clk-icst.c

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/*
 * Driver for the ICST307 VCO clock found in the ARM Reference designs.
 * We wrap the custom interface from <asm/hardware/icst.h> into the generic
 * clock framework.
 *
 * TODO: when all ARM reference designs are migrated to generic clocks, the
 * ICST clock code from the ARM tree should probably be merged into this
 * file.
 */
#include <linux/clk.h>
#include <linux/clkdev.h>
#include <linux/err.h>
#include <linux/clk-provider.h>

#include "clk-icst.h"

struct clk_icst {
    struct clk_hw hw;
    const struct icst_params *params;
    unsigned long rate;
    struct icst_vco (*getvco)(void);
    void (*setvco)(struct icst_vco);
};

#define to_icst(_hw) container_of(_hw, struct clk_icst, hw)

static unsigned long icst_recalc_rate(struct clk_hw *hw,
                      unsigned long parent_rate)
{
    struct clk_icst *icst = to_icst(hw);
    struct icst_vco vco;

    vco = icst->getvco();
    icst->rate = icst_hz(icst->params, vco);
    return icst->rate;
}

static long icst_round_rate(struct clk_hw *hw, unsigned long rate,
                unsigned long *prate)
{
    struct clk_icst *icst = to_icst(hw);
    struct icst_vco vco;

    vco = icst_hz_to_vco(icst->params, rate);
    return icst_hz(icst->params, vco);
}

static int icst_set_rate(struct clk_hw *hw, unsigned long rate,
             unsigned long parent_rate)
{
    struct clk_icst *icst = to_icst(hw);
    struct icst_vco vco;

    vco = icst_hz_to_vco(icst->params, rate);
    icst->rate = icst_hz(icst->params, vco);
    icst->setvco(vco);
    return 0;
}

static const struct clk_ops icst_ops = {
    .recalc_rate = icst_recalc_rate,
    .round_rate = icst_round_rate,
    .set_rate = icst_set_rate,
};

struct clk * __init icst_clk_register(struct device *dev,
                      const struct clk_icst_desc *desc)
{
    struct clk *clk;
    struct clk_icst *icst;
    struct clk_init_data init;

    icst = kzalloc(sizeof(struct clk_icst), GFP_KERNEL);
    if (!icst) {
        pr_err("could not allocate ICST clock!\n");
        return ERR_PTR(-ENOMEM);
    }
    init.name = "icst";
    init.ops = &icst_ops;
    init.flags = CLK_IS_ROOT;
    init.parent_names = NULL;
    init.num_parents = 0;
    icst->hw.init = &init;
    icst->params = desc->params;
    icst->getvco = desc->getvco;
    icst->setvco = desc->setvco;

    clk = clk_register(dev, &icst->hw);
    if (IS_ERR(clk))
        kfree(icst);

    return clk;
}