/*
<:copyright-BRCM:2018:DUAL/GPL:standard

   Copyright (c) 2018 Broadcom 
   All Rights Reserved

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License, version 2, as published by
the Free Software Foundation (the "GPL").

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.


A copy of the GPL is available at http://www.broadcom.com/licenses/GPLv2.php, or by
writing to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.

:>
*/

/*
 * Clock driver for bcm68560 based devices
 *
 *	Kevin Li <kevin-ke.li@broadcom.com>
 *
 */

#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/mfd/syscon.h>
#include <linux/slab.h>
#include <linux/regmap.h>

#define I2S_MCLK_CLKSEL_CLR_MASK       0x00F30000
#define I2S_MCLK_RATE_SHIFT            20 
#define I2S_CLKSEL_SHIFT               16 
#define I2S_CLK_100MHZ                 0
#define I2S_CLK_50MHZ                  1
#define I2S_CLK_25MHZ                  2
#define I2S_CLK_PLL                    3

#define I2S_CFG                        (0x0000)
#define I2S_SCLKS_PER_1FS_DIV32_SHIFT  4 
#define I2S_64BITS_PERFRAME            ( 2<<I2S_SCLKS_PER_1FS_DIV32_SHIFT )
#define I2S_SCLKS_PER_1FS_DIV32_MASK   ( 0x0f<<I2S_SCLKS_PER_1FS_DIV32_SHIFT )

struct clk_i2s_data {
  struct regmap *regmap_i2scfg;
};

struct clk_i2s {
	struct clk_hw hw;
	struct clk_i2s_data *i2s_data;
};

#define to_clk_i2s(_hw) container_of(_hw, struct clk_i2s, hw)

/* actual clock=64FS=MCLK/(2*Mclk_ratio) */
static int bcm_i2s_clk_set_rate(struct clk_hw *hw, unsigned long rate, unsigned long parent_rate)
{
   struct clk_i2s *clki2s     = to_clk_i2s(hw);
   struct clk_i2s_data *pdata = clki2s->i2s_data;
   
   regmap_update_bits(pdata->regmap_i2scfg, I2S_CFG, I2S_SCLKS_PER_1FS_DIV32_MASK, I2S_64BITS_PERFRAME );    
   regmap_update_bits(pdata->regmap_i2scfg, I2S_CFG, I2S_MCLK_CLKSEL_CLR_MASK, 0 );
   regmap_update_bits(pdata->regmap_i2scfg, I2S_CFG, I2S_MCLK_CLKSEL_CLR_MASK,
                                            DIV_ROUND_CLOSEST(parent_rate/rate,128) << I2S_MCLK_RATE_SHIFT | 
                                            I2S_CLK_50MHZ  << I2S_CLKSEL_SHIFT);

	return 0;
}

/* based on parent rate, re-calculate the rate and returns*/
static unsigned long bcm_i2s_clk_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
{
/* to do return smaple rate */
   return 0;
}
static long bcm_i2s_clk_round_rate(struct clk_hw *hw, unsigned long rate, unsigned long *parent_rate)
{
   return rate;
}

static const struct clk_ops clk_i2s_ops = {
  .set_rate    = bcm_i2s_clk_set_rate,
  .recalc_rate = bcm_i2s_clk_recalc_rate,
  .round_rate  = bcm_i2s_clk_round_rate,
};

static struct clk *bcm_i2s_clk_register(struct device *dev,
   const char *name,
   const char *parent_name,
   struct clk_i2s_data *i2s_data)
{
   struct clk_init_data init;
   struct clk_i2s *clki2s;
   struct clk *clk;
   clki2s = kzalloc(sizeof(*clki2s), GFP_KERNEL);
   if (!clki2s)
   {
      pr_err("%s: Out of memory\n", __func__);
      return ERR_PTR(-ENOMEM);
   }
   init.name  = name;
   init.ops   = &clk_i2s_ops;
   init.flags = 0;
   init.parent_names = (parent_name ? &parent_name : NULL);
   init.num_parents  = (parent_name ? 1 : 0);

   clki2s->i2s_data = i2s_data;
   clki2s->hw.init  = &init;

   clk = clk_register(NULL, &clki2s->hw);
   if (IS_ERR(clk))
   {
      kfree(clki2s);
   }
   return clk;
}

static void __init bcm_i2s_clk_init(struct device_node *node)
{
   const char *clk_name = node->name;
   const char *parent_name;
   struct clk_i2s_data *data;
   struct clk *clk;

   data = kzalloc(sizeof(*data), GFP_KERNEL);
   if (!data) {
      pr_err("%s: Out of memory\n", __func__);
      return;
   }

   data->regmap_i2scfg = syscon_regmap_lookup_by_phandle(node, "clk-mclk-syscon");
   if (IS_ERR(data->regmap_i2scfg)) {
     pr_err("%s(): %s: get regmap i2scfg failed\n",
          __func__, node->name);
      goto out;
   }

   of_property_read_string(node, "clock-output-names", &clk_name);
   parent_name = of_clk_get_parent_name(node, 0);
   if (!parent_name) {
      pr_err("%s(): %s: of_clk_get_parent_name() failed\n",
           __func__, node->name);
      goto out;
   }

   clk = bcm_i2s_clk_register(NULL, clk_name, parent_name, data);
   if (!IS_ERR(clk)) {
      of_clk_add_provider(node, of_clk_src_simple_get, clk);
      return;
   }
out:
   kfree(data);
   return;
}

static void __init of_bcm_i2s_clk_init(struct device_node *node)
{
   bcm_i2s_clk_init(node);
}
CLK_OF_DECLARE(bcm_gate_clk, "brcm,i2s-clock",	of_bcm_i2s_clk_init);