/*
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation version 2.
 *
 * 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.h>
#include <linux/clk-provider.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/math64.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/clk/ti.h>

/* FAPLL Control Register PLL_CTRL */
#define FAPLL_MAIN_MULT_N_SHIFT 16
#define FAPLL_MAIN_DIV_P_SHIFT  8
#define FAPLL_MAIN_LOCK         BIT(7)
#define FAPLL_MAIN_PLLEN        BIT(3)
#define FAPLL_MAIN_BP           BIT(2)
#define FAPLL_MAIN_LOC_CTL      BIT(0)

#define FAPLL_MAIN_MAX_MULT_N   0xffff
#define FAPLL_MAIN_MAX_DIV_P    0xff
#define FAPLL_MAIN_CLEAR_MASK   \
        ((FAPLL_MAIN_MAX_MULT_N << FAPLL_MAIN_MULT_N_SHIFT) | \
         (FAPLL_MAIN_DIV_P_SHIFT << FAPLL_MAIN_DIV_P_SHIFT) | \
         FAPLL_MAIN_LOC_CTL)

/* FAPLL powerdown register PWD */
#define FAPLL_PWD_OFFSET        4

#define MAX_FAPLL_OUTPUTS       7
#define FAPLL_MAX_RETRIES       1000

#define to_fapll(_hw)           container_of(_hw, struct fapll_data, hw)
#define to_synth(_hw)           container_of(_hw, struct fapll_synth, hw)

/* The bypass bit is inverted on the ddr_pll.. */
#define fapll_is_ddr_pll(va)    (((u32)(va) & 0xffff) == 0x0440)

/*
 * The audio_pll_clk1 input is hard wired to the 27MHz bypass clock,
 * and the audio_pll_clk1 synthesizer is hardwared to 32KiHz output.
 */
#define is_ddr_pll_clk1(va)     (((u32)(va) & 0xffff) == 0x044c)
#define is_audio_pll_clk1(va)   (((u32)(va) & 0xffff) == 0x04a8)

/* Synthesizer divider register */
#define SYNTH_LDMDIV1           BIT(8)

/* Synthesizer frequency register */
#define SYNTH_LDFREQ            BIT(31)

#define SYNTH_PHASE_K           8
#define SYNTH_MAX_INT_DIV       0xf
#define SYNTH_MAX_DIV_M         0xff

struct fapll_data {
        struct clk_hw hw;
        void __iomem *base;
        const char *name;
        struct clk *clk_ref;
        struct clk *clk_bypass;
        struct clk_onecell_data outputs;
        bool bypass_bit_inverted;
};

struct fapll_synth {
        struct clk_hw hw;
        struct fapll_data *fd;
        int index;
        void __iomem *freq;
        void __iomem *div;
        const char *name;
        struct clk *clk_pll;
};

static bool ti_fapll_clock_is_bypass(struct fapll_data *fd)
{
        u32 v = readl_relaxed(fd->base);

        if (fd->bypass_bit_inverted)
                return !(v & FAPLL_MAIN_BP);
        else
                return !!(v & FAPLL_MAIN_BP);
}

static void ti_fapll_set_bypass(struct fapll_data *fd)
{
        u32 v = readl_relaxed(fd->base);

        if (fd->bypass_bit_inverted)
                v &= ~FAPLL_MAIN_BP;
        else
                v |= FAPLL_MAIN_BP;
        writel_relaxed(v, fd->base);
}

static void ti_fapll_clear_bypass(struct fapll_data *fd)
{
        u32 v = readl_relaxed(fd->base);

        if (fd->bypass_bit_inverted)
                v |= FAPLL_MAIN_BP;
        else
                v &= ~FAPLL_MAIN_BP;
        writel_relaxed(v, fd->base);
}

static int ti_fapll_wait_lock(struct fapll_data *fd)
{
        int retries = FAPLL_MAX_RETRIES;
        u32 v;

        while ((v = readl_relaxed(fd->base))) {
                if (v & FAPLL_MAIN_LOCK)
                        return 0;

                if (retries-- <= 0)
                        break;

                udelay(1);
        }

        pr_err("%s failed to lock\n", fd->name);

