/* * Reset Controller framework * * Copyright 2013 Philipp Zabel, Pengutronix * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. */#include <linux/device.h>#include <linux/err.h>#include <linux/export.h>#include <linux/kernel.h>#include <linux/module.h>#include <linux/of.h>#include <linux/reset.h>#include <linux/reset-controller.h>#include <linux/slab.h> static DEFINE_MUTEX(reset_controller_list_mutex);static LIST_HEAD(reset_controller_list); /** * struct reset_control - a reset control * @rcdev: a pointer to the reset controller device *         this reset control belongs to * @id: ID of the reset controller in the reset *      controller device */struct reset_control {	struct reset_controller_dev *rcdev;	struct device *dev;	unsigned int id;}; /** * of_reset_simple_xlate - translate reset_spec to the reset line number * @rcdev: a pointer to the reset controller device * @reset_spec: reset line specifier as found in the device tree * @flags: a flags pointer to fill in (optional) * * This simple translation function should be used for reset controllers * with 1:1 mapping, where reset lines can be indexed by number without gaps. */int of_reset_simple_xlate(struct reset_controller_dev *rcdev,			  const struct of_phandle_args *reset_spec){	if (WARN_ON(reset_spec->args_count != rcdev->of_reset_n_cells))		return -EINVAL; 	if (reset_spec->args[0] >= rcdev->nr_resets)		return -EINVAL; 	return reset_spec->args[0];}EXPORT_SYMBOL_GPL(of_reset_simple_xlate); /** * reset_controller_register - register a reset controller device * @rcdev: a pointer to the initialized reset controller device */int reset_controller_register(struct reset_controller_dev *rcdev){	if (!rcdev->of_xlate) {		rcdev->of_reset_n_cells = 1;		rcdev->of_xlate = of_reset_simple_xlate;	} 	mutex_lock(&reset_controller_list_mutex);	list_add(&rcdev->list, &reset_controller_list);	mutex_unlock(&reset_controller_list_mutex); 	return 0;}EXPORT_SYMBOL_GPL(reset_controller_register); /** * reset_controller_unregister - unregister a reset controller device * @rcdev: a pointer to the reset controller device */void reset_controller_unregister(struct reset_controller_dev *rcdev){	mutex_lock(&reset_controller_list_mutex);	list_del(&rcdev->list);	mutex_unlock(&reset_controller_list_mutex);}EXPORT_SYMBOL_GPL(reset_controller_unregister); /** * reset_control_reset - reset the controlled device * @rstc: reset controller */int reset_control_reset(struct reset_control *rstc){	if (rstc->rcdev->ops->reset)		return rstc->rcdev->ops->reset(rstc->rcdev, rstc->id); 	return -ENOSYS;}EXPORT_SYMBOL_GPL(reset_control_reset); /** * reset_control_assert - asserts the reset line * @rstc: reset controller */int reset_control_assert(struct reset_control *rstc){	if (rstc->rcdev->ops->assert)		return rstc->rcdev->ops->assert(rstc->rcdev, rstc->id); 	return -ENOSYS;}EXPORT_SYMBOL_GPL(reset_control_assert); /** * reset_control_deassert - deasserts the reset line * @rstc: reset controller */int reset_control_deassert(struct reset_control *rstc){	if (rstc->rcdev->ops->deassert)		return rstc->rcdev->ops->deassert(rstc->rcdev, rstc->id); 	return -ENOSYS;}EXPORT_SYMBOL_GPL(reset_control_deassert); /** * reset_control_get - Lookup and obtain a reference to a reset controller. * @dev: device to be reset by the controller * @id: reset line name * * Returns a struct reset_control or IS_ERR() condition containing errno. * * Use of id names is optional. */struct reset_control *reset_control_get(struct device *dev, const char *id){	struct reset_control *rstc = ERR_PTR(-EPROBE_DEFER);	struct reset_controller_dev *r, *rcdev;	struct of_phandle_args args;	int index = 0;	int rstc_id;	int ret; 	if (!dev)		return ERR_PTR(-EINVAL); 	if (id)		index = of_property_match_string(dev->of_node,						 "reset-names", id);	ret = of_parse_phandle_with_args(dev->of_node, "resets", "#reset-cells",					 index, &args);	if (ret)		return ERR_PTR(ret); 	mutex_lock(&reset_controller_list_mutex);	rcdev = NULL;	list_for_each_entry(r, &reset_controller_list, list) {		if (args.np == r->of_node) {			rcdev = r;			break;		}	}	of_node_put(args.np); 	if (!rcdev) {		mutex_unlock(&reset_controller_list_mutex);		return ERR_PTR(-ENODEV);	} 	rstc_id = rcdev->of_xlate(rcdev, &args);	if (rstc_id < 0) {		mutex_unlock(&reset_controller_list_mutex);		return ERR_PTR(rstc_id);	} 	try_module_get(rcdev->owner);	mutex_unlock(&reset_controller_list_mutex); 	rstc = kzalloc(sizeof(*rstc), GFP_KERNEL);	if (!rstc) {		module_put(rcdev->owner);		return ERR_PTR(-ENOMEM);	} 	rstc->dev = dev;	rstc->rcdev = rcdev;	rstc->id = rstc_id; 	return rstc;}EXPORT_SYMBOL_GPL(reset_control_get); /** * reset_control_put - free the reset controller * @rstc: reset controller */ void reset_control_put(struct reset_control *rstc){	if (IS_ERR(rstc))		return; 	module_put(rstc->rcdev->owner);	kfree(rstc);}EXPORT_SYMBOL_GPL(reset_control_put); static void devm_reset_control_release(struct device *dev, void *res){	reset_control_put(*(struct reset_control **)res);} /** * devm_reset_control_get - resource managed reset_control_get() * @dev: device to be reset by the controller * @id: reset line name * * Managed reset_control_get(). For reset controllers returned from this * function, reset_control_put() is called automatically on driver detach. * See reset_control_get() for more information. */struct reset_control *devm_reset_control_get(struct device *dev, const char *id){	struct reset_control **ptr, *rstc; 	ptr = devres_alloc(devm_reset_control_release, sizeof(*ptr),			   GFP_KERNEL);	if (!ptr)		return ERR_PTR(-ENOMEM); 	rstc = reset_control_get(dev, id);	if (!IS_ERR(rstc)) {		*ptr = rstc;		devres_add(dev, ptr);	} else {		devres_free(ptr);	} 	return rstc;}EXPORT_SYMBOL_GPL(devm_reset_control_get); static int devm_reset_control_match(struct device *dev, void *res, void *data){	struct reset_control **rstc = res;	if (WARN_ON(!rstc || !*rstc))		return 0;	return *rstc == data;} /** * devm_reset_control_put - resource managed reset_control_put() * @rstc: reset controller to free * * Deallocate a reset control allocated withd devm_reset_control_get(). * This function will not need to be called normally, as devres will take * care of freeing the resource. */void devm_reset_control_put(struct reset_control *rstc){	int ret; 	ret = devres_release(rstc->dev, devm_reset_control_release,			     devm_reset_control_match, rstc);	if (ret)		WARN_ON(ret);}EXPORT_SYMBOL_GPL(devm_reset_control_put); /** * device_reset - find reset controller associated with the device *                and perform reset * @dev: device to be reset by the controller * * Convenience wrapper for reset_control_get() and reset_control_reset(). * This is useful for the common case of devices with single, dedicated reset * lines. */int device_reset(struct device *dev){	struct reset_control *rstc;	int ret; 	rstc = reset_control_get(dev, NULL);	if (IS_ERR(rstc))		return PTR_ERR(rstc); 	ret = reset_control_reset(rstc); 	reset_control_put(rstc); 	return ret;}EXPORT_SYMBOL_GPL(device_reset);