drivers/clk/at91/clk-slow.c

   1 /*
   2  * drivers/clk/at91/clk-slow.c
   3  *
   4  *  Copyright (C) 2013 Boris BREZILLON <b.brezillon@overkiz.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  */
  12
  13 #include <linux/clk-provider.h>
  14 #include <linux/clkdev.h>
  15 #include <linux/clk/at91_pmc.h>
  16 #include <linux/of.h>
  17 #include <linux/mfd/syscon.h>
  18 #include <linux/regmap.h>
  19
  20 #include "pmc.h"
  21
  22 struct clk_sam9260_slow {
  23         struct clk_hw hw;
  24         struct regmap *regmap;
  25 };
  26
  27 #define to_clk_sam9260_slow(hw) container_of(hw, struct clk_sam9260_slow, hw)
  28
  29 static u8 clk_sam9260_slow_get_parent(struct clk_hw *hw)
  30 {
  31         struct clk_sam9260_slow *slowck = to_clk_sam9260_slow(hw);
  32         unsigned int status;
  33
  34         regmap_read(slowck->regmap, AT91_PMC_SR, &status);
  35
  36         return status & AT91_PMC_OSCSEL ? 1 : 0;
  37 }
  38
  39 static const struct clk_ops sam9260_slow_ops = {
  40         .get_parent = clk_sam9260_slow_get_parent,
  41 };
  42
  43 static struct clk_hw * __init
  44 at91_clk_register_sam9260_slow(struct regmap *regmap,
  45                                const char *name,
  46                                const char **parent_names,
  47                                int num_parents)
  48 {
  49         struct clk_sam9260_slow *slowck;
  50         struct clk_hw *hw;
  51         struct clk_init_data init;
  52         int ret;
  53
  54         if (!name)
  55                 return ERR_PTR(-EINVAL);
  56
  57         if (!parent_names || !num_parents)
  58                 return ERR_PTR(-EINVAL);
  59
  60         slowck = kzalloc(sizeof(*slowck), GFP_KERNEL);
  61         if (!slowck)
  62                 return ERR_PTR(-ENOMEM);
  63
  64         init.name = name;
  65         init.ops = &sam9260_slow_ops;
  66         init.parent_names = parent_names;
  67         init.num_parents = num_parents;
  68         init.flags = 0;
  69
  70         slowck->hw.init = &init;
  71         slowck->regmap = regmap;
  72
  73         hw = &slowck->hw;
  74         ret = clk_hw_register(NULL, &slowck->hw);
  75         if (ret) {
  76                 kfree(slowck);
  77                 hw = ERR_PTR(ret);
  78         }
  79
  80         return hw;
  81 }
  82
  83 static void __init of_at91sam9260_clk_slow_setup(struct device_node *np)
  84 {
  85         struct clk_hw *hw;
  86         const char *parent_names[2];
  87         unsigned int num_parents;
  88         const char *name = np->name;
  89         struct regmap *regmap;
  90
  91         num_parents = of_clk_get_parent_count(np);
  92         if (num_parents != 2)
  93                 return;
  94
  95         of_clk_parent_fill(np, parent_names, num_parents);
  96         regmap = syscon_node_to_regmap(of_get_parent(np));
  97         if (IS_ERR(regmap))
  98                 return;
  99
 100         of_property_read_string(np, "clock-output-names", &name);
 101
 102         hw = at91_clk_register_sam9260_slow(regmap, name, parent_names,
 103                                              num_parents);
 104         if (IS_ERR(hw))
 105                 return;
 106
 107         of_clk_add_hw_provider(np, of_clk_hw_simple_get, hw);
 108 }
 109
 110 CLK_OF_DECLARE(at91sam9260_clk_slow, "atmel,at91sam9260-clk-slow",
 111                of_at91sam9260_clk_slow_setup);