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 #include <linux/platform_device.h> 19 20 /* 21 * DOC: basic fixed-rate clock that cannot gate 22 * 23 * Traits of this clock: 24 * prepare - clk_(un)prepare only ensures parents are prepared 25 * enable - clk_enable only ensures parents are enabled 26 * rate - rate is always a fixed value. No clk_set_rate support 27 * parent - fixed parent. No clk_set_parent support 28 */ 29 30 static unsigned long clk_fixed_rate_recalc_rate(struct clk_hw *hw, 31 unsigned long parent_rate) 32 { 33 return to_clk_fixed_rate(hw)->fixed_rate; 34 } 35 36 static unsigned long clk_fixed_rate_recalc_accuracy(struct clk_hw *hw, 37 unsigned long parent_accuracy) 38 { 39 return to_clk_fixed_rate(hw)->fixed_accuracy; 40 } 41 42 const struct clk_ops clk_fixed_rate_ops = { 43 .recalc_rate = clk_fixed_rate_recalc_rate, 44 .recalc_accuracy = clk_fixed_rate_recalc_accuracy, 45 }; 46 EXPORT_SYMBOL_GPL(clk_fixed_rate_ops); 47 48 /** 49 * clk_hw_register_fixed_rate_with_accuracy - register fixed-rate clock with 50 * the clock framework 51 * @dev: device that is registering this clock 52 * @name: name of this clock 53 * @parent_name: name of clock's parent 54 * @flags: framework-specific flags 55 * @fixed_rate: non-adjustable clock rate 56 * @fixed_accuracy: non-adjustable clock rate 57 */ 58 struct clk_hw *clk_hw_register_fixed_rate_with_accuracy(struct device *dev, 59 const char *name, const char *parent_name, unsigned long flags, 60 unsigned long fixed_rate, unsigned long fixed_accuracy) 61 { 62 struct clk_fixed_rate *fixed; 63 struct clk_hw *hw; 64 struct clk_init_data init; 65 int ret; 66 67 /* allocate fixed-rate clock */ 68 fixed = kzalloc(sizeof(*fixed), GFP_KERNEL); 69 if (!fixed) 70 return ERR_PTR(-ENOMEM); 71 72 init.name = name; 73 init.ops = &clk_fixed_rate_ops; 74 init.flags = flags | CLK_IS_BASIC; 75 init.parent_names = (parent_name ? &parent_name: NULL); 76 init.num_parents = (parent_name ? 1 : 0); 77 78 /* struct clk_fixed_rate assignments */ 79 fixed->fixed_rate = fixed_rate; 80 fixed->fixed_accuracy = fixed_accuracy; 81 fixed->hw.init = &init; 82 83 /* register the clock */ 84 hw = &fixed->hw; 85 ret = clk_hw_register(dev, hw); 86 if (ret) { 87 kfree(fixed); 88 hw = ERR_PTR(ret); 89 } 90 91 return hw; 92 } 93 EXPORT_SYMBOL_GPL(clk_hw_register_fixed_rate_with_accuracy); 94 95 struct clk *clk_register_fixed_rate_with_accuracy(struct device *dev, 96 const char *name, const char *parent_name, unsigned long flags, 97 unsigned long fixed_rate, unsigned long fixed_accuracy) 98 { 99 struct clk_hw *hw; 100 101 hw = clk_hw_register_fixed_rate_with_accuracy(dev, name, parent_name, 102 flags, fixed_rate, fixed_accuracy); 103 if (IS_ERR(hw)) 104 return ERR_CAST(hw); 105 return hw->clk; 106 } 107 EXPORT_SYMBOL_GPL(clk_register_fixed_rate_with_accuracy); 108 109 /** 110 * clk_hw_register_fixed_rate - register fixed-rate clock with the clock 111 * framework 112 * @dev: device that is registering this clock 113 * @name: name of this clock 114 * @parent_name: name of clock's parent 115 * @flags: framework-specific flags 116 * @fixed_rate: non-adjustable clock rate 117 */ 118 