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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Copyright (C) 2016 Rafał Miłecki <rafal@milecki.pl>4 */5 6#include <linux/clk-provider.h>7#include <linux/err.h>8#include <linux/io.h>9#include <linux/mfd/syscon.h>10#include <linux/of.h>11#include <linux/of_address.h>12#include <linux/regmap.h>13#include <linux/slab.h>14 15#define PMU_XTAL_FREQ_RATIO 0x66c16#define XTAL_ALP_PER_4ILP 0x00001fff17#define XTAL_CTL_EN 0x8000000018#define PMU_SLOW_CLK_PERIOD 0x6dc19 20struct bcm53573_ilp {21 struct clk_hw hw;22 struct regmap *regmap;23};24 25static int bcm53573_ilp_enable(struct clk_hw *hw)26{27 struct bcm53573_ilp *ilp = container_of(hw, struct bcm53573_ilp, hw);28 29 regmap_write(ilp->regmap, PMU_SLOW_CLK_PERIOD, 0x10199);30 regmap_write(ilp->regmap, 0x674, 0x10000);31 32 return 0;33}34 35static void bcm53573_ilp_disable(struct clk_hw *hw)36{37 struct bcm53573_ilp *ilp = container_of(hw, struct bcm53573_ilp, hw);38 39 regmap_write(ilp->regmap, PMU_SLOW_CLK_PERIOD, 0);40 regmap_write(ilp->regmap, 0x674, 0);41}42 43static unsigned long bcm53573_ilp_recalc_rate(struct clk_hw *hw,44 unsigned long parent_rate)45{46 struct bcm53573_ilp *ilp = container_of(hw, struct bcm53573_ilp, hw);47 struct regmap *regmap = ilp->regmap;48 u32 last_val, cur_val;49 int sum = 0, num = 0, loop_num = 0;50 int avg;51 52 /* Enable measurement */53 regmap_write(regmap, PMU_XTAL_FREQ_RATIO, XTAL_CTL_EN);54 55 /* Read initial value */56 regmap_read(regmap, PMU_XTAL_FREQ_RATIO, &last_val);57 last_val &= XTAL_ALP_PER_4ILP;58 59 /*60 * At minimum we should loop for a bit to let hardware do the61 * measurement. This isn't very accurate however, so for a better62 * precision lets try getting 20 different values for and use average.63 */64 while (num < 20) {65 regmap_read(regmap, PMU_XTAL_FREQ_RATIO, &cur_val);66 cur_val &= XTAL_ALP_PER_4ILP;67 68 if (cur_val != last_val) {69 /* Got different value, use it */70 sum += cur_val;71 num++;72 loop_num = 0;73 last_val = cur_val;74 } else if (++loop_num > 5000) {75 /* Same value over and over, give up */76 sum += cur_val;77 num++;78 break;79 }80 81 cpu_relax();82 }83 84 /* Disable measurement to save power */85 regmap_write(regmap, PMU_XTAL_FREQ_RATIO, 0x0);86 87 avg = sum / num;88 89 return parent_rate * 4 / avg;90}91 92static const struct clk_ops bcm53573_ilp_clk_ops = {93 .enable = bcm53573_ilp_enable,94 .disable = bcm53573_ilp_disable,95 .recalc_rate = bcm53573_ilp_recalc_rate,96};97 98static void bcm53573_ilp_init(struct device_node *np)99{100 struct bcm53573_ilp *ilp;101 struct clk_init_data init = { };102 const char *parent_name;103 int err;104 105 ilp = kzalloc(sizeof(*ilp), GFP_KERNEL);106 if (!ilp)107 return;108 109 parent_name = of_clk_get_parent_name(np, 0);110 if (!parent_name) {111 err = -ENOENT;112 goto err_free_ilp;113 }114 115 ilp->regmap = syscon_node_to_regmap(np->parent);116 if (IS_ERR(ilp->regmap)) {117 err = PTR_ERR(ilp->regmap);118 goto err_free_ilp;119 }120 121 init.name = np->name;122 init.ops = &bcm53573_ilp_clk_ops;123 init.parent_names = &parent_name;124 init.num_parents = 1;125 126 ilp->hw.init = &init;127 err = clk_hw_register(NULL, &ilp->hw);128 if (err)129 goto err_free_ilp;130 131 err = of_clk_add_hw_provider(np, of_clk_hw_simple_get, &ilp->hw);132 if (err)133 goto err_clk_hw_unregister;134 135 return;136 137err_clk_hw_unregister:138 clk_hw_unregister(&ilp->hw);139err_free_ilp:140 kfree(ilp);141 pr_err("Failed to init ILP clock: %d\n", err);142}143 144/* We need it very early for arch code, before device model gets ready */145CLK_OF_DECLARE(bcm53573_ilp_clk, "brcm,bcm53573-ilp", bcm53573_ilp_init);146