/*
   * clk-s2mps11.c - Clock driver for S2MPS11.
   *
   * Copyright (C) 2013 Samsung Electornics
   *
   * 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/module.h>
  #include <linux/err.h>
  #include <linux/of.h>
  #include <linux/clkdev.h>
  #include <linux/regmap.h>
  #include <linux/clk-provider.h>
  #include <linux/platform_device.h>
  #include <linux/mfd/samsung/s2mps11.h>
  #include <linux/mfd/samsung/core.h>
  
  #define s2mps11_name(a) (a->hw.init->name)
  
  static struct clk **clk_table;
  static struct clk_onecell_data clk_data;
  
  enum {
  	S2MPS11_CLK_AP = 0,
  	S2MPS11_CLK_CP,
  	S2MPS11_CLK_BT,
  	S2MPS11_CLKS_NUM,
  };
  
  struct s2mps11_clk {
  	struct sec_pmic_dev *iodev;
  	struct clk_hw hw;
  	struct clk *clk;
  	struct clk_lookup *lookup;
  	u32 mask;
  	bool enabled;
  };
  
  static struct s2mps11_clk *to_s2mps11_clk(struct clk_hw *hw)
  {
  	return container_of(hw, struct s2mps11_clk, hw);
  }
  
  static int s2mps11_clk_prepare(struct clk_hw *hw)
  {
  	struct s2mps11_clk *s2mps11 = to_s2mps11_clk(hw);
  	int ret;
  
  	ret = regmap_update_bits(s2mps11->iodev->regmap_pmic,
  				S2MPS11_REG_RTC_CTRL,
  				 s2mps11->mask, s2mps11->mask);
  	if (!ret)
  		s2mps11->enabled = true;
  
  	return ret;
  }
  
  static void s2mps11_clk_unprepare(struct clk_hw *hw)
  {
  	struct s2mps11_clk *s2mps11 = to_s2mps11_clk(hw);
  	int ret;
  
  	ret = regmap_update_bits(s2mps11->iodev->regmap_pmic, S2MPS11_REG_RTC_CTRL,
  			   s2mps11->mask, ~s2mps11->mask);
  
  	if (!ret)
  		s2mps11->enabled = false;
  }
  
  static int s2mps11_clk_is_enabled(struct clk_hw *hw)
  {
  	struct s2mps11_clk *s2mps11 = to_s2mps11_clk(hw);
  
  	return s2mps11->enabled;
  }
  
  static unsigned long s2mps11_clk_recalc_rate(struct clk_hw *hw,
  					     unsigned long parent_rate)
  {
  	struct s2mps11_clk *s2mps11 = to_s2mps11_clk(hw);
  	if (s2mps11->enabled)
  		return 32768;
  	else
  		return 0;
  }
  
  static struct clk_ops s2mps11_clk_ops = {
  	.prepare	= s2mps11_clk_prepare,
  	.unprepare	= s2mps11_clk_unprepare,
  	.is_enabled	= s2mps11_clk_is_enabled,
  	.recalc_rate	= s2mps11_clk_recalc_rate,
  };
  
  static struct clk_init_data s2mps11_clks_init[S2MPS11_CLKS_NUM] = {
  	[S2MPS11_CLK_AP] = {
  		.name = "s2mps11_ap",
  		.ops = &s2mps11_clk_ops,
  		.flags = CLK_IS_ROOT,
  	},
  	[S2MPS11_CLK_CP] = {
  		.name = "s2mps11_cp",
  		.ops = &s2mps11_clk_ops,
  		.flags = CLK_IS_ROOT,
  	},
  	[S2MPS11_CLK_BT] = {
  		.name = "s2mps11_bt",
  		.ops = &s2mps11_clk_ops,
  		.flags = CLK_IS_ROOT,
  	},
  };
  
  static struct device_node *s2mps11_clk_parse_dt(struct platform_device *pdev)
  {
  	struct sec_pmic_dev *iodev = dev_get_drvdata(pdev->dev.parent);
  	struct device_node *clk_np;
  	int i;
  
  	if (!iodev->dev->of_node)
  		return ERR_PTR(-EINVAL);
  
  	clk_np = of_find_node_by_name(iodev->dev->of_node, "clocks");
  	if (!clk_np) {
  		dev_err(&pdev->dev, "could not find clock sub-node
  ");
  		return ERR_PTR(-EINVAL);
  	}
  
  	clk_table = devm_kzalloc(&pdev->dev, sizeof(struct clk *) *
  				 S2MPS11_CLKS_NUM, GFP_KERNEL);
  	if (!clk_table)
  		return ERR_PTR(-ENOMEM);
  
  	for (i = 0; i < S2MPS11_CLKS_NUM; i++)
  		of_property_read_string_index(clk_np, "clock-output-names", i,
  				&s2mps11_clks_init[i].name);
  
