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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * CPU frequency scaling for DaVinci4 *5 * Copyright (C) 2009 Texas Instruments Incorporated - https://www.ti.com/6 *7 * Based on linux/arch/arm/plat-omap/cpu-omap.c. Original Copyright follows:8 *9 * Copyright (C) 2005 Nokia Corporation10 * Written by Tony Lindgren <tony@atomide.com>11 *12 * Based on cpu-sa1110.c, Copyright (C) 2001 Russell King13 *14 * Copyright (C) 2007-2008 Texas Instruments, Inc.15 * Updated to support OMAP316 * Rajendra Nayak <rnayak@ti.com>17 */18#include <linux/types.h>19#include <linux/cpufreq.h>20#include <linux/init.h>21#include <linux/err.h>22#include <linux/clk.h>23#include <linux/platform_data/davinci-cpufreq.h>24#include <linux/platform_device.h>25#include <linux/export.h>26 27struct davinci_cpufreq {28 struct device *dev;29 struct clk *armclk;30 struct clk *asyncclk;31 unsigned long asyncrate;32};33static struct davinci_cpufreq cpufreq;34 35static int davinci_target(struct cpufreq_policy *policy, unsigned int idx)36{37 struct davinci_cpufreq_config *pdata = cpufreq.dev->platform_data;38 struct clk *armclk = cpufreq.armclk;39 unsigned int old_freq, new_freq;40 int ret = 0;41 42 old_freq = policy->cur;43 new_freq = pdata->freq_table[idx].frequency;44 45 /* if moving to higher frequency, up the voltage beforehand */46 if (pdata->set_voltage && new_freq > old_freq) {47 ret = pdata->set_voltage(idx);48 if (ret)49 return ret;50 }51 52 ret = clk_set_rate(armclk, new_freq * 1000);53 if (ret)54 return ret;55 56 if (cpufreq.asyncclk) {57 ret = clk_set_rate(cpufreq.asyncclk, cpufreq.asyncrate);58 if (ret)59 return ret;60 }61 62 /* if moving to lower freq, lower the voltage after lowering freq */63 if (pdata->set_voltage && new_freq < old_freq)64 pdata->set_voltage(idx);65 66 return 0;67}68 69static int davinci_cpu_init(struct cpufreq_policy *policy)70{71 int result = 0;72 struct davinci_cpufreq_config *pdata = cpufreq.dev->platform_data;73 struct cpufreq_frequency_table *freq_table = pdata->freq_table;74 75 if (policy->cpu != 0)76 return -EINVAL;77 78 /* Finish platform specific initialization */79 if (pdata->init) {80 result = pdata->init();81 if (result)82 return result;83 }84 85 policy->clk = cpufreq.armclk;86 87 /*88 * Time measurement across the target() function yields ~1500-1800us89 * time taken with no drivers on notification list.90 * Setting the latency to 2000 us to accommodate addition of drivers91 * to pre/post change notification list.92 */93 cpufreq_generic_init(policy, freq_table, 2000 * 1000);94 return 0;95}96 97static struct cpufreq_driver davinci_driver = {98 .flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK,99 .verify = cpufreq_generic_frequency_table_verify,100 .target_index = davinci_target,101 .get = cpufreq_generic_get,102 .init = davinci_cpu_init,103 .name = "davinci",104 .attr = cpufreq_generic_attr,105};106 107static int __init davinci_cpufreq_probe(struct platform_device *pdev)108{109 struct davinci_cpufreq_config *pdata = pdev->dev.platform_data;110 struct clk *asyncclk;111 112 if (!pdata)113 return -EINVAL;114 if (!pdata->freq_table)115 return -EINVAL;116 117 cpufreq.dev = &pdev->dev;118 119 cpufreq.armclk = clk_get(NULL, "arm");120 if (IS_ERR(cpufreq.armclk)) {121 dev_err(cpufreq.dev, "Unable to get ARM clock\n");122 return PTR_ERR(cpufreq.armclk);123 }124 125 asyncclk = clk_get(cpufreq.dev, "async");126 if (!IS_ERR(asyncclk)) {127 cpufreq.asyncclk = asyncclk;128 cpufreq.asyncrate = clk_get_rate(asyncclk);129 }130 131 return cpufreq_register_driver(&davinci_driver);132}133 134static void __exit davinci_cpufreq_remove(struct platform_device *pdev)135{136 cpufreq_unregister_driver(&davinci_driver);137 138 clk_put(cpufreq.armclk);139 140 if (cpufreq.asyncclk)141 clk_put(cpufreq.asyncclk);142}143 144static struct platform_driver davinci_cpufreq_driver = {145 .driver = {146 .name = "cpufreq-davinci",147 },148 .remove_new = __exit_p(davinci_cpufreq_remove),149};150 151int __init davinci_cpufreq_init(void)152{153 return platform_driver_probe(&davinci_cpufreq_driver,154 davinci_cpufreq_probe);155}156 157