controller_dev *rcdev)
 	if (rcdev->of_node)
 		return rcdev->of_node->full_name;
 
+	if (rcdev->of_args)
+		return rcdev->of_args->np->full_name;
+
 	return NULL;
 }
 
@@ -99,6 +122,9 @@ static int of_reset_simple_xlate(struct reset_controller_dev *rcdev,
  */
 int reset_controller_register(struct reset_controller_dev *rcdev)
 {
+	if (rcdev->of_node && rcdev->of_args)
+		return -EINVAL;
+
 	if (!rcdev->of_xlate) {
 		rcdev->of_reset_n_cells = 1;
 		rcdev->of_xlate = of_reset_simple_xlate;
@@ -747,12 +773,19 @@ EXPORT_SYMBOL_GPL(reset_control_bulk_release);
 
 static struct reset_control *
 __reset_control_get_internal(struct reset_controller_dev *rcdev,
-			     unsigned int index, bool shared, bool acquired)
+			     unsigned int index, enum reset_control_flags flags)
 {
+	bool shared = flags & RESET_CONTROL_FLAGS_BIT_SHARED;
+	bool acquired = flags & RESET_CONTROL_FLAGS_BIT_ACQUIRED;
 	struct reset_control *rstc;
 
 	lockdep_assert_held(&reset_list_mutex);
 
+	/* Expect callers to filter out OPTIONAL and DEASSERTED bits */
+	if (WARN_ON(flags & ~(RESET_CONTROL_FLAGS_BIT_SHARED |
+			      RESET_CONTROL_FLAGS_BIT_ACQUIRED)))
+		return ERR_PTR(-EINVAL);
+
 	list_for_each_entry(rstc, &rcdev->reset_control_head, list) {
 		if (rstc->id == index) {
 			/*
@@ -786,6 +819,7 @@ __reset_control_get_internal(struct reset_controller_dev *rcdev,
 	kref_init(&rstc->refcnt);
 	rstc->acquired = acquired;
 	rstc->shared = shared;
+	get_device(rcdev->dev);
 
 	return rstc;
 }
@@ -800,6 +834,7 @@ static void __reset_control_release(struct kref *kref)
 	module_put(rstc->rcdev->owner);
 
 	list_del(&rstc->list);
+	put_device(rstc->rcdev->dev);
 	kfree(rstc);
 }
 
@@ -813,12 +848,165 @@ static void __reset_control_put_internal(struct reset_control *rstc)
 	kref_put(&rstc->refcnt, __reset_control_release);
 }
 
