/*
 * drivers/clk/clk-axm5516.c
 *
 * Provides clock implementations for three different types of clock devices on
 * the Axxia device: PLL clock, a clock divider and a clock mux.
 *
 * Copyright (C) 2014 LSI Corporation
 *
 * 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.
 */
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/platform_device.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/clk-provider.h>
#include <linux/regmap.h>
#include <dt-bindings/clock/lsi,axm5516-clks.h>


/**
 * struct axxia_clk - Common struct to all Axxia clocks.
 * @hw: clk_hw for the common clk framework
 * @regmap: Regmap for the clock control registers
 */
struct axxia_clk {
        struct clk_hw hw;
        struct regmap *regmap;
};
#define to_axxia_clk(_hw) container_of(_hw, struct axxia_clk, hw)

/**
 * struct axxia_pllclk - Axxia PLL generated clock.
 * @aclk: Common struct
 * @reg: Offset into regmap for PLL control register
 */
struct axxia_pllclk {
        struct axxia_clk aclk;
        u32 reg;
};
#define to_axxia_pllclk(_aclk) container_of(_aclk, struct axxia_pllclk, aclk)

/**
 * axxia_pllclk_recalc - Calculate the PLL generated clock rate given the
 * parent clock rate.
 */
static unsigned long
axxia_pllclk_recalc(struct clk_hw *hw, unsigned long parent_rate)
{
        struct axxia_clk *aclk = to_axxia_clk(hw);
        struct axxia_pllclk *pll = to_axxia_pllclk(aclk);
        unsigned long rate, fbdiv, refdiv, postdiv;
        u32 control;

        regmap_read(aclk->regmap, pll->reg, &control);
        postdiv = ((control >> 0) & 0xf) + 1;
        fbdiv   = ((control >> 4) & 0xfff) + 3;
        refdiv  = ((control >> 16) & 0x1f) + 1;
        rate = (parent_rate / (refdiv * postdiv)) * fbdiv;

        return rate;
}

static const struct clk_ops axxia_pllclk_ops = {
        .recalc_rate = axxia_pllclk_recalc,
};

/**
 * struct axxia_divclk - Axxia clock divider
 * @aclk: Common struct
 * @reg: Offset into regmap for PLL control register
 * @shift: Bit position for divider value
 * @width: Number of bits in divider value
 */
struct axxia_divclk {
        struct axxia_clk aclk;
        u32 reg;
        u32 shift;
        u32 width;
};
#define to_axxia_divclk(_aclk) container_of(_aclk, struct axxia_divclk, aclk)

/**
 * axxia_divclk_recalc_rate - Calculate clock divider output rage
 */
static unsigned long
axxia_divclk_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
{
        struct axxia_clk *aclk = to_axxia_clk(hw);
        struct axxia_divclk *divclk = to_axxia_divclk(aclk);
        u32 ctrl, div;

        regmap_read(aclk->regmap, divclk->reg, &ctrl);
        div = 1 + ((ctrl >> divclk->shift) & ((1 << divclk->width)-1));

        return parent_rate / div;
}

static const struct clk_ops axxia_divclk_ops = {
        .recalc_rate = axxia_divclk_recalc_rate,
};

/**
 * struct axxia_clkmux - Axxia clock mux
 * @aclk: Common struct
 * @reg: Offset into regmap for PLL control register
 * @shift: Bit position for selection value
 * @width: Number of bits in selection value
 */
struct axxia_clkmux {
        struct axxia_clk aclk;
        u32 reg;
        u32 shift;
        u32 width;
};
#define to_axxia_clkmux(_aclk) container_of(_aclk, struct axxia_clkmux, aclk)

/**
 * axxia_clkmux_get_parent - Return the index of selected parent clock
 */
static u8 axxia_clkmux_get_parent(struct clk_hw *hw)
{
        struct axxia_clk *aclk = to_axxia_clk(hw);
        struct axxia_clkmux *mux = to_axxia_clkmux(aclk);
        u32 ctrl, parent;

        regmap_read(aclk->regmap, mux->reg, &ctrl);
        parent = (ctrl >> mux->shift) & ((1 << mux->width) - 1);

        return (u8) parent;
}

static const struct clk_ops axxia_clkmux_ops = {
        .get_parent = axxia_clkmux_get_parent,
};


