drivers/clk/clk-fixed-factor.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2011 Sascha Hauer, Pengutronix <s.hauer@pengutronix.de>
   4  */
   5 #include <linux/module.h>
   6 #include <linux/clk-provider.h>
   7 #include <linux/slab.h>
   8 #include <linux/err.h>
   9 #include <linux/of.h>
  10 #include <linux/platform_device.h>
  11
  12 /*
  13  * DOC: basic fixed multiplier and divider clock that cannot gate
  14  *
  15  * Traits of this clock:
  16  * prepare - clk_prepare only ensures that parents are prepared
  17  * enable - clk_enable only ensures that parents are enabled
  18  * rate - rate is fixed.  clk->rate = parent->rate / div * mult
  19  * parent - fixed parent.  No clk_set_parent support
  20  */
  21
  22 static unsigned long clk_factor_recalc_rate(struct clk_hw *hw,
  23                 unsigned long parent_rate)
  24 {
  25         struct clk_fixed_factor *fix = to_clk_fixed_factor(hw);
  26         unsigned long long int rate;
  27
  28         rate = (unsigned long long int)parent_rate * fix->mult;
  29         do_div(rate, fix->div);
  30         return (unsigned long)rate;
  31 }
  32
  33 static long clk_factor_round_rate(struct clk_hw *hw, unsigned long rate,
  34                                 unsigned long *prate)
  35 {
  36         struct clk_fixed_factor *fix = to_clk_fixed_factor(hw);
  37
  38         if (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) {
  39                 unsigned long best_parent;
  40
  41                 best_parent = (rate / fix->mult) * fix->div;
  42                 *prate = clk_hw_round_rate(clk_hw_get_parent(hw), best_parent);
  43         }
  44
  45         return (*prate / fix->div) * fix->mult;
  46 }
  47
  48 static int clk_factor_set_rate(struct clk_hw *hw, unsigned long rate,
  49                                 unsigned long parent_rate)
  50 {
  51         /*
  52          * We must report success but we can do so unconditionally because
  53          * clk_factor_round_rate returns values that ensure this call is a
  54          * nop.
  55          */
  56
  57         return 0;
  58 }
  59
  60 const struct clk_ops clk_fixed_factor_ops = {
  61         .round_rate = clk_factor_round_rate,
  62         .set_rate = clk_factor_set_rate,
  63         .recalc_rate = clk_factor_recalc_rate,
  64 };
  65 EXPORT_SYMBOL_GPL(clk_fixed_factor_ops);
  66
  67 static struct clk_hw *
  68 __clk_hw_register_fixed_factor(struct device *dev, struct device_node *np,
  69                 const char *name, const char *parent_name, int index,
  70                 unsigned long flags, unsigned int mult, unsigned int div)
  71 {
  72         struct clk_fixed_factor *fix;
  73         struct clk_init_data init = { };
  74         struct clk_parent_data pdata = { .index = index };
  75         struct clk_hw *hw;
  76         int ret;
  77
  78         fix = kmalloc(sizeof(*fix), GFP_KERNEL);
  79         if (!fix)
  80                 return ERR_PTR(-ENOMEM);
  81
  82         /* struct clk_fixed_factor assignments */
  83         fix->mult = mult;
  84         fix->div = div;
  85         fix->hw.init = &init;
  86
  87         init.name = name;
  88         init.ops = &clk_fixed_factor_ops;
  89         init.flags = flags;
  90         if (parent_name)
  91                 init.parent_names = &parent_name;
  92         else
  93                 init.parent_data = &pdata;
  94         init.num_parents = 1;
  95
  96         hw = &fix->hw;
  97         if (dev)
  98                 ret = clk_hw_register(dev, hw);
  99         else
 100                 ret = of_clk_hw_register(np, hw);
 101         if (ret) {
 102                 kfree(fix);
 103                 hw = ERR_PTR(ret);
 104         }
 105
 106         return hw;
 107 }
 108
 109 struct clk_hw *clk_hw_register_fixed_factor(struct device *dev,
 110                 const char *name, const char *parent_name, unsigned long flags,
 111                 unsigned int mult, unsigned int div)
 112 {
 113         return __clk_hw_register_fixed_factor(dev, NULL, name, parent_name, -1,
 114                                               flags, mult, div);
 115 }
 116 EXPORT_SYMBOL_GPL(clk_hw_register_fixed_factor);
 117
 118 struct clk *clk_register_fixed_factor(struct device *dev, const char *name,
 119                 const char *parent_name, unsigned long flags,
 120                 unsigned int mult, unsigned int div)
 121 {
 122         struct clk_hw *hw;
 123
 124         hw = clk_hw_register_fixed_factor(dev, name, parent_name, flags, mult,
