/*
 * Copyright (c) 2012-2015, The Linux Foundation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; 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 "dsi_pll.h"
#include "dsi.xml.h"

/*
 * DSI PLL 28nm (8960/A family) - clock diagram (eg: DSI1):
 *
 *
 *                        +------+
 *  dsi1vco_clk ----o-----| DIV1 |---dsi1pllbit (not exposed as clock)
 *  F * byte_clk    |     +------+
 *                  | bit clock divider (F / 8)
 *                  |
 *                  |     +------+
 *                  o-----| DIV2 |---dsi0pllbyte---o---> To byte RCG
 *                  |     +------+                 | (sets parent rate)
 *                  | byte clock divider (F)       |
 *                  |                              |
 *                  |                              o---> To esc RCG
 *                  |                                (doesn't set parent rate)
 *                  |
 *                  |     +------+
 *                  o-----| DIV3 |----dsi0pll------o---> To dsi RCG
 *                        +------+                 | (sets parent rate)
 *                  dsi clock divider (F * magic)  |
 *                                                 |
 *                                                 o---> To pixel rcg
 *                                                  (doesn't set parent rate)
 */

#define POLL_MAX_READS          8000
#define POLL_TIMEOUT_US         1

#define NUM_PROVIDED_CLKS       2

#define VCO_REF_CLK_RATE        27000000
#define VCO_MIN_RATE            600000000
#define VCO_MAX_RATE            1200000000

#define DSI_BYTE_PLL_CLK        0
#define DSI_PIXEL_PLL_CLK       1

#define VCO_PREF_DIV_RATIO      27

struct pll_28nm_cached_state {
        unsigned long vco_rate;
        u8 postdiv3;
        u8 postdiv2;
        u8 postdiv1;
};

struct clk_bytediv {
        struct clk_hw hw;
        void __iomem *reg;
};

struct dsi_pll_28nm {
        struct msm_dsi_pll base;

        int id;
        struct platform_device *pdev;
        void __iomem *mmio;

        /* custom byte clock divider */
        struct clk_bytediv *bytediv;

        /* private clocks: */
        struct clk *clks[NUM_DSI_CLOCKS_MAX];
        u32 num_clks;

        /* clock-provider: */
        struct clk *provided_clks[NUM_PROVIDED_CLKS];
        struct clk_onecell_data clk_data;

        struct pll_28nm_cached_state cached_state;
};

#define to_pll_28nm(x)  container_of(x, struct dsi_pll_28nm, base)

static bool pll_28nm_poll_for_ready(struct dsi_pll_28nm *pll_28nm,
                                    int nb_tries, int timeout_us)
{
        bool pll_locked = false;
        u32 val;

        while (nb_tries--) {
                val = pll_read(pll_28nm->mmio + REG_DSI_28nm_8960_PHY_PLL_RDY);
                pll_locked = !!(val & DSI_28nm_8960_PHY_PLL_RDY_PLL_RDY);

                if (pll_locked)
                        break;

                udelay(timeout_us);
        }
        DBG("DSI PLL is %slocked", pll_locked ? "" : "*not* ");

        return pll_locked;
}

/*
 * Clock Callbacks
 */
static int dsi_pll_28nm_clk_set_rate(struct clk_hw *hw, unsigned long rate,
                                     unsigned long parent_rate)
{
        struct msm_dsi_pll *pll = hw_clk_to_pll(hw);
        struct dsi_pll_28nm *pll_28nm = to_pll_28nm(pll);
        void __iomem *base = pll_28nm->mmio;
        u32 val, temp, fb_divider;