/*
 * PLLs
 */

static struct axxia_pllclk clk_fab_pll = {
        .aclk.hw.init = &(struct clk_init_data){
                .name = "clk_fab_pll",
                .parent_names = (const char *[]){
                        "clk_ref0"
                },
                .num_parents = 1,
                .ops = &axxia_pllclk_ops,
        },
        .reg   = 0x01800,
};

static struct axxia_pllclk clk_cpu_pll = {
        .aclk.hw.init = &(struct clk_init_data){
                .name = "clk_cpu_pll",
                .parent_names = (const char *[]){
                        "clk_ref0"
                },
                .num_parents = 1,
                .ops = &axxia_pllclk_ops,
        },
        .reg   = 0x02000,
};

static struct axxia_pllclk clk_sys_pll = {
        .aclk.hw.init = &(struct clk_init_data){
                .name = "clk_sys_pll",
                .parent_names = (const char *[]){
                        "clk_ref0"
                },
                .num_parents = 1,
                .ops = &axxia_pllclk_ops,
        },
        .reg   = 0x02800,
};

static struct axxia_pllclk clk_sm0_pll = {
        .aclk.hw.init = &(struct clk_init_data){
                .name = "clk_sm0_pll",
                .parent_names = (const char *[]){
                        "clk_ref2"
                },
                .num_parents = 1,
                .ops = &axxia_pllclk_ops,
        },
        .reg   = 0x03000,
};

static struct axxia_pllclk clk_sm1_pll = {
        .aclk.hw.init = &(struct clk_init_data){
                .name = "clk_sm1_pll",
                .parent_names = (const char *[]){
                        "clk_ref1"
                },
                .num_parents = 1,
                .ops = &axxia_pllclk_ops,
        },
        .reg   = 0x03800,
};

/*
 * Clock dividers
 */

static struct axxia_divclk clk_cpu0_div = {
        .aclk.hw.init = &(struct clk_init_data){
                .name = "clk_cpu0_div",
                .parent_names = (const char *[]){
                        "clk_cpu_pll"
                },
                .num_parents = 1,
                .ops = &axxia_divclk_ops,
        },
        .reg   = 0x10008,
        .shift = 0,
        .width = 4,
};

static struct axxia_divclk clk_cpu1_div = {
        .aclk.hw.init = &(struct clk_init_data){
                .name = "clk_cpu1_div",
                .parent_names = (const char *[]){
                        "clk_cpu_pll"
                },
                .num_parents = 1,
                .ops = &axxia_divclk_ops,
        },
        .reg   = 0x10008,
        .shift = 4,
        .width = 4,
};

static struct axxia_divclk clk_cpu2_div = {
        .aclk.hw.init = &(struct clk_init_data){
                .name = "clk_cpu2_div",
                .parent_names = (const char *[]){
                        "clk_cpu_pll"
                },
                .num_parents = 1,
                .ops = &axxia_divclk_ops,
        },
        .reg   = 0x10008,
        .shift = 8,
        .width = 4,
};

static struct axxia_divclk clk_cpu3_div = {
        .aclk.hw.init = &(struct clk_init_data){
                .name = "clk_cpu3_div",
                .parent_names = (const char *[]){
                        "clk_cpu_pll"
                },
                .num_parents = 1,
                .ops = &axxia_divclk_ops,
        },
        .reg   = 0x10008,
        .shift = 12,
        .width = 4,
};

static struct axxia_divclk clk_nrcp_div = {
        .aclk.hw.init = &(struct clk_init_data){
                .name = "clk_nrcp_div",
                .parent_names = (const char *[]){
                        "clk_sys_pll"
                },
                .num_parents = 1,
                .ops = &axxia_divclk_ops,
        },
        .reg   = 0x1000c,
        .shift = 0,
        .width = 4,
};

static struct axxia_divclk clk_sys_div = {
        .aclk.hw.init = &(struct clk_init_data){
                .name = "clk_sys_div",
                .parent_names = (const char *[]){
                        "clk_sys_pll"
                },
                .num_parents = 1,
                .ops = &axxia_divclk_ops,
        },
        .reg   = 0x1000c,
        .shift = 4,
        .width = 4,
};

static struct axxia_divclk clk_fab_div = {
        .aclk.hw.init = &(struct clk_init_data){
                .name = "clk_fab_div",
                .parent_names = (const char *[]){
                        "clk_fab_pll"
                },
                .num_parents = 1,
                .ops = &axxia_divclk_ops,
        },
        .reg   = 0x1000c,
        .shift = 8,
        .width = 4,
};

static struct axxia_divclk clk_per_div = {
        .aclk.hw.init = &(struct clk_init_data){
                .name = "clk_per_div",
                .parent_names = (const char *[]){
                        "clk_sm1_pll"
                },
                .num_parents = 1,
                .flags = CLK_IS_BASIC,
                .ops = &axxia_divclk_ops,
        },
        .reg   = 0x1000c,
        .shift = 12,
        .width = 4,
};

static struct axxia_divclk clk_mmc_div = {
        .aclk.hw.init = &(struct clk_init_data){
                .name = "clk_mmc_div",
                .parent_names = (const char *[]){
                        "clk_sm1_pll"
                },
                .num_parents = 1,
                .flags = CLK_IS_BASIC,
                .ops = &axxia_divclk_ops,
        },
        .reg   = 0x1000c,
        .shift = 16,
        .width = 4,
};

