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1// SPDX-License-Identifier: GPL-2.02/*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 implementation7 */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 gate19 *20 * Traits of this clock:21 * prepare - clk_(un)prepare only ensures parents are prepared22 * enable - clk_enable only ensures parents are enabled23 * rate - rate is always a fixed value. No clk_set_rate support24 * parent - fixed parent. No clk_set_parent support25 */26 27#define to_clk_fixed_rate(_hw) container_of(_hw, struct clk_fixed_rate, hw)28 29static 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 35static 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 46const struct clk_ops clk_fixed_rate_ops = {47 .recalc_rate = clk_fixed_rate_recalc_rate,48 .recalc_accuracy = clk_fixed_rate_recalc_accuracy,49};50EXPORT_SYMBOL_GPL(clk_fixed_rate_ops);51 52static 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 let59 * devres code kfree() it.60 */61 clk_hw_unregister(&fix->hw);62}63 64struct 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 else81 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 else94 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 else107 ret = of_clk_hw_register(np, hw);108 if (ret) {109 if (devm)110 devres_free(fixed);111 else112 kfree(fixed);113 hw = ERR_PTR(ret);114 } else if (devm)115 devres_add(dev, fixed);116 117 return hw;118}119EXPORT_SYMBOL_GPL(__clk_hw_register_fixed_rate);120 121struct 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}133EXPORT_SYMBOL_GPL(clk_register_fixed_rate);134 135void 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}146EXPORT_SYMBOL_GPL(clk_unregister_fixed_rate);147 148void 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}157EXPORT_SYMBOL_GPL(clk_hw_unregister_fixed_rate);158 159#ifdef CONFIG_OF160static 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 clock191 * @node: device node for the clock192 */193void __init of_fixed_clk_setup(struct device_node *node)194{195 _of_fixed_clk_setup(node);196}197CLK_OF_DECLARE(fixed_clk, "fixed-clock", of_fixed_clk_setup);198 199static void 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 207static int of_fixed_clk_probe(struct platform_device *pdev)208{209 struct clk_hw *hw;210 211 /*212 * This function is not executed when of_fixed_clk_setup213 * succeeded.214 */215 hw = _of_fixed_clk_setup(pdev->dev.of_node);216 if (IS_ERR(hw))217 return PTR_ERR(hw);218 219 platform_set_drvdata(pdev, hw);220 221 return 0;222}223 224static const struct of_device_id of_fixed_clk_ids[] = {225 { .compatible = "fixed-clock" },226 { }227};228 229static struct platform_driver of_fixed_clk_driver = {230 .driver = {231 .name = "of_fixed_clk",232 .of_match_table = of_fixed_clk_ids,233 },234 .probe = of_fixed_clk_probe,235 .remove = of_fixed_clk_remove,236};237builtin_platform_driver(of_fixed_clk_driver);238#endif239