+static int __reset_add_reset_gpio_lookup(int id, struct device_node *np,
+					 unsigned int gpio,
+					 unsigned int of_flags)
+{
+	const struct fwnode_handle *fwnode = of_fwnode_handle(np);
+	unsigned int lookup_flags;
+	const char *label_tmp;
+
+	/*
+	 * Later we map GPIO flags between OF and Linux, however not all
+	 * constants from include/dt-bindings/gpio/gpio.h and
+	 * include/linux/gpio/machine.h match each other.
+	 */
+	if (of_flags > GPIO_ACTIVE_LOW) {
+		pr_err("reset-gpio code does not support GPIO flags %u for GPIO %u\n",
+		       of_flags, gpio);
+		return -EINVAL;
+	}
+
+	struct gpio_device *gdev __free(gpio_device_put) = gpio_device_find_by_fwnode(fwnode);
+	if (!gdev)
+		return -EPROBE_DEFER;
+
+	label_tmp = gpio_device_get_label(gdev);
+	if (!label_tmp)
+		return -EINVAL;
+
+	char *label __free(kfree) = kstrdup(label_tmp, GFP_KERNEL);
+	if (!label)
+		return -ENOMEM;
+
+	/* Size: one lookup entry plus sentinel */
+	struct gpiod_lookup_table *lookup __free(kfree) = kzalloc(struct_size(lookup, table, 2),
+								  GFP_KERNEL);
+	if (!lookup)
+		return -ENOMEM;
+
+	lookup->dev_id = kasprintf(GFP_KERNEL, "reset-gpio.%d", id);
+	if (!lookup->dev_id)
+		return -ENOMEM;
+
+	lookup_flags = GPIO_PERSISTENT;
+	lookup_flags |= of_flags & GPIO_ACTIVE_LOW;
+	lookup->table[0] = GPIO_LOOKUP(no_free_ptr(label), gpio, "reset",
+				       lookup_flags);
+
+	/* Not freed on success, because it is persisent subsystem data. */
+	gpiod_add_lookup_table(no_free_ptr(lookup));
+
+	return 0;
+}
+
+/*
+ * @args:	phandle to the GPIO provider with all the args like GPIO number
+ */
+static int __reset_add_reset_gpio_device(const struct of_phandle_args *args)
+{
+	struct reset_gpio_lookup *rgpio_dev;
+	struct platform_device *pdev;
+	int id, ret;
+
+	/*
+	 * Currently only #gpio-cells=2 is supported with the meaning of:
+	 * args[0]: GPIO number
+	 * args[1]: GPIO flags
+	 * TODO: Handle other cases.
+	 */
+	if (args->args_count != 2)
+		return -ENOENT;
+
+	/*
+	 * Registering reset-gpio device might cause immediate
+	 * bind, resulting in its probe() registering new reset controller thus
+	 * taking reset_list_mutex lock via reset_controller_register().
+	 */
+	lockdep_assert_not_held(&reset_list_mutex);
+
+	guard(mutex)(&reset_gpio_lookup_mutex);
+
+	list_for_each_entry(rgpio_dev, &reset_gpio_lookup_list, list) {
+		if (args->np == rgpio_dev->of_args.np) {
+			if (of_phandle_args_equal(args, &rgpio_dev->of_args))
+				return 0; /* Already on the list, done */
+		}
+	}
+
+	id = ida_alloc(&reset_gpio_ida, GFP_KERNEL);
+	if (id < 0)
+		return id;
+
+	/* Not freed on success, because it is persisent subsystem data. */
+	rgpio_dev = kzalloc(sizeof(*rgpio_dev), GFP_KERNEL);
+	if (!rgpio_dev) {
+		ret = -ENOMEM;
+		goto err_ida_free;
+	}
+
+	ret = __reset_add_reset_gpio_lookup(id, args->np, args->args[0],
+					    args->args[1]);
+	if (ret < 0)
+		goto err_kfree;
+
+	rgpio_dev->of_args = *args;
+	/*
+	 * We keep the device_node reference, but of_args.np is put at the end
+	 * of __of_reset_control_get(), so get it one more time.
+	 * Hold reference as long as rgpio_dev memory is valid.
+	 */
+	of_node_get(rgpio_dev->of_args.np);
+	pdev = platform_device_register_data(NULL, "reset-gpio", id,
+					     &rgpio_dev->of_args,
+					     sizeof(rgpio_dev->of_args));
+	ret = PTR_ERR_OR_ZERO(pdev);
+	if (ret)
+		goto err_put;
+
+	list_add(&rgpio_dev->list, &reset_gpio_lookup_list);
+
+	return 0;
+
+err_put:
+	of_node_put(rgpio_dev->of_args.np);
+err_kfree:
+	kfree(rgpio_dev);
+err_ida_free:
+	ida_free(&reset_gpio_ida, id);
+
+	return ret;
+}
+
+static struct reset_controller_dev *__reset_find_rcdev(const struct of_phandle_args *args,
+						       bool gpio_fallback)
+{
+	struct reset_controller_dev *rcdev;
+
+	lockdep_assert_held(&reset_list_mutex);
+
+	list_for_each_entry(rcdev, &reset_controller_list, list) {
+		if (gpio_fallback) {
+			if (rcdev->of_args && of_phandle_args_equal(args,
+								    rcdev->of_args))
+				return rcdev;
+		} else {
+			if (args->np == rcdev->of_node)
+				return rcdev;
+		}
+	}
+
+	return NULL;
+}
+
 struct reset_control *
 __of_reset_control_get(struct device_node *node, const char *id, int index,
-		       bool shared, bool optional, bool acquired)
+		       enum reset_control_flags flags)
 {
+	bool optional = flags & RESET_CONTROL_FLAGS_BIT_OPTIONAL;
+	bool gpio_fallback = false;
 	struct reset_control *rstc;
-	struct reset_controller_dev *r, *rcdev;
+	struct reset_controller_dev *rcdev;
 	struct of_phandle_args args;
 	int rstc_id;
 	int ret;
@@ -839,39 +1027,54 @@ __of_reset_control_get(struct device_node *node, const char *id, int index,
 					 index, &args);
 	if (ret == -EINVAL)
 		return ERR_PTR(ret);
-	if (ret)
-		return optional ? NULL : ERR_PTR(ret);
+	if (ret) {
+		if (!IS_ENABLED(CONFIG_RESET_GPIO))
+			return optional ? NULL : ERR_PTR(ret);
 
