clk-max77686.c

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/*
 * clk-max77686.c - Clock driver for Maxim 77686
 *
 * Copyright (C) 2012 Samsung Electornics
 * Jonghwa Lee <[email protected]>
 *
 * 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;  either version 2 of the  License, or (at your
 * option) any later version.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/mfd/max77686.h>
#include <linux/mfd/max77686-private.h>
#include <linux/clk-provider.h>
#include <linux/mutex.h>
#include <linux/clkdev.h>

enum {
    MAX77686_CLK_AP = 0,
    MAX77686_CLK_CP,
    MAX77686_CLK_PMIC,
    MAX77686_CLKS_NUM,
};

struct max77686_clk {
    struct max77686_dev *iodev;
    u32 mask;
    struct clk_hw hw;
    struct clk_lookup *lookup;
};

static struct max77686_clk *get_max77686_clk(struct clk_hw *hw)
{
    return container_of(hw, struct max77686_clk, hw);
}

static int max77686_clk_prepare(struct clk_hw *hw)
{
    struct max77686_clk *max77686;
    int ret;

    max77686 = get_max77686_clk(hw);
    if (!max77686)
        return -ENOMEM;

    ret = regmap_update_bits(max77686->iodev->regmap,
        MAX77686_REG_32KHZ, max77686->mask, max77686->mask);

    return ret;
}

static void max77686_clk_unprepare(struct clk_hw *hw)
{
    struct max77686_clk *max77686;

    max77686 = get_max77686_clk(hw);
    if (!max77686)
        return;

    regmap_update_bits(max77686->iodev->regmap,
        MAX77686_REG_32KHZ, max77686->mask, ~max77686->mask);
}

static int max77686_clk_is_enabled(struct clk_hw *hw)
{
    struct max77686_clk *max77686;
    int ret;
    u32 val;

    max77686 = get_max77686_clk(hw);
    if (!max77686)
        return -ENOMEM;

    ret = regmap_read(max77686->iodev->regmap,
                MAX77686_REG_32KHZ, &val);

    if (ret < 0)
        return -EINVAL;

    return val & max77686->mask;
}

static struct clk_ops max77686_clk_ops = {
    .prepare    = max77686_clk_prepare,
    .unprepare  = max77686_clk_unprepare,
    .is_enabled = max77686_clk_is_enabled,
};

static struct clk_init_data max77686_clks_init[MAX77686_CLKS_NUM] = {
    [MAX77686_CLK_AP] = {
        .name = "32khz_ap",
        .ops = &max77686_clk_ops,
        .flags = CLK_IS_ROOT,
    },
    [MAX77686_CLK_CP] = {
        .name = "32khz_cp",
        .ops = &max77686_clk_ops,
        .flags = CLK_IS_ROOT,
    },
    [MAX77686_CLK_PMIC] = {
        .name = "32khz_pmic",
        .ops = &max77686_clk_ops,
        .flags = CLK_IS_ROOT,
    },
};

static int max77686_clk_register(struct device *dev,
                struct max77686_clk *max77686)
{
    struct clk *clk;
    struct clk_hw *hw = &max77686->hw;

    clk = clk_register(dev, hw);

    if (IS_ERR(clk))
        return -ENOMEM;

    max77686->lookup = devm_kzalloc(dev, sizeof(struct clk_lookup),
                    GFP_KERNEL);
    if (IS_ERR(max77686->lookup))
        return -ENOMEM;

    max77686->lookup->con_id = hw->init->name;
    max77686->lookup->clk = clk;

    clkdev_add(max77686->lookup);

    return 0;
}

static __devinit int max77686_clk_probe(struct platform_device *pdev)
{
    struct max77686_dev *iodev = dev_get_drvdata(pdev->dev.parent);
    struct max77686_clk **max77686_clks;
    int i, ret;

    max77686_clks = devm_kzalloc(&pdev->dev, sizeof(struct max77686_clk *)
                    * MAX77686_CLKS_NUM, GFP_KERNEL);
    if (IS_ERR(max77686_clks))
        return -ENOMEM;

    for (i = 0; i < MAX77686_CLKS_NUM; i++) {
        max77686_clks[i] = devm_kzalloc(&pdev->dev,
                    sizeof(struct max77686_clk), GFP_KERNEL);
        if (IS_ERR(max77686_clks[i]))
            return -ENOMEM;
    }

    for (i = 0; i < MAX77686_CLKS_NUM; i++) {
        max77686_clks[i]->iodev = iodev;
        max77686_clks[i]->mask = 1 << i;
        max77686_clks[i]->hw.init = &max77686_clks_init[i];

        ret = max77686_clk_register(&pdev->dev, max77686_clks[i]);
        if (ret) {
            switch (i) {
            case MAX77686_CLK_AP:
                dev_err(&pdev->dev, "Fail to register CLK_AP\n");
                goto err_clk_ap;
                break;
            case MAX77686_CLK_CP:
                dev_err(&pdev->dev, "Fail to register CLK_CP\n");
                goto err_clk_cp;
                break;
            case MAX77686_CLK_PMIC:
                dev_err(&pdev->dev, "Fail to register CLK_PMIC\n");
                goto err_clk_pmic;
            }
        }
    }

    platform_set_drvdata(pdev, max77686_clks);

    goto out;

err_clk_pmic:
    clkdev_drop(max77686_clks[MAX77686_CLK_CP]->lookup);
    kfree(max77686_clks[MAX77686_CLK_CP]->hw.clk);
err_clk_cp:
    clkdev_drop(max77686_clks[MAX77686_CLK_AP]->lookup);
    kfree(max77686_clks[MAX77686_CLK_AP]->hw.clk);
err_clk_ap:
out:
    return ret;
}

static int __devexit max77686_clk_remove(struct platform_device *pdev)
{
    struct max77686_clk **max77686_clks = platform_get_drvdata(pdev);
    int i;

    for (i = 0; i < MAX77686_CLKS_NUM; i++) {
        clkdev_drop(max77686_clks[i]->lookup);
        kfree(max77686_clks[i]->hw.clk);
    }
    return 0;
}

static const struct platform_device_id max77686_clk_id[] = {
    { "max77686-clk", 0},
    { },
};
MODULE_DEVICE_TABLE(platform, max77686_clk_id);

static struct platform_driver max77686_clk_driver = {
    .driver = {
        .name  = "max77686-clk",
        .owner = THIS_MODULE,
    },
    .probe = max77686_clk_probe,
    .remove = __devexit_p(max77686_clk_remove),
    .id_table = max77686_clk_id,
};

static int __init max77686_clk_init(void)
{
    return platform_driver_register(&max77686_clk_driver);
}
subsys_initcall(max77686_clk_init);

static void __init max77686_clk_cleanup(void)
{
    platform_driver_unregister(&max77686_clk_driver);
}
module_exit(max77686_clk_cleanup);

MODULE_DESCRIPTION("MAXIM 77686 Clock Driver");
MODULE_AUTHOR("Jonghwa Lee <[email protected]>");
MODULE_LICENSE("GPL");