drivers/clk/mmp/clk-gate.c

   1 /*
   2  * mmp gate clock operation source file
   3  *
   4  * Copyright (C) 2014 Marvell
   5  * Chao Xie <chao.xie@marvell.com>
   6  *
   7  * This file is licensed under the terms of the GNU General Public
   8  * License version 2. This program is licensed "as is" without any
   9  * warranty of any kind, whether express or implied.
  10  */
  11
  12 #include <linux/clk-provider.h>
  13 #include <linux/slab.h>
  14 #include <linux/io.h>
  15 #include <linux/err.h>
  16 #include <linux/delay.h>
  17
  18 #include "clk.h"
  19
  20 /*
  21  * Some clocks will have mutiple bits to enable the clocks, and
  22  * the bits to disable the clock is not same as enabling bits.
  23  */
  24
  25 #define to_clk_mmp_gate(hw)     container_of(hw, struct mmp_clk_gate, hw)
  26
  27 static int mmp_clk_gate_enable(struct clk_hw *hw)
  28 {
  29         struct mmp_clk_gate *gate = to_clk_mmp_gate(hw);
  30         unsigned long flags = 0;
  31         unsigned long rate;
  32         u32 tmp;
  33
  34         if (gate->lock)
  35                 spin_lock_irqsave(gate->lock, flags);
  36
  37         tmp = readl(gate->reg);
  38         tmp &= ~gate->mask;
  39         tmp |= gate->val_enable;
  40         writel(tmp, gate->reg);
  41
  42         if (gate->lock)
  43                 spin_unlock_irqrestore(gate->lock, flags);
  44
  45         if (gate->flags & MMP_CLK_GATE_NEED_DELAY) {
  46                 rate = clk_hw_get_rate(hw);
  47                 /* Need delay 2 cycles. */
  48                 udelay(2000000/rate);
  49         }
  50
  51         return 0;
  52 }
  53
  54 static void mmp_clk_gate_disable(struct clk_hw *hw)
  55 {
  56         struct mmp_clk_gate *gate = to_clk_mmp_gate(hw);
  57         unsigned long flags = 0;
  58         u32 tmp;
  59
  60         if (gate->lock)
  61                 spin_lock_irqsave(gate->lock, flags);
  62
  63         tmp = readl(gate->reg);
  64         tmp &= ~gate->mask;
  65         tmp |= gate->val_disable;
  66         writel(tmp, gate->reg);
  67
  68         if (gate->lock)
  69                 spin_unlock_irqrestore(gate->lock, flags);
  70 }
  71
  72 static int mmp_clk_gate_is_enabled(struct clk_hw *hw)
  73 {
  74         struct mmp_clk_gate *gate = to_clk_mmp_gate(hw);
  75         unsigned long flags = 0;
  76         u32 tmp;
  77
  78         if (gate->lock)
  79                 spin_lock_irqsave(gate->lock, flags);
  80
  81         tmp = readl(gate->reg);
  82
  83         if (gate->lock)
  84                 spin_unlock_irqrestore(gate->lock, flags);
  85
  86         return (tmp & gate->mask) == gate->val_enable;
  87 }
  88
  89 const struct clk_ops mmp_clk_gate_ops = {
  90         .enable = mmp_clk_gate_enable,
  91         .disable = mmp_clk_gate_disable,
  92         .is_enabled = mmp_clk_gate_is_enabled,
  93 };
  94
  95 struct clk *mmp_clk_register_gate(struct device *dev, const char *name,
  96                 const char *parent_name, unsigned long flags,
  97                 void __iomem *reg, u32 mask, u32 val_enable, u32 val_disable,
  98                 unsigned int gate_flags, spinlock_t *lock)
  99 {
 100         struct mmp_clk_gate *gate;
 101         struct clk *clk;
 102         struct clk_init_data init;
 103
 104         /* allocate the gate */
 105         gate = kzalloc(sizeof(*gate), GFP_KERNEL);
 106         if (!gate) {
 107                 pr_err("%s:%s could not allocate gate clk\n", __func__, name);
 108                 return ERR_PTR(-ENOMEM);
 109         }
 110
 111         init.name = name;
 112         init.ops = &mmp_clk_gate_ops;
 113         init.flags = flags | CLK_IS_BASIC;
 114         init.parent_names = (parent_name ? &parent_name : NULL);
 115         init.num_parents = (parent_name ? 1 : 0);
 116
 117         /* struct clk_gate assignments */
 118         gate->reg = reg;
 119         gate->mask = mask;
 120         gate->val_enable = val_enable;
 121         gate->val_disable = val_disable;
 122         gate->flags = gate_flags;
 123         gate->lock = lock;
 124         gate->hw.init = &init;
 125
 126         clk = clk_register(dev, &gate->hw);
 127
 128         if (IS_ERR(clk))
 129                 kfree(gate);
 130
 131         return clk;
 132 }