/*
 * TI Multiplexer Clock
 *
 * Copyright (C) 2013 Texas Instruments, Inc.
 *
 * Tero Kristo <t-kristo@ti.com>
 *
 * 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.
 *
 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
 * kind, whether express or implied; without even the implied warranty
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/clk-provider.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/clk/ti.h>
#include "clock.h"

#undef pr_fmt
#define pr_fmt(fmt) "%s: " fmt, __func__

static u8 ti_clk_mux_get_parent(struct clk_hw *hw)
{
        struct clk_omap_mux *mux = to_clk_omap_mux(hw);
        int num_parents = clk_hw_get_num_parents(hw);
        u32 val;

        /*
         * FIXME need a mux-specific flag to determine if val is bitwise or
         * numeric. e.g. sys_clkin_ck's clksel field is 3 bits wide, but ranges
         * from 0x1 to 0x7 (index starts at one)
         * OTOH, pmd_trace_clk_mux_ck uses a separate bit for each clock, so
         * val = 0x4 really means "bit 2, index starts at bit 0"
         */
        val = ti_clk_ll_ops->clk_readl(&mux->reg) >> mux->shift;
        val &= mux->mask;

        if (mux->table) {
                int i;

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

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

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

        if (val >= num_parents)
                return -EINVAL;

        return val;
}

static int ti_clk_mux_set_parent(struct clk_hw *hw, u8 index)
{
        struct clk_omap_mux *mux = to_clk_omap_mux(hw);
        u32 val;

        if (mux->table) {
                index = mux->table[index];
        } else {
                if (mux->flags & CLK_MUX_INDEX_BIT)
                        index = (1 << ffs(index));

                if (mux->flags & CLK_MUX_INDEX_ONE)
                        index++;
        }

        if (mux->flags & CLK_MUX_HIWORD_MASK) {
                val = mux->mask << (mux->shift + 16);
        } else {
                val = ti_clk_ll_ops->clk_readl(&mux->reg);
                val &= ~(mux->mask << mux->shift);
        }
        val |= index << mux->shift;
        ti_clk_ll_ops->clk_writel(val, &mux->reg);
        ti_clk_latch(&mux->reg, mux->latch);

        return 0;
}

/**
 * clk_mux_save_context - Save the parent selcted in the mux
 * @hw: pointer  struct clk_hw
 *
 * Save the parent mux value.
 */
static int clk_mux_save_context(struct clk_hw *hw)
{
        struct clk_omap_mux *mux = to_clk_omap_mux(hw);

        mux->saved_parent = ti_clk_mux_get_parent(hw);
        return 0;
}

/**
 * clk_mux_restore_context - Restore the parent in the mux
 * @hw: pointer  struct clk_hw
 *
 * Restore the saved parent mux value.
 */
static void clk_mux_restore_context(struct clk_hw *hw)
{
        struct clk_omap_mux *mux = to_clk_omap_mux(hw);

        ti_clk_mux_set_parent(hw, mux->saved_parent);
}

const struct clk_ops ti_clk_mux_ops = {
        .get_parent = ti_clk_mux_get_parent,
        .set_parent = ti_clk_mux_set_parent,
        .determine_rate = __clk_mux_determine_rate,
        .save_context = clk_mux_save_context,
        .restore_context = clk_mux_restore_context,
};

static struct clk *_register_mux(struct device *dev, const char *name,
                                 const char * const *parent_names,
                                 u8 num_parents, unsigned long flags,
                                 struct clk_omap_reg *reg, u8 shift, u32 mask,
                                 s8 latch, u8 clk_mux_flags, u32 *table)
{
        struct clk_omap_mux *mux;
        struct clk *clk;
        struct clk_init_data init;

        /* allocate the mux */
        mux = kzalloc(sizeof(*mux), GFP_KERNEL);
        if (!mux)
                return ERR_PTR(-ENOMEM);

        init.name = name;
        init.ops = &ti_clk_mux_ops;
        init.flags = flags;
        init.parent_names = parent_names;
        init.num_parents = num_parents;

