linux/drivers/clk/zynqmp/clk-mux-zynqmp.c
<<
>>
Prefs
   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Zynq UltraScale+ MPSoC mux
   4 *
   5 *  Copyright (C) 2016-2018 Xilinx
   6 */
   7
   8#include <linux/clk-provider.h>
   9#include <linux/slab.h>
  10#include "clk-zynqmp.h"
  11
  12/*
  13 * DOC: basic adjustable multiplexer 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 only affected by parent switching.  No clk_set_rate support
  19 * parent - parent is adjustable through clk_set_parent
  20 */
  21
  22/**
  23 * struct zynqmp_clk_mux - multiplexer clock
  24 *
  25 * @hw:         handle between common and hardware-specific interfaces
  26 * @flags:      hardware-specific flags
  27 * @clk_id:     Id of clock
  28 */
  29struct zynqmp_clk_mux {
  30        struct clk_hw hw;
  31        u8 flags;
  32        u32 clk_id;
  33};
  34
  35#define to_zynqmp_clk_mux(_hw) container_of(_hw, struct zynqmp_clk_mux, hw)
  36
  37/**
  38 * zynqmp_clk_mux_get_parent() - Get parent of clock
  39 * @hw:         handle between common and hardware-specific interfaces
  40 *
  41 * Return: Parent index on success or number of parents in case of error
  42 */
  43static u8 zynqmp_clk_mux_get_parent(struct clk_hw *hw)
  44{
  45        struct zynqmp_clk_mux *mux = to_zynqmp_clk_mux(hw);
  46        const char *clk_name = clk_hw_get_name(hw);
  47        u32 clk_id = mux->clk_id;
  48        u32 val;
  49        int ret;
  50
  51        ret = zynqmp_pm_clock_getparent(clk_id, &val);
  52
  53        if (ret) {
  54                pr_warn_once("%s() getparent failed for clock: %s, ret = %d\n",
  55                             __func__, clk_name, ret);
  56                /*
  57                 * clk_core_get_parent_by_index() takes num_parents as incorrect
  58                 * index which is exactly what I want to return here
  59                 */
  60                return clk_hw_get_num_parents(hw);
  61        }
  62
  63        return val;
  64}
  65
  66/**
  67 * zynqmp_clk_mux_set_parent() - Set parent of clock
  68 * @hw:         handle between common and hardware-specific interfaces
  69 * @index:      Parent index
  70 *
  71 * Return: 0 on success else error+reason
  72 */
  73static int zynqmp_clk_mux_set_parent(struct clk_hw *hw, u8 index)
  74{
  75        struct zynqmp_clk_mux *mux = to_zynqmp_clk_mux(hw);
  76        const char *clk_name = clk_hw_get_name(hw);
  77        u32 clk_id = mux->clk_id;
  78        int ret;
  79
  80        ret = zynqmp_pm_clock_setparent(clk_id, index);
  81
  82        if (ret)
  83                pr_warn_once("%s() set parent failed for clock: %s, ret = %d\n",
  84                             __func__, clk_name, ret);
  85
  86        return ret;
  87}
  88
  89static const struct clk_ops zynqmp_clk_mux_ops = {
  90        .get_parent = zynqmp_clk_mux_get_parent,
  91        .set_parent = zynqmp_clk_mux_set_parent,
  92        .determine_rate = __clk_mux_determine_rate,
  93};
  94
  95static const struct clk_ops zynqmp_clk_mux_ro_ops = {
  96        .get_parent = zynqmp_clk_mux_get_parent,
  97};
  98
  99/**
 100 * zynqmp_clk_register_mux() - Register a mux table with the clock
 101 *                             framework
 102 * @name:               Name of this clock
 103 * @clk_id:             Id of this clock
 104 * @parents:            Name of this clock's parents
 105 * @num_parents:        Number of parents
 106 * @nodes:              Clock topology node
 107 *
 108 * Return: clock hardware of the registered clock mux
 109 */
 110struct clk_hw *zynqmp_clk_register_mux(const char *name, u32 clk_id,
 111                                       const char * const *parents,
 112                                       u8 num_parents,
 113                                       const struct clock_topology *nodes)
 114{
 115        struct zynqmp_clk_mux *mux;
 116        struct clk_hw *hw;
 117        struct clk_init_data init;
 118        int ret;
 119
 120        mux = kzalloc(sizeof(*mux), GFP_KERNEL);
 121        if (!mux)
 122                return ERR_PTR(-ENOMEM);
 123
 124        init.name = name;
 125        if (nodes->type_flag & CLK_MUX_READ_ONLY)
 126                init.ops = &zynqmp_clk_mux_ro_ops;
 127        else
 128                init.ops = &zynqmp_clk_mux_ops;
 129        init.flags = nodes->flag;
 130        init.parent_names = parents;
 131        init.num_parents = num_parents;
 132        mux->flags = nodes->type_flag;
 133        mux->hw.init = &init;
 134        mux->clk_id = clk_id;
 135
 136        hw = &mux->hw;
 137        ret = clk_hw_register(NULL, hw);
 138        if (ret) {
 139                kfree(hw);
 140                hw = ERR_PTR(ret);
 141        }
 142
 143        return hw;
 144}
 145