-	mutex_lock(&reset_list_mutex);
-	rcdev = NULL;
-	list_for_each_entry(r, &reset_controller_list, list) {
-		if (args.np == r->of_node) {
-			rcdev = r;
-			break;
+		/*
+		 * There can be only one reset-gpio for regular devices, so
+		 * don't bother with the "reset-gpios" phandle index.
+		 */
+		ret = of_parse_phandle_with_args(node, "reset-gpios", "#gpio-cells",
+						 0, &args);
+		if (ret)
+			return optional ? NULL : ERR_PTR(ret);
+
+		gpio_fallback = true;
+
+		ret = __reset_add_reset_gpio_device(&args);
+		if (ret) {
+			rstc = ERR_PTR(ret);
+			goto out_put;
 		}
 	}
 
+	mutex_lock(&reset_list_mutex);
+	rcdev = __reset_find_rcdev(&args, gpio_fallback);
 	if (!rcdev) {
 		rstc = ERR_PTR(-EPROBE_DEFER);
-		goto out;
+		goto out_unlock;
 	}
 
 	if (WARN_ON(args.args_count != rcdev->of_reset_n_cells)) {
 		rstc = ERR_PTR(-EINVAL);
-		goto out;
+		goto out_unlock;
 	}
 
 	rstc_id = rcdev->of_xlate(rcdev, &args);
 	if (rstc_id < 0) {
 		rstc = ERR_PTR(rstc_id);
-		goto out;
+		goto out_unlock;
 	}
 
+	flags &= ~RESET_CONTROL_FLAGS_BIT_OPTIONAL;
+
 	/* reset_list_mutex also protects the rcdev's reset_control list */
-	rstc = __reset_control_get_internal(rcdev, rstc_id, shared, acquired);
+	rstc = __reset_control_get_internal(rcdev, rstc_id, flags);
 
-out:
+out_unlock:
 	mutex_unlock(&reset_list_mutex);
+out_put:
 	of_node_put(args.np);
 
 	return rstc;
@@ -898,8 +1101,9 @@ __reset_controller_by_name(const char *name)
 
 static struct reset_control *
 __reset_control_get_from_lookup(struct device *dev, const char *con_id,
-				bool shared, bool optional, bool acquired)
+				enum reset_control_flags flags)
 {
+	bool optional = flags & RESET_CONTROL_FLAGS_BIT_OPTIONAL;
 	const struct reset_control_lookup *lookup;
 	struct reset_controller_dev *rcdev;
 	const char *dev_id = dev_name(dev);
@@ -923,9 +1127,11 @@ __reset_control_get_from_lookup(struct device *dev, const char *con_id,
 				return ERR_PTR(-EPROBE_DEFER);
 			}
 
+			flags &= ~RESET_CONTROL_FLAGS_BIT_OPTIONAL;
+
 			rstc = __reset_control_get_internal(rcdev,
 							    lookup->index,
-							    shared, acquired);
+							    flags);
 			mutex_unlock(&reset_list_mutex);
 			break;
 		}
@@ -940,30 +1146,29 @@ __reset_control_get_from_lookup(struct device *dev, const char *con_id,
 }
 
 struct reset_control *__reset_control_get(struct device *dev, const char *id,
-					  int index, bool shared, bool optional,
-					  bool acquired)
+					  int index, enum reset_control_flags flags)
 {
+	bool shared = flags & RESET_CONTROL_FLAGS_BIT_SHARED;
+	bool acquired = flags & RESET_CONTROL_FLAGS_BIT_ACQUIRED;
+
 	if (WARN_ON(shared && acquired))
 		return ERR_PTR(-EINVAL);
 
 	if (dev->of_node)
-		return __of_reset_control_get(dev->of_node, id, index, shared,
-					      optional, acquired);
+		return __of_reset_control_get(dev->of_node, id, index, flags);
 
