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