        return -ETIMEDOUT;
}

static int ti_fapll_enable(struct clk_hw *hw)
{
        struct fapll_data *fd = to_fapll(hw);
        u32 v = readl_relaxed(fd->base);

        v |= FAPLL_MAIN_PLLEN;
        writel_relaxed(v, fd->base);
        ti_fapll_wait_lock(fd);

        return 0;
}

static void ti_fapll_disable(struct clk_hw *hw)
{
        struct fapll_data *fd = to_fapll(hw);
        u32 v = readl_relaxed(fd->base);

        v &= ~FAPLL_MAIN_PLLEN;
        writel_relaxed(v, fd->base);
}

static int ti_fapll_is_enabled(struct clk_hw *hw)
{
        struct fapll_data *fd = to_fapll(hw);
        u32 v = readl_relaxed(fd->base);

        return v & FAPLL_MAIN_PLLEN;
}

static unsigned long ti_fapll_recalc_rate(struct clk_hw *hw,
                                          unsigned long parent_rate)
{
        struct fapll_data *fd = to_fapll(hw);
        u32 fapll_n, fapll_p, v;
        u64 rate;

        if (ti_fapll_clock_is_bypass(fd))
                return parent_rate;

        rate = parent_rate;

        /* PLL pre-divider is P and multiplier is N */
        v = readl_relaxed(fd->base);
        fapll_p = (v >> 8) & 0xff;
        if (fapll_p)
                do_div(rate, fapll_p);
        fapll_n = v >> 16;
        if (fapll_n)
                rate *= fapll_n;

        return rate;
}

static u8 ti_fapll_get_parent(struct clk_hw *hw)
{
        struct fapll_data *fd = to_fapll(hw);

        if (ti_fapll_clock_is_bypass(fd))
                return 1;

        return 0;
}

static int ti_fapll_set_div_mult(unsigned long rate,
                                 unsigned long parent_rate,
                                 u32 *pre_div_p, u32 *mult_n)
{
        /*
         * So far no luck getting decent clock with PLL divider,
         * PLL does not seem to lock and the signal does not look
         * right. It seems the divider can only be used together
         * with the multiplier?
         */
        if (rate < parent_rate) {
                pr_warn("FAPLL main divider rates unsupported\n");
                return -EINVAL;
        }

        *mult_n = rate / parent_rate;
        if (*mult_n > FAPLL_MAIN_MAX_MULT_N)
                return -EINVAL;
        *pre_div_p = 1;

        return 0;
}

static long ti_fapll_round_rate(struct clk_hw *hw, unsigned long rate,
                                unsigned long *parent_rate)
{
        u32 pre_div_p, mult_n;
        int error;

        if (!rate)
                return -EINVAL;

        error = ti_fapll_set_div_mult(rate, *parent_rate,
                                      &pre_div_p, &mult_n);
        if (error)
                return error;

        rate = *parent_rate / pre_div_p;
        rate *= mult_n;

        return rate;
}

static int ti_fapll_set_rate(struct clk_hw *hw, unsigned long rate,
                             unsigned long parent_rate)
{
        struct fapll_data *fd = to_fapll(hw);
        u32 pre_div_p, mult_n, v;
        int error;

        if (!rate)
                return -EINVAL;

        error = ti_fapll_set_div_mult(rate, parent_rate,
                                      &pre_div_p, &mult_n);
        if (error)
                return error;

        ti_fapll_set_bypass(fd);
        v = readl_relaxed(fd->base);
        v &= ~FAPLL_MAIN_CLEAR_MASK;
        v |= pre_div_p << FAPLL_MAIN_DIV_P_SHIFT;
        v |= mult_n << FAPLL_MAIN_MULT_N_SHIFT;
        writel_relaxed(v, fd->base);
        if (ti_fapll_is_enabled(hw))
                ti_fapll_wait_lock(fd);
        ti_fapll_clear_bypass(fd);

        return 0;
}

static const struct clk_ops ti_fapll_ops = {
        .enable = ti_fapll_enable,
        .disable = ti_fapll_disable,
        .is_enabled = ti_fapll_is_enabled,
        .recalc_rate = ti_fapll_recalc_rate,
        .get_parent = ti_fapll_get_parent,
        .round_rate = ti_fapll_round_rate,
        .set_rate = ti_fapll_set_rate,
};

