linux_dsm_epyc7002/drivers/clk/clk-gate.c
Saravana Kannan 0197b3ea0f clk: Use a separate struct for holding init data.
Create a struct clk_init_data to hold all data that needs to be passed from
the platfrom specific driver to the common clock framework during clock
registration. Add a pointer to this struct inside clk_hw.

This has several advantages:
* Completely hides struct clk from many clock platform drivers and static
  clock initialization code that don't care for static initialization of
  the struct clks.
* For platforms that want to do complete static initialization, it removed
  the need to directly mess with the struct clk's fields while still
  allowing to statically allocate struct clk. This keeps the code more
  future proof even if they include clk-private.h.
* Simplifies the generic clk_register() function and allows adding optional
  fields in the future without modifying the function signature.
* Simplifies the static initialization of clocks on all platforms by
  removing the need for forward delcarations or convoluted macros.

Signed-off-by: Saravana Kannan <skannan@codeaurora.org>
[mturquette@linaro.org: kept DEFINE_CLK_* macros and __clk_init]
Signed-off-by: Mike Turquette <mturquette@linaro.org>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Jeremy Kerr <jeremy.kerr@canonical.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Arnd Bergman <arnd.bergmann@linaro.org>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Shawn Guo <shawn.guo@freescale.com>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Jamie Iles <jamie@jamieiles.com>
Cc: Richard Zhao <richard.zhao@linaro.org>
Cc: Saravana Kannan <skannan@codeaurora.org>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Linus Walleij <linus.walleij@stericsson.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Amit Kucheria <amit.kucheria@linaro.org>
Cc: Deepak Saxena <dsaxena@linaro.org>
Cc: Grant Likely <grant.likely@secretlab.ca>
2012-05-01 18:13:20 -07:00

151 lines
3.6 KiB
C

/*
* Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com>
* Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd <mturquette@linaro.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Gated clock implementation
*/
#include <linux/clk-provider.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 it's ouput
*
* 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
*/
#define to_clk_gate(_hw) container_of(_hw, struct clk_gate, hw)
/*
* 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)
{
struct clk_gate *gate = to_clk_gate(hw);
int set = gate->flags & CLK_GATE_SET_TO_DISABLE ? 1 : 0;
unsigned long flags = 0;
u32 reg;
set ^= enable;
if (gate->lock)
spin_lock_irqsave(gate->lock, flags);
reg = readl(gate->reg);
if (set)
reg |= BIT(gate->bit_idx);
else
reg &= ~BIT(gate->bit_idx);
writel(reg, gate->reg);
if (gate->lock)
spin_unlock_irqrestore(gate->lock, flags);
}
static int clk_gate_enable(struct clk_hw *hw)
{
clk_gate_endisable(hw, 1);
return 0;
}
static void clk_gate_disable(struct clk_hw *hw)
{
clk_gate_endisable(hw, 0);
}
static int clk_gate_is_enabled(struct clk_hw *hw)
{
u32 reg;
struct clk_gate *gate = to_clk_gate(hw);
reg = readl(gate->reg);
/* if a set bit disables this clk, flip it before masking */
if (gate->flags & CLK_GATE_SET_TO_DISABLE)
reg ^= BIT(gate->bit_idx);
reg &= BIT(gate->bit_idx);
return reg ? 1 : 0;
}
const struct clk_ops clk_gate_ops = {
.enable = clk_gate_enable,
.disable = clk_gate_disable,
.is_enabled = clk_gate_is_enabled,
};
EXPORT_SYMBOL_GPL(clk_gate_ops);
/**
* clk_register_gate - register a gate clock with the clock framework
* @dev: device that is registering this clock
* @name: name of this clock
* @parent_name: name of this clock's parent
* @flags: framework-specific flags for this clock
* @reg: register address to control gating of this clock
* @bit_idx: which bit in the register controls gating of this clock
* @clk_gate_flags: gate-specific flags for this clock
* @lock: shared register lock for this clock
*/
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)
{
struct clk_gate *gate;
struct clk *clk;
struct clk_init_data init;
/* allocate the gate */
gate = kzalloc(sizeof(struct clk_gate), GFP_KERNEL);
if (!gate) {
pr_err("%s: could not allocate gated clk\n", __func__);
return ERR_PTR(-ENOMEM);
}
init.name = name;
init.ops = &clk_gate_ops;
init.flags = flags;
init.parent_names = (parent_name ? &parent_name: NULL);
init.num_parents = (parent_name ? 1 : 0);
/* struct clk_gate assignments */
gate->reg = reg;
gate->bit_idx = bit_idx;
gate->flags = clk_gate_flags;
gate->lock = lock;
gate->hw.init = &init;
clk = clk_register(dev, &gate->hw);
if (IS_ERR(clk))
kfree(gate);
return clk;
}