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 cgr_val; 35 u8 flags; 36 spinlock_t *lock; 37 unsigned int *share_count; 38 }; 39 40 #define to_clk_gate2(_hw) container_of(_hw, struct clk_gate2, hw) 41 42 static int clk_gate2_enable(struct clk_hw *hw) 43 { 44 struct clk_gate2 *gate = to_clk_gate2(hw); 45 u32 reg; 46 unsigned long flags = 0; 47 48 spin_lock_irqsave(gate->lock, flags); 49 50 if (gate->share_count && (*gate->share_count)++ > 0) 51 goto out; 52 53 reg = readl(gate->reg); 54 reg &= ~(3 << gate->bit_idx); 55 reg |= gate->cgr_val << gate->bit_idx; 56 writel(reg, gate->reg); 57 58 out: 59 spin_unlock_irqrestore(gate->lock, flags); 60 61 return 0; 62 } 63 64 static void clk_gate2_disable(struct clk_hw *hw) 65 { 66 struct clk_gate2 *gate = to_clk_gate2(hw); 67 u32 reg; 68 unsigned long flags = 0; 69 70 spin_lock_irqsave(gate->lock, flags); 71 72 if (gate->share_count) { 73 if (WARN_ON(*gate->share_count == 0)) 74 goto out; 75 else if (--(*gate->share_count) > 0) 76 goto out; 77 } 78 79 reg = readl(gate->reg); 80 reg &= ~(3 << gate->bit_idx); 81 writel(reg, gate->reg); 82 83 out: 84 spin_unlock_irqrestore(gate->lock, flags); 85 } 86 87 static int clk_gate2_reg_is_enabled(void __iomem *reg, u8 bit_idx) 88 { 89 u32 val = readl(reg); 90 91 if (((val >> bit_idx) & 1) == 1) 92 return 1; 93 94 return 0; 95 } 96 97 static int clk_gate2_is_enabled(struct clk_hw *hw) 98 { 99 struct clk_gate2 *gate = to_clk_gate2(hw); 100 101 return clk_gate2_reg_is_enabled(gate->reg, gate->bit_idx); 102 } 103 104 static void clk_gate2_disable_unused(struct clk_hw *hw) 105 { 106 struct clk_gate2 *gate = to_clk_gate2(hw); 107 unsigned long flags = 0; 108 u32 reg; 109 110 spin_lock_irqsave(gate->lock, flags); 111 112 if (!gate->share_count || *gate->share_count == 0) { 113 reg = readl(gate->reg); 114 reg &= ~(3 << gate->bit_idx); 115 writel(reg, gate->reg); 116 } 117 118 spin_unlock_irqrestore(gate->lock, flags); 119 } 120 121 static struct clk_ops clk_gate2_ops = { 122 .enable = clk_gate2_enable, 123 .disable = clk_gate2_disable, 124 .disable_unused = clk_gate2_disable_unused, 125 .is_enabled = clk_gate2_is_enabled, 126 }; 127 128 struct clk *clk_register_gate2(struct device *dev, const char *name, 129 const char *parent_name, unsigned long flags, 130 void __iomem *reg, u8 bit_idx, u8 cgr_val, 131 u8 clk_gate2_flags, spinlock_t *lock, 132 unsigned int *share_count) 133 { 134 struct clk_gate2 *gate; 135 struct clk *clk; 136 struct clk_init_data init; 137 138 gate = kzalloc(sizeof(struct clk_gate2), GFP_KERNEL); 139 if (!gate) 140 return ERR_PTR(-ENOMEM); 141 142 /* struct clk_gate2 assignments */ 143 gate->reg = reg; 144 gate->bit_idx = bit_idx; 145 gate->cgr_val = cgr_val; 146 gate->flags = clk_gate2_flags; 147 gate->lock = lock; 148 gate->share_count = share_count; 149 150 init.name = name; 151 init.ops = &clk_gate2_ops; 152 init.flags = flags; 153 init.parent_names = parent_name ? &parent_name : NULL; 154 init.num_parents = parent_name ? 1 : 0; 155 156 gate->hw.init = &init; 157 158 clk = clk_register(dev, &gate->hw); 159 if (IS_ERR(clk)) 160 kfree(gate); 161 162 return clk; 163 } 164