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![James Hogan](/assets/img/avatar_default.png)
Add core support to allow clock implementations to select the best parent clock when rounding a rate, e.g. the one which can provide the closest clock rate to that requested. This is by way of adding a new clock op, determine_rate(), which is like round_rate() but has an extra parameter to allow the clock implementation to optionally select a different parent clock. The core then takes care of reparenting the clock when setting the rate. The parent change takes place with the help of some new private data members. struct clk::new_parent specifies a clock's new parent (NULL indicates no change), and struct clk::new_child specifies a clock's new child (whose new_parent member points back to it). The purpose of these are to allow correct walking of the future tree for notifications prior to actually reparenting any clocks, specifically to skip child clocks who are being reparented to another clock (they will be notified via the new parent), and to include any new child clock. These pointers are set by clk_calc_subtree(), and the new_child pointer gets cleared when a child is actually reparented to avoid duplicate POST_RATE_CHANGE notifications. Each place where round_rate() is called, determine_rate() is checked first and called in preference. This restructures a few of the call sites to simplify the logic into if/else blocks. Signed-off-by: James Hogan <james.hogan@imgtec.com> Reviewed-by: Stephen Boyd <sboyd@codeaurora.org> Cc: Mike Turquette <mturquette@linaro.org> Cc: linux-arm-kernel@lists.infradead.org Signed-off-by: Mike Turquette <mturquette@linaro.org>
212 lines
6 KiB
C
212 lines
6 KiB
C
/*
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* linux/include/linux/clk-private.h
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*
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* Copyright (c) 2010-2011 Jeremy Kerr <jeremy.kerr@canonical.com>
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* Copyright (C) 2011-2012 Linaro Ltd <mturquette@linaro.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#ifndef __LINUX_CLK_PRIVATE_H
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#define __LINUX_CLK_PRIVATE_H
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#include <linux/clk-provider.h>
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#include <linux/list.h>
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/*
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* WARNING: Do not include clk-private.h from any file that implements struct
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* clk_ops. Doing so is a layering violation!
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*
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* This header exists only to allow for statically initialized clock data. Any
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* static clock data must be defined in a separate file from the logic that
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* implements the clock operations for that same data.
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*/
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#ifdef CONFIG_COMMON_CLK
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struct clk {
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const char *name;
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const struct clk_ops *ops;
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struct clk_hw *hw;
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struct clk *parent;
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const char **parent_names;
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struct clk **parents;
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u8 num_parents;
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u8 new_parent_index;
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unsigned long rate;
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unsigned long new_rate;
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struct clk *new_parent;
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struct clk *new_child;
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unsigned long flags;
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unsigned int enable_count;
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unsigned int prepare_count;
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struct hlist_head children;
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struct hlist_node child_node;
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unsigned int notifier_count;
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#ifdef CONFIG_COMMON_CLK_DEBUG
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struct dentry *dentry;
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#endif
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};
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/*
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* DOC: Basic clock implementations common to many platforms
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*
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* Each basic clock hardware type is comprised of a structure describing the
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* clock hardware, implementations of the relevant callbacks in struct clk_ops,
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* unique flags for that hardware type, a registration function and an
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* alternative macro for static initialization
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*/
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#define DEFINE_CLK(_name, _ops, _flags, _parent_names, \
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_parents) \
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static struct clk _name = { \
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.name = #_name, \
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.ops = &_ops, \
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.hw = &_name##_hw.hw, \
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.parent_names = _parent_names, \
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.num_parents = ARRAY_SIZE(_parent_names), \
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.parents = _parents, \
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.flags = _flags | CLK_IS_BASIC, \
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}
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#define DEFINE_CLK_FIXED_RATE(_name, _flags, _rate, \
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_fixed_rate_flags) \
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static struct clk _name; \
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static const char *_name##_parent_names[] = {}; \
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static struct clk_fixed_rate _name##_hw = { \
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.hw = { \
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.clk = &_name, \
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}, \
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.fixed_rate = _rate, \
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.flags = _fixed_rate_flags, \
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}; \
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DEFINE_CLK(_name, clk_fixed_rate_ops, _flags, \
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_name##_parent_names, NULL);
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#define DEFINE_CLK_GATE(_name, _parent_name, _parent_ptr, \
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_flags, _reg, _bit_idx, \
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_gate_flags, _lock) \
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static struct clk _name; \
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static const char *_name##_parent_names[] = { \
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_parent_name, \
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}; \
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static struct clk *_name##_parents[] = { \
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_parent_ptr, \
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}; \
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static struct clk_gate _name##_hw = { \