        DBG("rate=%lu, parent's=%lu", rate, parent_rate);

        temp = rate / 10;
        val = VCO_REF_CLK_RATE / 10;
        fb_divider = (temp * VCO_PREF_DIV_RATIO) / val;
        fb_divider = fb_divider / 2 - 1;
        pll_write(base + REG_DSI_28nm_8960_PHY_PLL_CTRL_1,
                        fb_divider & 0xff);

        val = pll_read(base + REG_DSI_28nm_8960_PHY_PLL_CTRL_2);

        val |= (fb_divider >> 8) & 0x07;

        pll_write(base + REG_DSI_28nm_8960_PHY_PLL_CTRL_2,
                        val);

        val = pll_read(base + REG_DSI_28nm_8960_PHY_PLL_CTRL_3);

        val |= (VCO_PREF_DIV_RATIO - 1) & 0x3f;

        pll_write(base + REG_DSI_28nm_8960_PHY_PLL_CTRL_3,
                        val);

        pll_write(base + REG_DSI_28nm_8960_PHY_PLL_CTRL_6,
                        0xf);

        val = pll_read(base + REG_DSI_28nm_8960_PHY_PLL_CTRL_8);
        val |= 0x7 << 4;
        pll_write(base + REG_DSI_28nm_8960_PHY_PLL_CTRL_8,
                        val);

        return 0;
}

static int dsi_pll_28nm_clk_is_enabled(struct clk_hw *hw)
{
        struct msm_dsi_pll *pll = hw_clk_to_pll(hw);
        struct dsi_pll_28nm *pll_28nm = to_pll_28nm(pll);

        return pll_28nm_poll_for_ready(pll_28nm, POLL_MAX_READS,
                                        POLL_TIMEOUT_US);
}

static unsigned long dsi_pll_28nm_clk_recalc_rate(struct clk_hw *hw,
                                                  unsigned long parent_rate)
{
        struct msm_dsi_pll *pll = hw_clk_to_pll(hw);
        struct dsi_pll_28nm *pll_28nm = to_pll_28nm(pll);
        void __iomem *base = pll_28nm->mmio;
        unsigned long vco_rate;
        u32 status, fb_divider, temp, ref_divider;

        VERB("parent_rate=%lu", parent_rate);

        status = pll_read(base + REG_DSI_28nm_8960_PHY_PLL_CTRL_0);

        if (status & DSI_28nm_8960_PHY_PLL_CTRL_0_ENABLE) {
                fb_divider = pll_read(base + REG_DSI_28nm_8960_PHY_PLL_CTRL_1);
                fb_divider &= 0xff;
                temp = pll_read(base + REG_DSI_28nm_8960_PHY_PLL_CTRL_2) & 0x07;
                fb_divider = (temp << 8) | fb_divider;
                fb_divider += 1;

                ref_divider = pll_read(base + REG_DSI_28nm_8960_PHY_PLL_CTRL_3);
                ref_divider &= 0x3f;
                ref_divider += 1;

                /* multiply by 2 */
                vco_rate = (parent_rate / ref_divider) * fb_divider * 2;
        } else {
                vco_rate = 0;
        }

        DBG("returning vco rate = %lu", vco_rate);

        return vco_rate;
}

static const struct clk_ops clk_ops_dsi_pll_28nm_vco = {
        .round_rate = msm_dsi_pll_helper_clk_round_rate,
        .set_rate = dsi_pll_28nm_clk_set_rate,
        .recalc_rate = dsi_pll_28nm_clk_recalc_rate,
        .prepare = msm_dsi_pll_helper_clk_prepare,
        .unprepare = msm_dsi_pll_helper_clk_unprepare,
        .is_enabled = dsi_pll_28nm_clk_is_enabled,
};

/*
 * Custom byte clock divier clk_ops
 *
 * This clock is the entry point to configuring the PLL. The user (dsi host)
 * will set this clock's rate to the desired byte clock rate. The VCO lock
 * frequency is a multiple of the byte clock rate. The multiplication factor
 * (shown as F in the diagram above) is a function of the byte clock rate.
 *
 * This custom divider clock ensures that its parent (VCO) is set to the
 * desired rate, and that the byte clock postdivider (POSTDIV2) is configured
 * accordingly
 */
#define to_clk_bytediv(_hw) container_of(_hw, struct clk_bytediv, hw)

static unsigned long clk_bytediv_recalc_rate(struct clk_hw *hw,
                unsigned long parent_rate)
{
        struct clk_bytediv *bytediv = to_clk_bytediv(hw);
        unsigned int div;

        div = pll_read(bytediv->reg) & 0xff;

        return parent_rate / (div + 1);
}

/* find multiplication factor(wrt byte clock) at which the VCO should be set */
static unsigned int get_vco_mul_factor(unsigned long byte_clk_rate)
{
        unsigned long bit_mhz;