  	return clk_np;
  }
  
  static int s2mps11_clk_probe(struct platform_device *pdev)
  {
  	struct sec_pmic_dev *iodev = dev_get_drvdata(pdev->dev.parent);
  	struct s2mps11_clk *s2mps11_clks, *s2mps11_clk;
  	struct device_node *clk_np = NULL;
  	int i, ret = 0;
  	u32 val;
  
  	s2mps11_clks = devm_kzalloc(&pdev->dev, sizeof(*s2mps11_clk) *
  					S2MPS11_CLKS_NUM, GFP_KERNEL);
  	if (!s2mps11_clks)
  		return -ENOMEM;
  
  	s2mps11_clk = s2mps11_clks;
  
  	clk_np = s2mps11_clk_parse_dt(pdev);
  	if (IS_ERR(clk_np))
  		return PTR_ERR(clk_np);
  
  	for (i = 0; i < S2MPS11_CLKS_NUM; i++, s2mps11_clk++) {
  		s2mps11_clk->iodev = iodev;
  		s2mps11_clk->hw.init = &s2mps11_clks_init[i];
  		s2mps11_clk->mask = 1 << i;
  
  		ret = regmap_read(s2mps11_clk->iodev->regmap_pmic,
  				  S2MPS11_REG_RTC_CTRL, &val);
  		if (ret < 0)
  			goto err_reg;
  
  		s2mps11_clk->enabled = val & s2mps11_clk->mask;
  
  		s2mps11_clk->clk = devm_clk_register(&pdev->dev,
  							&s2mps11_clk->hw);
  		if (IS_ERR(s2mps11_clk->clk)) {
  			dev_err(&pdev->dev, "Fail to register : %s
  ",
  						s2mps11_name(s2mps11_clk));
  			ret = PTR_ERR(s2mps11_clk->clk);
  			goto err_reg;
  		}
  
  		s2mps11_clk->lookup = clkdev_alloc(s2mps11_clk->clk,
  					s2mps11_name(s2mps11_clk), NULL);
  		if (!s2mps11_clk->lookup) {
  			ret = -ENOMEM;
  			goto err_lup;
  		}
  
  		clkdev_add(s2mps11_clk->lookup);
  	}
  
  	if (clk_table) {
  		for (i = 0; i < S2MPS11_CLKS_NUM; i++)
  			clk_table[i] = s2mps11_clks[i].clk;
  
  		clk_data.clks = clk_table;
  		clk_data.clk_num = S2MPS11_CLKS_NUM;
  		of_clk_add_provider(clk_np, of_clk_src_onecell_get, &clk_data);
  	}
  
  	platform_set_drvdata(pdev, s2mps11_clks);
  
  	return ret;
  err_lup:
  	devm_clk_unregister(&pdev->dev, s2mps11_clk->clk);
  err_reg:
  	while (s2mps11_clk > s2mps11_clks) {
  		if (s2mps11_clk->lookup) {
  			clkdev_drop(s2mps11_clk->lookup);
  			devm_clk_unregister(&pdev->dev, s2mps11_clk->clk);
  		}
  		s2mps11_clk--;
  	}
  
  	return ret;
  }
  
  static int s2mps11_clk_remove(struct platform_device *pdev)
  {
  	struct s2mps11_clk *s2mps11_clks = platform_get_drvdata(pdev);
  	int i;
  
  	for (i = 0; i < S2MPS11_CLKS_NUM; i++)
  		clkdev_drop(s2mps11_clks[i].lookup);
  
  	return 0;
  }
  
  static const struct platform_device_id s2mps11_clk_id[] = {
  	{ "s2mps11-clk", 0},
  	{ },
  };
  MODULE_DEVICE_TABLE(platform, s2mps11_clk_id);
  
  static struct platform_driver s2mps11_clk_driver = {
  	.driver = {
  		.name  = "s2mps11-clk",
  		.owner = THIS_MODULE,
  	},
  	.probe = s2mps11_clk_probe,
  	.remove = s2mps11_clk_remove,
  	.id_table = s2mps11_clk_id,
  };
  
  static int __init s2mps11_clk_init(void)
  {
  	return platform_driver_register(&s2mps11_clk_driver);
  }
  subsys_initcall(s2mps11_clk_init);
  
  static void __init s2mps11_clk_cleanup(void)
  {
  	platform_driver_unregister(&s2mps11_clk_driver);
  }
  module_exit(s2mps11_clk_cleanup);
  
  MODULE_DESCRIPTION("S2MPS11 Clock Driver");
  MODULE_AUTHOR("Yadwinder Singh Brar <yadi.brar@samsung.com>");
  MODULE_LICENSE("GPL");