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/*
* clk-max77686.c - Clock driver for Maxim 77686
*
* Copyright (C) 2012 Samsung Electornics
* Jonghwa Lee <jonghwa3.lee@samsung.com>
*
* 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 *to_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 = to_max77686_clk(hw);

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

static void max77686_clk_unprepare(struct clk_hw *hw)
{
struct max77686_clk *max77686 = to_max77686_clk(hw);

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

static int max77686_clk_is_prepared(struct clk_hw *hw)
{
struct max77686_clk *max77686 = to_max77686_clk(hw);
int ret;
u32 val;

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

if (ret < 0)
return -EINVAL;

return val & max77686->mask;
}

static unsigned long max77686_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
return 32768;
}

static struct clk_ops max77686_clk_ops = {
.prepare = max77686_clk_prepare,
.unprepare = max77686_clk_unprepare,
.is_prepared = max77686_clk_is_prepared,
.recalc_rate = max77686_recalc_rate,
};

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 struct clk *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 clk;

max77686->lookup = kzalloc(sizeof(struct clk_lookup), GFP_KERNEL);
if (!max77686->lookup)
return ERR_PTR(-ENOMEM);

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

clkdev_add(max77686->lookup);

return clk;
}

static int max77686_clk_probe(struct platform_device *pdev)
{
struct max77686_dev *iodev = dev_get_drvdata(pdev->dev.parent);
struct max77686_clk *max77686_clks[MAX77686_CLKS_NUM];
struct clk **clocks;
int i, ret;

clocks = devm_kzalloc(&pdev->dev, sizeof(struct clk *)
* MAX77686_CLKS_NUM, GFP_KERNEL);
if (!clocks)
return -ENOMEM;

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

clocks[i] = max77686_clk_register(&pdev->dev, max77686_clks[i]);
if (IS_ERR(clocks[i])) {
ret = PTR_ERR(clocks[i]);
dev_err(&pdev->dev, "failed to register %s\n",
max77686_clks[i]->hw.init->name);
goto err_clocks;
}
}

platform_set_drvdata(pdev, clocks);

if (iodev->dev->of_node) {
struct clk_onecell_data *of_data;

of_data = devm_kzalloc(&pdev->dev,
sizeof(*of_data), GFP_KERNEL);
if (!of_data) {
ret = -ENOMEM;
goto err_clocks;
}

of_data->clks = clocks;
of_data->clk_num = MAX77686_CLKS_NUM;
ret = of_clk_add_provider(iodev->dev->of_node,
of_clk_src_onecell_get, of_data);
if (ret) {
dev_err(&pdev->dev, "failed to register OF clock provider\n");
goto err_clocks;
}
}

return 0;

err_clocks:
for (--i; i >= 0; --i) {
clkdev_drop(max77686_clks[i]->lookup);
clk_unregister(max77686_clks[i]->hw.clk);
}

return ret;
}

static int max77686_clk_remove(struct platform_device *pdev)
{
struct max77686_dev *iodev = dev_get_drvdata(pdev->dev.parent);
struct clk **clocks = platform_get_drvdata(pdev);
int i;

if (iodev->dev->of_node)
of_clk_del_provider(iodev->dev->of_node);

for (i = 0; i < MAX77686_CLKS_NUM; i++) {
struct clk_hw *hw = __clk_get_hw(clocks[i]);
struct max77686_clk *max77686 = to_max77686_clk(hw);

clkdev_drop(max77686->lookup);
clk_unregister(clocks[i]);
}
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 = 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 <jonghwa3.lee@samsung.com>");
MODULE_LICENSE("GPL");
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