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https://github.com/AsahiLinux/u-boot
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83d290c56f
When U-Boot started using SPDX tags we were among the early adopters and there weren't a lot of other examples to borrow from. So we picked the area of the file that usually had a full license text and replaced it with an appropriate SPDX-License-Identifier: entry. Since then, the Linux Kernel has adopted SPDX tags and they place it as the very first line in a file (except where shebangs are used, then it's second line) and with slightly different comment styles than us. In part due to community overlap, in part due to better tag visibility and in part for other minor reasons, switch over to that style. This commit changes all instances where we have a single declared license in the tag as both the before and after are identical in tag contents. There's also a few places where I found we did not have a tag and have introduced one. Signed-off-by: Tom Rini <trini@konsulko.com>
293 lines
9.8 KiB
C
293 lines
9.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright (c) 2016, NVIDIA CORPORATION.
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*/
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#ifndef _RESET_H
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#define _RESET_H
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#include <linux/errno.h>
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/**
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* A reset is a hardware signal indicating that a HW module (or IP block, or
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* sometimes an entire off-CPU chip) reset all of its internal state to some
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* known-good initial state. Drivers will often reset HW modules when they
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* begin execution to ensure that hardware correctly responds to all requests,
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* or in response to some error condition. Reset signals are often controlled
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* externally to the HW module being reset, by an entity this API calls a reset
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* controller. This API provides a standard means for drivers to request that
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* reset controllers set or clear reset signals.
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*
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* A driver that implements UCLASS_RESET is a reset controller or provider. A
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* controller will often implement multiple separate reset signals, since the
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* hardware it manages often has this capability. reset-uclass.h describes the
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* interface which reset controllers must implement.
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*
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* Reset consumers/clients are the HW modules affected by reset signals. This
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* header file describes the API used by drivers for those HW modules.
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*/
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struct udevice;
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/**
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* struct reset_ctl - A handle to (allowing control of) a single reset signal.
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*
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* Clients provide storage for reset control handles. The content of the
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* structure is managed solely by the reset API and reset drivers. A reset
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* control struct is initialized by "get"ing the reset control struct. The
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* reset control struct is passed to all other reset APIs to identify which
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* reset signal to operate upon.
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*
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* @dev: The device which implements the reset signal.
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* @id: The reset signal ID within the provider.
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*
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* Currently, the reset API assumes that a single integer ID is enough to
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* identify and configure any reset signal for any reset provider. If this
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* assumption becomes invalid in the future, the struct could be expanded to
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* either (a) add more fields to allow reset providers to store additional
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* information, or (b) replace the id field with an opaque pointer, which the
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* provider would dynamically allocated during its .of_xlate op, and process
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* during is .request op. This may require the addition of an extra op to clean
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* up the allocation.
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*/
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struct reset_ctl {
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struct udevice *dev;
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/*
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* Written by of_xlate. We assume a single id is enough for now. In the
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* future, we might add more fields here.
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*/
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unsigned long id;
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};
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/**
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* struct reset_ctl_bulk - A handle to (allowing control of) a bulk of reset
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* signals.
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*
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* Clients provide storage for the reset control bulk. The content of the
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* structure is managed solely by the reset API. A reset control bulk struct is
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* initialized by "get"ing the reset control bulk struct.
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* The reset control bulk struct is passed to all other bulk reset APIs to apply
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* the API to all the reset signals in the bulk struct.
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*
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* @resets: An array of reset signal handles handles.
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* @count: The number of reset signal handles in the reset array.
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*/
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struct reset_ctl_bulk {
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struct reset_ctl *resets;
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unsigned int count;
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};
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#ifdef CONFIG_DM_RESET
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/**
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* reset_get_by_index - Get/request a reset signal by integer index.
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*
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* This looks up and requests a reset signal. The index is relative to the
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* client device; each device is assumed to have n reset signals associated
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* with it somehow, and this function finds and requests one of them. The
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* mapping of client device reset signal indices to provider reset signals may
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* be via device-tree properties, board-provided mapping tables, or some other
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* mechanism.
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*
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* @dev: The client device.
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* @index: The index of the reset signal to request, within the client's
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* list of reset signals.
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* @reset_ctl A pointer to a reset control struct to initialize.
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* @return 0 if OK, or a negative error code.
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*/
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int reset_get_by_index(struct udevice *dev, int index,
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struct reset_ctl *reset_ctl);
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/**
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* reset_get_bulk - Get/request all reset signals of a device.
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*
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* This looks up and requests all reset signals of the client device; each
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* device is assumed to have n reset signals associated with it somehow,
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* and this function finds and requests all of them in a separate structure.
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* The mapping of client device reset signals indices to provider reset signals
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* may be via device-tree properties, board-provided mapping tables, or some
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* other mechanism.
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*
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* @dev: The client device.
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* @bulk A pointer to a reset control bulk struct to initialize.
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* @return 0 if OK, or a negative error code.
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*/
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int reset_get_bulk(struct udevice *dev, struct reset_ctl_bulk *bulk);
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/**
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* reset_get_by_name - Get/request a reset signal by name.
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*
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* This looks up and requests a reset signal. The name is relative to the
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* client device; each device is assumed to have n reset signals associated
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* with it somehow, and this function finds and requests one of them. The
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* mapping of client device reset signal names to provider reset signal may be
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* via device-tree properties, board-provided mapping tables, or some other
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* mechanism.
