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![Philipp Tomsich](/assets/img/avatar_default.png)
Linux uses the properties 'assigned-clocks', 'assigned-clock-parents' and 'assigned-clock-rates' to configure the clock subsystem for use with various peripheral nodes. This implements clk_set_defaults() and hooks it up with the general device probibin in drivers/core/device.c: when a new device is probed, clk_set_defaults() will be called for it and will process the properties mentioned above. Note that this functionality is designed to fail gracefully (i.e. if a clock-driver does not implement set_parent(), we simply accept this and ignore the error) as not to break existing board-support. Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com> Tested-by: David Wu <david.wu@rock-chips.com> Series-changes: 2 - Fixed David's email address. Series-version: 2 Cover-letter: clk: support assigned-clock, assigned-clock-parents, assigned-clock-rates For various peripherals on Rockchip SoCs (e.g. for the Ethernet GMAC), the parent-clock needs to be set via the DTS. This adds the required plumbing and implements the GMAC case for the RK3399. END
229 lines
7.5 KiB
C
229 lines
7.5 KiB
C
/*
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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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* SPDX-License-Identifier: GPL-2.0+
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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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#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_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_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_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_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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int soc_clk_dump(void);
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#endif
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