struct clk_hw *clk_hw_register_fixed_rate(struct device *dev, const char *name, 119 const char *parent_name, unsigned long flags, 120 unsigned long fixed_rate) 121 { 122 return clk_hw_register_fixed_rate_with_accuracy(dev, name, parent_name, 123 flags, fixed_rate, 0); 124 } 125 EXPORT_SYMBOL_GPL(clk_hw_register_fixed_rate); 126 127 struct clk *clk_register_fixed_rate(struct device *dev, const char *name, 128 const char *parent_name, unsigned long flags, 129 unsigned long fixed_rate) 130 { 131 return clk_register_fixed_rate_with_accuracy(dev, name, parent_name, 132 flags, fixed_rate, 0); 133 } 134 EXPORT_SYMBOL_GPL(clk_register_fixed_rate); 135 136 void clk_unregister_fixed_rate(struct clk *clk) 137 { 138 struct clk_hw *hw; 139 140 hw = __clk_get_hw(clk); 141 if (!hw) 142 return; 143 144 clk_unregister(clk); 145 kfree(to_clk_fixed_rate(hw)); 146 } 147 EXPORT_SYMBOL_GPL(clk_unregister_fixed_rate); 148 149 void clk_hw_unregister_fixed_rate(struct clk_hw *hw) 150 { 151 struct clk_fixed_rate *fixed; 152 153 fixed = to_clk_fixed_rate(hw); 154 155 clk_hw_unregister(hw); 156 kfree(fixed); 157 } 158 EXPORT_SYMBOL_GPL(clk_hw_unregister_fixed_rate); 159 160 #ifdef CONFIG_OF 161 static struct clk *_of_fixed_clk_setup(struct device_node *node) 162 { 163 struct clk *clk; 164 const char *clk_name = node->name; 165 u32 rate; 166 u32 accuracy = 0; 167 int ret; 168 169 if (of_property_read_u32(node, "clock-frequency", &rate)) 170 return ERR_PTR(-EIO); 171 172 of_property_read_u32(node, "clock-accuracy", &accuracy); 173 174 of_property_read_string(node, "clock-output-names", &clk_name); 175 176 clk = clk_register_fixed_rate_with_accuracy(NULL, clk_name, NULL, 177 0, rate, accuracy); 178 if (IS_ERR(clk)) 179 return clk; 180 181 ret = of_clk_add_provider(node, of_clk_src_simple_get, clk); 182 if (ret) { 183 clk_unregister(clk); 184 return ERR_PTR(ret); 185 } 186 187 return clk; 188 } 189 190 /** 191 * of_fixed_clk_setup() - Setup function for simple fixed rate clock 192 */ 193 void __init of_fixed_clk_setup(struct device_node *node) 194 { 195 _of_fixed_clk_setup(node); 196 } 197 CLK_OF_DECLARE(fixed_clk, "fixed-clock", of_fixed_clk_setup); 198 199 static int of_fixed_clk_remove(struct platform_device *pdev) 200 { 201 struct clk *clk = platform_get_drvdata(pdev); 202 203 clk_unregister_fixed_rate(clk); 204 205 return 0; 206 } 207 208 static int of_fixed_clk_probe(struct platform_device *pdev) 209 { 210 struct clk *clk; 211 212 /* 213 * This function is not executed when of_fixed_clk_setup 214 * succeeded. 215 */ 216 clk = _of_fixed_clk_setup(pdev->dev.of_node); 217 if (IS_ERR(clk)) 218 return PTR_ERR(clk); 219 220 platform_set_drvdata(pdev, clk); 221 222 return 0; 223 } 224 225 static const struct of_device_id of_fixed_clk_ids[] = { 226 { .compatible = "fixed-clock" }, 227 { } 228 }; 229 MODULE_DEVICE_TABLE(of, of_fixed_clk_ids); 230 231 static struct platform_driver of_fixed_clk_driver = { 232 .driver = { 233 .name = "of_fixed_clk", 234 .of_match_table = of_fixed_clk_ids, 235 }, 236 .probe = of_fixed_clk_probe, 237 .remove = of_fixed_clk_remove, 238 }; 239 builtin_platform_driver(of_fixed_clk_driver); 240 #endif 241