drivers/clk/at91/clk-utmi.c

   1 /*
   2  *  Copyright (C) 2013 Boris BREZILLON <b.brezillon@overkiz.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  */
  10
  11 #include <linux/clk-provider.h>
  12 #include <linux/clkdev.h>
  13 #include <linux/clk/at91_pmc.h>
  14 #include <linux/of.h>
  15 #include <linux/mfd/syscon.h>
  16 #include <linux/regmap.h>
  17
  18 #include "pmc.h"
  19
  20 #define UTMI_FIXED_MUL          40
  21
  22 struct clk_utmi {
  23         struct clk_hw hw;
  24         struct regmap *regmap;
  25 };
  26
  27 #define to_clk_utmi(hw) container_of(hw, struct clk_utmi, hw)
  28
  29 static inline bool clk_utmi_ready(struct regmap *regmap)
  30 {
  31         unsigned int status;
  32
  33         regmap_read(regmap, AT91_PMC_SR, &status);
  34
  35         return status & AT91_PMC_LOCKU;
  36 }
  37
  38 static int clk_utmi_prepare(struct clk_hw *hw)
  39 {
  40         struct clk_utmi *utmi = to_clk_utmi(hw);
  41         unsigned int uckr = AT91_PMC_UPLLEN | AT91_PMC_UPLLCOUNT |
  42                             AT91_PMC_BIASEN;
  43
  44         regmap_update_bits(utmi->regmap, AT91_CKGR_UCKR, uckr, uckr);
  45
  46         while (!clk_utmi_ready(utmi->regmap))
  47                 cpu_relax();
  48
  49         return 0;
  50 }
  51
  52 static int clk_utmi_is_prepared(struct clk_hw *hw)
  53 {
  54         struct clk_utmi *utmi = to_clk_utmi(hw);
  55
  56         return clk_utmi_ready(utmi->regmap);
  57 }
  58
  59 static void clk_utmi_unprepare(struct clk_hw *hw)
  60 {
  61         struct clk_utmi *utmi = to_clk_utmi(hw);
  62
  63         regmap_update_bits(utmi->regmap, AT91_CKGR_UCKR, AT91_PMC_UPLLEN, 0);
  64 }
  65
  66 static unsigned long clk_utmi_recalc_rate(struct clk_hw *hw,
  67                                           unsigned long parent_rate)
  68 {
  69         /* UTMI clk is a fixed clk multiplier */
  70         return parent_rate * UTMI_FIXED_MUL;
  71 }
  72
  73 static const struct clk_ops utmi_ops = {
  74         .prepare = clk_utmi_prepare,
  75         .unprepare = clk_utmi_unprepare,
  76         .is_prepared = clk_utmi_is_prepared,
  77         .recalc_rate = clk_utmi_recalc_rate,
  78 };
  79
  80 static struct clk * __init
  81 at91_clk_register_utmi(struct regmap *regmap,
  82                        const char *name, const char *parent_name)
  83 {
  84         struct clk_utmi *utmi;
  85         struct clk *clk = NULL;
  86         struct clk_init_data init;
  87
  88         utmi = kzalloc(sizeof(*utmi), GFP_KERNEL);
  89         if (!utmi)
  90                 return ERR_PTR(-ENOMEM);
  91
  92         init.name = name;
  93         init.ops = &utmi_ops;
  94         init.parent_names = parent_name ? &parent_name : NULL;
  95         init.num_parents = parent_name ? 1 : 0;
  96         init.flags = CLK_SET_RATE_GATE;
  97
  98         utmi->hw.init = &init;
  99         utmi->regmap = regmap;
 100
 101         clk = clk_register(NULL, &utmi->hw);
 102         if (IS_ERR(clk))
 103                 kfree(utmi);
 104
 105         return clk;
 106 }
 107
 108 static void __init of_at91sam9x5_clk_utmi_setup(struct device_node *np)
 109 {
 110         struct clk *clk;
 111         const char *parent_name;
 112         const char *name = np->name;
 113         struct regmap *regmap;
 114
 115         parent_name = of_clk_get_parent_name(np, 0);
 116
 117         of_property_read_string(np, "clock-output-names", &name);
 118
 119         regmap = syscon_node_to_regmap(of_get_parent(np));
 120         if (IS_ERR(regmap))
 121                 return;
 122
 123         clk = at91_clk_register_utmi(regmap, name, parent_name);
 124         if (IS_ERR(clk))
 125                 return;
 126
 127         of_clk_add_provider(np, of_clk_src_simple_get, clk);
 128         return;
 129 }
 130 CLK_OF_DECLARE(at91sam9x5_clk_utmi, "atmel,at91sam9x5-clk-utmi",
 131                of_at91sam9x5_clk_utmi_setup);