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 * Fixed rate 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/of.h> 18 19 /* 20 * DOC: basic fixed-rate clock that cannot gate 21 * 22 * Traits of this clock: 23 * prepare - clk_(un)prepare only ensures parents are prepared 24 * enable - clk_enable only ensures parents are enabled 25 * rate - rate is always a fixed value. No clk_set_rate support 26 * parent - fixed parent. No clk_set_parent support 27 */ 28 29 static unsigned long clk_fixed_rate_recalc_rate(struct clk_hw *hw, 30 unsigned long parent_rate) 31 { 32 return to_clk_fixed_rate(hw)->fixed_rate; 33 } 34 35 static unsigned long clk_fixed_rate_recalc_accuracy(struct clk_hw *hw, 36 unsigned long parent_accuracy) 37 { 38 return to_clk_fixed_rate(hw)->fixed_accuracy; 39 } 40 41 const struct clk_ops clk_fixed_rate_ops = { 42 .recalc_rate = clk_fixed_rate_recalc_rate, 43 .recalc_accuracy = clk_fixed_rate_recalc_accuracy, 44 }; 45 EXPORT_SYMBOL_GPL(clk_fixed_rate_ops); 46 47 /** 48 * clk_hw_register_fixed_rate_with_accuracy - register fixed-rate clock with 49 * the clock framework 50 * @dev: device that is registering this clock 51 * @name: name of this clock 52 * @parent_name: name of clock's parent 53 * @flags: framework-specific flags 54 * @fixed_rate: non-adjustable clock rate 55 * @fixed_accuracy: non-adjustable clock rate 56 */ 57 struct clk_hw *clk_hw_register_fixed_rate_with_accuracy(struct device *dev, 58 const char *name, const char *parent_name, unsigned long flags, 59 unsigned long fixed_rate, unsigned long fixed_accuracy) 60 { 61 struct clk_fixed_rate *fixed; 62 struct clk_hw *hw; 63 struct clk_init_data init; 64 int ret; 65 66 /* allocate fixed-rate clock */ 67 fixed = kzalloc(sizeof(*fixed), GFP_KERNEL); 68 if (!fixed) 69 return ERR_PTR(-ENOMEM); 70 71 init.name = name; 72 init.ops = &clk_fixed_rate_ops; 73 init.flags = flags | CLK_IS_BASIC; 74 init.parent_names = (parent_name ? &parent_name: NULL); 75 init.num_parents = (parent_name ? 1 : 0); 76 77 /* struct clk_fixed_rate assignments */ 78 fixed->fixed_rate = fixed_rate; 79 fixed->fixed_accuracy = fixed_accuracy; 80 fixed->hw.init = &init; 81 82 /* register the clock */ 83 hw = &fixed->hw; 84 ret = clk_hw_register(dev, hw); 85 if (ret) { 86 kfree(fixed); 87 hw = ERR_PTR(ret); 88 } 89 90 return hw; 91 } 92 EXPORT_SYMBOL_GPL(clk_hw_register_fixed_rate_with_accuracy); 93 94 struct clk *clk_register_fixed_rate_with_accuracy(struct device *dev, 95 const char *name, const char *parent_name, unsigned long flags, 96 unsigned long fixed_rate, unsigned long fixed_accuracy) 97 { 98 struct clk_hw *hw; 99 100 hw = clk_hw_register_fixed_rate_with_accuracy(dev, name, parent_name, 101 flags, fixed_rate, fixed_accuracy); 102 if (IS_ERR(hw)) 103 return ERR_CAST(hw); 104 return hw->clk; 105 } 106 EXPORT_SYMBOL_GPL(clk_register_fixed_rate_with_accuracy); 107 108 /** 109 * clk_hw_register_fixed_rate - register fixed-rate clock with the clock 110 * framework 111 * @dev: device that is registering this clock 112 * @name: name of this clock 113 * @parent_name: name of clock's parent 114 * @flags: framework-specific flags 115 * @fixed_rate: non-adjustable clock rate 116 */ 117 struct clk_hw *clk_hw_register_fixed_rate(struct device *dev, const char *name, 118 const char *parent_name, unsigned long flags, 119 unsigned long fixed_rate) 120 { 121 return clk_hw_register_fixed_rate_with_accuracy(dev, name, parent_name, 122 flags, fixed_rate, 0); 123 } 124 EXPORT_SYMBOL_GPL(clk_hw_register_fixed_rate); 125 126 struct clk *clk_register_fixed_rate(struct device *dev, const char *name, 127 const char *parent_name, unsigned long flags, 128 unsigned long fixed_rate) 129 { 130 return clk_register_fixed_rate_with_accuracy(dev, name, parent_name, 131 flags, fixed_rate, 0); 132 } 133 EXPORT_SYMBOL_GPL(clk_register_fixed_rate); 134 135 void clk_unregister_fixed_rate(struct clk *clk) 136 { 137 struct clk_hw *hw; 138 139 hw = __clk_get_hw(clk); 140 if (!hw) 141 return; 142 143 clk_unregister(clk); 144 kfree(to_clk_fixed_rate(hw)); 145 } 146 EXPORT_SYMBOL_GPL(clk_unregister_fixed_rate); 147 148 #ifdef CONFIG_OF 149 /** 150 * of_fixed_clk_setup() - Setup function for simple fixed rate clock 151 */ 152 void of_fixed_clk_setup(struct device_node *node) 153 { 154 struct clk *clk; 155 const char *clk_name = node->name; 156 u32 rate; 157 u32 accuracy = 0; 158 159 if (of_property_read_u32(node, "clock-frequency", &rate)) 160 return; 161 162 of_property_read_u32(node, "clock-accuracy", &accuracy); 163 164 of_property_read_string(node, "clock-output-names", &clk_name); 165 166 clk = clk_register_fixed_rate_with_accuracy(NULL, clk_name, NULL, 167 0, rate, accuracy); 168 if (!IS_ERR(clk)) 169 of_clk_add_provider(node, of_clk_src_simple_get, clk); 170 } 171 EXPORT_SYMBOL_GPL(of_fixed_clk_setup); 172 CLK_OF_DECLARE(fixed_clk, "fixed-clock", of_fixed_clk_setup); 173 #endif 174