 125                                           div);
 126         if (IS_ERR(hw))
 127                 return ERR_CAST(hw);
 128         return hw->clk;
 129 }
 130 EXPORT_SYMBOL_GPL(clk_register_fixed_factor);
 131
 132 void clk_unregister_fixed_factor(struct clk *clk)
 133 {
 134         struct clk_hw *hw;
 135
 136         hw = __clk_get_hw(clk);
 137         if (!hw)
 138                 return;
 139
 140         clk_unregister(clk);
 141         kfree(to_clk_fixed_factor(hw));
 142 }
 143 EXPORT_SYMBOL_GPL(clk_unregister_fixed_factor);
 144
 145 void clk_hw_unregister_fixed_factor(struct clk_hw *hw)
 146 {
 147         struct clk_fixed_factor *fix;
 148
 149         fix = to_clk_fixed_factor(hw);
 150
 151         clk_hw_unregister(hw);
 152         kfree(fix);
 153 }
 154 EXPORT_SYMBOL_GPL(clk_hw_unregister_fixed_factor);
 155
 156 #ifdef CONFIG_OF
 157 static const struct of_device_id set_rate_parent_matches[] = {
 158         { .compatible = "allwinner,sun4i-a10-pll3-2x-clk" },
 159         { /* Sentinel */ },
 160 };
 161
 162 static struct clk_hw *_of_fixed_factor_clk_setup(struct device_node *node)
 163 {
 164         struct clk_hw *hw;
 165         const char *clk_name = node->name;
 166         unsigned long flags = 0;
 167         u32 div, mult;
 168         int ret;
 169
 170         if (of_property_read_u32(node, "clock-div", &div)) {
 171                 pr_err("%s Fixed factor clock <%pOFn> must have a clock-div property\n",
 172                         __func__, node);
 173                 return ERR_PTR(-EIO);
 174         }
 175
 176         if (of_property_read_u32(node, "clock-mult", &mult)) {
 177                 pr_err("%s Fixed factor clock <%pOFn> must have a clock-mult property\n",
 178                         __func__, node);
 179                 return ERR_PTR(-EIO);
 180         }
 181
 182         of_property_read_string(node, "clock-output-names", &clk_name);
 183
 184         if (of_match_node(set_rate_parent_matches, node))
 185                 flags |= CLK_SET_RATE_PARENT;
 186
 187         hw = __clk_hw_register_fixed_factor(NULL, node, clk_name, NULL, 0,
 188                                             flags, mult, div);
 189         if (IS_ERR(hw)) {
 190                 /*
 191                  * Clear OF_POPULATED flag so that clock registration can be
 192                  * attempted again from probe function.
 193                  */
 194                 of_node_clear_flag(node, OF_POPULATED);
 195                 return ERR_CAST(hw);
 196         }
 197
 198         ret = of_clk_add_hw_provider(node, of_clk_hw_simple_get, hw);
 199         if (ret) {
 200                 clk_hw_unregister_fixed_factor(hw);
 201                 return ERR_PTR(ret);
 202         }
 203
 204         return hw;
 205 }
 206
 207 /**
 208  * of_fixed_factor_clk_setup() - Setup function for simple fixed factor clock
 209  * @node:       device node for the clock
 210  */
 211 void __init of_fixed_factor_clk_setup(struct device_node *node)
 212 {
 213         _of_fixed_factor_clk_setup(node);
 214 }
 215 CLK_OF_DECLARE(fixed_factor_clk, "fixed-factor-clock",
 216                 of_fixed_factor_clk_setup);
 217
 218 static int of_fixed_factor_clk_remove(struct platform_device *pdev)
 219 {
 220         struct clk_hw *clk = platform_get_drvdata(pdev);
 221
 222         of_clk_del_provider(pdev->dev.of_node);
 223         clk_hw_unregister_fixed_factor(clk);
 224
 225         return 0;
 226 }
 227
 228 static int of_fixed_factor_clk_probe(struct platform_device *pdev)
 229 {
 230         struct clk_hw *clk;
 231
 232         /*
 233          * This function is not executed when of_fixed_factor_clk_setup
 234          * succeeded.
 235          */
 236         clk = _of_fixed_factor_clk_setup(pdev->dev.of_node);
 237         if (IS_ERR(clk))
 238                 return PTR_ERR(clk);
 239
 240         platform_set_drvdata(pdev, clk);
 241
 242         return 0;
 243 }
 244
 245 static const struct of_device_id of_fixed_factor_clk_ids[] = {
 246         { .compatible = "fixed-factor-clock" },
 247         { }
 248 };
 249 MODULE_DEVICE_TABLE(of, of_fixed_factor_clk_ids);
 250
 251 static struct platform_driver of_fixed_factor_clk_driver = {
 252         .driver = {
 253                 .name = "of_fixed_factor_clk",
 254                 .of_match_table = of_fixed_factor_clk_ids,
 255         },
 256         .probe = of_fixed_factor_clk_probe,
 257         .remove = of_fixed_factor_clk_remove,
 258 };
 259 builtin_platform_driver(of_fixed_factor_clk_driver);
 260 #endif