/*
   * Copyright (c) 2013, The Linux Foundation. All rights reserved.
   *
   * This software is licensed under the terms of the GNU General Public
   * License version 2, as published by the Free Software Foundation, and
   * may be copied, distributed, and modified under those terms.
   *
   * 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.
   */
  
  #include <linux/kernel.h>
  #include <linux/bitops.h>
  #include <linux/err.h>
  #include <linux/bug.h>
  #include <linux/delay.h>
  #include <linux/export.h>
  #include <linux/clk-provider.h>
  #include <linux/regmap.h>
  
  #include <asm/div64.h>
  
  #include "clk-pll.h"
  
  #define PLL_OUTCTRL		BIT(0)
  #define PLL_BYPASSNL		BIT(1)
  #define PLL_RESET_N		BIT(2)
  #define PLL_LOCK_COUNT_SHIFT	8
  #define PLL_LOCK_COUNT_MASK	0x3f
  #define PLL_BIAS_COUNT_SHIFT	14
  #define PLL_BIAS_COUNT_MASK	0x3f
  #define PLL_VOTE_FSM_ENA	BIT(20)
  #define PLL_VOTE_FSM_RESET	BIT(21)
  
  static int clk_pll_enable(struct clk_hw *hw)
  {
  	struct clk_pll *pll = to_clk_pll(hw);
  	int ret;
  	u32 mask, val;
  
  	mask = PLL_OUTCTRL | PLL_RESET_N | PLL_BYPASSNL;
  	ret = regmap_read(pll->clkr.regmap, pll->mode_reg, &val);
  	if (ret)
  		return ret;
  
  	/* Skip if already enabled or in FSM mode */
  	if ((val & mask) == mask || val & PLL_VOTE_FSM_ENA)
  		return 0;
  
  	/* Disable PLL bypass mode. */
  	ret = regmap_update_bits(pll->clkr.regmap, pll->mode_reg, PLL_BYPASSNL,
  				 PLL_BYPASSNL);
  	if (ret)
  		return ret;
  
  	/*
  	 * H/W requires a 5us delay between disabling the bypass and
  	 * de-asserting the reset. Delay 10us just to be safe.
  	 */
  	udelay(10);
  
  	/* De-assert active-low PLL reset. */
  	ret = regmap_update_bits(pll->clkr.regmap, pll->mode_reg, PLL_RESET_N,
  				 PLL_RESET_N);
  	if (ret)
  		return ret;
  
  	/* Wait until PLL is locked. */
  	udelay(50);
  
  	/* Enable PLL output. */
  	ret = regmap_update_bits(pll->clkr.regmap, pll->mode_reg, PLL_OUTCTRL,
  				 PLL_OUTCTRL);
  	if (ret)
  		return ret;
  
  	return 0;
  }
  
  static void clk_pll_disable(struct clk_hw *hw)
  {
  	struct clk_pll *pll = to_clk_pll(hw);
  	u32 mask;
  	u32 val;
  
  	regmap_read(pll->clkr.regmap, pll->mode_reg, &val);
  	/* Skip if in FSM mode */
  	if (val & PLL_VOTE_FSM_ENA)
  		return;
  	mask = PLL_OUTCTRL | PLL_RESET_N | PLL_BYPASSNL;
  	regmap_update_bits(pll->clkr.regmap, pll->mode_reg, mask, 0);
  }
  
  static unsigned long
  clk_pll_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
  {
  	struct clk_pll *pll = to_clk_pll(hw);
  	u32 l, m, n;
  	unsigned long rate;
  	u64 tmp;
  
  	regmap_read(pll->clkr.regmap, pll->l_reg, &l);
  	regmap_read(pll->clkr.regmap, pll->m_reg, &m);
  	regmap_read(pll->clkr.regmap, pll->n_reg, &n);
  
  	l &= 0x3ff;
  	m &= 0x7ffff;
  	n &= 0x7ffff;
  