/*
 * Clock MUXes
 */

static struct axxia_clkmux clk_cpu0_mux = {
        .aclk.hw.init = &(struct clk_init_data){
                .name = "clk_cpu0",
                .parent_names = (const char *[]){
                        "clk_ref0",
                        "clk_cpu_pll",
                        "clk_cpu0_div",
                        "clk_cpu0_div"
                },
                .num_parents = 4,
                .ops = &axxia_clkmux_ops,
        },
        .reg   = 0x10000,
        .shift = 0,
        .width = 2,
};

static struct axxia_clkmux clk_cpu1_mux = {
        .aclk.hw.init = &(struct clk_init_data){
                .name = "clk_cpu1",
                .parent_names = (const char *[]){
                        "clk_ref0",
                        "clk_cpu_pll",
                        "clk_cpu1_div",
                        "clk_cpu1_div"
                },
                .num_parents = 4,
                .ops = &axxia_clkmux_ops,
        },
        .reg   = 0x10000,
        .shift = 2,
        .width = 2,
};

static struct axxia_clkmux clk_cpu2_mux = {
        .aclk.hw.init = &(struct clk_init_data){
                .name = "clk_cpu2",
                .parent_names = (const char *[]){
                        "clk_ref0",
                        "clk_cpu_pll",
                        "clk_cpu2_div",
                        "clk_cpu2_div"
                },
                .num_parents = 4,
                .ops = &axxia_clkmux_ops,
        },
        .reg   = 0x10000,
        .shift = 4,
        .width = 2,
};

static struct axxia_clkmux clk_cpu3_mux = {
        .aclk.hw.init = &(struct clk_init_data){
                .name = "clk_cpu3",
                .parent_names = (const char *[]){
                        "clk_ref0",
                        "clk_cpu_pll",
                        "clk_cpu3_div",
                        "clk_cpu3_div"
                },
                .num_parents = 4,
                .ops = &axxia_clkmux_ops,
        },
        .reg   = 0x10000,
        .shift = 6,
        .width = 2,
};

static struct axxia_clkmux clk_nrcp_mux = {
        .aclk.hw.init = &(struct clk_init_data){
                .name = "clk_nrcp",
                .parent_names = (const char *[]){
                        "clk_ref0",
                        "clk_sys_pll",
                        "clk_nrcp_div",
                        "clk_nrcp_div"
                },
                .num_parents = 4,
                .ops = &axxia_clkmux_ops,
        },
        .reg   = 0x10004,
        .shift = 0,
        .width = 2,
};

static struct axxia_clkmux clk_sys_mux = {
        .aclk.hw.init = &(struct clk_init_data){
                .name = "clk_sys",
                .parent_names = (const char *[]){
                        "clk_ref0",
                        "clk_sys_pll",
                        "clk_sys_div",
                        "clk_sys_div"
                },
                .num_parents = 4,
                .ops = &axxia_clkmux_ops,
        },
        .reg   = 0x10004,
        .shift = 2,
        .width = 2,
};

static struct axxia_clkmux clk_fab_mux = {
        .aclk.hw.init = &(struct clk_init_data){
                .name = "clk_fab",
                .parent_names = (const char *[]){
                        "clk_ref0",
                        "clk_fab_pll",
                        "clk_fab_div",
                        "clk_fab_div"
                },
                .num_parents = 4,
                .ops = &axxia_clkmux_ops,
        },
        .reg   = 0x10004,
        .shift = 4,
        .width = 2,
};

static struct axxia_clkmux clk_per_mux = {
        .aclk.hw.init = &(struct clk_init_data){
                .name = "clk_per",
                .parent_names = (const char *[]){
                        "clk_ref1",
                        "clk_per_div"
                },
                .num_parents = 2,
                .ops = &axxia_clkmux_ops,
        },
        .reg   = 0x10004,
        .shift = 6,
        .width = 1,
};

static struct axxia_clkmux clk_mmc_mux = {
        .aclk.hw.init = &(struct clk_init_data){
                .name = "clk_mmc",
                .parent_names = (const char *[]){
                        "clk_ref1",
                        "clk_mmc_div"
                },
                .num_parents = 2,
                .ops = &axxia_clkmux_ops,
        },
        .reg   = 0x10004,
        .shift = 9,
        .width = 1,
};

