/*
 * OMAP gate clock support
 *
 * 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/io.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 int omap36xx_gate_clk_enable_with_hsdiv_restore(struct clk_hw *clk);

static const struct clk_ops omap_gate_clkdm_clk_ops = {
        .init           = &omap2_init_clk_clkdm,
        .enable         = &omap2_clkops_enable_clkdm,
        .disable        = &omap2_clkops_disable_clkdm,
};

const struct clk_ops omap_gate_clk_ops = {
        .init           = &omap2_init_clk_clkdm,
        .enable         = &omap2_dflt_clk_enable,
        .disable        = &omap2_dflt_clk_disable,
        .is_enabled     = &omap2_dflt_clk_is_enabled,
};

static const struct clk_ops omap_gate_clk_hsdiv_restore_ops = {
        .init           = &omap2_init_clk_clkdm,
        .enable         = &omap36xx_gate_clk_enable_with_hsdiv_restore,
        .disable        = &omap2_dflt_clk_disable,
        .is_enabled     = &omap2_dflt_clk_is_enabled,
};

/**
 * omap36xx_gate_clk_enable_with_hsdiv_restore - enable clocks suffering
 *         from HSDivider PWRDN problem Implements Errata ID: i556.
 * @clk: DPLL output struct clk
 *
 * 3630 only: dpll3_m3_ck, dpll4_m2_ck, dpll4_m3_ck, dpll4_m4_ck,
 * dpll4_m5_ck & dpll4_m6_ck dividers gets loaded with reset
 * valueafter their respective PWRDN bits are set.  Any dummy write
 * (Any other value different from the Read value) to the
 * corresponding CM_CLKSEL register will refresh the dividers.
 */
static int omap36xx_gate_clk_enable_with_hsdiv_restore(struct clk_hw *hw)
{
        struct clk_omap_divider *parent;
        struct clk_hw *parent_hw;
        u32 dummy_v, orig_v;
        int ret;

        /* Clear PWRDN bit of HSDIVIDER */
        ret = omap2_dflt_clk_enable(hw);

        /* Parent is the x2 node, get parent of parent for the m2 div */
        parent_hw = clk_hw_get_parent(clk_hw_get_parent(hw));
        parent = to_clk_omap_divider(parent_hw);

        /* Restore the dividers */
        if (!ret) {
                orig_v = ti_clk_ll_ops->clk_readl(&parent->reg);
                dummy_v = orig_v;

                /* Write any other value different from the Read value */
                dummy_v ^= (1 << parent->shift);
                ti_clk_ll_ops->clk_writel(dummy_v, &parent->reg);

                /* Write the original divider */
                ti_clk_ll_ops->clk_writel(orig_v, &parent->reg);
        }

        return ret;
}

static struct clk *_register_gate(struct device *dev, const char *name,
                                  const char *parent_name, unsigned long flags,
                                  struct clk_omap_reg *reg, u8 bit_idx,
                                  u8 clk_gate_flags, const struct clk_ops *ops,
                                  const struct clk_hw_omap_ops *hw_ops)
{
        struct clk_init_data init = { NULL };
        struct clk_hw_omap *clk_hw;
        struct clk *clk;

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

        clk_hw->hw.init = &init;

        init.name = name;
        init.ops = ops;

        memcpy(&clk_hw->enable_reg, reg, sizeof(*reg));
        clk_hw->enable_bit = bit_idx;
        clk_hw->ops = hw_ops;

        clk_hw->flags = clk_gate_flags;

        init.parent_names = &parent_name;
        init.num_parents = 1;

        init.flags = flags;

        clk = ti_clk_register(NULL, &clk_hw->hw, name);

        if (IS_ERR(clk))
                kfree(clk_hw);

        return clk;
}

#if defined(CONFIG_ARCH_OMAP3) && defined(CONFIG_ATAGS)
struct clk *ti_clk_register_gate(struct ti_clk *setup)
{
        const struct clk_ops *ops = &omap_gate_clk_ops;
        const struct clk_hw_omap_ops *hw_ops = NULL;
        struct clk_omap_reg reg;
        u32 flags = 0;
        u8 clk_gate_flags = 0;
        struct ti_clk_gate *gate;

        gate = setup->data;

        if (gate->flags & CLKF_INTERFACE)
                return ti_clk_register_interface(setup);

        if (gate->flags & CLKF_SET_RATE_PARENT)
                flags |= CLK_SET_RATE_PARENT;

        if (gate->flags & CLKF_SET_BIT_TO_DISABLE)
                clk_gate_flags |= INVERT_ENABLE;

        if (gate->flags & CLKF_HSDIV) {
                ops = &omap_gate_clk_hsdiv_restore_ops;
                hw_ops = &clkhwops_wait;
        }

        if (gate->flags & CLKF_DSS)
                hw_ops = &clkhwops_omap3430es2_dss_usbhost_wait;

        if (gate->flags & CLKF_WAIT)
                hw_ops = &clkhwops_wait;

        if (gate->flags & CLKF_CLKDM)
                ops = &omap_gate_clkdm_clk_ops;

        if (gate->flags & CLKF_AM35XX)
                hw_ops = &clkhwops_am35xx_ipss_module_wait;

        reg.index = gate->module;
        reg.offset = gate->reg;
        reg.ptr = NULL;

        return _register_gate(NULL, setup->name, gate->parent, flags,
                              &reg, gate->bit_shift,
                              clk_gate_flags, ops, hw_ops);
}

struct clk_hw *ti_clk_build_component_gate(struct ti_clk_gate *setup)
{
        struct clk_hw_omap *gate;
        struct clk_omap_reg *reg;
        const struct clk_hw_omap_ops *ops = &clkhwops_wait;

        if (!setup)
                return NULL;

