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kernel/linux-rt-4.4.41/drivers/clk/socfpga/clk-periph.c 3.03 KB
5113f6f70   김현기   kernel add
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  /*
   *  Copyright 2011-2012 Calxeda, Inc.
   *  Copyright (C) 2012-2013 Altera Corporation <www.altera.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.
   *
   * Based from clk-highbank.c
   *
   */
  #include <linux/slab.h>
  #include <linux/clk-provider.h>
  #include <linux/io.h>
  #include <linux/of.h>
  
  #include "clk.h"
  
  #define to_socfpga_periph_clk(p) container_of(p, struct socfpga_periph_clk, hw.hw)
  
  static unsigned long clk_periclk_recalc_rate(struct clk_hw *hwclk,
  					     unsigned long parent_rate)
  {
  	struct socfpga_periph_clk *socfpgaclk = to_socfpga_periph_clk(hwclk);
  	u32 div, val;
  
  	if (socfpgaclk->fixed_div) {
  		div = socfpgaclk->fixed_div;
  	} else {
  		if (socfpgaclk->div_reg) {
  			val = readl(socfpgaclk->div_reg) >> socfpgaclk->shift;
  			val &= GENMASK(socfpgaclk->width - 1, 0);
  			parent_rate /= (val + 1);
  		}
  		div = ((readl(socfpgaclk->hw.reg) & 0x1ff) + 1);
  	}
  
  	return parent_rate / div;
  }
  
  static u8 clk_periclk_get_parent(struct clk_hw *hwclk)
  {
  	u32 clk_src;
  
  	clk_src = readl(clk_mgr_base_addr + CLKMGR_DBCTRL);
  	return clk_src & 0x1;
  }
  
  static const struct clk_ops periclk_ops = {
  	.recalc_rate = clk_periclk_recalc_rate,
  	.get_parent = clk_periclk_get_parent,
  };
  
  static __init void __socfpga_periph_init(struct device_node *node,
  	const struct clk_ops *ops)
  {
  	u32 reg;
  	struct clk *clk;
  	struct socfpga_periph_clk *periph_clk;
  	const char *clk_name = node->name;
  	const char *parent_name[SOCFPGA_MAX_PARENTS];
  	struct clk_init_data init;
  	int rc;
  	u32 fixed_div;
  	u32 div_reg[3];
  
  	of_property_read_u32(node, "reg", &reg);
  
  	periph_clk = kzalloc(sizeof(*periph_clk), GFP_KERNEL);
  	if (WARN_ON(!periph_clk))
  		return;
  
  	periph_clk->hw.reg = clk_mgr_base_addr + reg;
  
  	rc = of_property_read_u32_array(node, "div-reg", div_reg, 3);
  	if (!rc) {
  		periph_clk->div_reg = clk_mgr_base_addr + div_reg[0];
  		periph_clk->shift = div_reg[1];
  		periph_clk->width = div_reg[2];
  	} else {
  		periph_clk->div_reg = NULL;
  	}
  
  	rc = of_property_read_u32(node, "fixed-divider", &fixed_div);
  	if (rc)
  		periph_clk->fixed_div = 0;
  	else
  		periph_clk->fixed_div = fixed_div;
  
  	of_property_read_string(node, "clock-output-names", &clk_name);
  
  	init.name = clk_name;
  	init.ops = ops;
  	init.flags = 0;
  
  	init.num_parents = of_clk_parent_fill(node, parent_name,
  					      SOCFPGA_MAX_PARENTS);
  	init.parent_names = parent_name;
  
  	periph_clk->hw.hw.init = &init;
  
  	clk = clk_register(NULL, &periph_clk->hw.hw);
  	if (WARN_ON(IS_ERR(clk))) {
  		kfree(periph_clk);
  		return;
  	}
  	rc = of_clk_add_provider(node, of_clk_src_simple_get, clk);
  }
  
  void __init socfpga_periph_init(struct device_node *node)
  {
  	__socfpga_periph_init(node, &periclk_ops);
  }