drivers/clk/clk-fixed-factor.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * Copyright (C) 2011 Sascha Hauer, Pengutronix <s.hauer@pengutronix.de>
0004  */
0005 #include <linux/module.h>
0006 #include <linux/clk-provider.h>
0007 #include <linux/slab.h>
0008 #include <linux/err.h>
0009 #include <linux/of.h>
0010 #include <linux/platform_device.h>
0011
0012 /*
0013  * DOC: basic fixed multiplier and divider clock that cannot gate
0014  *
0015  * Traits of this clock:
0016  * prepare - clk_prepare only ensures that parents are prepared
0017  * enable - clk_enable only ensures that parents are enabled
0018  * rate - rate is fixed.  clk->rate = parent->rate / div * mult
0019  * parent - fixed parent.  No clk_set_parent support
0020  */
0021
0022 static unsigned long clk_factor_recalc_rate(struct clk_hw *hw,
0023         unsigned long parent_rate)
0024 {
0025     struct clk_fixed_factor *fix = to_clk_fixed_factor(hw);
0026     unsigned long long int rate;
0027
0028     rate = (unsigned long long int)parent_rate * fix->mult;
0029     do_div(rate, fix->div);
0030     return (unsigned long)rate;
0031 }
0032
0033 static long clk_factor_round_rate(struct clk_hw *hw, unsigned long rate,
0034                 unsigned long *prate)
0035 {
0036     struct clk_fixed_factor *fix = to_clk_fixed_factor(hw);
0037
0038     if (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) {
0039         unsigned long best_parent;
0040
0041         best_parent = (rate / fix->mult) * fix->div;
0042         *prate = clk_hw_round_rate(clk_hw_get_parent(hw), best_parent);
0043     }
0044
0045     return (*prate / fix->div) * fix->mult;
0046 }
0047
0048 static int clk_factor_set_rate(struct clk_hw *hw, unsigned long rate,
0049                 unsigned long parent_rate)
0050 {
0051     /*
0052      * We must report success but we can do so unconditionally because
0053      * clk_factor_round_rate returns values that ensure this call is a
0054      * nop.
0055      */
0056
0057     return 0;
0058 }
0059
0060 const struct clk_ops clk_fixed_factor_ops = {
0061     .round_rate = clk_factor_round_rate,
0062     .set_rate = clk_factor_set_rate,
0063     .recalc_rate = clk_factor_recalc_rate,
0064 };
0065 EXPORT_SYMBOL_GPL(clk_fixed_factor_ops);
0066
0067 static void devm_clk_hw_register_fixed_factor_release(struct device *dev, void *res)
0068 {
0069     struct clk_fixed_factor *fix = res;
0070
0071     /*
0072      * We can not use clk_hw_unregister_fixed_factor, since it will kfree()
0073      * the hw, resulting in double free. Just unregister the hw and let
0074      * devres code kfree() it.
0075      */
0076     clk_hw_unregister(&fix->hw);
0077 }
0078
0079 static struct clk_hw *
0080 __clk_hw_register_fixed_factor(struct device *dev, struct device_node *np,
0081         const char *name, const char *parent_name,
0082         const struct clk_hw *parent_hw, int index,
0083         unsigned long flags, unsigned int mult, unsigned int div,
0084         bool devm)
0085 {
0086     struct clk_fixed_factor *fix;
0087     struct clk_init_data init = { };
0088     struct clk_parent_data pdata = { .index = index };
0089     struct clk_hw *hw;
0090     int ret;
0091
0092     /* You can't use devm without a dev */
0093     if (devm && !dev)
0094         return ERR_PTR(-EINVAL);
0095
0096     if (devm)
0097         fix = devres_alloc(devm_clk_hw_register_fixed_factor_release,
0098                 sizeof(*fix), GFP_KERNEL);
0099     else
0100         fix = kmalloc(sizeof(*fix), GFP_KERNEL);
0101     if (!fix)
0102         return ERR_PTR(-ENOMEM);
0103
0104     /* struct clk_fixed_factor assignments */
0105     fix->mult = mult;
0106     fix->div = div;
0107     fix->hw.init = &init;
0108
0109     init.name = name;
0110     init.ops = &clk_fixed_factor_ops;
0111     init.flags = flags;
0112     if (parent_name)
0113         init.parent_names = &parent_name;
0114     else if (parent_hw)
0115         init.parent_hws = &parent_hw;
0116     else
0117         init.parent_data = &pdata;
0118     init.num_parents = 1;
0119
0120     hw = &fix->hw;
0121     if (dev)
0122         ret = clk_hw_register(dev, hw);
0123     else
0124         ret = of_clk_hw_register(np, hw);
0125     if (ret) {
0126         if (devm)
0127             devres_free(fix);
0128         else
0129             kfree(fix);
0130         hw = ERR_PTR(ret);
0131     } else if (devm)
0132         devres_add(dev, fix);
0133
0134     return hw;
0135 }
0136
0137 /**
0138  * devm_clk_hw_register_fixed_factor_index - Register a fixed factor clock with
0139  * parent from DT index
0140  * @dev: device that is registering this clock
0141  * @name: name of this clock
0142  * @index: index of phandle in @dev 'clocks' property
0143  * @flags: fixed factor flags
0144  * @mult: multiplier
0145  * @div: divider
0146  *
0147  * Return: Pointer to fixed factor clk_hw structure that was registered or
0148  * an error pointer.
