1 /* 2 * Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com> 3 * Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd <mturquette@linaro.org> 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License version 2 as 7 * published by the Free Software Foundation. 8 * 9 * Gated clock implementation 10 */ 11 12 #include <linux/clk-provider.h> 13 #include <linux/module.h> 14 #include <linux/slab.h> 15 #include <linux/io.h> 16 #include <linux/err.h> 17 #include <linux/string.h> 18 #include "clk.h" 19 20 /** 21 * DOC: basic gatable clock which can gate and ungate it's ouput 22 * 23 * Traits of this clock: 24 * prepare - clk_(un)prepare only ensures parent is (un)prepared 25 * enable - clk_enable and clk_disable are functional & control gating 26 * rate - inherits rate from parent. No clk_set_rate support 27 * parent - fixed parent. No clk_set_parent support 28 */ 29 30 struct clk_gate2 { 31 struct clk_hw hw; 32 void __iomem *reg; 33 u8 bit_idx; 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 int clk_gate2_enable(struct clk_hw *hw) 42 { 43 struct clk_gate2 *gate = to_clk_gate2(hw); 44 u32 reg; 45 unsigned long flags = 0; 46 47 spin_lock_irqsave(gate->lock, flags); 48 49 if (gate->share_count && (*gate->share_count)++ > 0) 50 goto out; 51 52 reg = readl(gate->reg); 53 reg |= 3 << gate->bit_idx; 54 writel(reg, gate->reg); 55 56 out: 57 spin_unlock_irqrestore(gate->lock, flags); 58 59 return 0; 60 } 61 62 static void clk_gate2_disable(struct clk_hw *hw) 63 { 64 struct clk_gate2 *gate = to_clk_gate2(hw); 65 u32 reg; 66 unsigned long flags = 0; 67 68 spin_lock_irqsave(gate->lock, flags); 69 70 if (gate->share_count) { 71 if (WARN_ON(*gate->share_count == 0)) 72 goto out; 73 else if (--(*gate->share_count) > 0) 74 goto out; 75 } 76 77 reg = readl(gate->reg); 78 reg &= ~(3 << gate->bit_idx); 79 writel(reg, gate->reg); 80 81 out: 82 spin_unlock_irqrestore(gate->lock, flags); 83 } 84 85 static int clk_gate2_reg_is_enabled(void __iomem *reg, u8 bit_idx) 86 { 87 u32 val = readl(reg); 88 89 if (((val >> bit_idx) & 1) == 1) 90 return 1; 91 92 return 0; 93 } 94 95 static int clk_gate2_is_enabled(struct clk_hw *hw) 96 { 97 struct clk_gate2 *gate = to_clk_gate2(hw); 98 99 return clk_gate2_reg_is_enabled(gate->reg, gate->bit_idx); 100 } 101 102 static void clk_gate2_disable_unused(struct clk_hw *hw) 103 { 104 struct clk_gate2 *gate = to_clk_gate2(hw); 105 unsigned long flags = 0; 106 u32 reg; 107 108 spin_lock_irqsave(gate->lock, flags); 109 110 if (!gate->share_count || *gate->share_count == 0) { 111 reg = readl(gate->reg); 112 reg &= ~(3 << gate->bit_idx); 113 writel(reg, gate->reg); 114 } 115 116 spin_unlock_irqrestore(gate->lock, flags); 117 } 118 119 static struct clk_ops clk_gate2_ops = { 120 .enable = clk_gate2_enable, 121 .disable = clk_gate2_disable, 122 .disable_unused = clk_gate2_disable_unused, 123 .is_enabled = clk_gate2_is_enabled, 124 }; 125 126 struct clk *clk_register_gate2(struct device *dev, const char *name, 127 const char *parent_name, unsigned long flags, 128 void __iomem *reg, u8 bit_idx, 129 u8 clk_gate2_flags, spinlock_t *lock, 130 unsigned int *share_count) 131 { 132 struct clk_gate2 *gate; 133 struct clk *clk; 134 struct clk_init_data init; 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->flags = clk_gate2_flags; 144 gate->lock = lock; 145 gate->share_count = share_count; 146 147 init.name = name; 148 init.ops = &clk_gate2_ops; 149 init.flags = flags; 150 init.parent_names = parent_name ? &parent_name : NULL; 151 init.num_parents = parent_name ? 1 : 0; 152 153 gate->hw.init = &init; 154 155 clk = clk_register(dev, &gate->hw); 156 if (IS_ERR(clk)) 157 kfree(gate); 158 159 return clk; 160 } 161