static int ti_fapll_synth_enable(struct clk_hw *hw)
{
        struct fapll_synth *synth = to_synth(hw);
        u32 v = readl_relaxed(synth->fd->base + FAPLL_PWD_OFFSET);

        v &= ~(1 << synth->index);
        writel_relaxed(v, synth->fd->base + FAPLL_PWD_OFFSET);

        return 0;
}

static void ti_fapll_synth_disable(struct clk_hw *hw)
{
        struct fapll_synth *synth = to_synth(hw);
        u32 v = readl_relaxed(synth->fd->base + FAPLL_PWD_OFFSET);

        v |= 1 << synth->index;
        writel_relaxed(v, synth->fd->base + FAPLL_PWD_OFFSET);
}

static int ti_fapll_synth_is_enabled(struct clk_hw *hw)
{
        struct fapll_synth *synth = to_synth(hw);
        u32 v = readl_relaxed(synth->fd->base + FAPLL_PWD_OFFSET);

        return !(v & (1 << synth->index));
}

/*
 * See dm816x TRM chapter 1.10.3 Flying Adder PLL fore more info
 */
static unsigned long ti_fapll_synth_recalc_rate(struct clk_hw *hw,
                                                unsigned long parent_rate)
{
        struct fapll_synth *synth = to_synth(hw);
        u32 synth_div_m;
        u64 rate;

        /* The audio_pll_clk1 is hardwired to produce 32.768KiHz clock */
        if (!synth->div)
                return 32768;

        /*
         * PLL in bypass sets the synths in bypass mode too. The PLL rate
         * can be also be set to 27MHz, so we can't use parent_rate to
         * check for bypass mode.
         */
        if (ti_fapll_clock_is_bypass(synth->fd))
                return parent_rate;

        rate = parent_rate;

        /*
         * Synth frequency integer and fractional divider.
         * Note that the phase output K is 8, so the result needs
         * to be multiplied by SYNTH_PHASE_K.
         */
        if (synth->freq) {
                u32 v, synth_int_div, synth_frac_div, synth_div_freq;

                v = readl_relaxed(synth->freq);
                synth_int_div = (v >> 24) & 0xf;
                synth_frac_div = v & 0xffffff;
                synth_div_freq = (synth_int_div * 10000000) + synth_frac_div;
                rate *= 10000000;
                do_div(rate, synth_div_freq);
                rate *= SYNTH_PHASE_K;
        }

        /* Synth post-divider M */
        synth_div_m = readl_relaxed(synth->div) & SYNTH_MAX_DIV_M;

        return DIV_ROUND_UP_ULL(rate, synth_div_m);
}

static unsigned long ti_fapll_synth_get_frac_rate(struct clk_hw *hw,
                                                  unsigned long parent_rate)
{
        struct fapll_synth *synth = to_synth(hw);
        unsigned long current_rate, frac_rate;
        u32 post_div_m;

        current_rate = ti_fapll_synth_recalc_rate(hw, parent_rate);
        post_div_m = readl_relaxed(synth->div) & SYNTH_MAX_DIV_M;
        frac_rate = current_rate * post_div_m;

        return frac_rate;
}

static u32 ti_fapll_synth_set_frac_rate(struct fapll_synth *synth,
                                        unsigned long rate,
                                        unsigned long parent_rate)
{
        u32 post_div_m, synth_int_div = 0, synth_frac_div = 0, v;

        post_div_m = DIV_ROUND_UP_ULL((u64)parent_rate * SYNTH_PHASE_K, rate);
        post_div_m = post_div_m / SYNTH_MAX_INT_DIV;
        if (post_div_m > SYNTH_MAX_DIV_M)
                return -EINVAL;
        if (!post_div_m)
                post_div_m = 1;

        for (; post_div_m < SYNTH_MAX_DIV_M; post_div_m++) {
                synth_int_div = DIV_ROUND_UP_ULL((u64)parent_rate *
                                                 SYNTH_PHASE_K *
                                                 10000000,
                                                 rate * post_div_m);
                synth_frac_div = synth_int_div % 10000000;
                synth_int_div /= 10000000;