-	return __reset_control_get_from_lookup(dev, id, shared, optional,
-					       acquired);
+	return __reset_control_get_from_lookup(dev, id, flags);
 }
 EXPORT_SYMBOL_GPL(__reset_control_get);
 
 int __reset_control_bulk_get(struct device *dev, int num_rstcs,
 			     struct reset_control_bulk_data *rstcs,
-			     bool shared, bool optional, bool acquired)
+			     enum reset_control_flags flags)
 {
 	int ret, i;
 
 	for (i = 0; i < num_rstcs; i++) {
-		rstcs[i].rstc = __reset_control_get(dev, rstcs[i].id, 0,
-						    shared, optional, acquired);
+		rstcs[i].rstc = __reset_control_get(dev, rstcs[i].id, 0, flags);
 		if (IS_ERR(rstcs[i].rstc)) {
 			ret = PTR_ERR(rstcs[i].rstc);
 			goto err;
@@ -1031,23 +1236,46 @@ static void devm_reset_control_release(struct device *dev, void *res)
 	reset_control_put(*(struct reset_control **)res);
 }
 
+static void devm_reset_control_release_deasserted(struct device *dev, void *res)
+{
+	struct reset_control *rstc = *(struct reset_control **)res;
+
+	reset_control_assert(rstc);
+	reset_control_put(rstc);
+}
+
 struct reset_control *
 __devm_reset_control_get(struct device *dev, const char *id, int index,
-			 bool shared, bool optional, bool acquired)
+			 enum reset_control_flags flags)
 {
 	struct reset_control **ptr, *rstc;
+	bool deasserted = flags & RESET_CONTROL_FLAGS_BIT_DEASSERTED;
 
-	ptr = devres_alloc(devm_reset_control_release, sizeof(*ptr),
+	ptr = devres_alloc(deasserted ? devm_reset_control_release_deasserted :
+			   devm_reset_control_release, sizeof(*ptr),
 			   GFP_KERNEL);
 	if (!ptr)
 		return ERR_PTR(-ENOMEM);
 
-	rstc = __reset_control_get(dev, id, index, shared, optional, acquired);
+	flags &= ~RESET_CONTROL_FLAGS_BIT_DEASSERTED;
+
+	rstc = __reset_control_get(dev, id, index, flags);
 	if (IS_ERR_OR_NULL(rstc)) {
 		devres_free(ptr);
 		return rstc;
 	}
 
+	if (deasserted) {
+		int ret;
+
+		ret = reset_control_deassert(rstc);
+		if (ret) {
+			reset_control_put(rstc);
+			devres_free(ptr);
+			return ERR_PTR(ret);
+		}
+	}
+
 	*ptr = rstc;
 	devres_add(dev, ptr);
 
@@ -1067,24 +1295,45 @@ static void devm_reset_control_bulk_release(struct device *dev, void *res)
 	reset_control_bulk_put(devres->num_rstcs, devres->rstcs);
 }
 
+static void devm_reset_control_bulk_release_deasserted(struct device *dev, void *res)
+{
+	struct reset_control_bulk_devres *devres = res;
+
+	reset_control_bulk_assert(devres->num_rstcs, devres->rstcs);
+	reset_control_bulk_put(devres->num_rstcs, devres->rstcs);
+}
+
 int __devm_reset_control_bulk_get(struct device *dev, int num_rstcs,
 				  struct reset_control_bulk_data *rstcs,
-				  bool shared, bool optional, bool acquired)
+				  enum reset_control_flags flags)
 {
 	struct reset_control_bulk_devres *ptr;
+	bool deasserted = flags & RESET_CONTROL_FLAGS_BIT_DEASSERTED;
 	int ret;
 
-	ptr = devres_alloc(devm_reset_control_bulk_release, sizeof(*ptr),
+	ptr = devres_alloc(deasserted ? devm_reset_control_bulk_release_deasserted :
+			   devm_reset_control_bulk_release, sizeof(*ptr),
 			   GFP_KERNEL);
 	if (!ptr)
 		return -ENOMEM;
 
