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drivers/reset/core.c
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/* * 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; |
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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. */ |
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static int of_reset_simple_xlate(struct reset_controller_dev *rcdev, |
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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]; } |
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/** * 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); |
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return -ENOTSUPP; |
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} 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); |
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return -ENOTSUPP; |
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} 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); |
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return -ENOTSUPP; |
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} EXPORT_SYMBOL_GPL(reset_control_deassert); /** |
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* reset_control_status - returns a negative errno if not supported, a * positive value if the reset line is asserted, or zero if the reset * line is not asserted. * @rstc: reset controller */ int reset_control_status(struct reset_control *rstc) { if (rstc->rcdev->ops->status) return rstc->rcdev->ops->status(rstc->rcdev, rstc->id); |
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return -ENOTSUPP; |
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} EXPORT_SYMBOL_GPL(reset_control_status); /** |
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* of_reset_control_get_by_index - Lookup and obtain a reference to a reset * controller by index. |
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* @node: device to be reset by the controller |
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* @index: index of the reset controller |
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* |
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* This is to be used to perform a list of resets for a device or power domain * in whatever order. Returns a struct reset_control or IS_ERR() condition * containing errno. |
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*/ |
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struct reset_control *of_reset_control_get_by_index(struct device_node *node, int index) |
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{ struct reset_control *rstc = ERR_PTR(-EPROBE_DEFER); struct reset_controller_dev *r, *rcdev; struct of_phandle_args args; |
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int rstc_id; int ret; |
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ret = of_parse_phandle_with_args(node, "resets", "#reset-cells", |
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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); |
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return ERR_PTR(-EPROBE_DEFER); |
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} 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) { |
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module_put(rcdev->owner); |
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return ERR_PTR(-ENOMEM); } |
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rstc->rcdev = rcdev; rstc->id = rstc_id; return rstc; } |
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EXPORT_SYMBOL_GPL(of_reset_control_get_by_index); /** * of_reset_control_get - Lookup and obtain a reference to a reset controller. * @node: 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 *of_reset_control_get(struct device_node *node, const char *id) { int index = 0; |
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if (id) { |
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index = of_property_match_string(node, "reset-names", id); |
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if (index < 0) return ERR_PTR(-ENOENT); } |
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return of_reset_control_get_by_index(node, index); } |
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EXPORT_SYMBOL_GPL(of_reset_control_get); /** * 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) { |
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if (!dev) return ERR_PTR(-EINVAL); |
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return of_reset_control_get(dev->of_node, id); |
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} |
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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); |
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/** * 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); |