                if (synth_int_div <= SYNTH_MAX_INT_DIV)
                        break;
        }

        if (synth_int_div > SYNTH_MAX_INT_DIV)
                return -EINVAL;

        v = readl_relaxed(synth->freq);
        v &= ~0x1fffffff;
        v |= (synth_int_div & SYNTH_MAX_INT_DIV) << 24;
        v |= (synth_frac_div & 0xffffff);
        v |= SYNTH_LDFREQ;
        writel_relaxed(v, synth->freq);

        return post_div_m;
}

static long ti_fapll_synth_round_rate(struct clk_hw *hw, unsigned long rate,
                                      unsigned long *parent_rate)
{
        struct fapll_synth *synth = to_synth(hw);
        struct fapll_data *fd = synth->fd;
        unsigned long r;

        if (ti_fapll_clock_is_bypass(fd) || !synth->div || !rate)
                return -EINVAL;

        /* Only post divider m available with no fractional divider? */
        if (!synth->freq) {
                unsigned long frac_rate;
                u32 synth_post_div_m;

                frac_rate = ti_fapll_synth_get_frac_rate(hw, *parent_rate);
                synth_post_div_m = DIV_ROUND_UP(frac_rate, rate);
                r = DIV_ROUND_UP(frac_rate, synth_post_div_m);
                goto out;
        }

        r = *parent_rate * SYNTH_PHASE_K;
        if (rate > r)
                goto out;

        r = DIV_ROUND_UP_ULL(r, SYNTH_MAX_INT_DIV * SYNTH_MAX_DIV_M);
        if (rate < r)
                goto out;

        r = rate;
out:
        return r;
}

static int ti_fapll_synth_set_rate(struct clk_hw *hw, unsigned long rate,
                                   unsigned long parent_rate)
{
        struct fapll_synth *synth = to_synth(hw);
        struct fapll_data *fd = synth->fd;
        unsigned long frac_rate, post_rate = 0;
        u32 post_div_m = 0, v;

        if (ti_fapll_clock_is_bypass(fd) || !synth->div || !rate)
                return -EINVAL;

        /* Produce the rate with just post divider M? */
        frac_rate = ti_fapll_synth_get_frac_rate(hw, parent_rate);
        if (frac_rate < rate) {
                if (!synth->freq)
                        return -EINVAL;
        } else {
                post_div_m = DIV_ROUND_UP(frac_rate, rate);
                if (post_div_m && (post_div_m <= SYNTH_MAX_DIV_M))
                        post_rate = DIV_ROUND_UP(frac_rate, post_div_m);
                if (!synth->freq && !post_rate)
                        return -EINVAL;
        }

        /* Need to recalculate the fractional divider? */
        if ((post_rate != rate) && synth->freq)
                post_div_m = ti_fapll_synth_set_frac_rate(synth,
                                                          rate,
                                                          parent_rate);

        v = readl_relaxed(synth->div);
        v &= ~SYNTH_MAX_DIV_M;
        v |= post_div_m;
        v |= SYNTH_LDMDIV1;
        writel_relaxed(v, synth->div);

        return 0;
}

static const struct clk_ops ti_fapll_synt_ops = {
        .enable = ti_fapll_synth_enable,
        .disable = ti_fapll_synth_disable,
        .is_enabled = ti_fapll_synth_is_enabled,
        .recalc_rate = ti_fapll_synth_recalc_rate,
        .round_rate = ti_fapll_synth_round_rate,
        .set_rate = ti_fapll_synth_set_rate,
};

static struct clk * __init ti_fapll_synth_setup(struct fapll_data *fd,
                                                void __iomem *freq,
                                                void __iomem *div,
                                                int index,
                                                const char *name,
                                                const char *parent,
                                                struct clk *pll_clk)
{
        struct clk_init_data *init;
        struct fapll_synth *synth;