/* Table of all supported clocks indexed by the clock identifiers from the
 * device tree binding
 */
static struct axxia_clk *axmclk_clocks[] = {
        [AXXIA_CLK_FAB_PLL]  = &clk_fab_pll.aclk,
        [AXXIA_CLK_CPU_PLL]  = &clk_cpu_pll.aclk,
        [AXXIA_CLK_SYS_PLL]  = &clk_sys_pll.aclk,
        [AXXIA_CLK_SM0_PLL]  = &clk_sm0_pll.aclk,
        [AXXIA_CLK_SM1_PLL]  = &clk_sm1_pll.aclk,
        [AXXIA_CLK_FAB_DIV]  = &clk_fab_div.aclk,
        [AXXIA_CLK_SYS_DIV]  = &clk_sys_div.aclk,
        [AXXIA_CLK_NRCP_DIV] = &clk_nrcp_div.aclk,
        [AXXIA_CLK_CPU0_DIV] = &clk_cpu0_div.aclk,
        [AXXIA_CLK_CPU1_DIV] = &clk_cpu1_div.aclk,
        [AXXIA_CLK_CPU2_DIV] = &clk_cpu2_div.aclk,
        [AXXIA_CLK_CPU3_DIV] = &clk_cpu3_div.aclk,
        [AXXIA_CLK_PER_DIV]  = &clk_per_div.aclk,
        [AXXIA_CLK_MMC_DIV]  = &clk_mmc_div.aclk,
        [AXXIA_CLK_FAB]      = &clk_fab_mux.aclk,
        [AXXIA_CLK_SYS]      = &clk_sys_mux.aclk,
        [AXXIA_CLK_NRCP]     = &clk_nrcp_mux.aclk,
        [AXXIA_CLK_CPU0]     = &clk_cpu0_mux.aclk,
        [AXXIA_CLK_CPU1]     = &clk_cpu1_mux.aclk,
        [AXXIA_CLK_CPU2]     = &clk_cpu2_mux.aclk,
        [AXXIA_CLK_CPU3]     = &clk_cpu3_mux.aclk,
        [AXXIA_CLK_PER]      = &clk_per_mux.aclk,
        [AXXIA_CLK_MMC]      = &clk_mmc_mux.aclk,
};

static const struct regmap_config axmclk_regmap_config = {
        .reg_bits       = 32,
        .reg_stride     = 4,
        .val_bits       = 32,
        .max_register   = 0x1fffc,
        .fast_io        = true,
};

static const struct of_device_id axmclk_match_table[] = {
        { .compatible = "lsi,axm5516-clks" },
        { }
};
MODULE_DEVICE_TABLE(of, axmclk_match_table);

struct axmclk_priv {
        struct clk_onecell_data onecell;
        struct clk *clks[];
};

static int axmclk_probe(struct platform_device *pdev)
{
        void __iomem *base;
        struct resource *res;
        int i, ret;
        struct device *dev = &pdev->dev;
        struct clk *clk;
        struct regmap *regmap;
        size_t num_clks;
        struct axmclk_priv *priv;

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        base = devm_ioremap_resource(dev, res);
        if (IS_ERR(base))
                return PTR_ERR(base);

        regmap = devm_regmap_init_mmio(dev, base, &axmclk_regmap_config);
        if (IS_ERR(regmap))
                return PTR_ERR(regmap);

        num_clks = ARRAY_SIZE(axmclk_clocks);
        pr_info("axmclk: supporting %u clocks\n", num_clks);
        priv = devm_kzalloc(dev, sizeof(*priv) + sizeof(*priv->clks) * num_clks,
                            GFP_KERNEL);
        if (!priv)
                return -ENOMEM;

        priv->onecell.clks = priv->clks;
        priv->onecell.clk_num = num_clks;

        /* Update each entry with the allocated regmap and register the clock
         * with the common clock framework
         */
        for (i = 0; i < num_clks; i++) {
                axmclk_clocks[i]->regmap = regmap;
                clk = devm_clk_register(dev, &axmclk_clocks[i]->hw);
                if (IS_ERR(clk))
                        return PTR_ERR(clk);
                priv->clks[i] = clk;
        }

        ret = of_clk_add_provider(dev->of_node,
                                  of_clk_src_onecell_get, &priv->onecell);

        return ret;
}

static int axmclk_remove(struct platform_device *pdev)
{
        of_clk_del_provider(pdev->dev.of_node);
        return 0;
}

static struct platform_driver axmclk_driver = {
        .probe          = axmclk_probe,
        .remove         = axmclk_remove,
        .driver         = {
                .name   = "clk-axm5516",
                .of_match_table = axmclk_match_table,
        },
};

static int __init axmclk_init(void)
{
        return platform_driver_register(&axmclk_driver);
}
core_initcall(axmclk_init);

static void __exit axmclk_exit(void)
{
        platform_driver_unregister(&axmclk_driver);
}
module_exit(axmclk_exit);

MODULE_DESCRIPTION("AXM5516 clock driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:clk-axm5516");