        /* convert to bit clock in Mhz */
        bit_mhz = (byte_clk_rate * 8) / 1000000;

        if (bit_mhz < 125)
                return 64;
        else if (bit_mhz < 250)
                return 32;
        else if (bit_mhz < 600)
                return 16;
        else
                return 8;
}

static long clk_bytediv_round_rate(struct clk_hw *hw, unsigned long rate,
                                   unsigned long *prate)
{
        unsigned long best_parent;
        unsigned int factor;

        factor = get_vco_mul_factor(rate);

        best_parent = rate * factor;
        *prate = clk_hw_round_rate(clk_hw_get_parent(hw), best_parent);

        return *prate / factor;
}

static int clk_bytediv_set_rate(struct clk_hw *hw, unsigned long rate,
                                unsigned long parent_rate)
{
        struct clk_bytediv *bytediv = to_clk_bytediv(hw);
        u32 val;
        unsigned int factor;

        factor = get_vco_mul_factor(rate);

        val = pll_read(bytediv->reg);
        val |= (factor - 1) & 0xff;
        pll_write(bytediv->reg, val);

        return 0;
}

/* Our special byte clock divider ops */
static const struct clk_ops clk_bytediv_ops = {
        .round_rate = clk_bytediv_round_rate,
        .set_rate = clk_bytediv_set_rate,
        .recalc_rate = clk_bytediv_recalc_rate,
};

/*
 * PLL Callbacks
 */
static int dsi_pll_28nm_enable_seq(struct msm_dsi_pll *pll)
{
        struct dsi_pll_28nm *pll_28nm = to_pll_28nm(pll);
        struct device *dev = &pll_28nm->pdev->dev;
        void __iomem *base = pll_28nm->mmio;
        bool locked;
        unsigned int bit_div, byte_div;
        int max_reads = 1000, timeout_us = 100;
        u32 val;

        DBG("id=%d", pll_28nm->id);

        /*
         * before enabling the PLL, configure the bit clock divider since we
         * don't expose it as a clock to the outside world
         * 1: read back the byte clock divider that should already be set
         * 2: divide by 8 to get bit clock divider
         * 3: write it to POSTDIV1
         */
        val = pll_read(base + REG_DSI_28nm_8960_PHY_PLL_CTRL_9);
        byte_div = val + 1;
        bit_div = byte_div / 8;

        val = pll_read(base + REG_DSI_28nm_8960_PHY_PLL_CTRL_8);
        val &= ~0xf;
        val |= (bit_div - 1);
        pll_write(base + REG_DSI_28nm_8960_PHY_PLL_CTRL_8, val);

        /* enable the PLL */
        pll_write(base + REG_DSI_28nm_8960_PHY_PLL_CTRL_0,
                        DSI_28nm_8960_PHY_PLL_CTRL_0_ENABLE);

        locked = pll_28nm_poll_for_ready(pll_28nm, max_reads, timeout_us);

        if (unlikely(!locked))
                dev_err(dev, "DSI PLL lock failed\n");
        else
                DBG("DSI PLL lock success");

        return locked ? 0 : -EINVAL;
}

static void dsi_pll_28nm_disable_seq(struct msm_dsi_pll *pll)
{
        struct dsi_pll_28nm *pll_28nm = to_pll_28nm(pll);

