drivers/clk/clk-mux.c

root/drivers/clk/clk-mux.c
// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2011 Sascha Hauer, Pengutronix <s.hauer@pengutronix.de>
 * Copyright (C) 2011 Richard Zhao, Linaro <richard.zhao@linaro.org>
 * Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd <mturquette@linaro.org>
 *
 * Simple multiplexer 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>

/*
 * DOC: basic adjustable multiplexer clock that cannot gate
 *
 * Traits of this clock:
 * prepare - clk_prepare only ensures that parents are prepared
 * enable - clk_enable only ensures that parents are enabled
 * rate - rate is only affected by parent switching.  No clk_set_rate support
 * parent - parent is adjustable through clk_set_parent
 */

static inline u32 clk_mux_readl(struct clk_mux *mux)
{
        if (mux->flags & CLK_MUX_BIG_ENDIAN)
                return ioread32be(mux->reg);

        return readl(mux->reg);
}

static inline void clk_mux_writel(struct clk_mux *mux, u32 val)
{
        if (mux->flags & CLK_MUX_BIG_ENDIAN)
                iowrite32be(val, mux->reg);
        else
                writel(val, mux->reg);
}

int clk_mux_val_to_index(struct clk_hw *hw, const u32 *table, unsigned int flags,
                         unsigned int val)
{
        int num_parents = clk_hw_get_num_parents(hw);

        if (table) {
                int i;

                for (i = 0; i < num_parents; i++)
                        if (table[i] == val)
                                return i;
                return -EINVAL;
        }

        if (val && (flags & CLK_MUX_INDEX_BIT))
                val = ffs(val) - 1;

        if (val && (flags & CLK_MUX_INDEX_ONE))
                val--;

        if (val >= num_parents)
                return -EINVAL;

        return val;
}
EXPORT_SYMBOL_GPL(clk_mux_val_to_index);

unsigned int clk_mux_index_to_val(const u32 *table, unsigned int flags, u8 index)
{
        unsigned int val = index;

        if (table) {
                val = table[index];
        } else {
                if (flags & CLK_MUX_INDEX_BIT)
                        val = 1 << index;

                if (flags & CLK_MUX_INDEX_ONE)
                        val++;
        }

        return val;
}
EXPORT_SYMBOL_GPL(clk_mux_index_to_val);

static u8 clk_mux_get_parent(struct clk_hw *hw)
{
        struct clk_mux *mux = to_clk_mux(hw);
        u32 val;

        val = clk_mux_readl(mux) >> mux->shift;
        val &= mux->mask;

        return clk_mux_val_to_index(hw, mux->table, mux->flags, val);
}

static int clk_mux_set_parent(struct clk_hw *hw, u8 index)
{
        struct clk_mux *mux = to_clk_mux(hw);
        u32 val = clk_mux_index_to_val(mux->table, mux->flags, index);
        unsigned long flags = 0;
        u32 reg;

        if (mux->lock)
                spin_lock_irqsave(mux->lock, flags);
        else
                __acquire(mux->lock);

        if (mux->flags & CLK_MUX_HIWORD_MASK) {
                reg = mux->mask << (mux->shift + 16);
        } else {
                reg = clk_mux_readl(mux);
                reg &= ~(mux->mask << mux->shift);
        }
        val = val << mux->shift;
        reg |= val;
        clk_mux_writel(mux, reg);

        if (mux->lock)
                spin_unlock_irqrestore(mux->lock, flags);
        else
                __release(mux->lock);

        return 0;
}

static int clk_mux_determine_rate(struct clk_hw *hw,
                                  struct clk_rate_request *req)
{
        struct clk_mux *mux = to_clk_mux(hw);

        return clk_mux_determine_rate_flags(hw, req, mux->flags);
}

const struct clk_ops clk_mux_ops = {
        .get_parent = clk_mux_get_parent,
        .set_parent = clk_mux_set_parent,
        .determine_rate = clk_mux_determine_rate,
};
EXPORT_SYMBOL_GPL(clk_mux_ops);

const struct clk_ops clk_mux_ro_ops = {
        .get_parent = clk_mux_get_parent,
};
EXPORT_SYMBOL_GPL(clk_mux_ro_ops);

