clk-aux-synth.c

Go to the documentation of this file.

/*
 * Copyright (C) 2012 ST Microelectronics
 * Viresh Kumar <[email protected]>
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 *
 * Auxiliary Synthesizer clock implementation
 */

#define pr_fmt(fmt) "clk-aux-synth: " fmt

#include <linux/clk-provider.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/err.h>
#include "clk.h"

/*
 * DOC: Auxiliary Synthesizer clock
 *
 * Aux synth gives rate for different values of eq, x and y
 *
 * Fout from synthesizer can be given from two equations:
 * Fout1 = (Fin * X/Y)/2        EQ1
 * Fout2 = Fin * X/Y            EQ2
 */

#define to_clk_aux(_hw) container_of(_hw, struct clk_aux, hw)

static struct aux_clk_masks default_aux_masks = {
    .eq_sel_mask = AUX_EQ_SEL_MASK,
    .eq_sel_shift = AUX_EQ_SEL_SHIFT,
    .eq1_mask = AUX_EQ1_SEL,
    .eq2_mask = AUX_EQ2_SEL,
    .xscale_sel_mask = AUX_XSCALE_MASK,
    .xscale_sel_shift = AUX_XSCALE_SHIFT,
    .yscale_sel_mask = AUX_YSCALE_MASK,
    .yscale_sel_shift = AUX_YSCALE_SHIFT,
    .enable_bit = AUX_SYNT_ENB,
};

static unsigned long aux_calc_rate(struct clk_hw *hw, unsigned long prate,
        int index)
{
    struct clk_aux *aux = to_clk_aux(hw);
    struct aux_rate_tbl *rtbl = aux->rtbl;
    u8 eq = rtbl[index].eq ? 1 : 2;

    return (((prate / 10000) * rtbl[index].xscale) /
            (rtbl[index].yscale * eq)) * 10000;
}

static long clk_aux_round_rate(struct clk_hw *hw, unsigned long drate,
        unsigned long *prate)
{
    struct clk_aux *aux = to_clk_aux(hw);
    int unused;

    return clk_round_rate_index(hw, drate, *prate, aux_calc_rate,
            aux->rtbl_cnt, &unused);
}

static unsigned long clk_aux_recalc_rate(struct clk_hw *hw,
        unsigned long parent_rate)
{
    struct clk_aux *aux = to_clk_aux(hw);
    unsigned int num = 1, den = 1, val, eqn;
    unsigned long flags = 0;

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

    val = readl_relaxed(aux->reg);

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

    eqn = (val >> aux->masks->eq_sel_shift) & aux->masks->eq_sel_mask;
    if (eqn == aux->masks->eq1_mask)
        den = 2;

    /* calculate numerator */
    num = (val >> aux->masks->xscale_sel_shift) &
        aux->masks->xscale_sel_mask;

    /* calculate denominator */
    den *= (val >> aux->masks->yscale_sel_shift) &
        aux->masks->yscale_sel_mask;

    if (!den)
        return 0;

    return (((parent_rate / 10000) * num) / den) * 10000;
}

/* Configures new clock rate of aux */
static int clk_aux_set_rate(struct clk_hw *hw, unsigned long drate,
                unsigned long prate)
{
    struct clk_aux *aux = to_clk_aux(hw);
    struct aux_rate_tbl *rtbl = aux->rtbl;
    unsigned long val, flags = 0;
    int i;

    clk_round_rate_index(hw, drate, prate, aux_calc_rate, aux->rtbl_cnt,
            &i);

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

    val = readl_relaxed(aux->reg) &
        ~(aux->masks->eq_sel_mask << aux->masks->eq_sel_shift);
    val |= (rtbl[i].eq & aux->masks->eq_sel_mask) <<
        aux->masks->eq_sel_shift;
    val &= ~(aux->masks->xscale_sel_mask << aux->masks->xscale_sel_shift);
    val |= (rtbl[i].xscale & aux->masks->xscale_sel_mask) <<
        aux->masks->xscale_sel_shift;
    val &= ~(aux->masks->yscale_sel_mask << aux->masks->yscale_sel_shift);
    val |= (rtbl[i].yscale & aux->masks->yscale_sel_mask) <<
        aux->masks->yscale_sel_shift;
    writel_relaxed(val, aux->reg);

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

    return 0;
}

static struct clk_ops clk_aux_ops = {
    .recalc_rate = clk_aux_recalc_rate,
    .round_rate = clk_aux_round_rate,
    .set_rate = clk_aux_set_rate,
};

struct clk *clk_register_aux(const char *aux_name, const char *gate_name,
        const char *parent_name, unsigned long flags, void __iomem *reg,
        struct aux_clk_masks *masks, struct aux_rate_tbl *rtbl,
        u8 rtbl_cnt, spinlock_t *lock, struct clk **gate_clk)
{
    struct clk_aux *aux;
    struct clk_init_data init;
    struct clk *clk;

    if (!aux_name || !parent_name || !reg || !rtbl || !rtbl_cnt) {
        pr_err("Invalid arguments passed");
        return ERR_PTR(-EINVAL);
    }

    aux = kzalloc(sizeof(*aux), GFP_KERNEL);
    if (!aux) {
        pr_err("could not allocate aux clk\n");
        return ERR_PTR(-ENOMEM);
    }

    /* struct clk_aux assignments */
    if (!masks)
        aux->masks = &default_aux_masks;
    else
        aux->masks = masks;

    aux->reg = reg;
    aux->rtbl = rtbl;
    aux->rtbl_cnt = rtbl_cnt;
    aux->lock = lock;
    aux->hw.init = &init;

    init.name = aux_name;
    init.ops = &clk_aux_ops;
    init.flags = flags;
    init.parent_names = &parent_name;
    init.num_parents = 1;

    clk = clk_register(NULL, &aux->hw);
    if (IS_ERR_OR_NULL(clk))
        goto free_aux;

    if (gate_name) {
        struct clk *tgate_clk;

        tgate_clk = clk_register_gate(NULL, gate_name, aux_name, 0, reg,
                aux->masks->enable_bit, 0, lock);
        if (IS_ERR_OR_NULL(tgate_clk))
            goto free_aux;

        if (gate_clk)
            *gate_clk = tgate_clk;
    }

    return clk;

free_aux:
    kfree(aux);
    pr_err("clk register failed\n");

    return NULL;
}