// SPDX-License-Identifier: GPL-2.0-only
/*
 *
 * Copyright (C) 2013 ARM Limited
 */

#include <linux/amba/sp810.h>
#include <linux/slab.h>
#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_address.h>

#define to_clk_sp810_timerclken(_hw) \
                container_of(_hw, struct clk_sp810_timerclken, hw)

struct clk_sp810;

struct clk_sp810_timerclken {
        struct clk_hw hw;
        struct clk *clk;
        struct clk_sp810 *sp810;
        int channel;
};

struct clk_sp810 {
        struct device_node *node;
        void __iomem *base;
        spinlock_t lock;
        struct clk_sp810_timerclken timerclken[4];
};

static u8 clk_sp810_timerclken_get_parent(struct clk_hw *hw)
{
        struct clk_sp810_timerclken *timerclken = to_clk_sp810_timerclken(hw);
        u32 val = readl(timerclken->sp810->base + SCCTRL);

        return !!(val & (1 << SCCTRL_TIMERENnSEL_SHIFT(timerclken->channel)));
}

static int clk_sp810_timerclken_set_parent(struct clk_hw *hw, u8 index)
{
        struct clk_sp810_timerclken *timerclken = to_clk_sp810_timerclken(hw);
        struct clk_sp810 *sp810 = timerclken->sp810;
        u32 val, shift = SCCTRL_TIMERENnSEL_SHIFT(timerclken->channel);
        unsigned long flags = 0;

        if (WARN_ON(index > 1))
                return -EINVAL;

        spin_lock_irqsave(&sp810->lock, flags);

        val = readl(sp810->base + SCCTRL);
        val &= ~(1 << shift);
        val |= index << shift;
        writel(val, sp810->base + SCCTRL);

        spin_unlock_irqrestore(&sp810->lock, flags);

        return 0;
}

static const struct clk_ops clk_sp810_timerclken_ops = {
        .determine_rate = clk_hw_determine_rate_no_reparent,
        .get_parent = clk_sp810_timerclken_get_parent,
        .set_parent = clk_sp810_timerclken_set_parent,
};

static struct clk *clk_sp810_timerclken_of_get(struct of_phandle_args *clkspec,
                void *data)
{
        struct clk_sp810 *sp810 = data;

        if (WARN_ON(clkspec->args_count != 1 ||
                    clkspec->args[0] >= ARRAY_SIZE(sp810->timerclken)))
                return NULL;

        return sp810->timerclken[clkspec->args[0]].clk;
}

static void __init clk_sp810_of_setup(struct device_node *node)
{
        struct clk_sp810 *sp810 = kzalloc_obj(*sp810);
        const char *parent_names[2];
        int num = ARRAY_SIZE(parent_names);
        char name[12];
        struct clk_init_data init;
        static int instance;
        int i;
        bool deprecated;

        if (!sp810)
                return;

        if (of_clk_parent_fill(node, parent_names, num) != num) {
                pr_warn("Failed to obtain parent clocks for SP810!\n");
                kfree(sp810);
                return;
        }

        sp810->node = node;
        sp810->base = of_iomap(node, 0);
        spin_lock_init(&sp810->lock);

        init.name = name;
        init.ops = &clk_sp810_timerclken_ops;
        init.flags = 0;
        init.parent_names = parent_names;
        init.num_parents = num;

        deprecated = !of_property_present(node, "assigned-clock-parents");

        for (i = 0; i < ARRAY_SIZE(sp810->timerclken); i++) {
                snprintf(name, sizeof(name), "sp810_%d_%d", instance, i);

                sp810->timerclken[i].sp810 = sp810;
                sp810->timerclken[i].channel = i;
                sp810->timerclken[i].hw.init = &init;

                /*
                 * If DT isn't setting the parent, force it to be
                 * the 1 MHz clock without going through the framework.
                 * We do this before clk_register() so that it can determine
                 * the parent and setup the tree properly.
                 */
                if (deprecated)
                        init.ops->set_parent(&sp810->timerclken[i].hw, 1);

                sp810->timerclken[i].clk = clk_register(NULL,
                                &sp810->timerclken[i].hw);
                WARN_ON(IS_ERR(sp810->timerclken[i].clk));
        }

        of_clk_add_provider(node, clk_sp810_timerclken_of_get, sp810);
        instance++;
}
CLK_OF_DECLARE(sp810, "arm,sp810", clk_sp810_of_setup);