/*
 * Copyright (C) 2014 STMicroelectronics R&D Ltd
 *
 * 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.
 *
 */

/*
 * Authors:
 * Stephen Gallimore <stephen.gallimore@st.com>,
 * Pankaj Dev <pankaj.dev@st.com>.
 */

#include <linux/slab.h>
#include <linux/of_address.h>
#include <linux/clk.h>
#include <linux/clk-provider.h>

#include "clkgen.h"

/*
 * Maximum input clock to the PLL before we divide it down by 2
 * although in reality in actual systems this has never been seen to
 * be used.
 */
#define QUADFS_NDIV_THRESHOLD 30000000

#define PLL_BW_GOODREF   (0L)
#define PLL_BW_VBADREF   (1L)
#define PLL_BW_BADREF    (2L)
#define PLL_BW_VGOODREF  (3L)

#define QUADFS_MAX_CHAN 4

struct stm_fs {
        unsigned long ndiv;
        unsigned long mdiv;
        unsigned long pe;
        unsigned long sdiv;
        unsigned long nsdiv;
};

struct clkgen_quadfs_data {
        bool reset_present;
        bool bwfilter_present;
        bool lockstatus_present;
        bool powerup_polarity;
        bool standby_polarity;
        bool nsdiv_present;
        bool nrst_present;
        struct clkgen_field ndiv;
        struct clkgen_field ref_bw;
        struct clkgen_field nreset;
        struct clkgen_field npda;
        struct clkgen_field lock_status;

        struct clkgen_field nrst[QUADFS_MAX_CHAN];
        struct clkgen_field nsb[QUADFS_MAX_CHAN];
        struct clkgen_field en[QUADFS_MAX_CHAN];
        struct clkgen_field mdiv[QUADFS_MAX_CHAN];
        struct clkgen_field pe[QUADFS_MAX_CHAN];
        struct clkgen_field sdiv[QUADFS_MAX_CHAN];
        struct clkgen_field nsdiv[QUADFS_MAX_CHAN];

        const struct clk_ops *pll_ops;
        int  (*get_params)(unsigned long, unsigned long, struct stm_fs *);
        int  (*get_rate)(unsigned long , const struct stm_fs *,
                        unsigned long *);
};

static const struct clk_ops st_quadfs_pll_c32_ops;
static const struct clk_ops st_quadfs_fs660c32_ops;

static int clk_fs660c32_dig_get_params(unsigned long input,
                unsigned long output, struct stm_fs *fs);
static int clk_fs660c32_dig_get_rate(unsigned long, const struct stm_fs *,
                unsigned long *);

static const struct clkgen_quadfs_data st_fs660c32_C = {
        .nrst_present = true,
        .nrst   = { CLKGEN_FIELD(0x2f0, 0x1, 0),
                    CLKGEN_FIELD(0x2f0, 0x1, 1),
                    CLKGEN_FIELD(0x2f0, 0x1, 2),
                    CLKGEN_FIELD(0x2f0, 0x1, 3) },
        .npda   = CLKGEN_FIELD(0x2f0, 0x1, 12),
        .nsb    = { CLKGEN_FIELD(0x2f0, 0x1, 8),
                    CLKGEN_FIELD(0x2f0, 0x1, 9),
                    CLKGEN_FIELD(0x2f0, 0x1, 10),
                    CLKGEN_FIELD(0x2f0, 0x1, 11) },
        .nsdiv_present = true,
        .nsdiv  = { CLKGEN_FIELD(0x304, 0x1, 24),
                    CLKGEN_FIELD(0x308, 0x1, 24),
                    CLKGEN_FIELD(0x30c, 0x1, 24),
                    CLKGEN_FIELD(0x310, 0x1, 24) },
        .mdiv   = { CLKGEN_FIELD(0x304, 0x1f, 15),
                    CLKGEN_FIELD(0x308, 0x1f, 15),
                    CLKGEN_FIELD(0x30c, 0x1f, 15),
                    CLKGEN_FIELD(0x310, 0x1f, 15) },
        .en     = { CLKGEN_FIELD(0x2fc, 0x1, 0),
                    CLKGEN_FIELD(0x2fc, 0x1, 1),
                    CLKGEN_FIELD(0x2fc, 0x1, 2),
                    CLKGEN_FIELD(0x2fc, 0x1, 3) },
        .ndiv   = CLKGEN_FIELD(0x2f4, 0x7, 16),
        .pe     = { CLKGEN_FIELD(0x304, 0x7fff, 0),
                    CLKGEN_FIELD(0x308, 0x7fff, 0),
                    CLKGEN_FIELD(0x30c, 0x7fff, 0),
                    CLKGEN_FIELD(0x310, 0x7fff, 0) },
        .sdiv   = { CLKGEN_FIELD(0x304, 0xf, 20),
                    CLKGEN_FIELD(0x308, 0xf, 20),
                    CLKGEN_FIELD(0x30c, 0xf, 20),
                    CLKGEN_FIELD(0x310, 0xf, 20) },
        .lockstatus_present = true,
        .lock_status = CLKGEN_FIELD(0x2f0, 0x1, 24),
        .powerup_polarity = 1,
        .standby_polarity = 1,
        .pll_ops        = &st_quadfs_pll_c32_ops,
        .get_params     = clk_fs660c32_dig_get_params,
        .get_rate       = clk_fs660c32_dig_get_rate,
};

