1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Allwinner CPUFreq nvmem based driver 4 * 5 * The sun50i-cpufreq-nvmem driver reads the efuse value from the SoC to 6 * provide the OPP framework with required information. 7 * 8 * Copyright (C) 2019 Yangtao Li <tiny.windzz@gmail.com> 9 */ 10 11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 12 13 #include <linux/module.h> 14 #include <linux/nvmem-consumer.h> 15 #include <linux/of_device.h> 16 #include <linux/platform_device.h> 17 #include <linux/pm_opp.h> 18 #include <linux/slab.h> 19 20 #define MAX_NAME_LEN 7 21 22 #define NVMEM_MASK 0x7 23 #define NVMEM_SHIFT 5 24 25 static struct platform_device *cpufreq_dt_pdev, *sun50i_cpufreq_pdev; 26 27 /** 28 * sun50i_cpufreq_get_efuse() - Parse and return efuse value present on SoC 29 * @versions: Set to the value parsed from efuse 30 * 31 * Returns 0 if success. 32 */ 33 static int sun50i_cpufreq_get_efuse(u32 *versions) 34 { 35 struct nvmem_cell *speedbin_nvmem; 36 struct device_node *np; 37 struct device *cpu_dev; 38 u32 *speedbin, efuse_value; 39 size_t len; 40 int ret; 41 42 cpu_dev = get_cpu_device(0); 43 if (!cpu_dev) 44 return -ENODEV; 45 46 np = dev_pm_opp_of_get_opp_desc_node(cpu_dev); 47 if (!np) 48 return -ENOENT; 49 50 ret = of_device_is_compatible(np, 51 "allwinner,sun50i-h6-operating-points"); 52 if (!ret) { 53 of_node_put(np); 54 return -ENOENT; 55 } 56 57 speedbin_nvmem = of_nvmem_cell_get(np, NULL); 58 of_node_put(np); 59 if (IS_ERR(speedbin_nvmem)) { 60 if (PTR_ERR(speedbin_nvmem) != -EPROBE_DEFER) 61 pr_err("Could not get nvmem cell: %ld\n", 62 PTR_ERR(speedbin_nvmem)); 63 return PTR_ERR(speedbin_nvmem); 64 } 65 66 speedbin = nvmem_cell_read(speedbin_nvmem, &len); 67 nvmem_cell_put(speedbin_nvmem); 68 if (IS_ERR(speedbin)) 69 return PTR_ERR(speedbin); 70 71 efuse_value = (*speedbin >> NVMEM_SHIFT) & NVMEM_MASK; 72 switch (efuse_value) { 73 case 0b0001: 74 *versions = 1; 75 break; 76 case 0b0011: 77 *versions = 2; 78 break; 79 default: 80 /* 81 * For other situations, we treat it as bin0. 82 * This vf table can be run for any good cpu. 83 */ 84 *versions = 0; 85 break; 86 } 87 88 kfree(speedbin); 89 return 0; 90 }; 91 92 static int sun50i_cpufreq_nvmem_probe(struct platform_device *pdev) 93 { 94 struct opp_table **opp_tables; 95 char name[MAX_NAME_LEN]; 96 unsigned int cpu; 97 u32 speed = 0; 98 int ret; 99 100 opp_tables = kcalloc(num_possible_cpus(), sizeof(*opp_tables), 101 GFP_KERNEL); 102 if (!opp_tables) 103 return -ENOMEM; 104 105 ret = sun50i_cpufreq_get_efuse(&speed); 106 if (ret) 107 return ret; 108 109 snprintf(name, MAX_NAME_LEN, "speed%d", speed); 110 111 for_each_possible_cpu(cpu) { 112 struct device *cpu_dev = get_cpu_device(cpu); 113 114 if (!cpu_dev) { 115 ret = -ENODEV; 116 goto free_opp; 117 } 118 119 opp_tables[cpu] = dev_pm_opp_set_prop_name(cpu_dev, name); 120 if (IS_ERR(opp_tables[cpu])) { 121 ret = PTR_ERR(opp_tables[cpu]); 122 pr_err("Failed to set prop name\n"); 123 goto free_opp; 124 } 125 } 126 127 cpufreq_dt_pdev = platform_device_register_simple("cpufreq-dt", -1, 128 NULL, 0); 129 if (!IS_ERR(cpufreq_dt_pdev)) { 130 platform_set_drvdata(pdev, opp_tables); 131 return 0; 132 } 133 134 ret = PTR_ERR(cpufreq_dt_pdev); 135 pr_err("Failed to register platform device\n"); 136 137 free_opp: 138 for_each_possible_cpu(cpu) { 139 if (IS_ERR_OR_NULL(opp_tables[cpu])) 140 break; 141 dev_pm_opp_put_prop_name(opp_tables[cpu]); 142 } 143 kfree(opp_tables); 144 145 return ret; 146 } 147 148 static int sun50i_cpufreq_nvmem_remove(struct platform_device *pdev) 149 { 150 struct opp_table **opp_tables = platform_get_drvdata(pdev); 151 unsigned int cpu; 152 153 platform_device_unregister(cpufreq_dt_pdev); 154 155 for_each_possible_cpu(cpu) 156 dev_pm_opp_put_prop_name(opp_tables[cpu]); 157 158 kfree(opp_tables); 159 160 return 0; 161 } 162 163 static struct platform_driver sun50i_cpufreq_driver = { 164 .probe = sun50i_cpufreq_nvmem_probe, 165 .remove = sun50i_cpufreq_nvmem_remove, 166 .driver = { 167 .name = "sun50i-cpufreq-nvmem", 168 }, 169 }; 170 171 static const struct of_device_id sun50i_cpufreq_match_list[] = { 172 { .compatible = "allwinner,sun50i-h6" }, 173 {} 174 }; 175 176 static const struct of_device_id *sun50i_cpufreq_match_node(void) 177 { 178 const struct of_device_id *match; 179 struct device_node *np; 180 181 np = of_find_node_by_path("/"); 182 match = of_match_node(sun50i_cpufreq_match_list, np); 183 of_node_put(np); 184 185 return match; 186 } 187 188 /* 189 * Since the driver depends on nvmem drivers, which may return EPROBE_DEFER, 190 * all the real activity is done in the probe, which may be defered as well. 191 * The init here is only registering the driver and the platform device. 192 */ 193 static int __init sun50i_cpufreq_init(void) 194 { 195 const struct of_device_id *match; 196 int ret; 197 198 match = sun50i_cpufreq_match_node(); 199 if (!match) 200 return -ENODEV; 201 202 ret = platform_driver_register(&sun50i_cpufreq_driver); 203 if (unlikely(ret < 0)) 204 return ret; 205 206 sun50i_cpufreq_pdev = 207 platform_device_register_simple("sun50i-cpufreq-nvmem", 208 -1, NULL, 0); 209 ret = PTR_ERR_OR_ZERO(sun50i_cpufreq_pdev); 210 if (ret == 0) 211 return 0; 212 213 platform_driver_unregister(&sun50i_cpufreq_driver); 214 return ret; 215 } 216 module_init(sun50i_cpufreq_init); 217 218 static void __exit sun50i_cpufreq_exit(void) 219 { 220 platform_device_unregister(sun50i_cpufreq_pdev); 221 platform_driver_unregister(&sun50i_cpufreq_driver); 222 } 223 module_exit(sun50i_cpufreq_exit); 224 225 MODULE_DESCRIPTION("Sun50i-h6 cpufreq driver"); 226 MODULE_LICENSE("GPL v2"); 227