drivers/clk/imx/clk-cpu.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2014 Lucas Stach <l.stach@pengutronix.de>, Pengutronix
   4  */
   5
   6 #include <linux/clk.h>
   7 #include <linux/clk-provider.h>
   8 #include <linux/export.h>
   9 #include <linux/slab.h>
  10 #include "clk.h"
  11
  12 struct clk_cpu {
  13         struct clk_hw   hw;
  14         struct clk      *div;
  15         struct clk      *mux;
  16         struct clk      *pll;
  17         struct clk      *step;
  18 };
  19
  20 static inline struct clk_cpu *to_clk_cpu(struct clk_hw *hw)
  21 {
  22         return container_of(hw, struct clk_cpu, hw);
  23 }
  24
  25 static unsigned long clk_cpu_recalc_rate(struct clk_hw *hw,
  26                                          unsigned long parent_rate)
  27 {
  28         struct clk_cpu *cpu = to_clk_cpu(hw);
  29
  30         return clk_get_rate(cpu->div);
  31 }
  32
  33 static long clk_cpu_round_rate(struct clk_hw *hw, unsigned long rate,
  34                                unsigned long *prate)
  35 {
  36         struct clk_cpu *cpu = to_clk_cpu(hw);
  37
  38         return clk_round_rate(cpu->pll, rate);
  39 }
  40
  41 static int clk_cpu_set_rate(struct clk_hw *hw, unsigned long rate,
  42                             unsigned long parent_rate)
  43 {
  44         struct clk_cpu *cpu = to_clk_cpu(hw);
  45         int ret;
  46
  47         /* switch to PLL bypass clock */
  48         ret = clk_set_parent(cpu->mux, cpu->step);
  49         if (ret)
  50                 return ret;
  51
  52         /* reprogram PLL */
  53         ret = clk_set_rate(cpu->pll, rate);
  54         if (ret) {
  55                 clk_set_parent(cpu->mux, cpu->pll);
  56                 return ret;
  57         }
  58         /* switch back to PLL clock */
  59         clk_set_parent(cpu->mux, cpu->pll);
  60
  61         /* Ensure the divider is what we expect */
  62         clk_set_rate(cpu->div, rate);
  63
  64         return 0;
  65 }
  66
  67 static const struct clk_ops clk_cpu_ops = {
  68         .recalc_rate    = clk_cpu_recalc_rate,
  69         .round_rate     = clk_cpu_round_rate,
  70         .set_rate       = clk_cpu_set_rate,
  71 };
  72
  73 struct clk_hw *imx_clk_hw_cpu(const char *name, const char *parent_name,
  74                 struct clk *div, struct clk *mux, struct clk *pll,
  75                 struct clk *step)
  76 {
  77         struct clk_cpu *cpu;
  78         struct clk_hw *hw;
  79         struct clk_init_data init;
  80         int ret;
  81
  82         cpu = kzalloc(sizeof(*cpu), GFP_KERNEL);
  83         if (!cpu)
  84                 return ERR_PTR(-ENOMEM);
  85
  86         cpu->div = div;
  87         cpu->mux = mux;
  88         cpu->pll = pll;
  89         cpu->step = step;
  90
  91         init.name = name;
  92         init.ops = &clk_cpu_ops;
  93         init.flags = CLK_IS_CRITICAL;
  94         init.parent_names = &parent_name;
  95         init.num_parents = 1;
  96
  97         cpu->hw.init = &init;
  98         hw = &cpu->hw;
  99
 100         ret = clk_hw_register(NULL, hw);
 101         if (ret) {
 102                 kfree(cpu);
 103                 return ERR_PTR(ret);
 104         }
 105
 106         return hw;
 107 }
 108 EXPORT_SYMBOL_GPL(imx_clk_hw_cpu);