static const struct clkgen_quadfs_data st_fs660c32_D = {
        .nrst_present = true,
        .nrst   = { CLKGEN_FIELD(0x2a0, 0x1, 0),
                    CLKGEN_FIELD(0x2a0, 0x1, 1),
                    CLKGEN_FIELD(0x2a0, 0x1, 2),
                    CLKGEN_FIELD(0x2a0, 0x1, 3) },
        .ndiv   = CLKGEN_FIELD(0x2a4, 0x7, 16),
        .pe     = { CLKGEN_FIELD(0x2b4, 0x7fff, 0),
                    CLKGEN_FIELD(0x2b8, 0x7fff, 0),
                    CLKGEN_FIELD(0x2bc, 0x7fff, 0),
                    CLKGEN_FIELD(0x2c0, 0x7fff, 0) },
        .sdiv   = { CLKGEN_FIELD(0x2b4, 0xf, 20),
                    CLKGEN_FIELD(0x2b8, 0xf, 20),
                    CLKGEN_FIELD(0x2bc, 0xf, 20),
                    CLKGEN_FIELD(0x2c0, 0xf, 20) },
        .npda   = CLKGEN_FIELD(0x2a0, 0x1, 12),
        .nsb    = { CLKGEN_FIELD(0x2a0, 0x1, 8),
                    CLKGEN_FIELD(0x2a0, 0x1, 9),
                    CLKGEN_FIELD(0x2a0, 0x1, 10),
                    CLKGEN_FIELD(0x2a0, 0x1, 11) },
        .nsdiv_present = true,
        .nsdiv  = { CLKGEN_FIELD(0x2b4, 0x1, 24),
                    CLKGEN_FIELD(0x2b8, 0x1, 24),
                    CLKGEN_FIELD(0x2bc, 0x1, 24),
                    CLKGEN_FIELD(0x2c0, 0x1, 24) },
        .mdiv   = { CLKGEN_FIELD(0x2b4, 0x1f, 15),
                    CLKGEN_FIELD(0x2b8, 0x1f, 15),
                    CLKGEN_FIELD(0x2bc, 0x1f, 15),
                    CLKGEN_FIELD(0x2c0, 0x1f, 15) },
        .en     = { CLKGEN_FIELD(0x2ac, 0x1, 0),
                    CLKGEN_FIELD(0x2ac, 0x1, 1),
                    CLKGEN_FIELD(0x2ac, 0x1, 2),
                    CLKGEN_FIELD(0x2ac, 0x1, 3) },
        .lockstatus_present = true,
        .lock_status = CLKGEN_FIELD(0x2A0, 0x1, 24),
        .powerup_polarity = 1,
        .standby_polarity = 1,
        .pll_ops        = &st_quadfs_pll_c32_ops,
        .get_params     = clk_fs660c32_dig_get_params,
        .get_rate       = clk_fs660c32_dig_get_rate,};

/**
 * DOC: A Frequency Synthesizer that multiples its input clock by a fixed factor
 *
 * Traits of this clock:
 * prepare - clk_(un)prepare only ensures parent is (un)prepared
 * enable - clk_enable and clk_disable are functional & control the Fsyn
 * rate - inherits rate from parent. set_rate/round_rate/recalc_rate
 * parent - fixed parent.  No clk_set_parent support
 */