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

        reg = (struct clk_omap_reg *)&gate->enable_reg;
        reg->index = setup->module;
        reg->offset = setup->reg;

        gate->enable_bit = setup->bit_shift;

        if (setup->flags & CLKF_NO_WAIT)
                ops = NULL;

        if (setup->flags & CLKF_INTERFACE)
                ops = &clkhwops_iclk_wait;

        gate->ops = ops;

        return &gate->hw;
}
#endif

static void __init _of_ti_gate_clk_setup(struct device_node *node,
                                         const struct clk_ops *ops,
                                         const struct clk_hw_omap_ops *hw_ops)
{
        struct clk *clk;
        const char *parent_name;
        struct clk_omap_reg reg;
        u8 enable_bit = 0;
        u32 val;
        u32 flags = 0;
        u8 clk_gate_flags = 0;

        if (ops != &omap_gate_clkdm_clk_ops) {
                if (ti_clk_get_reg_addr(node, 0, &reg))
                        return;

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

        if (of_clk_get_parent_count(node) != 1) {
                pr_err("%s must have 1 parent\n", node->name);
                return;
        }

        parent_name = of_clk_get_parent_name(node, 0);

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

        if (of_property_read_bool(node, "ti,set-bit-to-disable"))
                clk_gate_flags |= INVERT_ENABLE;

        clk = _register_gate(NULL, node->name, parent_name, flags, &reg,
                             enable_bit, clk_gate_flags, ops, hw_ops);

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

static void __init
_of_ti_composite_gate_clk_setup(struct device_node *node,
                                const struct clk_hw_omap_ops *hw_ops)
{
        struct clk_hw_omap *gate;
        u32 val = 0;

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

        if (ti_clk_get_reg_addr(node, 0, &gate->enable_reg))
                goto cleanup;

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

        gate->enable_bit = val;
        gate->ops = hw_ops;

        if (!ti_clk_add_component(node, &gate->hw, CLK_COMPONENT_TYPE_GATE))
                return;

cleanup:
        kfree(gate);
}

static void __init
of_ti_composite_no_wait_gate_clk_setup(struct device_node *node)
{
        _of_ti_composite_gate_clk_setup(node, NULL);
}
CLK_OF_DECLARE(ti_composite_no_wait_gate_clk, "ti,composite-no-wait-gate-clock",
               of_ti_composite_no_wait_gate_clk_setup);

#if defined(CONFIG_ARCH_OMAP2) || defined(CONFIG_ARCH_OMAP3)
static void __init of_ti_composite_interface_clk_setup(struct device_node *node)
{
        _of_ti_composite_gate_clk_setup(node, &clkhwops_iclk_wait);
}
CLK_OF_DECLARE(ti_composite_interface_clk, "ti,composite-interface-clock",
               of_ti_composite_interface_clk_setup);
#endif

static void __init of_ti_composite_gate_clk_setup(struct device_node *node)
{
        _of_ti_composite_gate_clk_setup(node, &clkhwops_wait);
}
CLK_OF_DECLARE(ti_composite_gate_clk, "ti,composite-gate-clock",
               of_ti_composite_gate_clk_setup);


static void __init of_ti_clkdm_gate_clk_setup(struct device_node *node)
{
        _of_ti_gate_clk_setup(node, &omap_gate_clkdm_clk_ops, NULL);
}
CLK_OF_DECLARE(ti_clkdm_gate_clk, "ti,clkdm-gate-clock",
               of_ti_clkdm_gate_clk_setup);

static void __init of_ti_hsdiv_gate_clk_setup(struct device_node *node)
{
        _of_ti_gate_clk_setup(node, &omap_gate_clk_hsdiv_restore_ops,
                              &clkhwops_wait);
}
CLK_OF_DECLARE(ti_hsdiv_gate_clk, "ti,hsdiv-gate-clock",
               of_ti_hsdiv_gate_clk_setup);

static void __init of_ti_gate_clk_setup(struct device_node *node)
{
        _of_ti_gate_clk_setup(node, &omap_gate_clk_ops, NULL);
}
CLK_OF_DECLARE(ti_gate_clk, "ti,gate-clock", of_ti_gate_clk_setup);

static void __init of_ti_wait_gate_clk_setup(struct device_node *node)
{
        _of_ti_gate_clk_setup(node, &omap_gate_clk_ops, &clkhwops_wait);
}
CLK_OF_DECLARE(ti_wait_gate_clk, "ti,wait-gate-clock",
               of_ti_wait_gate_clk_setup);

#ifdef CONFIG_ARCH_OMAP3
static void __init of_ti_am35xx_gate_clk_setup(struct device_node *node)
{
        _of_ti_gate_clk_setup(node, &omap_gate_clk_ops,
                              &clkhwops_am35xx_ipss_module_wait);
}
CLK_OF_DECLARE(ti_am35xx_gate_clk, "ti,am35xx-gate-clock",
               of_ti_am35xx_gate_clk_setup);

static void __init of_ti_dss_gate_clk_setup(struct device_node *node)
{
        _of_ti_gate_clk_setup(node, &omap_gate_clk_ops,
                              &clkhwops_omap3430es2_dss_usbhost_wait);
}
CLK_OF_DECLARE(ti_dss_gate_clk, "ti,dss-gate-clock",
               of_ti_dss_gate_clk_setup);
#endif