Eric Lee / smarc-fsl-linux-kernel

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drivers/clk/sunxi-ng/ccu_nm.c 2.93 KB
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  /*
   * Copyright (C) 2016 Maxime Ripard
   * Maxime Ripard <maxime.ripard@free-electrons.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.
   */
  
  #include <linux/clk-provider.h>
  #include <linux/rational.h>
  
  #include "ccu_frac.h"
  #include "ccu_gate.h"
  #include "ccu_nm.h"
  
  static void ccu_nm_disable(struct clk_hw *hw)
  {
  	struct ccu_nm *nm = hw_to_ccu_nm(hw);
  
  	return ccu_gate_helper_disable(&nm->common, nm->enable);
  }
  
  static int ccu_nm_enable(struct clk_hw *hw)
  {
  	struct ccu_nm *nm = hw_to_ccu_nm(hw);
  
  	return ccu_gate_helper_enable(&nm->common, nm->enable);
  }
  
  static int ccu_nm_is_enabled(struct clk_hw *hw)
  {
  	struct ccu_nm *nm = hw_to_ccu_nm(hw);
  
  	return ccu_gate_helper_is_enabled(&nm->common, nm->enable);
  }
  
  static unsigned long ccu_nm_recalc_rate(struct clk_hw *hw,
  					unsigned long parent_rate)
  {
  	struct ccu_nm *nm = hw_to_ccu_nm(hw);
  	unsigned long n, m;
  	u32 reg;
  
  	if (ccu_frac_helper_is_enabled(&nm->common, &nm->frac))
  		return ccu_frac_helper_read_rate(&nm->common, &nm->frac);
  
  	reg = readl(nm->common.base + nm->common.reg);
  
  	n = reg >> nm->n.shift;
  	n &= (1 << nm->n.width) - 1;
  
  	m = reg >> nm->m.shift;
  	m &= (1 << nm->m.width) - 1;
  
  	return parent_rate * (n + 1) / (m + 1);
  }
  
  static long ccu_nm_round_rate(struct clk_hw *hw, unsigned long rate,
  			      unsigned long *parent_rate)
  {
  	struct ccu_nm *nm = hw_to_ccu_nm(hw);
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  	unsigned long max_n, max_m;
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  	unsigned long n, m;
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  	max_n = 1 << nm->n.width;
  	max_m = nm->m.max ?: 1 << nm->m.width;
  
  	rational_best_approximation(rate, *parent_rate, max_n, max_m, &n, &m);
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  	return *parent_rate * n / m;
  }
  
  static int ccu_nm_set_rate(struct clk_hw *hw, unsigned long rate,
  			   unsigned long parent_rate)
  {
  	struct ccu_nm *nm = hw_to_ccu_nm(hw);
  	unsigned long flags;
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  	unsigned long max_n, max_m;
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  	unsigned long n, m;
  	u32 reg;
  
  	if (ccu_frac_helper_has_rate(&nm->common, &nm->frac, rate))
  		return ccu_frac_helper_set_rate(&nm->common, &nm->frac, rate);
  	else
  		ccu_frac_helper_disable(&nm->common, &nm->frac);
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  	max_n = 1 << nm->n.width;
  	max_m = nm->m.max ?: 1 << nm->m.width;
  
  	rational_best_approximation(rate, parent_rate, max_n, max_m, &n, &m);
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  	spin_lock_irqsave(nm->common.lock, flags);
  
  	reg = readl(nm->common.base + nm->common.reg);
  	reg &= ~GENMASK(nm->n.width + nm->n.shift - 1, nm->n.shift);
  	reg &= ~GENMASK(nm->m.width + nm->m.shift - 1, nm->m.shift);
  
  	writel(reg | ((m - 1) << nm->m.shift) | ((n - 1) << nm->n.shift),
  	       nm->common.base + nm->common.reg);
  
  	spin_unlock_irqrestore(nm->common.lock, flags);
  
  	ccu_helper_wait_for_lock(&nm->common, nm->lock);
  
  	return 0;
  }
  
  const struct clk_ops ccu_nm_ops = {
  	.disable	= ccu_nm_disable,
  	.enable		= ccu_nm_enable,
  	.is_enabled	= ccu_nm_is_enabled,
  
  	.recalc_rate	= ccu_nm_recalc_rate,
  	.round_rate	= ccu_nm_round_rate,
  	.set_rate	= ccu_nm_set_rate,
  };