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![Tom Rini](/assets/img/avatar_default.png)
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>
298 lines
9.8 KiB
C
298 lines
9.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0+ */
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/*
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* Copyright (c) 2015 Google, Inc
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* Written by Simon Glass <sjg@chromium.org>
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* Copyright (c) 2016, NVIDIA CORPORATION.
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*/
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#ifndef _CLK_H_
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#define _CLK_H_
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#include <linux/errno.h>
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#include <linux/types.h>
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/**
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* A clock is a hardware signal that oscillates autonomously at a specific
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* frequency and duty cycle. Most hardware modules require one or more clock
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* signal to drive their operation. Clock signals are typically generated
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* externally to the HW module consuming them, by an entity this API calls a
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* clock provider. This API provides a standard means for drivers to enable and
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* disable clocks, and to set the rate at which they oscillate.
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*
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* A driver that implements UCLASS_CLOCK is a clock provider. A provider will
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* often implement multiple separate clocks, since the hardware it manages
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* often has this capability. clock_uclass.h describes the interface which
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* clock providers must implement.
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*
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* Clock consumers/clients are the HW modules driven by the clock 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 clk - A handle to (allowing control of) a single clock.
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*
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* Clients provide storage for clock handles. The content of the structure is
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* managed solely by the clock API and clock drivers. A clock struct is
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* initialized by "get"ing the clock struct. The clock struct is passed to all
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* other clock APIs to identify which clock signal to operate upon.
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*
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* @dev: The device which implements the clock signal.
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* @id: The clock signal ID within the provider.
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*
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* Currently, the clock API assumes that a single integer ID is enough to
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* identify and configure any clock signal for any clock 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 clock 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 clk {
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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 clk_bulk - A handle to (allowing control of) a bulk of clocks.
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*
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* Clients provide storage for the clock bulk. The content of the structure is
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* managed solely by the clock API. A clock bulk struct is
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* initialized by "get"ing the clock bulk struct.
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* The clock bulk struct is passed to all other bulk clock APIs to apply
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* the API to all the clock in the bulk struct.
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*
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* @clks: An array of clock handles.
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* @count: The number of clock handles in the clks array.
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*/
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struct clk_bulk {
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struct clk *clks;
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unsigned int count;
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};
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#if CONFIG_IS_ENABLED(OF_CONTROL) && CONFIG_IS_ENABLED(CLK)
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struct phandle_1_arg;
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int clk_get_by_index_platdata(struct udevice *dev, int index,
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struct phandle_1_arg *cells, struct clk *clk);
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/**
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* clock_get_by_index - Get/request a clock by integer index.
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*
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* This looks up and requests a clock. The index is relative to the client
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* device; each device is assumed to have n clocks associated with it somehow,
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* and this function finds and requests one of them. The mapping of client
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* device clock indices to provider clocks may be via device-tree properties,
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* board-provided mapping tables, or some other mechanism.
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*
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* @dev: The client device.
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* @index: The index of the clock to request, within the client's list of
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* clocks.
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* @clock A pointer to a clock 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 clk_get_by_index(struct udevice *dev, int index, struct clk *clk);
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/**
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* clock_get_bulk - Get/request all clocks of a device.
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*
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* This looks up and requests all clocks of the client device; each device is
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* assumed to have n clocks associated with it somehow, and this function finds
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* and requests all of them in a separate structure. The mapping of client
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* device clock indices to provider clocks may be via device-tree properties,
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* board-provided mapping tables, or some other mechanism.
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*
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* @dev: The client device.
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* @bulk A pointer to a clock 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 clk_get_bulk(struct udevice *dev, struct clk_bulk *bulk);
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/**
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* clock_get_by_name - Get/request a clock by name.
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*
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* This looks up and requests a clock. The name is relative to the client
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* device; each device is assumed to have n clocks associated with it somehow,
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* and this function finds and requests one of them. The mapping of client
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* device clock names to provider clocks may be via device-tree properties,
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* board-provided mapping tables, or some other mechanism.
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*
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* @dev: The client device.
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* @name: The name of the clock to request, within the client's list of
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* clocks.
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* @clock: A pointer to a clock 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 clk_get_by_name(struct udevice *dev, const char *name, struct clk *clk);
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/**
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* clk_release_all() - Disable (turn off)/Free an array of previously
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* requested clocks.
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*
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* For each clock contained in the clock array, this function will check if
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* clock has been previously requested and then will disable and free it.
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*
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* @clk: A clock struct array that was previously successfully
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* requested by clk_request/get_by_*().
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* @count Number of clock contained in the array
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* @return zero on success, or -ve error code.
