1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2011 Sascha Hauer, Pengutronix <s.hauer@pengutronix.de> 4 */ 5 #include <linux/module.h> 6 #include <linux/clk-provider.h> 7 #include <linux/slab.h> 8 #include <linux/err.h> 9 #include <linux/of.h> 10 #include <linux/platform_device.h> 11 12 /* 13 * DOC: basic fixed multiplier and divider clock that cannot gate 14 * 15 * Traits of this clock: 16 * prepare - clk_prepare only ensures that parents are prepared 17 * enable - clk_enable only ensures that parents are enabled 18 * rate - rate is fixed. clk->rate = parent->rate / div * mult 19 * parent - fixed parent. No clk_set_parent support 20 */ 21 22 static unsigned long clk_factor_recalc_rate(struct clk_hw *hw, 23 unsigned long parent_rate) 24 { 25 struct clk_fixed_factor *fix = to_clk_fixed_factor(hw); 26 unsigned long long int rate; 27 28 rate = (unsigned long long int)parent_rate * fix->mult; 29 do_div(rate, fix->div); 30 return (unsigned long)rate; 31 } 32 33 static long clk_factor_round_rate(struct clk_hw *hw, unsigned long rate, 34 unsigned long *prate) 35 { 36 struct clk_fixed_factor *fix = to_clk_fixed_factor(hw); 37 38 if (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) { 39 unsigned long best_parent; 40 41 best_parent = (rate / fix->mult) * fix->div; 42 *prate = clk_hw_round_rate(clk_hw_get_parent(hw), best_parent); 43 } 44 45 return (*prate / fix->div) * fix->mult; 46 } 47 48 static int clk_factor_set_rate(struct clk_hw *hw, unsigned long rate, 49 unsigned long parent_rate) 50 { 51 /* 52 * We must report success but we can do so unconditionally because 53 * clk_factor_round_rate returns values that ensure this call is a 54 * nop. 55 */ 56 57 return 0; 58 } 59 60 const struct clk_ops clk_fixed_factor_ops = { 61 .round_rate = clk_factor_round_rate, 62 .set_rate = clk_factor_set_rate, 63 .recalc_rate = clk_factor_recalc_rate, 64 }; 65 EXPORT_SYMBOL_GPL(clk_fixed_factor_ops); 66 67 static struct clk_hw * 68 __clk_hw_register_fixed_factor(struct device *dev, struct device_node *np, 69 const char *name, const char *parent_name, int index, 70 unsigned long flags, unsigned int mult, unsigned int div) 71 { 72 struct clk_fixed_factor *fix; 73 struct clk_init_data init = { }; 74 struct clk_parent_data pdata = { .index = index }; 75 struct clk_hw *hw; 76 int ret; 77 78 fix = kmalloc(sizeof(*fix), GFP_KERNEL); 79 if (!fix) 80 return ERR_PTR(-ENOMEM); 81 82 /* struct clk_fixed_factor assignments */ 83 fix->mult = mult; 84 fix->div = div; 85 fix->hw.init = &init; 86 87 init.name = name; 88 init.ops = &clk_fixed_factor_ops; 89 init.flags = flags; 90 if (parent_name) 91 init.parent_names = &parent_name; 92 else 93 init.parent_data = &pdata; 94 init.num_parents = 1; 95 96 hw = &fix->hw; 97 if (dev) 98 ret = clk_hw_register(dev, hw); 99 else 100 ret = of_clk_hw_register(np, hw); 101 if (ret) { 102 kfree(fix); 103 hw = ERR_PTR(ret); 104 } 105 106 return hw; 107 } 108 109 struct clk_hw *clk_hw_register_fixed_factor(struct device *dev, 110 const char *name, const char *parent_name, unsigned long flags, 111 unsigned int mult, unsigned int div) 112 { 113 return __clk_hw_register_fixed_factor(dev, NULL, name, parent_name, -1, 114 flags, mult, div); 115 } 116 EXPORT_SYMBOL_GPL(clk_hw_register_fixed_factor); 117 118 struct clk *clk_register_fixed_factor(struct device *dev, const char *name, 119 const char *parent_name, unsigned long flags, 120 unsigned int mult, unsigned int div) 121 { 122 struct clk_hw *hw; 123 124 hw = clk_hw_register_fixed_factor(dev, name, parent_name, flags, mult, 