drivers/clk/clk-fixed-rate.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com>
   4  * Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd <mturquette@linaro.org>
   5  *
   6  * Fixed rate clock implementation
   7  */
   8
   9 #include <linux/clk-provider.h>
  10 #include <linux/module.h>
  11 #include <linux/slab.h>
  12 #include <linux/io.h>
  13 #include <linux/err.h>
  14 #include <linux/of.h>
  15 #include <linux/platform_device.h>
  16
  17 /*
  18  * DOC: basic fixed-rate clock that cannot gate
  19  *
  20  * Traits of this clock:
  21  * prepare - clk_(un)prepare only ensures parents are prepared
  22  * enable - clk_enable only ensures parents are enabled
  23  * rate - rate is always a fixed value.  No clk_set_rate support
  24  * parent - fixed parent.  No clk_set_parent support
  25  */
  26
  27 #define to_clk_fixed_rate(_hw) container_of(_hw, struct clk_fixed_rate, hw)
  28
  29 static unsigned long clk_fixed_rate_recalc_rate(struct clk_hw *hw,
  30                 unsigned long parent_rate)
  31 {
  32         return to_clk_fixed_rate(hw)->fixed_rate;
  33 }
  34
  35 static unsigned long clk_fixed_rate_recalc_accuracy(struct clk_hw *hw,
  36                 unsigned long parent_accuracy)
  37 {
  38         struct clk_fixed_rate *fixed = to_clk_fixed_rate(hw);
  39
  40         if (fixed->flags & CLK_FIXED_RATE_PARENT_ACCURACY)
  41                 return parent_accuracy;
  42
  43         return fixed->fixed_accuracy;
  44 }
  45
  46 const struct clk_ops clk_fixed_rate_ops = {
  47         .recalc_rate = clk_fixed_rate_recalc_rate,
  48         .recalc_accuracy = clk_fixed_rate_recalc_accuracy,
  49 };
  50 EXPORT_SYMBOL_GPL(clk_fixed_rate_ops);
  51
  52 struct clk_hw *__clk_hw_register_fixed_rate(struct device *dev,
  53                 struct device_node *np, const char *name,
  54                 const char *parent_name, const struct clk_hw *parent_hw,
  55                 const struct clk_parent_data *parent_data, unsigned long flags,
  56                 unsigned long fixed_rate, unsigned long fixed_accuracy,
  57                 unsigned long clk_fixed_flags)
  58 {
  59         struct clk_fixed_rate *fixed;
  60         struct clk_hw *hw;
  61         struct clk_init_data init = {};
  62         int ret = -EINVAL;
  63
  64         /* allocate fixed-rate clock */
  65         fixed = kzalloc(sizeof(*fixed), GFP_KERNEL);
  66         if (!fixed)
  67                 return ERR_PTR(-ENOMEM);
  68
  69         init.name = name;
  70         init.ops = &clk_fixed_rate_ops;
  71         init.flags = flags;
  72         init.parent_names = parent_name ? &parent_name : NULL;
  73         init.parent_hws = parent_hw ? &parent_hw : NULL;
  74         init.parent_data = parent_data;
  75         if (parent_name || parent_hw || parent_data)
  76                 init.num_parents = 1;
  77         else
  78                 init.num_parents = 0;
  79
  80         /* struct clk_fixed_rate assignments */
  81         fixed->flags = clk_fixed_flags;
  82         fixed->fixed_rate = fixed_rate;
  83         fixed->fixed_accuracy = fixed_accuracy;
  84         fixed->hw.init = &init;
  85
  86         /* register the clock */
  87         hw = &fixed->hw;
  88         if (dev || !np)
  89                 ret = clk_hw_register(dev, hw);
  90         else if (np)
  91                 ret = of_clk_hw_register(np, hw);
  92         if (ret) {
  93                 kfree(fixed);
  94                 hw = ERR_PTR(ret);
  95         }
  96
  97         return hw;
  98 }
  99 EXPORT_SYMBOL_GPL(__clk_hw_register_fixed_rate);
 100
 101 struct clk *clk_register_fixed_rate(struct device *dev, const char *name,