/**
 * struct st_clk_quadfs_pll - A pll which outputs a fixed multiplier of
 *                                  its parent clock, found inside a type of
 *                                  ST quad channel frequency synthesizer block
 *
 * @hw: handle between common and hardware-specific interfaces.
 * @ndiv: regmap field for the ndiv control.
 * @regs_base: base address of the configuration registers.
 * @lock: spinlock.
 *
 */
struct st_clk_quadfs_pll {
        struct clk_hw   hw;
        void __iomem    *regs_base;
        spinlock_t      *lock;
        struct clkgen_quadfs_data *data;
        u32 ndiv;
};

#define to_quadfs_pll(_hw) container_of(_hw, struct st_clk_quadfs_pll, hw)

static int quadfs_pll_enable(struct clk_hw *hw)
{
        struct st_clk_quadfs_pll *pll = to_quadfs_pll(hw);
        unsigned long flags = 0, timeout = jiffies + msecs_to_jiffies(10);

        if (pll->lock)
                spin_lock_irqsave(pll->lock, flags);

        /*
         * Bring block out of reset if we have reset control.
         */
        if (pll->data->reset_present)
                CLKGEN_WRITE(pll, nreset, 1);

        /*
         * Use a fixed input clock noise bandwidth filter for the moment
         */
        if (pll->data->bwfilter_present)
                CLKGEN_WRITE(pll, ref_bw, PLL_BW_GOODREF);


        CLKGEN_WRITE(pll, ndiv, pll->ndiv);

        /*
         * Power up the PLL
         */
        CLKGEN_WRITE(pll, npda, !pll->data->powerup_polarity);

        if (pll->lock)
                spin_unlock_irqrestore(pll->lock, flags);

        if (pll->data->lockstatus_present)
                while (!CLKGEN_READ(pll, lock_status)) {
                        if (time_after(jiffies, timeout))
                                return -ETIMEDOUT;
                        cpu_relax();
                }

        return 0;
}

static void quadfs_pll_disable(struct clk_hw *hw)
{
        struct st_clk_quadfs_pll *pll = to_quadfs_pll(hw);
        unsigned long flags = 0;

        if (pll->lock)
                spin_lock_irqsave(pll->lock, flags);

        /*
         * Powerdown the PLL and then put block into soft reset if we have
         * reset control.
         */
        CLKGEN_WRITE(pll, npda, pll->data->powerup_polarity);

        if (pll->data->reset_present)
                CLKGEN_WRITE(pll, nreset, 0);

        if (pll->lock)
                spin_unlock_irqrestore(pll->lock, flags);
}

static int quadfs_pll_is_enabled(struct clk_hw *hw)
{
        struct st_clk_quadfs_pll *pll = to_quadfs_pll(hw);
        u32 npda = CLKGEN_READ(pll, npda);

        return pll->data->powerup_polarity ? !npda : !!npda;
}

static int clk_fs660c32_vco_get_rate(unsigned long input, struct stm_fs *fs,
                           unsigned long *rate)
{
        unsigned long nd = fs->ndiv + 16; /* ndiv value */

        *rate = input * nd;

        return 0;
}

static unsigned long quadfs_pll_fs660c32_recalc_rate(struct clk_hw *hw,
                                        unsigned long parent_rate)
{
        struct st_clk_quadfs_pll *pll = to_quadfs_pll(hw);
        unsigned long rate = 0;
        struct stm_fs params;

        params.ndiv = CLKGEN_READ(pll, ndiv);
        if (clk_fs660c32_vco_get_rate(parent_rate, &params, &rate))
                pr_err("%s:%s error calculating rate\n",
                       clk_hw_get_name(hw), __func__);

        pll->ndiv = params.ndiv;

        return rate;
}

static int clk_fs660c32_vco_get_params(unsigned long input,
                                unsigned long output, struct stm_fs *fs)
{
/* Formula
   VCO frequency = (fin x ndiv) / pdiv
   ndiv = VCOfreq * pdiv / fin
   */
        unsigned long pdiv = 1, n;