        DBG("id=%d", pll_28nm->id);
        pll_write(pll_28nm->mmio + REG_DSI_28nm_8960_PHY_PLL_CTRL_0, 0x00);
}

static void dsi_pll_28nm_save_state(struct msm_dsi_pll *pll)
{
        struct dsi_pll_28nm *pll_28nm = to_pll_28nm(pll);
        struct pll_28nm_cached_state *cached_state = &pll_28nm->cached_state;
        void __iomem *base = pll_28nm->mmio;

        cached_state->postdiv3 =
                        pll_read(base + REG_DSI_28nm_8960_PHY_PLL_CTRL_10);
        cached_state->postdiv2 =
                        pll_read(base + REG_DSI_28nm_8960_PHY_PLL_CTRL_9);
        cached_state->postdiv1 =
                        pll_read(base + REG_DSI_28nm_8960_PHY_PLL_CTRL_8);

        cached_state->vco_rate = clk_hw_get_rate(&pll->clk_hw);
}

static int dsi_pll_28nm_restore_state(struct msm_dsi_pll *pll)
{
        struct dsi_pll_28nm *pll_28nm = to_pll_28nm(pll);
        struct pll_28nm_cached_state *cached_state = &pll_28nm->cached_state;
        void __iomem *base = pll_28nm->mmio;
        int ret;

        ret = dsi_pll_28nm_clk_set_rate(&pll->clk_hw,
                                        cached_state->vco_rate, 0);
        if (ret) {
                dev_err(&pll_28nm->pdev->dev,
                        "restore vco rate failed. ret=%d\n", ret);
                return ret;
        }

        pll_write(base + REG_DSI_28nm_8960_PHY_PLL_CTRL_10,
                        cached_state->postdiv3);
        pll_write(base + REG_DSI_28nm_8960_PHY_PLL_CTRL_9,
                        cached_state->postdiv2);
        pll_write(base + REG_DSI_28nm_8960_PHY_PLL_CTRL_8,
                        cached_state->postdiv1);

        return 0;
}

static int dsi_pll_28nm_get_provider(struct msm_dsi_pll *pll,
                                struct clk **byte_clk_provider,
                                struct clk **pixel_clk_provider)
{
        struct dsi_pll_28nm *pll_28nm = to_pll_28nm(pll);

        if (byte_clk_provider)
                *byte_clk_provider = pll_28nm->provided_clks[DSI_BYTE_PLL_CLK];
        if (pixel_clk_provider)
                *pixel_clk_provider =
                                pll_28nm->provided_clks[DSI_PIXEL_PLL_CLK];

        return 0;
}

static void dsi_pll_28nm_destroy(struct msm_dsi_pll *pll)
{
        struct dsi_pll_28nm *pll_28nm = to_pll_28nm(pll);

        msm_dsi_pll_helper_unregister_clks(pll_28nm->pdev,
                                        pll_28nm->clks, pll_28nm->num_clks);
}

static int pll_28nm_register(struct dsi_pll_28nm *pll_28nm)
{
        char *clk_name, *parent_name, *vco_name;
        struct clk_init_data vco_init = {
                .parent_names = (const char *[]){ "pxo" },
                .num_parents = 1,
                .flags = CLK_IGNORE_UNUSED,
                .ops = &clk_ops_dsi_pll_28nm_vco,
        };
        struct device *dev = &pll_28nm->pdev->dev;
        struct clk **clks = pll_28nm->clks;
        struct clk **provided_clks = pll_28nm->provided_clks;
        struct clk_bytediv *bytediv;
        struct clk_init_data bytediv_init = { };
        int ret, num = 0;