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.hw = { \
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.clk = &_name, \
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}, \
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.reg = _reg, \
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.bit_idx = _bit_idx, \
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.flags = _gate_flags, \
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.lock = _lock, \
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}; \
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DEFINE_CLK(_name, clk_gate_ops, _flags, \
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_name##_parent_names, _name##_parents);
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#define _DEFINE_CLK_DIVIDER(_name, _parent_name, _parent_ptr, \
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_flags, _reg, _shift, _width, \
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_divider_flags, _table, _lock) \
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static struct clk _name; \
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static const char *_name##_parent_names[] = { \
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_parent_name, \
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}; \
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static struct clk *_name##_parents[] = { \
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_parent_ptr, \
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}; \
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static struct clk_divider _name##_hw = { \
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.hw = { \
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.clk = &_name, \
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}, \
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.reg = _reg, \
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.shift = _shift, \
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.width = _width, \
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.flags = _divider_flags, \
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.table = _table, \
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.lock = _lock, \
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}; \
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DEFINE_CLK(_name, clk_divider_ops, _flags, \
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_name##_parent_names, _name##_parents);
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#define DEFINE_CLK_DIVIDER(_name, _parent_name, _parent_ptr, \
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_flags, _reg, _shift, _width, \
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_divider_flags, _lock) \
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_DEFINE_CLK_DIVIDER(_name, _parent_name, _parent_ptr, \
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_flags, _reg, _shift, _width, \
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_divider_flags, NULL, _lock)
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#define DEFINE_CLK_DIVIDER_TABLE(_name, _parent_name, \
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_parent_ptr, _flags, _reg, \
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_shift, _width, _divider_flags, \
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_table, _lock) \
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_DEFINE_CLK_DIVIDER(_name, _parent_name, _parent_ptr, \
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_flags, _reg, _shift, _width, \
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_divider_flags, _table, _lock) \
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#define DEFINE_CLK_MUX(_name, _parent_names, _parents, _flags, \
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_reg, _shift, _width, \
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_mux_flags, _lock) \
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static struct clk _name; \
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static struct clk_mux _name##_hw = { \
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.hw = { \
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.clk = &_name, \
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}, \
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.reg = _reg, \
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.shift = _shift, \
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.mask = BIT(_width) - 1, \
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.flags = _mux_flags, \
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.lock = _lock, \
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}; \
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DEFINE_CLK(_name, clk_mux_ops, _flags, _parent_names, \
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_parents);
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#define DEFINE_CLK_FIXED_FACTOR(_name, _parent_name, \
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_parent_ptr, _flags, \
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_mult, _div) \
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static struct clk _name; \
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static const char *_name##_parent_names[] = { \
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_parent_name, \
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}; \
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static struct clk *_name##_parents[] = { \
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_parent_ptr, \
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}; \
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static struct clk_fixed_factor _name##_hw = { \
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.hw = { \
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.clk = &_name, \
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}, \
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.mult = _mult, \
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.div = _div, \
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}; \
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DEFINE_CLK(_name, clk_fixed_factor_ops, _flags, \
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_name##_parent_names, _name##_parents);
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/**
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* __clk_init - initialize the data structures in a struct clk
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* @dev: device initializing this clk, placeholder for now
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* @clk: clk being initialized
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*
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* Initializes the lists in struct clk, queries the hardware for the
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* parent and rate and sets them both.
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*
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* Any struct clk passed into __clk_init must have the following members
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* populated:
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* .name
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* .ops
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* .hw
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* .parent_names
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* .num_parents
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* .flags
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*
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* It is not necessary to call clk_register if __clk_init is used directly with
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* statically initialized clock data.
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*
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* Returns 0 on success, otherwise an error code.
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*/
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int __clk_init(struct device *dev, struct clk *clk);
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struct clk *__clk_register(struct device *dev, struct clk_hw *hw);
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#endif /* CONFIG_COMMON_CLK */
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#endif /* CLK_PRIVATE_H */
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