        /* Output clock range: 384Mhz to 660Mhz */
        if (output < 384000000 || output > 660000000)
                return -EINVAL;

        if (input > 40000000)
                /* This means that PDIV would be 2 instead of 1.
                   Not supported today. */
                return -EINVAL;

        input /= 1000;
        output /= 1000;

        n = output * pdiv / input;
        if (n < 16)
                n = 16;
        fs->ndiv = n - 16; /* Converting formula value to reg value */

        return 0;
}

static long quadfs_pll_fs660c32_round_rate(struct clk_hw *hw,
                                           unsigned long rate,
                                           unsigned long *prate)
{
        struct stm_fs params;

        if (clk_fs660c32_vco_get_params(*prate, rate, &params))
                return rate;

        clk_fs660c32_vco_get_rate(*prate, &params, &rate);

        pr_debug("%s: %s new rate %ld [ndiv=%u]\n",
                 __func__, clk_hw_get_name(hw),
                 rate, (unsigned int)params.ndiv);

        return rate;
}

static int quadfs_pll_fs660c32_set_rate(struct clk_hw *hw, unsigned long rate,
                                unsigned long parent_rate)
{
        struct st_clk_quadfs_pll *pll = to_quadfs_pll(hw);
        struct stm_fs params;
        long hwrate = 0;
        unsigned long flags = 0;
        int ret;

        if (!rate || !parent_rate)
                return -EINVAL;

        ret = clk_fs660c32_vco_get_params(parent_rate, rate, &params);
        if (ret)
                return ret;

        clk_fs660c32_vco_get_rate(parent_rate, &params, &hwrate);

        pr_debug("%s: %s new rate %ld [ndiv=0x%x]\n",
                 __func__, clk_hw_get_name(hw),
                 hwrate, (unsigned int)params.ndiv);

        if (!hwrate)
                return -EINVAL;

        pll->ndiv = params.ndiv;

        if (pll->lock)
                spin_lock_irqsave(pll->lock, flags);

        CLKGEN_WRITE(pll, ndiv, pll->ndiv);

        if (pll->lock)
                spin_unlock_irqrestore(pll->lock, flags);

        return 0;
}

static const struct clk_ops st_quadfs_pll_c32_ops = {
        .enable         = quadfs_pll_enable,
        .disable        = quadfs_pll_disable,
        .is_enabled     = quadfs_pll_is_enabled,
        .recalc_rate    = quadfs_pll_fs660c32_recalc_rate,
        .round_rate     = quadfs_pll_fs660c32_round_rate,
        .set_rate       = quadfs_pll_fs660c32_set_rate,
};

static struct clk * __init st_clk_register_quadfs_pll(
                const char *name, const char *parent_name,
                struct clkgen_quadfs_data *quadfs, void __iomem *reg,
                spinlock_t *lock)
{
        struct st_clk_quadfs_pll *pll;
        struct clk *clk;
        struct clk_init_data init;

        /*
         * Sanity check required pointers.
         */
        if (WARN_ON(!name || !parent_name))
                return ERR_PTR(-EINVAL);

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

        init.name = name;
        init.ops = quadfs->pll_ops;
        init.flags = CLK_IS_BASIC | CLK_GET_RATE_NOCACHE;
        init.parent_names = &parent_name;
        init.num_parents = 1;

        pll->data = quadfs;
        pll->regs_base = reg;
        pll->lock = lock;
        pll->hw.init = &init;

        clk = clk_register(NULL, &pll->hw);

        if (IS_ERR(clk))
                kfree(pll);

        return clk;
}

/**
 * DOC: A digital frequency synthesizer
 *
 * Traits of this clock:
 * prepare - clk_(un)prepare only ensures parent is (un)prepared
 * enable - clk_enable and clk_disable are functional
 * rate - set rate is functional
 * parent - fixed parent.  No clk_set_parent support
 */