-	ret = __reset_control_bulk_get(dev, num_rstcs, rstcs, shared, optional, acquired);
+	flags &= ~RESET_CONTROL_FLAGS_BIT_DEASSERTED;
+
+	ret = __reset_control_bulk_get(dev, num_rstcs, rstcs, flags);
 	if (ret < 0) {
 		devres_free(ptr);
 		return ret;
 	}
 
+	if (deasserted) {
+		ret = reset_control_bulk_deassert(num_rstcs, rstcs);
+		if (ret) {
+			reset_control_bulk_put(num_rstcs, rstcs);
+			devres_free(ptr);
+			return ret;
+		}
+	}
+
 	ptr->num_rstcs = num_rstcs;
 	ptr->rstcs = rstcs;
 	devres_add(dev, ptr);
@@ -1105,6 +1354,7 @@ EXPORT_SYMBOL_GPL(__devm_reset_control_bulk_get);
  */
 int __device_reset(struct device *dev, bool optional)
 {
+	enum reset_control_flags flags;
 	struct reset_control *rstc;
 	int ret;
 
@@ -1120,7 +1370,8 @@ int __device_reset(struct device *dev, bool optional)
 	}
 #endif
 
-	rstc = __reset_control_get(dev, NULL, 0, 0, optional, true);
+	flags = optional ? RESET_CONTROL_OPTIONAL_EXCLUSIVE : RESET_CONTROL_EXCLUSIVE;
+	rstc = __reset_control_get(dev, NULL, 0, flags);
 	if (IS_ERR(rstc))
 		return PTR_ERR(rstc);
 
@@ -1163,17 +1414,14 @@ static int of_reset_control_get_count(struct device_node *node)
  *				device node.
  *
  * @np: device node for the device that requests the reset controls array
- * @shared: whether reset controls are shared or not
- * @optional: whether it is optional to get the reset controls
- * @acquired: only one reset control may be acquired for a given controller
- *            and ID
+ * @flags: whether reset controls are shared, optional, acquired
  *
  * Returns pointer to allocated reset_control on success or error on failure
  */
 struct reset_control *
-of_reset_control_array_get(struct device_node *np, bool shared, bool optional,
-			   bool acquired)
+of_reset_control_array_get(struct device_node *np, enum reset_control_flags flags)
 {
+	bool optional = flags & RESET_CONTROL_FLAGS_BIT_OPTIONAL;
 	struct reset_control_array *resets;
 	struct reset_control *rstc;
 	int num, i;
@@ -1188,8 +1436,7 @@ of_reset_control_array_get(struct device_node *np, bool shared, bool optional,
 	resets->num_rstcs = num;
 
 	for (i = 0; i < num; i++) {
-		rstc = __of_reset_control_get(np, NULL, i, shared, optional,
-					      acquired);
+		rstc = __of_reset_control_get(np, NULL, i, flags);
 		if (IS_ERR(rstc))
 			goto err_rst;
 		resets->rstc[i] = rstc;
@@ -1214,8 +1461,7 @@ EXPORT_SYMBOL_GPL(of_reset_control_array_get);
  * devm_reset_control_array_get - Resource managed reset control array get
  *
  * @dev: device that requests the list of reset controls
- * @shared: whether reset controls are shared or not
- * @optional: whether it is optional to get the reset controls
+ * @flags: whether reset controls are shared, optional, acquired
  *
  * The reset control array APIs are intended for a list of resets
  * that just have to be asserted or deasserted, without any
@@ -1224,7 +1470,7 @@ EXPORT_SYMBOL_GPL(of_reset_control_array_get);
  * Returns pointer to allocated reset_control on success or error on failure
  */
 struct reset_control *
-devm_reset_control_array_get(struct device *dev, bool shared, bool optional)
+devm_reset_control_array_get(struct device *dev, enum reset_control_flags flags)
 {
 	struct reset_control **ptr, *rstc;
 
@@ -1233,7 +1479,7 @@ devm_reset_control_array_get(struct device *dev, bool shared, bool optional)
 	if (!ptr)
 		return ERR_PTR(-ENOMEM);
 
-	rstc = of_reset_control_array_get(dev->of_node, shared, optional, true);
+	rstc = of_reset_control_array_get(dev->of_node, flags);
 	if (IS_ERR_OR_NULL(rstc)) {
 		devres_free(ptr);
 		return rstc;