  	rate = parent_rate * l;
  	if (n) {
  		tmp = parent_rate;
  		tmp *= m;
  		do_div(tmp, n);
  		rate += tmp;
  	}
  	return rate;
  }
  
  const struct clk_ops clk_pll_ops = {
  	.enable = clk_pll_enable,
  	.disable = clk_pll_disable,
  	.recalc_rate = clk_pll_recalc_rate,
  };
  EXPORT_SYMBOL_GPL(clk_pll_ops);
  
  static int wait_for_pll(struct clk_pll *pll)
  {
  	u32 val;
  	int count;
  	int ret;
  	const char *name = __clk_get_name(pll->clkr.hw.clk);
  
  	/* Wait for pll to enable. */
  	for (count = 200; count > 0; count--) {
  		ret = regmap_read(pll->clkr.regmap, pll->status_reg, &val);
  		if (ret)
  			return ret;
  		if (val & BIT(pll->status_bit))
  			return 0;
  		udelay(1);
  	}
  
  	WARN(1, "%s didn't enable after voting for it!
  ", name);
  	return -ETIMEDOUT;
  }
  
  static int clk_pll_vote_enable(struct clk_hw *hw)
  {
  	int ret;
  	struct clk_pll *p = to_clk_pll(__clk_get_hw(__clk_get_parent(hw->clk)));
  
  	ret = clk_enable_regmap(hw);
  	if (ret)
  		return ret;
  
  	return wait_for_pll(p);
  }
  
  const struct clk_ops clk_pll_vote_ops = {
  	.enable = clk_pll_vote_enable,
  	.disable = clk_disable_regmap,
  };
  EXPORT_SYMBOL_GPL(clk_pll_vote_ops);
  
  static void
  clk_pll_set_fsm_mode(struct clk_pll *pll, struct regmap *regmap)
  {
  	u32 val;
  	u32 mask;
  
  	/* De-assert reset to FSM */
  	regmap_update_bits(regmap, pll->mode_reg, PLL_VOTE_FSM_RESET, 0);
  
  	/* Program bias count and lock count */
  	val = 1 << PLL_BIAS_COUNT_SHIFT;
  	mask = PLL_BIAS_COUNT_MASK << PLL_BIAS_COUNT_SHIFT;
  	mask |= PLL_LOCK_COUNT_MASK << PLL_LOCK_COUNT_SHIFT;
  	regmap_update_bits(regmap, pll->mode_reg, mask, val);
  
  	/* Enable PLL FSM voting */
  	regmap_update_bits(regmap, pll->mode_reg, PLL_VOTE_FSM_ENA,
  		PLL_VOTE_FSM_ENA);
  }
  
  static void clk_pll_configure(struct clk_pll *pll, struct regmap *regmap,
  	const struct pll_config *config)
  {
  	u32 val;
  	u32 mask;
  
  	regmap_write(regmap, pll->l_reg, config->l);
  	regmap_write(regmap, pll->m_reg, config->m);
  	regmap_write(regmap, pll->n_reg, config->n);
  
  	val = config->vco_val;
  	val |= config->pre_div_val;
  	val |= config->post_div_val;
  	val |= config->mn_ena_mask;
  	val |= config->main_output_mask;
  	val |= config->aux_output_mask;
  
  	mask = config->vco_mask;
  	mask |= config->pre_div_mask;
  	mask |= config->post_div_mask;
  	mask |= config->mn_ena_mask;
  	mask |= config->main_output_mask;
  	mask |= config->aux_output_mask;
  
  	regmap_update_bits(regmap, pll->config_reg, mask, val);
  }
  
  void clk_pll_configure_sr_hpm_lp(struct clk_pll *pll, struct regmap *regmap,
  		const struct pll_config *config, bool fsm_mode)
  {
  	clk_pll_configure(pll, regmap, config);
  	if (fsm_mode)
  		clk_pll_set_fsm_mode(pll, regmap);
  }
  EXPORT_SYMBOL_GPL(clk_pll_configure_sr_hpm_lp);