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

        init->ops = &ti_fapll_synt_ops;
        init->name = name;
        init->parent_names = &parent;
        init->num_parents = 1;

        synth = kzalloc(sizeof(*synth), GFP_KERNEL);
        if (!synth)
                goto free;

        synth->fd = fd;
        synth->index = index;
        synth->freq = freq;
        synth->div = div;
        synth->name = name;
        synth->hw.init = init;
        synth->clk_pll = pll_clk;

        return clk_register(NULL, &synth->hw);

free:
        kfree(synth);
        kfree(init);

        return ERR_PTR(-ENOMEM);
}

static void __init ti_fapll_setup(struct device_node *node)
{
        struct fapll_data *fd;
        struct clk_init_data *init = NULL;
        const char *parent_name[2];
        struct clk *pll_clk;
        int i;

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

        fd->outputs.clks = kzalloc(sizeof(struct clk *) *
                                   MAX_FAPLL_OUTPUTS + 1,
                                   GFP_KERNEL);
        if (!fd->outputs.clks)
                goto free;

        init = kzalloc(sizeof(*init), GFP_KERNEL);
        if (!init)
                goto free;

        init->ops = &ti_fapll_ops;
        init->name = node->name;

        init->num_parents = of_clk_get_parent_count(node);
        if (init->num_parents != 2) {
                pr_err("%pOFn must have two parents\n", node);
                goto free;
        }

        of_clk_parent_fill(node, parent_name, 2);
        init->parent_names = parent_name;

        fd->clk_ref = of_clk_get(node, 0);
        if (IS_ERR(fd->clk_ref)) {
                pr_err("%pOFn could not get clk_ref\n", node);
                goto free;
        }

        fd->clk_bypass = of_clk_get(node, 1);
        if (IS_ERR(fd->clk_bypass)) {
                pr_err("%pOFn could not get clk_bypass\n", node);
                goto free;
        }

        fd->base = of_iomap(node, 0);
        if (!fd->base) {
                pr_err("%pOFn could not get IO base\n", node);
                goto free;
        }

        if (fapll_is_ddr_pll(fd->base))
                fd->bypass_bit_inverted = true;

        fd->name = node->name;
        fd->hw.init = init;

        /* Register the parent PLL */
        pll_clk = clk_register(NULL, &fd->hw);
        if (IS_ERR(pll_clk))
                goto unmap;

        fd->outputs.clks[0] = pll_clk;
        fd->outputs.clk_num++;

        /*
         * Set up the child synthesizers starting at index 1 as the
         * PLL output is at index 0. We need to check the clock-indices
         * for numbering in case there are holes in the synth mapping,
         * and then probe the synth register to see if it has a FREQ
         * register available.
         */
        for (i = 0; i < MAX_FAPLL_OUTPUTS; i++) {
                const char *output_name;
                void __iomem *freq, *div;
                struct clk *synth_clk;
                int output_instance;
                u32 v;

                if (of_property_read_string_index(node, "clock-output-names",
                                                  i, &output_name))
                        continue;

                if (of_property_read_u32_index(node, "clock-indices", i,
                                               &output_instance))
                        output_instance = i;

                freq = fd->base + (output_instance * 8);
                div = freq + 4;

                /* Check for hardwired audio_pll_clk1 */
                if (is_audio_pll_clk1(freq)) {
                        freq = NULL;
                        div = NULL;
                } else {
                        /* Does the synthesizer have a FREQ register? */
                        v = readl_relaxed(freq);
                        if (!v)
                                freq = NULL;
                }
                synth_clk = ti_fapll_synth_setup(fd, freq, div, output_instance,
                                                 output_name, node->name,
                                                 pll_clk);
                if (IS_ERR(synth_clk))
                        continue;

                fd->outputs.clks[output_instance] = synth_clk;
                fd->outputs.clk_num++;

                clk_register_clkdev(synth_clk, output_name, NULL);
        }

        /* Register the child synthesizers as the FAPLL outputs */
        of_clk_add_provider(node, of_clk_src_onecell_get, &fd->outputs);
        /* Add clock alias for the outputs */

        kfree(init);

        return;

unmap:
        iounmap(fd->base);
free:
        if (fd->clk_bypass)
                clk_put(fd->clk_bypass);
        if (fd->clk_ref)
                clk_put(fd->clk_ref);
        kfree(fd->outputs.clks);
        kfree(fd);
        kfree(init);
}

CLK_OF_DECLARE(ti_fapll_clock, "ti,dm816-fapll-clock", ti_fapll_setup);