        /* struct clk_mux assignments */
        memcpy(&mux->reg, reg, sizeof(*reg));
        mux->shift = shift;
        mux->mask = mask;
        mux->latch = latch;
        mux->flags = clk_mux_flags;
        mux->table = table;
        mux->hw.init = &init;

        clk = ti_clk_register(dev, &mux->hw, name);

        if (IS_ERR(clk))
                kfree(mux);

        return clk;
}

/**
 * of_mux_clk_setup - Setup function for simple mux rate clock
 * @node: DT node for the clock
 *
 * Sets up a basic clock multiplexer.
 */
static void of_mux_clk_setup(struct device_node *node)
{
        struct clk *clk;
        struct clk_omap_reg reg;
        unsigned int num_parents;
        const char **parent_names;
        u8 clk_mux_flags = 0;
        u32 mask = 0;
        u32 shift = 0;
        s32 latch = -EINVAL;
        u32 flags = CLK_SET_RATE_NO_REPARENT;

        num_parents = of_clk_get_parent_count(node);
        if (num_parents < 2) {
                pr_err("mux-clock %pOFn must have parents\n", node);
                return;
        }
        parent_names = kzalloc((sizeof(char *) * num_parents), GFP_KERNEL);
        if (!parent_names)
                goto cleanup;

        of_clk_parent_fill(node, parent_names, num_parents);

        if (ti_clk_get_reg_addr(node, 0, &reg))
                goto cleanup;

        of_property_read_u32(node, "ti,bit-shift", &shift);

        of_property_read_u32(node, "ti,latch-bit", &latch);

        if (of_property_read_bool(node, "ti,index-starts-at-one"))
                clk_mux_flags |= CLK_MUX_INDEX_ONE;

        if (of_property_read_bool(node, "ti,set-rate-parent"))
                flags |= CLK_SET_RATE_PARENT;

        /* Generate bit-mask based on parent info */
        mask = num_parents;
        if (!(clk_mux_flags & CLK_MUX_INDEX_ONE))
                mask--;

        mask = (1 << fls(mask)) - 1;

        clk = _register_mux(NULL, node->name, parent_names, num_parents,
                            flags, &reg, shift, mask, latch, clk_mux_flags,
                            NULL);

        if (!IS_ERR(clk))
                of_clk_add_provider(node, of_clk_src_simple_get, clk);

cleanup:
        kfree(parent_names);
}
CLK_OF_DECLARE(mux_clk, "ti,mux-clock", of_mux_clk_setup);

struct clk_hw *ti_clk_build_component_mux(struct ti_clk_mux *setup)
{
        struct clk_omap_mux *mux;
        int num_parents;

        if (!setup)
                return NULL;

        mux = kzalloc(sizeof(*mux), GFP_KERNEL);
        if (!mux)
                return ERR_PTR(-ENOMEM);

        mux->shift = setup->bit_shift;
        mux->latch = -EINVAL;

        mux->reg.index = setup->module;
        mux->reg.offset = setup->reg;

        if (setup->flags & CLKF_INDEX_STARTS_AT_ONE)
                mux->flags |= CLK_MUX_INDEX_ONE;

        num_parents = setup->num_parents;

        mux->mask = num_parents - 1;
        mux->mask = (1 << fls(mux->mask)) - 1;

        return &mux->hw;
}

static void __init of_ti_composite_mux_clk_setup(struct device_node *node)
{
        struct clk_omap_mux *mux;
        unsigned int num_parents;
        u32 val;

        mux = kzalloc(sizeof(*mux), GFP_KERNEL);
        if (!mux)
                return;

        if (ti_clk_get_reg_addr(node, 0, &mux->reg))
                goto cleanup;

        if (!of_property_read_u32(node, "ti,bit-shift", &val))
                mux->shift = val;

        if (of_property_read_bool(node, "ti,index-starts-at-one"))
                mux->flags |= CLK_MUX_INDEX_ONE;

        num_parents = of_clk_get_parent_count(node);

        if (num_parents < 2) {
                pr_err("%pOFn must have parents\n", node);
                goto cleanup;
        }

        mux->mask = num_parents - 1;
        mux->mask = (1 << fls(mux->mask)) - 1;

        if (!ti_clk_add_component(node, &mux->hw, CLK_COMPONENT_TYPE_MUX))
                return;

cleanup:
        kfree(mux);
}
CLK_OF_DECLARE(ti_composite_mux_clk_setup, "ti,composite-mux-clock",
               of_ti_composite_mux_clk_setup);