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*
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* @dev: The client device.
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* @name: The name of the reset signal to request, within the client's
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* list of reset signals.
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* @reset_ctl: A pointer to a reset control struct to initialize.
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* @return 0 if OK, or a negative error code.
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*/
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int reset_get_by_name(struct udevice *dev, const char *name,
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struct reset_ctl *reset_ctl);
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/**
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* reset_request - Request a reset signal.
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*
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* @reset_ctl: A reset control struct.
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*
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* @return 0 if OK, or a negative error code.
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*/
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int reset_request(struct reset_ctl *reset_ctl);
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/**
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* reset_free - Free a previously requested reset signal.
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*
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* @reset_ctl: A reset control struct that was previously successfully
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* requested by reset_get_by_*().
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* @return 0 if OK, or a negative error code.
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*/
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int reset_free(struct reset_ctl *reset_ctl);
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/**
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* reset_assert - Assert a reset signal.
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*
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* This function will assert the specified reset signal, thus resetting the
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* affected HW module(s). Depending on the reset controller hardware, the reset
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* signal will either stay asserted until reset_deassert() is called, or the
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* hardware may autonomously clear the reset signal itself.
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*
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* @reset_ctl: A reset control struct that was previously successfully
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* requested by reset_get_by_*().
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* @return 0 if OK, or a negative error code.
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*/
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int reset_assert(struct reset_ctl *reset_ctl);
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/**
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* reset_assert_bulk - Assert all reset signals in a reset control bulk struct.
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*
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* This function will assert the specified reset signals in a reset control
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* bulk struct, thus resetting the affected HW module(s). Depending on the
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* reset controller hardware, the reset signals will either stay asserted
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* until reset_deassert_bulk() is called, or the hardware may autonomously
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* clear the reset signals itself.
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*
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* @bulk: A reset control bulk struct that was previously successfully
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* requested by reset_get_bulk().
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* @return 0 if OK, or a negative error code.
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*/
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int reset_assert_bulk(struct reset_ctl_bulk *bulk);
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/**
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* reset_deassert - Deassert a reset signal.
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*
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* This function will deassert the specified reset signal, thus releasing the
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* affected HW modules() from reset, and allowing them to continue normal
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* operation.
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*
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* @reset_ctl: A reset control struct that was previously successfully
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* requested by reset_get_by_*().
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* @return 0 if OK, or a negative error code.
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*/
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int reset_deassert(struct reset_ctl *reset_ctl);
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/**
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* reset_deassert_bulk - Deassert all reset signals in a reset control bulk
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* struct.
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*
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* This function will deassert the specified reset signals in a reset control
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* bulk struct, thus releasing the affected HW modules() from reset, and
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* allowing them to continue normal operation.
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*
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* @bulk: A reset control bulk struct that was previously successfully
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* requested by reset_get_bulk().
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* @return 0 if OK, or a negative error code.
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*/
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int reset_deassert_bulk(struct reset_ctl_bulk *bulk);
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/**
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* reset_release_all - Assert/Free an array of previously requested resets.
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*
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* For each reset contained in the reset array, this function will check if
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* reset has been previously requested and then will assert and free it.
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*
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* @reset_ctl: A reset struct array that was previously successfully
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* requested by reset_get_by_*().
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* @count Number of reset contained in the array
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* @return 0 if OK, or a negative error code.
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*/
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int reset_release_all(struct reset_ctl *reset_ctl, int count);
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/**
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* reset_release_bulk - Assert/Free an array of previously requested reset
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* signals in a reset control bulk struct.
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*
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* For each reset contained in the reset control bulk struct, this function
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* will check if reset has been previously requested and then will assert
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* and free it.
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*
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* @bulk: A reset control bulk struct that was previously successfully
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* requested by reset_get_bulk().
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* @return 0 if OK, or a negative error code.
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*/
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static inline int reset_release_bulk(struct reset_ctl_bulk *bulk)
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{
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return reset_release_all(bulk->resets, bulk->count);
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}
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#else
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static inline int reset_get_by_index(struct udevice *dev, int index,
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struct reset_ctl *reset_ctl)
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{
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return -ENOTSUPP;
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}
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static inline int reset_get_bulk(struct udevice *dev,
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struct reset_ctl_bulk *bulk)
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{
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return -ENOTSUPP;
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}
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static inline int reset_get_by_name(struct udevice *dev, const char *name,
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struct reset_ctl *reset_ctl)
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{
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return -ENOTSUPP;
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}
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static inline int reset_free(struct reset_ctl *reset_ctl)
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{
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return 0;
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}
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static inline int reset_assert(struct reset_ctl *reset_ctl)
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{
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return 0;
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}
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static inline int reset_assert_bulk(struct reset_ctl_bulk *bulk)
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{
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return 0;
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}
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static inline int reset_deassert(struct reset_ctl *reset_ctl)
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{
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return 0;
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}
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static inline int reset_deassert_bulk(struct reset_ctl_bulk *bulk)
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{
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return 0;
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}
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static inline int reset_release_all(struct reset_ctl *reset_ctl, int count)
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{
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return 0;
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}
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static inline int reset_release_bulk(struct reset_ctl_bulk *bulk)
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{
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return 0;
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}
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#endif
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#endif
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