/**
 * struct st_clk_quadfs_fsynth - One clock output from a four channel digital
 *                                  frequency synthesizer (fsynth) block.
 *
 * @hw: handle between common and hardware-specific interfaces
 *
 * @nsb: regmap field in the output control register for the digital
 *       standby of this fsynth channel. This control is active low so
 *       the channel is in standby when the control bit is cleared.
 *
 * @nsdiv: regmap field in the output control register for
 *          for the optional divide by 3 of this fsynth channel. This control
 *          is active low so the divide by 3 is active when the control bit is
 *          cleared and the divide is bypassed when the bit is set.
 */
struct st_clk_quadfs_fsynth {
        struct clk_hw   hw;
        void __iomem    *regs_base;
        spinlock_t      *lock;
        struct clkgen_quadfs_data *data;

        u32 chan;
        /*
         * Cached hardware values from set_rate so we can program the
         * hardware in enable. There are two reasons for this:
         *
         *  1. The registers may not be writable until the parent has been
         *     enabled.
         *
         *  2. It restores the clock rate when a driver does an enable
         *     on PM restore, after a suspend to RAM has lost the hardware
         *     setup.
         */
        u32 md;
        u32 pe;
        u32 sdiv;
        u32 nsdiv;
};

#define to_quadfs_fsynth(_hw) \
        container_of(_hw, struct st_clk_quadfs_fsynth, hw)

static void quadfs_fsynth_program_enable(struct st_clk_quadfs_fsynth *fs)
{
        /*
         * Pulse the program enable register lsb to make the hardware take
         * notice of the new md/pe values with a glitchless transition.
         */
        CLKGEN_WRITE(fs, en[fs->chan], 1);
        CLKGEN_WRITE(fs, en[fs->chan], 0);
}

static void quadfs_fsynth_program_rate(struct st_clk_quadfs_fsynth *fs)
{
        unsigned long flags = 0;

        /*
         * Ensure the md/pe parameters are ignored while we are
         * reprogramming them so we can get a glitchless change
         * when fine tuning the speed of a running clock.
         */
        CLKGEN_WRITE(fs, en[fs->chan], 0);

        CLKGEN_WRITE(fs, mdiv[fs->chan], fs->md);
        CLKGEN_WRITE(fs, pe[fs->chan], fs->pe);
        CLKGEN_WRITE(fs, sdiv[fs->chan], fs->sdiv);

        if (fs->lock)
                spin_lock_irqsave(fs->lock, flags);

        if (fs->data->nsdiv_present)
                CLKGEN_WRITE(fs, nsdiv[fs->chan], fs->nsdiv);

        if (fs->lock)
                spin_unlock_irqrestore(fs->lock, flags);
}

static int quadfs_fsynth_enable(struct clk_hw *hw)
{
        struct st_clk_quadfs_fsynth *fs = to_quadfs_fsynth(hw);
        unsigned long flags = 0;

        pr_debug("%s: %s\n", __func__, clk_hw_get_name(hw));

        quadfs_fsynth_program_rate(fs);

        if (fs->lock)
                spin_lock_irqsave(fs->lock, flags);

        CLKGEN_WRITE(fs, nsb[fs->chan], !fs->data->standby_polarity);

        if (fs->data->nrst_present)
                CLKGEN_WRITE(fs, nrst[fs->chan], 0);

        if (fs->lock)
                spin_unlock_irqrestore(fs->lock, flags);

        quadfs_fsynth_program_enable(fs);

        return 0;
}

static void quadfs_fsynth_disable(struct clk_hw *hw)
{
        struct st_clk_quadfs_fsynth *fs = to_quadfs_fsynth(hw);
        unsigned long flags = 0;

        pr_debug("%s: %s\n", __func__, clk_hw_get_name(hw));

        if (fs->lock)
                spin_lock_irqsave(fs->lock, flags);

        CLKGEN_WRITE(fs, nsb[fs->chan], fs->data->standby_polarity);

        if (fs->lock)
                spin_unlock_irqrestore(fs->lock, flags);
}

static int quadfs_fsynth_is_enabled(struct clk_hw *hw)
{
        struct st_clk_quadfs_fsynth *fs = to_quadfs_fsynth(hw);
        u32 nsb = CLKGEN_READ(fs, nsb[fs->chan]);

        pr_debug("%s: %s enable bit = 0x%x\n",
                 __func__, clk_hw_get_name(hw), nsb);

        return fs->data->standby_polarity ? !nsb : !!nsb;
}

#define P20             (uint64_t)(1 << 20)

static int clk_fs660c32_dig_get_rate(unsigned long input,
                                const struct stm_fs *fs, unsigned long *rate)
{
        unsigned long s = (1 << fs->sdiv);
        unsigned long ns;
        uint64_t res;

