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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 | // SPDX-License-Identifier: GPL-2.0-only /* * CPU frequency scaling for DaVinci * * Copyright (C) 2009 Texas Instruments Incorporated - https://www.ti.com/ * * Based on linux/arch/arm/plat-omap/cpu-omap.c. Original Copyright follows: * * Copyright (C) 2005 Nokia Corporation * Written by Tony Lindgren <tony@atomide.com> * * Based on cpu-sa1110.c, Copyright (C) 2001 Russell King * * Copyright (C) 2007-2008 Texas Instruments, Inc. * Updated to support OMAP3 * Rajendra Nayak <rnayak@ti.com> */ #include <linux/types.h> #include <linux/cpufreq.h> #include <linux/init.h> #include <linux/err.h> #include <linux/clk.h> #include <linux/platform_data/davinci-cpufreq.h> #include <linux/platform_device.h> #include <linux/export.h> struct davinci_cpufreq { struct device *dev; struct clk *armclk; struct clk *asyncclk; unsigned long asyncrate; }; static struct davinci_cpufreq cpufreq; static int davinci_target(struct cpufreq_policy *policy, unsigned int idx) { struct davinci_cpufreq_config *pdata = cpufreq.dev->platform_data; struct clk *armclk = cpufreq.armclk; unsigned int old_freq, new_freq; int ret = 0; old_freq = policy->cur; new_freq = pdata->freq_table[idx].frequency; /* if moving to higher frequency, up the voltage beforehand */ if (pdata->set_voltage && new_freq > old_freq) { ret = pdata->set_voltage(idx); if (ret) return ret; } ret = clk_set_rate(armclk, new_freq * 1000); if (ret) return ret; if (cpufreq.asyncclk) { ret = clk_set_rate(cpufreq.asyncclk, cpufreq.asyncrate); if (ret) return ret; } /* if moving to lower freq, lower the voltage after lowering freq */ if (pdata->set_voltage && new_freq < old_freq) pdata->set_voltage(idx); return 0; } static int davinci_cpu_init(struct cpufreq_policy *policy) { int result = 0; struct davinci_cpufreq_config *pdata = cpufreq.dev->platform_data; struct cpufreq_frequency_table *freq_table = pdata->freq_table; if (policy->cpu != 0) return -EINVAL; /* Finish platform specific initialization */ if (pdata->init) { result = pdata->init(); if (result) return result; } policy->clk = cpufreq.armclk; /* * Time measurement across the target() function yields ~1500-1800us * time taken with no drivers on notification list. * Setting the latency to 2000 us to accommodate addition of drivers * to pre/post change notification list. */ cpufreq_generic_init(policy, freq_table, 2000 * 1000); return 0; } static struct cpufreq_driver davinci_driver = { .flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK, .verify = cpufreq_generic_frequency_table_verify, .target_index = davinci_target, .get = cpufreq_generic_get, .init = davinci_cpu_init, .name = "davinci", .attr = cpufreq_generic_attr, }; static int __init davinci_cpufreq_probe(struct platform_device *pdev) { struct davinci_cpufreq_config *pdata = pdev->dev.platform_data; struct clk *asyncclk; if (!pdata) return -EINVAL; if (!pdata->freq_table) return -EINVAL; cpufreq.dev = &pdev->dev; cpufreq.armclk = clk_get(NULL, "arm"); if (IS_ERR(cpufreq.armclk)) { dev_err(cpufreq.dev, "Unable to get ARM clock\n"); return PTR_ERR(cpufreq.armclk); } asyncclk = clk_get(cpufreq.dev, "async"); if (!IS_ERR(asyncclk)) { cpufreq.asyncclk = asyncclk; cpufreq.asyncrate = clk_get_rate(asyncclk); } return cpufreq_register_driver(&davinci_driver); } static int __exit davinci_cpufreq_remove(struct platform_device *pdev) { cpufreq_unregister_driver(&davinci_driver); clk_put(cpufreq.armclk); if (cpufreq.asyncclk) clk_put(cpufreq.asyncclk); return 0; } static struct platform_driver davinci_cpufreq_driver = { .driver = { .name = "cpufreq-davinci", }, .remove = __exit_p(davinci_cpufreq_remove), }; int __init davinci_cpufreq_init(void) { return platform_driver_probe(&davinci_cpufreq_driver, davinci_cpufreq_probe); } |