125 div); 126 if (IS_ERR(hw)) 127 return ERR_CAST(hw); 128 return hw->clk; 129 } 130 EXPORT_SYMBOL_GPL(clk_register_fixed_factor); 131 132 void clk_unregister_fixed_factor(struct clk *clk) 133 { 134 struct clk_hw *hw; 135 136 hw = __clk_get_hw(clk); 137 if (!hw) 138 return; 139 140 clk_unregister(clk); 141 kfree(to_clk_fixed_factor(hw)); 142 } 143 EXPORT_SYMBOL_GPL(clk_unregister_fixed_factor); 144 145 void clk_hw_unregister_fixed_factor(struct clk_hw *hw) 146 { 147 struct clk_fixed_factor *fix; 148 149 fix = to_clk_fixed_factor(hw); 150 151 clk_hw_unregister(hw); 152 kfree(fix); 153 } 154 EXPORT_SYMBOL_GPL(clk_hw_unregister_fixed_factor); 155 156 #ifdef CONFIG_OF 157 static const struct of_device_id set_rate_parent_matches[] = { 158 { .compatible = "allwinner,sun4i-a10-pll3-2x-clk" }, 159 { /* Sentinel */ }, 160 }; 161 162 static struct clk_hw *_of_fixed_factor_clk_setup(struct device_node *node) 163 { 164 struct clk_hw *hw; 165 const char *clk_name = node->name; 166 unsigned long flags = 0; 167 u32 div, mult; 168 int ret; 169 170 if (of_property_read_u32(node, "clock-div", &div)) { 171 pr_err("%s Fixed factor clock <%pOFn> must have a clock-div property\n", 172 __func__, node); 173 return ERR_PTR(-EIO); 174 } 175 176 if (of_property_read_u32(node, "clock-mult", &mult)) { 177 pr_err("%s Fixed factor clock <%pOFn> must have a clock-mult property\n", 178 __func__, node); 179 return ERR_PTR(-EIO); 180 } 181 182 of_property_read_string(node, "clock-output-names", &clk_name); 183 184 if (of_match_node(set_rate_parent_matches, node)) 185 flags |= CLK_SET_RATE_PARENT; 186 187 hw = __clk_hw_register_fixed_factor(NULL, node, clk_name, NULL, 0, 188 flags, mult, div); 189 if (IS_ERR(hw)) { 190 /* 191 * Clear OF_POPULATED flag so that clock registration can be 192 * attempted again from probe function. 193 */ 194 of_node_clear_flag(node, OF_POPULATED); 195 return ERR_CAST(hw); 196 } 197 198 ret = of_clk_add_hw_provider(node, of_clk_hw_simple_get, hw); 199 if (ret) { 200 clk_hw_unregister_fixed_factor(hw); 201 return ERR_PTR(ret); 202 } 203 204 return hw; 205 } 206 207 /** 208 * of_fixed_factor_clk_setup() - Setup function for simple fixed factor clock 209 */ 210 void __init of_fixed_factor_clk_setup(struct device_node *node) 211 { 212 _of_fixed_factor_clk_setup(node); 213 } 214 CLK_OF_DECLARE(fixed_factor_clk, "fixed-factor-clock", 215 of_fixed_factor_clk_setup); 216 217 static int of_fixed_factor_clk_remove(struct platform_device *pdev) 218 { 219 struct clk_hw *clk = platform_get_drvdata(pdev); 220 221 of_clk_del_provider(pdev->dev.of_node); 222 clk_hw_unregister_fixed_factor(clk); 223 224 return 0; 225 } 226 227 static int of_fixed_factor_clk_probe(struct platform_device *pdev) 228 { 229 struct clk_hw *clk; 230 231 /* 232 * This function is not executed when of_fixed_factor_clk_setup 233 * succeeded. 234 */ 235 clk = _of_fixed_factor_clk_setup(pdev->dev.of_node); 236 if (IS_ERR(clk)) 237 return PTR_ERR(clk); 238 239 platform_set_drvdata(pdev, clk); 240 241 return 0; 242 } 243 244 static const struct of_device_id of_fixed_factor_clk_ids[] = { 245 { .compatible = "fixed-factor-clock" }, 246 { } 247 }; 248 MODULE_DEVICE_TABLE(of, of_fixed_factor_clk_ids); 249 250 static struct platform_driver of_fixed_factor_clk_driver = { 251 .driver = { 252 .name = "of_fixed_factor_clk", 253 .of_match_table = of_fixed_factor_clk_ids, 254 }, 255 .probe = of_fixed_factor_clk_probe, 256 .remove = of_fixed_factor_clk_remove, 257 }; 258 builtin_platform_driver(of_fixed_factor_clk_driver); 259 #endif 260