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*/
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int clk_release_all(struct clk *clk, int count);
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#else
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static inline int clk_get_by_index(struct udevice *dev, int index,
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struct clk *clk)
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{
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return -ENOSYS;
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}
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static inline int clk_get_bulk(struct udevice *dev, struct clk_bulk *bulk)
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{
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return -ENOSYS;
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}
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static inline int clk_get_by_name(struct udevice *dev, const char *name,
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struct clk *clk)
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{
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return -ENOSYS;
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}
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static inline int clk_release_all(struct clk *clk, int count)
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{
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return -ENOSYS;
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}
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#endif
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#if (CONFIG_IS_ENABLED(OF_CONTROL) && !CONFIG_IS_ENABLED(OF_PLATDATA)) && \
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CONFIG_IS_ENABLED(CLK)
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/**
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* clk_set_defaults - Process 'assigned-{clocks/clock-parents/clock-rates}'
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* properties to configure clocks
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*
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* @dev: A device to process (the ofnode associated with this device
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* will be processed).
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*/
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int clk_set_defaults(struct udevice *dev);
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#else
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static inline int clk_set_defaults(struct udevice *dev)
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{
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return 0;
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}
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#endif
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/**
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* clk_release_bulk() - Disable (turn off)/Free an array of previously
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* requested clocks in a clock bulk struct.
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*
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* For each clock contained in the clock bulk struct, this function will check
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* if clock has been previously requested and then will disable and free it.
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*
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* @clk: A clock bulk struct that was previously successfully
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* requested by clk_get_bulk().
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* @return zero on success, or -ve error code.
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*/
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static inline int clk_release_bulk(struct clk_bulk *bulk)
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{
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return clk_release_all(bulk->clks, bulk->count);
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}
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/**
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* clk_request - Request a clock by provider-specific ID.
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*
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* This requests a clock using a provider-specific ID. Generally, this function
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* should not be used, since clk_get_by_index/name() provide an interface that
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* better separates clients from intimate knowledge of clock providers.
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* However, this function may be useful in core SoC-specific code.
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*
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* @dev: The clock provider device.
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* @clock: A pointer to a clock struct to initialize. The caller must
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* have already initialized any field in this struct which the
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* clock provider uses to identify the clock.
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* @return 0 if OK, or a negative error code.
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*/
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int clk_request(struct udevice *dev, struct clk *clk);
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/**
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* clock_free - Free a previously requested clock.
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*
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* @clock: A clock struct that was previously successfully requested by
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* clk_request/get_by_*().
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* @return 0 if OK, or a negative error code.
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*/
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int clk_free(struct clk *clk);
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/**
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* clk_get_rate() - Get current clock rate.
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*
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* @clk: A clock struct that was previously successfully requested by
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* clk_request/get_by_*().
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* @return clock rate in Hz, or -ve error code.
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*/
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ulong clk_get_rate(struct clk *clk);
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/**
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* clk_set_rate() - Set current clock rate.
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*
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* @clk: A clock struct that was previously successfully requested by
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* clk_request/get_by_*().
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* @rate: New clock rate in Hz.
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* @return new rate, or -ve error code.
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*/
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ulong clk_set_rate(struct clk *clk, ulong rate);
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/**
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* clk_set_parent() - Set current clock parent.
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*
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* @clk: A clock struct that was previously successfully requested by
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* clk_request/get_by_*().
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* @parent: A clock struct that was previously successfully requested by
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* clk_request/get_by_*().
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* @return new rate, or -ve error code.
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*/
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int clk_set_parent(struct clk *clk, struct clk *parent);
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/**
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* clk_enable() - Enable (turn on) a clock.
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*
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* @clk: A clock struct that was previously successfully requested by
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* clk_request/get_by_*().
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* @return zero on success, or -ve error code.
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*/
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int clk_enable(struct clk *clk);
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/**
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* clk_enable_bulk() - Enable (turn on) all clocks in a clock bulk struct.
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*
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* @bulk: A clock bulk struct that was previously successfully requested
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* by clk_get_bulk().
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* @return zero on success, or -ve error code.
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*/
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int clk_enable_bulk(struct clk_bulk *bulk);
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/**
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* clk_disable() - Disable (turn off) a clock.
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*
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* @clk: A clock struct that was previously successfully requested by
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* clk_request/get_by_*().
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* @return zero on success, or -ve error code.
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*/
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int clk_disable(struct clk *clk);
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/**
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* clk_disable_bulk() - Disable (turn off) all clocks in a clock bulk struct.
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*
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* @bulk: A clock bulk struct that was previously successfully requested
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* by clk_get_bulk().
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* @return zero on success, or -ve error code.
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*/
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int clk_disable_bulk(struct clk_bulk *bulk);
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int soc_clk_dump(void);
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#endif
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