drivers/clk/imx/clk-gate2.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com>
   4  * Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd <mturquette@linaro.org>
   5  *
   6  * Gated clock implementation
   7  */
   8
   9 #include <linux/clk-provider.h>
  10 #include <linux/export.h>
  11 #include <linux/module.h>
  12 #include <linux/slab.h>
  13 #include <linux/io.h>
  14 #include <linux/err.h>
  15 #include <linux/string.h>
  16 #include "clk.h"
  17
  18 /**
  19  * DOC: basic gateable clock which can gate and ungate its output
  20  *
  21  * Traits of this clock:
  22  * prepare - clk_(un)prepare only ensures parent is (un)prepared
  23  * enable - clk_enable and clk_disable are functional & control gating
  24  * rate - inherits rate from parent.  No clk_set_rate support
  25  * parent - fixed parent.  No clk_set_parent support
  26  */
  27
  28 struct clk_gate2 {
  29         struct clk_hw hw;
  30         void __iomem    *reg;
  31         u8              bit_idx;
  32         u8              cgr_val;
  33         u8              cgr_mask;
  34         u8              flags;
  35         spinlock_t      *lock;
  36         unsigned int    *share_count;
  37 };
  38
  39 #define to_clk_gate2(_hw) container_of(_hw, struct clk_gate2, hw)
  40
  41 static void clk_gate2_do_shared_clks(struct clk_hw *hw, bool enable)
  42 {
  43         struct clk_gate2 *gate = to_clk_gate2(hw);
  44         u32 reg;
  45
  46         reg = readl(gate->reg);
  47         reg &= ~(gate->cgr_mask << gate->bit_idx);
  48         if (enable)
  49                 reg |= (gate->cgr_val & gate->cgr_mask) << gate->bit_idx;
  50         writel(reg, gate->reg);
  51 }
  52
  53 static int clk_gate2_enable(struct clk_hw *hw)
  54 {
  55         struct clk_gate2 *gate = to_clk_gate2(hw);
  56         unsigned long flags;
  57
  58         spin_lock_irqsave(gate->lock, flags);
  59
  60         if (gate->share_count && (*gate->share_count)++ > 0)
  61                 goto out;
  62
  63         clk_gate2_do_shared_clks(hw, true);
  64 out:
  65         spin_unlock_irqrestore(gate->lock, flags);
  66
  67         return 0;
  68 }
  69
  70 static void clk_gate2_disable(struct clk_hw *hw)
  71 {
  72         struct clk_gate2 *gate = to_clk_gate2(hw);
  73         unsigned long flags;
  74
  75         spin_lock_irqsave(gate->lock, flags);
  76
  77         if (gate->share_count) {
  78                 if (WARN_ON(*gate->share_count == 0))
  79                         goto out;
  80                 else if (--(*gate->share_count) > 0)
  81                         goto out;
  82         }
  83
  84         clk_gate2_do_shared_clks(hw, false);
  85 out:
  86         spin_unlock_irqrestore(gate->lock, flags);
  87 }
  88
  89 static int clk_gate2_reg_is_enabled(void __iomem *reg, u8 bit_idx,
  90                                         u8 cgr_val, u8 cgr_mask)
  91 {
  92         u32 val = readl(reg);
  93
  94         if (((val >> bit_idx) & cgr_mask) == cgr_val)
  95                 return 1;
  96
  97         return 0;
  98 }
  99
 100 static int clk_gate2_is_enabled(struct clk_hw *hw)
 101 {
 102         struct clk_gate2 *gate = to_clk_gate2(hw);
 103         unsigned long flags;
 104         int ret = 0;
 105
 106         spin_lock_irqsave(gate->lock, flags);
 107
 108         ret = clk_gate2_reg_is_enabled(gate->reg, gate->bit_idx,
 109                                         gate->cgr_val, gate->cgr_mask);
 110
 111         spin_unlock_irqrestore(gate->lock, flags);
 112
 113         return ret;
 114 }
 115
 116 static void clk_gate2_disable_unused(struct clk_hw *hw)
 117 {
 118         struct clk_gate2 *gate = to_clk_gate2(hw);
 119         unsigned long flags;
 120
 121         spin_lock_irqsave(gate->lock, flags);
 122
 123         if (!gate->share_count || *gate->share_count == 0)
 124                 clk_gate2_do_shared_clks(hw, false);
 125
 126         spin_unlock_irqrestore(gate->lock, flags);
 127 }
 128
 129 static const struct clk_ops clk_gate2_ops = {
 130         .enable = clk_gate2_enable,
 131         .disable = clk_gate2_disable,
 132         .disable_unused = clk_gate2_disable_unused,
 133         .is_enabled = clk_gate2_is_enabled,
 134 };
 135
 136 struct clk_hw *clk_hw_register_gate2(struct device *dev, const char *name,
 137                 const char *parent_name, unsigned long flags,
 138                 void __iomem *reg, u8 bit_idx, u8 cgr_val, u8 cgr_mask,
 139                 u8 clk_gate2_flags, spinlock_t *lock,
 140                 unsigned int *share_count)
 141 {
 142         struct clk_gate2 *gate;
 143         struct clk_hw *hw;
 144         struct clk_init_data init;
 145         int ret;
 146
 147         gate = kzalloc(sizeof(struct clk_gate2), GFP_KERNEL);
 148         if (!gate)
 149                 return ERR_PTR(-ENOMEM);
 150
 151         /* struct clk_gate2 assignments */
 152         gate->reg = reg;
 153         gate->bit_idx = bit_idx;
 154         gate->cgr_val = cgr_val;
 155         gate->cgr_mask = cgr_mask;
 156         gate->flags = clk_gate2_flags;
 157         gate->lock = lock;
 158         gate->share_count = share_count;
 159
 160         init.name = name;
 161         init.ops = &clk_gate2_ops;
 162         init.flags = flags;
 163         init.parent_names = parent_name ? &parent_name : NULL;
 164         init.num_parents = parent_name ? 1 : 0;
 165
 166         gate->hw.init = &init;
 167         hw = &gate->hw;
 168
 169         ret = clk_hw_register(dev, hw);
 170         if (ret) {
 171                 kfree(gate);
 172                 return ERR_PTR(ret);
 173         }
 174
 175         return hw;
 176 }
 177 EXPORT_SYMBOL_GPL(clk_hw_register_gate2);