        /*
         * 'nsdiv' is a register value ('BIN') which is translated
         * to a decimal value according to following rules.
         *
         *     nsdiv      ns.dec
         *       0        3
         *       1        1
         */
        ns = (fs->nsdiv == 1) ? 1 : 3;

        res = (P20 * (32 + fs->mdiv) + 32 * fs->pe) * s * ns;
        *rate = (unsigned long)div64_u64(input * P20 * 32, res);

        return 0;
}


static int clk_fs660c32_get_pe(int m, int si, unsigned long *deviation,
                signed long input, unsigned long output, uint64_t *p,
                struct stm_fs *fs)
{
        unsigned long new_freq, new_deviation;
        struct stm_fs fs_tmp;
        uint64_t val;

        val = (uint64_t)output << si;

        *p = (uint64_t)input * P20 - (32LL  + (uint64_t)m) * val * (P20 / 32LL);

        *p = div64_u64(*p, val);

        if (*p > 32767LL)
                return 1;

        fs_tmp.mdiv = (unsigned long) m;
        fs_tmp.pe = (unsigned long)*p;
        fs_tmp.sdiv = si;
        fs_tmp.nsdiv = 1;

        clk_fs660c32_dig_get_rate(input, &fs_tmp, &new_freq);

        new_deviation = abs(output - new_freq);

        if (new_deviation < *deviation) {
                fs->mdiv = m;
                fs->pe = (unsigned long)*p;
                fs->sdiv = si;
                fs->nsdiv = 1;
                *deviation = new_deviation;
        }
        return 0;
}

static int clk_fs660c32_dig_get_params(unsigned long input,
                unsigned long output, struct stm_fs *fs)
{
        int si; /* sdiv_reg (8 downto 0) */
        int m; /* md value */
        unsigned long new_freq, new_deviation;
        /* initial condition to say: "infinite deviation" */
        unsigned long deviation = ~0;
        uint64_t p, p1, p2;     /* pe value */
        int r1, r2;

        struct stm_fs fs_tmp;

        for (si = 0; (si <= 8) && deviation; si++) {

                /* Boundary test to avoid useless iteration */
                r1 = clk_fs660c32_get_pe(0, si, &deviation,
                                input, output, &p1, fs);
                r2 = clk_fs660c32_get_pe(31, si, &deviation,
                                input, output, &p2, fs);

                /* No solution */
                if (r1 && r2 && (p1 > p2))
                        continue;

                /* Try to find best deviation */
                for (m = 1; (m < 31) && deviation; m++)
                        clk_fs660c32_get_pe(m, si, &deviation,
                                        input, output, &p, fs);

        }

        if (deviation == ~0) /* No solution found */
                return -1;

        /* pe fine tuning if deviation not 0: +/- 2 around computed pe value */
        if (deviation) {
                fs_tmp.mdiv = fs->mdiv;
                fs_tmp.sdiv = fs->sdiv;
                fs_tmp.nsdiv = fs->nsdiv;

                if (fs->pe > 2)
                        p2 = fs->pe - 2;
                else
                        p2 = 0;

                for (; p2 < 32768ll && (p2 <= (fs->pe + 2)); p2++) {
                        fs_tmp.pe = (unsigned long)p2;

                        clk_fs660c32_dig_get_rate(input, &fs_tmp, &new_freq);

                        new_deviation = abs(output - new_freq);

                        /* Check if this is a better solution */
                        if (new_deviation < deviation) {
                                fs->pe = (unsigned long)p2;
                                deviation = new_deviation;

                        }
                }
        }
        return 0;
}

static int quadfs_fsynt_get_hw_value_for_recalc(struct st_clk_quadfs_fsynth *fs,
                struct stm_fs *params)
{
        /*
         * Get the initial hardware values for recalc_rate
         */
        params->mdiv    = CLKGEN_READ(fs, mdiv[fs->chan]);
        params->pe      = CLKGEN_READ(fs, pe[fs->chan]);
        params->sdiv    = CLKGEN_READ(fs, sdiv[fs->chan]);

        if (fs->data->nsdiv_present)
                params->nsdiv = CLKGEN_READ(fs, nsdiv[fs->chan]);
        else
                params->nsdiv = 1;