        DBG("%d", pll_28nm->id);

        bytediv = devm_kzalloc(dev, sizeof(*bytediv), GFP_KERNEL);
        if (!bytediv)
                return -ENOMEM;

        vco_name = devm_kzalloc(dev, 32, GFP_KERNEL);
        if (!vco_name)
                return -ENOMEM;

        parent_name = devm_kzalloc(dev, 32, GFP_KERNEL);
        if (!parent_name)
                return -ENOMEM;

        clk_name = devm_kzalloc(dev, 32, GFP_KERNEL);
        if (!clk_name)
                return -ENOMEM;

        pll_28nm->bytediv = bytediv;

        snprintf(vco_name, 32, "dsi%dvco_clk", pll_28nm->id);
        vco_init.name = vco_name;

        pll_28nm->base.clk_hw.init = &vco_init;

        clks[num++] = clk_register(dev, &pll_28nm->base.clk_hw);

        /* prepare and register bytediv */
        bytediv->hw.init = &bytediv_init;
        bytediv->reg = pll_28nm->mmio + REG_DSI_28nm_8960_PHY_PLL_CTRL_9;

        snprintf(parent_name, 32, "dsi%dvco_clk", pll_28nm->id);
        snprintf(clk_name, 32, "dsi%dpllbyte", pll_28nm->id);

        bytediv_init.name = clk_name;
        bytediv_init.ops = &clk_bytediv_ops;
        bytediv_init.flags = CLK_SET_RATE_PARENT;
        bytediv_init.parent_names = (const char * const *) &parent_name;
        bytediv_init.num_parents = 1;

        /* DIV2 */
        clks[num++] = provided_clks[DSI_BYTE_PLL_CLK] =
                        clk_register(dev, &bytediv->hw);

        snprintf(clk_name, 32, "dsi%dpll", pll_28nm->id);
        /* DIV3 */
        clks[num++] = provided_clks[DSI_PIXEL_PLL_CLK] =
                        clk_register_divider(dev, clk_name,
                                parent_name, 0, pll_28nm->mmio +
                                REG_DSI_28nm_8960_PHY_PLL_CTRL_10,
                                0, 8, 0, NULL);

        pll_28nm->num_clks = num;

        pll_28nm->clk_data.clk_num = NUM_PROVIDED_CLKS;
        pll_28nm->clk_data.clks = provided_clks;

        ret = of_clk_add_provider(dev->of_node,
                        of_clk_src_onecell_get, &pll_28nm->clk_data);
        if (ret) {
                dev_err(dev, "failed to register clk provider: %d\n", ret);
                return ret;
        }

        return 0;
}

struct msm_dsi_pll *msm_dsi_pll_28nm_8960_init(struct platform_device *pdev,
                                               int id)
{
        struct dsi_pll_28nm *pll_28nm;
        struct msm_dsi_pll *pll;
        int ret;

        if (!pdev)
                return ERR_PTR(-ENODEV);

        pll_28nm = devm_kzalloc(&pdev->dev, sizeof(*pll_28nm), GFP_KERNEL);
        if (!pll_28nm)
                return ERR_PTR(-ENOMEM);

        pll_28nm->pdev = pdev;
        pll_28nm->id = id + 1;

        pll_28nm->mmio = msm_ioremap(pdev, "dsi_pll", "DSI_PLL");
        if (IS_ERR_OR_NULL(pll_28nm->mmio)) {
                dev_err(&pdev->dev, "%s: failed to map pll base\n", __func__);
                return ERR_PTR(-ENOMEM);
        }

        pll = &pll_28nm->base;
        pll->min_rate = VCO_MIN_RATE;
        pll->max_rate = VCO_MAX_RATE;
        pll->get_provider = dsi_pll_28nm_get_provider;
        pll->destroy = dsi_pll_28nm_destroy;
        pll->disable_seq = dsi_pll_28nm_disable_seq;
        pll->save_state = dsi_pll_28nm_save_state;
        pll->restore_state = dsi_pll_28nm_restore_state;

        pll->en_seq_cnt = 1;
        pll->enable_seqs[0] = dsi_pll_28nm_enable_seq;

        ret = pll_28nm_register(pll_28nm);
        if (ret) {
                dev_err(&pdev->dev, "failed to register PLL: %d\n", ret);
                return ERR_PTR(ret);
        }

        return pll;
}