/*
   * 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
  ",
  				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
  ");
  			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");