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