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_register_fixed_rate_with_accuracy - register fixed-rate clock with the 49 * 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 *clk_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 *clk; 63 struct clk_init_data init; 64 65 /* allocate fixed-rate clock */ 66 fixed = kzalloc(sizeof(*fixed), GFP_KERNEL); 67 if (!fixed) 68 return ERR_PTR(-ENOMEM); 69 70 init.name = name; 71 init.ops = &clk_fixed_rate_ops; 72 init.flags = flags | CLK_IS_BASIC; 73 init.parent_names = (parent_name ? &parent_name: NULL); 74 init.num_parents = (parent_name ? 1 : 0); 75 76 /* struct clk_fixed_rate assignments */ 77 fixed->fixed_rate = fixed_rate; 78 fixed->fixed_accuracy = fixed_accuracy; 79 fixed->hw.init = &init; 80 81 /* register the clock */ 82 clk = clk_register(dev, &fixed->hw); 83 if (IS_ERR(clk)) 84 kfree(fixed); 85 86 return clk; 87 } 88 EXPORT_SYMBOL_GPL(clk_register_fixed_rate_with_accuracy); 89 90 /** 91 * clk_register_fixed_rate - register fixed-rate clock with the clock framework 92 * @dev: device that is registering this clock 93 * @name: name of this clock 94 * @parent_name: name of clock's parent 95 * @flags: framework-specific flags 96 * @fixed_rate: non-adjustable clock rate 97 */ 98 struct clk *clk_register_fixed_rate(struct device *dev, const char *name, 99 const char *parent_name, unsigned long flags, 100 unsigned long fixed_rate) 101 { 102 return clk_register_fixed_rate_with_accuracy(dev, name, parent_name, 103 flags, fixed_rate, 0); 104 } 105 EXPORT_SYMBOL_GPL(clk_register_fixed_rate); 106 107 void clk_unregister_fixed_rate(struct clk *clk) 108 { 109 struct clk_hw *hw; 110 111 hw = __clk_get_hw(clk); 112 if (!hw) 113 return; 114 115 clk_unregister(clk); 116 kfree(to_clk_fixed_rate(hw)); 117 } 118 EXPORT_SYMBOL_GPL(clk_unregister_fixed_rate); 119 120 #ifdef CONFIG_OF 121 /** 122 * of_fixed_clk_setup() - Setup function for simple fixed rate clock 123 */ 124 void of_fixed_clk_setup(struct device_node *node) 125 { 126 struct clk *clk; 127 const char *clk_name = node->name; 128 u32 rate; 129 u32 accuracy = 0; 130 131 if (of_property_read_u32(node, "clock-frequency", &rate)) 132 return; 133 134 of_property_read_u32(node, "clock-accuracy", &accuracy); 135 136 of_property_read_string(node, "clock-output-names", &clk_name); 137 138 clk = clk_register_fixed_rate_with_accuracy(NULL, clk_name, NULL, 139 0, rate, accuracy); 140 if (!IS_ERR(clk)) 141 of_clk_add_provider(node, of_clk_src_simple_get, clk); 142 } 143 EXPORT_SYMBOL_GPL(of_fixed_clk_setup); 144 CLK_OF_DECLARE(fixed_clk, "fixed-clock", of_fixed_clk_setup); 145 #endif 146