linux/drivers/clk/clk-gate.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2010-2011 Canonical Ltd <[email protected]>
 * Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd <[email protected]>
 *
 * Gated clock implementation
 */

#include <linux/clk-provider.h>
#include <linux/device.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/err.h>
#include <linux/string.h>

/**
 * DOC: basic gatable clock which can gate and ungate its output
 *
 * Traits of this clock:
 * prepare - clk_(un)prepare only ensures parent is (un)prepared
 * enable - clk_enable and clk_disable are functional & control gating
 * rate - inherits rate from parent.  No clk_set_rate support
 * parent - fixed parent.  No clk_set_parent support
 */

static inline u32 clk_gate_readl(struct clk_gate *gate)
{ … }

static inline void clk_gate_writel(struct clk_gate *gate, u32 val)
{ … }

/*
 * It works on following logic:
 *
 * For enabling clock, enable = 1
 *	set2dis = 1	-> clear bit	-> set = 0
 *	set2dis = 0	-> set bit	-> set = 1
 *
 * For disabling clock, enable = 0
 *	set2dis = 1	-> set bit	-> set = 1
 *	set2dis = 0	-> clear bit	-> set = 0
 *
 * So, result is always: enable xor set2dis.
 */
static void clk_gate_endisable(struct clk_hw *hw, int enable)
{ … }

static int clk_gate_enable(struct clk_hw *hw)
{ … }

static void clk_gate_disable(struct clk_hw *hw)
{ … }

int clk_gate_is_enabled(struct clk_hw *hw)
{ … }
EXPORT_SYMBOL_GPL(…);

const struct clk_ops clk_gate_ops = …;
EXPORT_SYMBOL_GPL(…);

struct clk_hw *__clk_hw_register_gate(struct device *dev,
		struct device_node *np, const char *name,
		const char *parent_name, const struct clk_hw *parent_hw,
		const struct clk_parent_data *parent_data,
		unsigned long flags,
		void __iomem *reg, u8 bit_idx,
		u8 clk_gate_flags, spinlock_t *lock)
{ … }
EXPORT_SYMBOL_GPL(…);

struct clk *clk_register_gate(struct device *dev, const char *name,
		const char *parent_name, unsigned long flags,
		void __iomem *reg, u8 bit_idx,
		u8 clk_gate_flags, spinlock_t *lock)
{ … }
EXPORT_SYMBOL_GPL(…);

void clk_unregister_gate(struct clk *clk)
{ … }
EXPORT_SYMBOL_GPL(…);

void clk_hw_unregister_gate(struct clk_hw *hw)
{ … }
EXPORT_SYMBOL_GPL(…);

static void devm_clk_hw_release_gate(struct device *dev, void *res)
{ … }

struct clk_hw *__devm_clk_hw_register_gate(struct device *dev,
		struct device_node *np, const char *name,
		const char *parent_name, const struct clk_hw *parent_hw,
		const struct clk_parent_data *parent_data,
		unsigned long flags,
		void __iomem *reg, u8 bit_idx,
		u8 clk_gate_flags, spinlock_t *lock)
{ … }
EXPORT_SYMBOL_GPL(…);