drivers/clk/imgtec/clk-boston.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) 2016-2017 Imagination Technologies
   4  * Author: Paul Burton <paul.burton@mips.com>
   5  */
   6
   7 #define pr_fmt(fmt) "clk-boston: " fmt
   8
   9 #include <linux/clk-provider.h>
  10 #include <linux/kernel.h>
  11 #include <linux/of.h>
  12 #include <linux/regmap.h>
  13 #include <linux/slab.h>
  14 #include <linux/mfd/syscon.h>
  15
  16 #include <dt-bindings/clock/boston-clock.h>
  17
  18 #define BOSTON_PLAT_MMCMDIV             0x30
  19 # define BOSTON_PLAT_MMCMDIV_CLK0DIV    (0xff << 0)
  20 # define BOSTON_PLAT_MMCMDIV_INPUT      (0xff << 8)
  21 # define BOSTON_PLAT_MMCMDIV_MUL        (0xff << 16)
  22 # define BOSTON_PLAT_MMCMDIV_CLK1DIV    (0xff << 24)
  23
  24 #define BOSTON_CLK_COUNT 3
  25
  26 static u32 ext_field(u32 val, u32 mask)
  27 {
  28         return (val & mask) >> (ffs(mask) - 1);
  29 }
  30
  31 static void __init clk_boston_setup(struct device_node *np)
  32 {
  33         unsigned long in_freq, cpu_freq, sys_freq;
  34         uint mmcmdiv, mul, cpu_div, sys_div;
  35         struct clk_hw_onecell_data *onecell;
  36         struct regmap *regmap;
  37         struct clk_hw *hw;
  38         int err;
  39
  40         regmap = syscon_node_to_regmap(np->parent);
  41         if (IS_ERR(regmap)) {
  42                 pr_err("failed to find regmap\n");
  43                 return;
  44         }
  45
  46         err = regmap_read(regmap, BOSTON_PLAT_MMCMDIV, &mmcmdiv);
  47         if (err) {
  48                 pr_err("failed to read mmcm_div register: %d\n", err);
  49                 return;
  50         }
  51
  52         in_freq = ext_field(mmcmdiv, BOSTON_PLAT_MMCMDIV_INPUT) * 1000000;
  53         mul = ext_field(mmcmdiv, BOSTON_PLAT_MMCMDIV_MUL);
  54
  55         sys_div = ext_field(mmcmdiv, BOSTON_PLAT_MMCMDIV_CLK0DIV);
  56         sys_freq = mult_frac(in_freq, mul, sys_div);
  57
  58         cpu_div = ext_field(mmcmdiv, BOSTON_PLAT_MMCMDIV_CLK1DIV);
  59         cpu_freq = mult_frac(in_freq, mul, cpu_div);
  60
  61         onecell = kzalloc(struct_size(onecell, hws, BOSTON_CLK_COUNT),
  62                           GFP_KERNEL);
  63         if (!onecell)
  64                 return;
  65
  66         onecell->num = BOSTON_CLK_COUNT;
  67
  68         hw = clk_hw_register_fixed_rate(NULL, "input", NULL, 0, in_freq);
  69         if (IS_ERR(hw)) {
  70                 pr_err("failed to register input clock: %ld\n", PTR_ERR(hw));
  71                 goto fail_input;
  72         }
  73         onecell->hws[BOSTON_CLK_INPUT] = hw;
  74
  75         hw = clk_hw_register_fixed_rate(NULL, "sys", "input", 0, sys_freq);
  76         if (IS_ERR(hw)) {
  77                 pr_err("failed to register sys clock: %ld\n", PTR_ERR(hw));
  78                 goto fail_sys;
  79         }
  80         onecell->hws[BOSTON_CLK_SYS] = hw;
  81
  82         hw = clk_hw_register_fixed_rate(NULL, "cpu", "input", 0, cpu_freq);
  83         if (IS_ERR(hw)) {
  84                 pr_err("failed to register cpu clock: %ld\n", PTR_ERR(hw));
  85                 goto fail_cpu;
  86         }
  87         onecell->hws[BOSTON_CLK_CPU] = hw;
  88
  89         err = of_clk_add_hw_provider(np, of_clk_hw_onecell_get, onecell);
  90         if (err) {
  91                 pr_err("failed to add DT provider: %d\n", err);
  92                 goto fail_clk_add;
  93         }
  94
  95         return;
  96
  97 fail_clk_add:
  98         clk_hw_unregister_fixed_rate(onecell->hws[BOSTON_CLK_CPU]);
  99 fail_cpu:
 100         clk_hw_unregister_fixed_rate(onecell->hws[BOSTON_CLK_SYS]);
 101 fail_sys:
 102         clk_hw_unregister_fixed_rate(onecell->hws[BOSTON_CLK_INPUT]);
 103 fail_input:
 104         kfree(onecell);
 105 }
 106
 107 /*
 108  * Use CLK_OF_DECLARE so that this driver is probed early enough to provide the
 109  * CPU frequency for use with the GIC or cop0 counters/timers.
 110  */
 111 CLK_OF_DECLARE(clk_boston, "img,boston-clock", clk_boston_setup);