0149  */
0150 struct clk_hw *devm_clk_hw_register_fixed_factor_index(struct device *dev,
0151         const char *name, unsigned int index, unsigned long flags,
0152         unsigned int mult, unsigned int div)
0153 {
0154     return __clk_hw_register_fixed_factor(dev, NULL, name, NULL, NULL, index,
0155                           flags, mult, div, true);
0156 }
0157 EXPORT_SYMBOL_GPL(devm_clk_hw_register_fixed_factor_index);
0158
0159 /**
0160  * devm_clk_hw_register_fixed_factor_parent_hw - Register a fixed factor clock with
0161  * pointer to parent clock
0162  * @dev: device that is registering this clock
0163  * @name: name of this clock
0164  * @parent_hw: pointer to parent clk
0165  * @flags: fixed factor flags
0166  * @mult: multiplier
0167  * @div: divider
0168  *
0169  * Return: Pointer to fixed factor clk_hw structure that was registered or
0170  * an error pointer.
0171  */
0172 struct clk_hw *devm_clk_hw_register_fixed_factor_parent_hw(struct device *dev,
0173         const char *name, const struct clk_hw *parent_hw,
0174         unsigned long flags, unsigned int mult, unsigned int div)
0175 {
0176     return __clk_hw_register_fixed_factor(dev, NULL, name, NULL, parent_hw,
0177                           -1, flags, mult, div, true);
0178 }
0179 EXPORT_SYMBOL_GPL(devm_clk_hw_register_fixed_factor_parent_hw);
0180
0181 struct clk_hw *clk_hw_register_fixed_factor_parent_hw(struct device *dev,
0182         const char *name, const struct clk_hw *parent_hw,
0183         unsigned long flags, unsigned int mult, unsigned int div)
0184 {
0185     return __clk_hw_register_fixed_factor(dev, NULL, name, NULL,
0186                           parent_hw, -1, flags, mult, div,
0187                           false);
0188 }
0189 EXPORT_SYMBOL_GPL(clk_hw_register_fixed_factor_parent_hw);
0190
0191 struct clk_hw *clk_hw_register_fixed_factor(struct device *dev,
0192         const char *name, const char *parent_name, unsigned long flags,
0193         unsigned int mult, unsigned int div)
0194 {
0195     return __clk_hw_register_fixed_factor(dev, NULL, name, parent_name, NULL, -1,
0196                           flags, mult, div, false);
0197 }
0198 EXPORT_SYMBOL_GPL(clk_hw_register_fixed_factor);
0199
0200 struct clk *clk_register_fixed_factor(struct device *dev, const char *name,
0201         const char *parent_name, unsigned long flags,
0202         unsigned int mult, unsigned int div)
0203 {
0204     struct clk_hw *hw;
0205
0206     hw = clk_hw_register_fixed_factor(dev, name, parent_name, flags, mult,
0207                       div);
0208     if (IS_ERR(hw))
0209         return ERR_CAST(hw);
0210     return hw->clk;
0211 }
0212 EXPORT_SYMBOL_GPL(clk_register_fixed_factor);
0213
0214 void clk_unregister_fixed_factor(struct clk *clk)
0215 {
0216     struct clk_hw *hw;
0217
0218     hw = __clk_get_hw(clk);
0219     if (!hw)
0220         return;
0221
0222     clk_unregister(clk);
0223     kfree(to_clk_fixed_factor(hw));
0224 }
0225 EXPORT_SYMBOL_GPL(clk_unregister_fixed_factor);
0226
0227 void clk_hw_unregister_fixed_factor(struct clk_hw *hw)
0228 {
0229     struct clk_fixed_factor *fix;
0230
0231     fix = to_clk_fixed_factor(hw);
0232
0233     clk_hw_unregister(hw);
0234     kfree(fix);
0235 }
0236 EXPORT_SYMBOL_GPL(clk_hw_unregister_fixed_factor);
0237
0238 struct clk_hw *devm_clk_hw_register_fixed_factor(struct device *dev,
