clk-gate2.c

Go to the documentation of this file.

/*
 * Copyright (C) 2010-2011 Canonical Ltd <[email protected]>
 * Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd <[email protected]>
 *
 * 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>

#define to_clk_gate(_hw) container_of(_hw, struct clk_gate, hw)

static int clk_gate2_enable(struct clk_hw *hw)
{
    struct clk_gate *gate = to_clk_gate(hw);
    u32 reg;
    unsigned long flags = 0;

    if (gate->lock)
        spin_lock_irqsave(gate->lock, flags);

    reg = readl(gate->reg);
    reg |= 3 << gate->bit_idx;
    writel(reg, gate->reg);

    if (gate->lock)
        spin_unlock_irqrestore(gate->lock, flags);

    return 0;
}

static void clk_gate2_disable(struct clk_hw *hw)
{
    struct clk_gate *gate = to_clk_gate(hw);
    u32 reg;
    unsigned long flags = 0;

    if (gate->lock)
        spin_lock_irqsave(gate->lock, flags);

    reg = readl(gate->reg);
    reg &= ~(3 << gate->bit_idx);
    writel(reg, gate->reg);

    if (gate->lock)
        spin_unlock_irqrestore(gate->lock, flags);
}

static int clk_gate2_is_enabled(struct clk_hw *hw)
{
    u32 reg;
    struct clk_gate *gate = to_clk_gate(hw);

    reg = readl(gate->reg);

    if (((reg >> gate->bit_idx) & 3) == 3)
        return 1;

    return 0;
}

static struct clk_ops clk_gate2_ops = {
    .enable = clk_gate2_enable,
    .disable = clk_gate2_disable,
    .is_enabled = clk_gate2_is_enabled,
};

struct clk *clk_register_gate2(struct device *dev, const char *name,
        const char *parent_name, unsigned long flags,
        void __iomem *reg, u8 bit_idx,
        u8 clk_gate2_flags, spinlock_t *lock)
{
    struct clk_gate *gate;
    struct clk *clk;
    struct clk_init_data init;

    gate = kzalloc(sizeof(struct clk_gate), GFP_KERNEL);
    if (!gate)
        return ERR_PTR(-ENOMEM);

    /* struct clk_gate assignments */
    gate->reg = reg;
    gate->bit_idx = bit_idx;
    gate->flags = clk_gate2_flags;
    gate->lock = lock;

    init.name = name;
    init.ops = &clk_gate2_ops;
    init.flags = flags;
    init.parent_names = parent_name ? &parent_name : NULL;
    init.num_parents = parent_name ? 1 : 0;

    gate->hw.init = &init;

    clk = clk_register(dev, &gate->hw);
    if (IS_ERR(clk))
        kfree(gate);

    return clk;
}