        /*
         * If All are NULL then assume no clock rate is programmed.
         */
        if (!params->mdiv && !params->pe && !params->sdiv)
                return 1;

        fs->md = params->mdiv;
        fs->pe = params->pe;
        fs->sdiv = params->sdiv;
        fs->nsdiv = params->nsdiv;

        return 0;
}

static long quadfs_find_best_rate(struct clk_hw *hw, unsigned long drate,
                                unsigned long prate, struct stm_fs *params)
{
        struct st_clk_quadfs_fsynth *fs = to_quadfs_fsynth(hw);
        int (*clk_fs_get_rate)(unsigned long ,
                                const struct stm_fs *, unsigned long *);
        int (*clk_fs_get_params)(unsigned long, unsigned long, struct stm_fs *);
        unsigned long rate = 0;

        clk_fs_get_rate = fs->data->get_rate;
        clk_fs_get_params = fs->data->get_params;

        if (!clk_fs_get_params(prate, drate, params))
                clk_fs_get_rate(prate, params, &rate);

        return rate;
}

static unsigned long quadfs_recalc_rate(struct clk_hw *hw,
                unsigned long parent_rate)
{
        struct st_clk_quadfs_fsynth *fs = to_quadfs_fsynth(hw);
        unsigned long rate = 0;
        struct stm_fs params;
        int (*clk_fs_get_rate)(unsigned long ,
                                const struct stm_fs *, unsigned long *);

        clk_fs_get_rate = fs->data->get_rate;

        if (quadfs_fsynt_get_hw_value_for_recalc(fs, &params))
                return 0;

        if (clk_fs_get_rate(parent_rate, &params, &rate)) {
                pr_err("%s:%s error calculating rate\n",
                       clk_hw_get_name(hw), __func__);
        }

        pr_debug("%s:%s rate %lu\n", clk_hw_get_name(hw), __func__, rate);

        return rate;
}

static long quadfs_round_rate(struct clk_hw *hw, unsigned long rate,
                                     unsigned long *prate)
{
        struct stm_fs params;

        rate = quadfs_find_best_rate(hw, rate, *prate, &params);

        pr_debug("%s: %s new rate %ld [sdiv=0x%x,md=0x%x,pe=0x%x,nsdiv3=%u]\n",
                 __func__, clk_hw_get_name(hw),
                 rate, (unsigned int)params.sdiv, (unsigned int)params.mdiv,
                         (unsigned int)params.pe, (unsigned int)params.nsdiv);

        return rate;
}


static void quadfs_program_and_enable(struct st_clk_quadfs_fsynth *fs,
                struct stm_fs *params)
{
        fs->md = params->mdiv;
        fs->pe = params->pe;
        fs->sdiv = params->sdiv;
        fs->nsdiv = params->nsdiv;

        /*
         * In some integrations you can only change the fsynth programming when
         * the parent entity containing it is enabled.
         */
        quadfs_fsynth_program_rate(fs);
        quadfs_fsynth_program_enable(fs);
}

static int quadfs_set_rate(struct clk_hw *hw, unsigned long rate,
                                  unsigned long parent_rate)
{
        struct st_clk_quadfs_fsynth *fs = to_quadfs_fsynth(hw);
        struct stm_fs params;
        long hwrate;
        int uninitialized_var(i);

        if (!rate || !parent_rate)
                return -EINVAL;

        memset(&params, 0, sizeof(struct stm_fs));

        hwrate = quadfs_find_best_rate(hw, rate, parent_rate, &params);
        if (!hwrate)
                return -EINVAL;

        quadfs_program_and_enable(fs, &params);

        return 0;
}



static const struct clk_ops st_quadfs_ops = {
        .enable         = quadfs_fsynth_enable,
        .disable        = quadfs_fsynth_disable,
        .is_enabled     = quadfs_fsynth_is_enabled,
        .round_rate     = quadfs_round_rate,
        .set_rate       = quadfs_set_rate,
        .recalc_rate    = quadfs_recalc_rate,
};

static struct clk * __init st_clk_register_quadfs_fsynth(
                const char *name, const char *parent_name,
                struct clkgen_quadfs_data *quadfs, void __iomem *reg, u32 chan,
                unsigned long flags, spinlock_t *lock)
{
        struct st_clk_quadfs_fsynth *fs;
        struct clk *clk;
        struct clk_init_data init;

