linux/drivers/clk/clk-gate.c
Mike Turquette 9d9f78ed9a clk: basic clock hardware types
Many platforms support simple gateable clocks, fixed-rate clocks,
adjustable divider clocks and multi-parent multiplexer clocks.

This patch introduces basic clock types for the above-mentioned hardware
which share some common characteristics.

Based on original work by Jeremy Kerr and contribution by Jamie Iles.
Dividers and multiplexor clocks originally contributed by Richard Zhao &
Sascha Hauer.

Signed-off-by: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Mike Turquette <mturquette@ti.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: 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>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2012-03-16 20:35:02 +00:00

150 lines
3.3 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)
static void clk_gate_set_bit(struct clk_gate *gate)
{
u32 reg;
unsigned long flags = 0;
if (gate->lock)
spin_lock_irqsave(gate->lock, flags);
reg = readl(gate->reg);
reg |= BIT(gate->bit_idx);
writel(reg, gate->reg);
if (gate->lock)
spin_unlock_irqrestore(gate->lock, flags);
}
static void clk_gate_clear_bit(struct clk_gate *gate)
{
u32 reg;
unsigned long flags = 0;
if (gate->lock)
spin_lock_irqsave(gate->lock, flags);
reg = readl(gate->reg);
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)
{
struct clk_gate *gate = to_clk_gate(hw);
if (gate->flags & CLK_GATE_SET_TO_DISABLE)
clk_gate_clear_bit(gate);
else
clk_gate_set_bit(gate);
return 0;
}
EXPORT_SYMBOL_GPL(clk_gate_enable);
static void clk_gate_disable(struct clk_hw *hw)
{
struct clk_gate *gate = to_clk_gate(hw);
if (gate->flags & CLK_GATE_SET_TO_DISABLE)
clk_gate_set_bit(gate);
else
clk_gate_clear_bit(gate);
}
EXPORT_SYMBOL_GPL(clk_gate_disable);
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;
}
EXPORT_SYMBOL_GPL(clk_gate_is_enabled);
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);
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;
gate = kzalloc(sizeof(struct clk_gate), GFP_KERNEL);
if (!gate) {
pr_err("%s: could not allocate gated clk\n", __func__);
return NULL;
}
/* struct clk_gate assignments */
gate->reg = reg;
gate->bit_idx = bit_idx;
gate->flags = clk_gate_flags;
gate->lock = lock;
if (parent_name) {
gate->parent[0] = kstrdup(parent_name, GFP_KERNEL);
if (!gate->parent[0])
goto out;
}
clk = clk_register(dev, name,
&clk_gate_ops, &gate->hw,
gate->parent,
(parent_name ? 1 : 0),
flags);
if (clk)
return clk;
out:
kfree(gate->parent[0]);
kfree(gate);
return NULL;
}