1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com> 4 * Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd <mturquette@linaro.org> 5 * 6 * Fixed rate clock implementation 7 */ 8 9 #include <linux/clk-provider.h> 10 #include <linux/module.h> 11 #include <linux/slab.h> 12 #include <linux/io.h> 13 #include <linux/err.h> 14 #include <linux/of.h> 15 #include <linux/platform_device.h> 16 17 /* 18 * DOC: basic fixed-rate clock that cannot gate 19 * 20 * Traits of this clock: 21 * prepare - clk_(un)prepare only ensures parents are prepared 22 * enable - clk_enable only ensures parents are enabled 23 * rate - rate is always a fixed value. No clk_set_rate support 24 * parent - fixed parent. No clk_set_parent support 25 */ 26 27 #define to_clk_fixed_rate(_hw) container_of(_hw, struct clk_fixed_rate, hw) 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 struct clk_fixed_rate *fixed = to_clk_fixed_rate(hw); 39 40 if (fixed->flags & CLK_FIXED_RATE_PARENT_ACCURACY) 41 return parent_accuracy; 42 43 return fixed->fixed_accuracy; 44 } 45 46 const struct clk_ops clk_fixed_rate_ops = { 47 .recalc_rate = clk_fixed_rate_recalc_rate, 48 .recalc_accuracy = clk_fixed_rate_recalc_accuracy, 49 }; 50 EXPORT_SYMBOL_GPL(clk_fixed_rate_ops); 51 52 static void devm_clk_hw_register_fixed_rate_release(struct device *dev, void *res) 53 { 54 struct clk_fixed_rate *fix = res; 55 56 /* 57 * We can not use clk_hw_unregister_fixed_rate, since it will kfree() 58 * the hw, resulting in double free. Just unregister the hw and let 59 * devres code kfree() it. 60 */ 61 clk_hw_unregister(&fix->hw); 62 } 63 64 struct clk_hw *__clk_hw_register_fixed_rate(struct device *dev, 65 struct device_node *np, const char *name, 66 const char *parent_name, const struct clk_hw *parent_hw, 67 const struct clk_parent_data *parent_data, unsigned long flags, 68 unsigned long fixed_rate, unsigned long fixed_accuracy, 69 unsigned long clk_fixed_flags, bool devm) 70 { 71 struct clk_fixed_rate *fixed; 72 struct clk_hw *hw; 73 struct clk_init_data init = {}; 74 int ret = -EINVAL; 75 76 /* allocate fixed-rate clock */ 77 if (devm) 78 fixed = devres_alloc(devm_clk_hw_register_fixed_rate_release, 79 sizeof(*fixed), GFP_KERNEL); 80 else 81 fixed = kzalloc(sizeof(*fixed), GFP_KERNEL); 82 if (!fixed) 83 return ERR_PTR(-ENOMEM); 84 85 init.name = name; 86 init.ops = &clk_fixed_rate_ops; 87 init.flags = flags; 88 init.parent_names = parent_name ? &parent_name : NULL; 89 init.parent_hws = parent_hw ? &parent_hw : NULL; 90 init.parent_data = parent_data; 91 if (parent_name || parent_hw || parent_data) 92 init.num_parents = 1; 93 else 94 init.num_parents = 0; 95 96 /* struct clk_fixed_rate assignments */ 97 fixed->flags = clk_fixed_flags; 98 fixed->fixed_rate = fixed_rate; 99 fixed->fixed_accuracy = fixed_accuracy; 100 fixed->hw.init = &init; 101 102 /* register the clock */ 103 hw = &fixed->hw; 104 if (dev || !np) 105 ret = clk_hw_register(dev, hw); 106 else 107 ret = of_clk_hw_register(np, hw); 108 if (ret) { 109 if (devm) 110 devres_free(fixed); 111 else 112 kfree(fixed); 113 hw = ERR_PTR(ret); 114 } else if (devm) 115 devres_add(dev, fixed); 116 117 return hw; 118 } 119 EXPORT_SYMBOL_GPL(__clk_hw_register_fixed_rate); 120 121 struct clk *clk_register_fixed_rate(struct device *dev, const char *name, 122 const char *parent_name, unsigned long flags, 123 unsigned long fixed_rate) 124 { 125 struct clk_hw *hw; 126 127 hw = clk_hw_register_fixed_rate_with_accuracy(dev, name, parent_name, 128 flags, fixed_rate, 0); 129 if (IS_ERR(hw)) 130 return ERR_CAST(hw); 131 return hw->clk; 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 void clk_hw_unregister_fixed_rate(struct clk_hw *hw) 149 { 150 struct clk_fixed_rate *fixed; 151 152 fixed = to_clk_fixed_rate(hw); 153 154 clk_hw_unregister(hw); 155 kfree(fixed); 156 } 157 EXPORT_SYMBOL_GPL(clk_hw_unregister_fixed_rate); 158 159 #ifdef CONFIG_OF 160 static struct clk_hw *_of_fixed_clk_setup(struct device_node *node) 161 { 162 struct clk_hw *hw; 163 const char *clk_name = node->name; 164 u32 rate; 165 u32 accuracy = 0; 166 int ret; 167 168 if (of_property_read_u32(node, "clock-frequency", &rate)) 169 return ERR_PTR(-EIO); 170 171 of_property_read_u32(node, "clock-accuracy", &accuracy); 172 173 of_property_read_string(node, "clock-output-names", &clk_name); 174 175 hw = clk_hw_register_fixed_rate_with_accuracy(NULL, clk_name, NULL, 176 0, rate, accuracy); 177 if (IS_ERR(hw)) 178 return hw; 179 180 ret = of_clk_add_hw_provider(node, of_clk_hw_simple_get, hw); 181 if (ret) { 182 clk_hw_unregister_fixed_rate(hw); 183 return ERR_PTR(ret); 184 } 185 186 return hw; 187 } 188 189 /** 190 * of_fixed_clk_setup() - Setup function for simple fixed rate clock 191 * @node: device node for the 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_hw *hw = platform_get_drvdata(pdev); 202 203 of_clk_del_provider(pdev->dev.of_node); 204 clk_hw_unregister_fixed_rate(hw); 205 206 return 0; 207 } 208 209 static int of_fixed_clk_probe(struct platform_device *pdev) 210 { 211 struct clk_hw *hw; 212 213 /* 214 * This function is not executed when of_fixed_clk_setup 215 * succeeded. 216 */ 217 hw = _of_fixed_clk_setup(pdev->dev.of_node); 218 if (IS_ERR(hw)) 219 return PTR_ERR(hw); 220 221 platform_set_drvdata(pdev, hw); 222 223 return 0; 224 } 225 226 static const struct of_device_id of_fixed_clk_ids[] = { 227 { .compatible = "fixed-clock" }, 228 { } 229 }; 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