        /*
         * Sanity check required pointers, note that nsdiv3 is optional.
         */
        if (WARN_ON(!name || !parent_name))
                return ERR_PTR(-EINVAL);

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

        init.name = name;
        init.ops = &st_quadfs_ops;
        init.flags = flags | CLK_GET_RATE_NOCACHE | CLK_IS_BASIC;
        init.parent_names = &parent_name;
        init.num_parents = 1;

        fs->data = quadfs;
        fs->regs_base = reg;
        fs->chan = chan;
        fs->lock = lock;
        fs->hw.init = &init;

        clk = clk_register(NULL, &fs->hw);

        if (IS_ERR(clk))
                kfree(fs);

        return clk;
}

static void __init st_of_create_quadfs_fsynths(
                struct device_node *np, const char *pll_name,
                struct clkgen_quadfs_data *quadfs, void __iomem *reg,
                spinlock_t *lock)
{
        struct clk_onecell_data *clk_data;
        int fschan;

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

        clk_data->clk_num = QUADFS_MAX_CHAN;
        clk_data->clks = kcalloc(QUADFS_MAX_CHAN, sizeof(struct clk *),
                                 GFP_KERNEL);

        if (!clk_data->clks) {
                kfree(clk_data);
                return;
        }

        for (fschan = 0; fschan < QUADFS_MAX_CHAN; fschan++) {
                struct clk *clk;
                const char *clk_name;
                unsigned long flags = 0;

                if (of_property_read_string_index(np, "clock-output-names",
                                                  fschan, &clk_name)) {
                        break;
                }

                /*
                 * If we read an empty clock name then the channel is unused
                 */
                if (*clk_name == '\0')
                        continue;

                of_clk_detect_critical(np, fschan, &flags);

                clk = st_clk_register_quadfs_fsynth(clk_name, pll_name,
                                                    quadfs, reg, fschan,
                                                    flags, lock);

                /*
                 * If there was an error registering this clock output, clean
                 * up and move on to the next one.
                 */
                if (!IS_ERR(clk)) {
                        clk_data->clks[fschan] = clk;
                        pr_debug("%s: parent %s rate %u\n",
                                __clk_get_name(clk),
                                __clk_get_name(clk_get_parent(clk)),
                                (unsigned int)clk_get_rate(clk));
                }
        }

        of_clk_add_provider(np, of_clk_src_onecell_get, clk_data);
}

static void __init st_of_quadfs_setup(struct device_node *np,
                struct clkgen_quadfs_data *data)
{
        struct clk *clk;
        const char *pll_name, *clk_parent_name;
        void __iomem *reg;
        spinlock_t *lock;

        reg = of_iomap(np, 0);
        if (!reg)
                return;

        clk_parent_name = of_clk_get_parent_name(np, 0);
        if (!clk_parent_name)
                return;

        pll_name = kasprintf(GFP_KERNEL, "%s.pll", np->name);
        if (!pll_name)
                return;

        lock = kzalloc(sizeof(*lock), GFP_KERNEL);
        if (!lock)
                goto err_exit;

        spin_lock_init(lock);

        clk = st_clk_register_quadfs_pll(pll_name, clk_parent_name, data,
                        reg, lock);
        if (IS_ERR(clk))
                goto err_exit;
        else
                pr_debug("%s: parent %s rate %u\n",
                        __clk_get_name(clk),
                        __clk_get_name(clk_get_parent(clk)),
                        (unsigned int)clk_get_rate(clk));

        st_of_create_quadfs_fsynths(np, pll_name, data, reg, lock);

err_exit:
        kfree(pll_name); /* No longer need local copy of the PLL name */
}

static void __init st_of_quadfs660C_setup(struct device_node *np)
{
        st_of_quadfs_setup(np, (struct clkgen_quadfs_data *) &st_fs660c32_C);
}
CLK_OF_DECLARE(quadfs660C, "st,quadfs-pll", st_of_quadfs660C_setup);

static void __init st_of_quadfs660D_setup(struct device_node *np)
{
        st_of_quadfs_setup(np, (struct clkgen_quadfs_data *) &st_fs660c32_D);
}
CLK_OF_DECLARE(quadfs660D, "st,quadfs", st_of_quadfs660D_setup);