0239         const char *name, const char *parent_name, unsigned long flags,
0240         unsigned int mult, unsigned int div)
0241 {
0242     return __clk_hw_register_fixed_factor(dev, NULL, name, parent_name, NULL, -1,
0243             flags, mult, div, true);
0244 }
0245 EXPORT_SYMBOL_GPL(devm_clk_hw_register_fixed_factor);
0246
0247 #ifdef CONFIG_OF
0248 static struct clk_hw *_of_fixed_factor_clk_setup(struct device_node *node)
0249 {
0250     struct clk_hw *hw;
0251     const char *clk_name = node->name;
0252     u32 div, mult;
0253     int ret;
0254
0255     if (of_property_read_u32(node, "clock-div", &div)) {
0256         pr_err("%s Fixed factor clock <%pOFn> must have a clock-div property\n",
0257             __func__, node);
0258         return ERR_PTR(-EIO);
0259     }
0260
0261     if (of_property_read_u32(node, "clock-mult", &mult)) {
0262         pr_err("%s Fixed factor clock <%pOFn> must have a clock-mult property\n",
0263             __func__, node);
0264         return ERR_PTR(-EIO);
0265     }
0266
0267     of_property_read_string(node, "clock-output-names", &clk_name);
0268
0269     hw = __clk_hw_register_fixed_factor(NULL, node, clk_name, NULL, NULL, 0,
0270                         0, mult, div, false);
0271     if (IS_ERR(hw)) {
0272         /*
0273          * Clear OF_POPULATED flag so that clock registration can be
0274          * attempted again from probe function.
0275          */
0276         of_node_clear_flag(node, OF_POPULATED);
0277         return ERR_CAST(hw);
0278     }
0279
0280     ret = of_clk_add_hw_provider(node, of_clk_hw_simple_get, hw);
0281     if (ret) {
0282         clk_hw_unregister_fixed_factor(hw);
0283         return ERR_PTR(ret);
0284     }
0285
0286     return hw;
0287 }
0288
0289 /**
0290  * of_fixed_factor_clk_setup() - Setup function for simple fixed factor clock
0291  * @node:   device node for the clock
0292  */
0293 void __init of_fixed_factor_clk_setup(struct device_node *node)
0294 {
0295     _of_fixed_factor_clk_setup(node);
0296 }
0297 CLK_OF_DECLARE(fixed_factor_clk, "fixed-factor-clock",
0298         of_fixed_factor_clk_setup);
0299
0300 static int of_fixed_factor_clk_remove(struct platform_device *pdev)
0301 {
0302     struct clk_hw *clk = platform_get_drvdata(pdev);
0303
0304     of_clk_del_provider(pdev->dev.of_node);
0305     clk_hw_unregister_fixed_factor(clk);
0306
0307     return 0;
0308 }
0309
0310 static int of_fixed_factor_clk_probe(struct platform_device *pdev)
0311 {
0312     struct clk_hw *clk;
0313
0314     /*
0315      * This function is not executed when of_fixed_factor_clk_setup
0316      * succeeded.
0317      */
0318     clk = _of_fixed_factor_clk_setup(pdev->dev.of_node);
0319     if (IS_ERR(clk))
0320         return PTR_ERR(clk);
0321
0322     platform_set_drvdata(pdev, clk);
0323
0324     return 0;
0325 }
0326
0327 static const struct of_device_id of_fixed_factor_clk_ids[] = {
0328     { .compatible = "fixed-factor-clock" },
0329     { }
0330 };
0331 MODULE_DEVICE_TABLE(of, of_fixed_factor_clk_ids);
0332
0333 static struct platform_driver of_fixed_factor_clk_driver = {
0334     .driver = {
0335         .name = "of_fixed_factor_clk",
0336         .of_match_table = of_fixed_factor_clk_ids,
0337     },
0338     .probe = of_fixed_factor_clk_probe,
0339     .remove = of_fixed_factor_clk_remove,
0340 };
0341 builtin_platform_driver(of_fixed_factor_clk_driver);
0342 #endif