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 #define to_clk_fixed_rate(_hw) container_of(_hw, struct clk_fixed_rate, hw) 30 31 static unsigned long clk_fixed_rate_recalc_rate(struct clk_hw *hw, 32 unsigned long parent_rate) 33 { 34 return to_clk_fixed_rate(hw)->fixed_rate; 35 } 36 37 static unsigned long clk_fixed_rate_recalc_accuracy(struct clk_hw *hw, 38 unsigned long parent_accuracy) 39 { 40 return to_clk_fixed_rate(hw)->fixed_accuracy; 41 } 42 43 const struct clk_ops clk_fixed_rate_ops = { 44 .recalc_rate = clk_fixed_rate_recalc_rate, 45 .recalc_accuracy = clk_fixed_rate_recalc_accuracy, 46 }; 47 EXPORT_SYMBOL_GPL(clk_fixed_rate_ops); 48 49 /** 50 * clk_register_fixed_rate_with_accuracy - register fixed-rate clock with the 51 * clock framework 52 * @dev: device that is registering this clock 53 * @name: name of this clock 54 * @parent_name: name of clock's parent 55 * @flags: framework-specific flags 56 * @fixed_rate: non-adjustable clock rate 57 * @fixed_accuracy: non-adjustable clock rate 58 */ 59 struct clk *clk_register_fixed_rate_with_accuracy(struct device *dev, 60 const char *name, const char *parent_name, unsigned long flags, 61 unsigned long fixed_rate, unsigned long fixed_accuracy) 62 { 63 struct clk_fixed_rate *fixed; 64 struct clk *clk; 65 struct clk_init_data init; 66 67 /* allocate fixed-rate clock */ 68 fixed = kzalloc(sizeof(struct clk_fixed_rate), GFP_KERNEL); 69 if (!fixed) { 70 pr_err("%s: could not allocate fixed clk\n", __func__); 71 return ERR_PTR(-ENOMEM); 72 } 73 74 init.name = name; 75 init.ops = &clk_fixed_rate_ops; 76 init.flags = flags | CLK_IS_BASIC; 77 init.parent_names = (parent_name ? &parent_name: NULL); 78 init.num_parents = (parent_name ? 1 : 0); 79 80 /* struct clk_fixed_rate assignments */ 81 fixed->fixed_rate = fixed_rate; 82 fixed->fixed_accuracy = fixed_accuracy; 83 fixed->hw.init = &init; 84 85 /* register the clock */ 86 clk = clk_register(dev, &fixed->hw); 87 if (IS_ERR(clk)) 88 kfree(fixed); 89 90 return clk; 91 } 92 EXPORT_SYMBOL_GPL(clk_register_fixed_rate_with_accuracy); 93 94 /** 95 * clk_register_fixed_rate - register fixed-rate clock with the clock framework 96 * @dev: device that is registering this clock 97 * @name: name of this clock 98 * @parent_name: name of clock's parent 99 * @flags: framework-specific flags 100 * @fixed_rate: non-adjustable clock rate 101 */ 102 struct clk *clk_register_fixed_rate(struct device *dev, const char *name, 103 const char *parent_name, unsigned long flags, 104 unsigned long fixed_rate) 105 { 106 return clk_register_fixed_rate_with_accuracy(dev, name, parent_name, 107 flags, fixed_rate, 0); 108 } 109 EXPORT_SYMBOL_GPL(clk_register_fixed_rate); 110 111 #ifdef CONFIG_OF 112 /** 113 * of_fixed_clk_setup() - Setup function for simple fixed rate clock 114 */ 115 void of_fixed_clk_setup(struct device_node *node) 116 { 117 struct clk *clk; 118 const char *clk_name = node->name; 119 u32 rate; 120 u32 accuracy = 0; 121 122 if (of_property_read_u32(node, "clock-frequency", &rate)) 123 return; 124 125 of_property_read_u32(node, "clock-accuracy", &accuracy); 126 127 of_property_read_string(node, "clock-output-names", &clk_name); 128 129 clk = clk_register_fixed_rate_with_accuracy(NULL, clk_name, NULL, 130 CLK_IS_ROOT, rate, 131 accuracy); 132 if (!IS_ERR(clk)) 133 of_clk_add_provider(node, of_clk_src_simple_get, clk); 134 } 135 EXPORT_SYMBOL_GPL(of_fixed_clk_setup); 136 CLK_OF_DECLARE(fixed_clk, "fixed-clock", of_fixed_clk_setup); 137 #endif 138