 102                 const char *parent_name, unsigned long flags,
 103                 unsigned long fixed_rate)
 104 {
 105         struct clk_hw *hw;
 106
 107         hw = clk_hw_register_fixed_rate_with_accuracy(dev, name, parent_name,
 108                                                       flags, fixed_rate, 0);
 109         if (IS_ERR(hw))
 110                 return ERR_CAST(hw);
 111         return hw->clk;
 112 }
 113 EXPORT_SYMBOL_GPL(clk_register_fixed_rate);
 114
 115 void clk_unregister_fixed_rate(struct clk *clk)
 116 {
 117         struct clk_hw *hw;
 118
 119         hw = __clk_get_hw(clk);
 120         if (!hw)
 121                 return;
 122
 123         clk_unregister(clk);
 124         kfree(to_clk_fixed_rate(hw));
 125 }
 126 EXPORT_SYMBOL_GPL(clk_unregister_fixed_rate);
 127
 128 void clk_hw_unregister_fixed_rate(struct clk_hw *hw)
 129 {
 130         struct clk_fixed_rate *fixed;
 131
 132         fixed = to_clk_fixed_rate(hw);
 133
 134         clk_hw_unregister(hw);
 135         kfree(fixed);
 136 }
 137 EXPORT_SYMBOL_GPL(clk_hw_unregister_fixed_rate);
 138
 139 #ifdef CONFIG_OF
 140 static struct clk_hw *_of_fixed_clk_setup(struct device_node *node)
 141 {
 142         struct clk_hw *hw;
 143         const char *clk_name = node->name;
 144         u32 rate;
 145         u32 accuracy = 0;
 146         int ret;
 147
 148         if (of_property_read_u32(node, "clock-frequency", &rate))
 149                 return ERR_PTR(-EIO);
 150
 151         of_property_read_u32(node, "clock-accuracy", &accuracy);
 152
 153         of_property_read_string(node, "clock-output-names", &clk_name);
 154
 155         hw = clk_hw_register_fixed_rate_with_accuracy(NULL, clk_name, NULL,
 156                                                     0, rate, accuracy);
 157         if (IS_ERR(hw))
 158                 return hw;
 159
 160         ret = of_clk_add_hw_provider(node, of_clk_hw_simple_get, hw);
 161         if (ret) {
 162                 clk_hw_unregister_fixed_rate(hw);
 163                 return ERR_PTR(ret);
 164         }
 165
 166         return hw;
 167 }
 168
 169 /**
 170  * of_fixed_clk_setup() - Setup function for simple fixed rate clock
 171  */
 172 void __init of_fixed_clk_setup(struct device_node *node)
 173 {
 174         _of_fixed_clk_setup(node);
 175 }
 176 CLK_OF_DECLARE(fixed_clk, "fixed-clock", of_fixed_clk_setup);
 177
 178 static int of_fixed_clk_remove(struct platform_device *pdev)
 179 {
 180         struct clk_hw *hw = platform_get_drvdata(pdev);
 181
 182         of_clk_del_provider(pdev->dev.of_node);
 183         clk_hw_unregister_fixed_rate(hw);
 184
 185         return 0;
 186 }
 187
 188 static int of_fixed_clk_probe(struct platform_device *pdev)
 189 {
 190         struct clk_hw *hw;
 191
 192         /*
 193          * This function is not executed when of_fixed_clk_setup
 194          * succeeded.
 195          */
 196         hw = _of_fixed_clk_setup(pdev->dev.of_node);
 197         if (IS_ERR(hw))
 198                 return PTR_ERR(hw);
 199
 200         platform_set_drvdata(pdev, hw);
 201
 202         return 0;
 203 }
 204
 205 static const struct of_device_id of_fixed_clk_ids[] = {
 206         { .compatible = "fixed-clock" },
 207         { }
 208 };
 209
 210 static struct platform_driver of_fixed_clk_driver = {
 211         .driver = {
 212                 .name = "of_fixed_clk",
 213                 .of_match_table = of_fixed_clk_ids,
 214         },
 215         .probe = of_fixed_clk_probe,
 216         .remove = of_fixed_clk_remove,
 217 };
 218 builtin_platform_driver(of_fixed_clk_driver);
 219 #endif