struct clk_hw *__clk_hw_register_mux(struct device *dev, struct device_node *np,
                const char *name, u8 num_parents,
                const char * const *parent_names,
                const struct clk_hw **parent_hws,
                const struct clk_parent_data *parent_data,
                unsigned long flags, void __iomem *reg, u8 shift, u32 mask,
                u8 clk_mux_flags, const u32 *table, spinlock_t *lock)
{
        struct clk_mux *mux;
        struct clk_hw *hw;
        struct clk_init_data init = {};
        int ret = -EINVAL;

        if (clk_mux_flags & CLK_MUX_HIWORD_MASK) {
                u8 width = fls(mask) - ffs(mask) + 1;

                if (width + shift > 16) {
                        pr_err("mux value exceeds LOWORD field\n");
                        return ERR_PTR(-EINVAL);
                }
        }

        /* allocate the mux */
        mux = kzalloc_obj(*mux);
        if (!mux)
                return ERR_PTR(-ENOMEM);

        init.name = name;
        if (clk_mux_flags & CLK_MUX_READ_ONLY)
                init.ops = &clk_mux_ro_ops;
        else
                init.ops = &clk_mux_ops;
        init.flags = flags;
        init.parent_names = parent_names;
        init.parent_data = parent_data;
        init.parent_hws = parent_hws;
        init.num_parents = num_parents;

        /* struct clk_mux assignments */
        mux->reg = reg;
        mux->shift = shift;
        mux->mask = mask;
        mux->flags = clk_mux_flags;
        mux->lock = lock;
        mux->table = table;
        mux->hw.init = &init;

        hw = &mux->hw;
        if (dev || !np)
                ret = clk_hw_register(dev, hw);
        else if (np)
                ret = of_clk_hw_register(np, hw);
        if (ret) {
                kfree(mux);
                hw = ERR_PTR(ret);
        }

        return hw;
}
EXPORT_SYMBOL_GPL(__clk_hw_register_mux);

static void devm_clk_hw_release_mux(struct device *dev, void *res)
{
        clk_hw_unregister_mux(*(struct clk_hw **)res);
}

struct clk_hw *__devm_clk_hw_register_mux(struct device *dev, struct device_node *np,
                const char *name, u8 num_parents,
                const char * const *parent_names,
                const struct clk_hw **parent_hws,
                const struct clk_parent_data *parent_data,
                unsigned long flags, void __iomem *reg, u8 shift, u32 mask,
                u8 clk_mux_flags, const u32 *table, spinlock_t *lock)
{
        struct clk_hw **ptr, *hw;

        ptr = devres_alloc(devm_clk_hw_release_mux, sizeof(*ptr), GFP_KERNEL);
        if (!ptr)
                return ERR_PTR(-ENOMEM);

        hw = __clk_hw_register_mux(dev, np, name, num_parents, parent_names, parent_hws,
                                       parent_data, flags, reg, shift, mask,
                                       clk_mux_flags, table, lock);

        if (!IS_ERR(hw)) {
                *ptr = hw;
                devres_add(dev, ptr);
        } else {
                devres_free(ptr);
        }

        return hw;
}
EXPORT_SYMBOL_GPL(__devm_clk_hw_register_mux);

struct clk *clk_register_mux_table(struct device *dev, const char *name,
                const char * const *parent_names, u8 num_parents,
                unsigned long flags, void __iomem *reg, u8 shift, u32 mask,
                u8 clk_mux_flags, const u32 *table, spinlock_t *lock)
{
        struct clk_hw *hw;

        hw = clk_hw_register_mux_table(dev, name, parent_names,
                                       num_parents, flags, reg, shift, mask,
                                       clk_mux_flags, table, lock);
        if (IS_ERR(hw))
                return ERR_CAST(hw);
        return hw->clk;
}
EXPORT_SYMBOL_GPL(clk_register_mux_table);

void clk_unregister_mux(struct clk *clk)
{
        struct clk_mux *mux;
        struct clk_hw *hw;

        hw = __clk_get_hw(clk);
        if (!hw)
                return;

        mux = to_clk_mux(hw);

        clk_unregister(clk);
        kfree(mux);
}
EXPORT_SYMBOL_GPL(clk_unregister_mux);

void clk_hw_unregister_mux(struct clk_hw *hw)
{
        struct clk_mux *mux;

        mux = to_clk_mux(hw);

        clk_hw_unregister(hw);
        kfree(mux);
}
EXPORT_SYMBOL_GPL(clk_hw_unregister_mux);
Linux
