1 // SPDX-License-Identifier: GPL-2.0 2 // Copyright (C) 2018 Spreadtrum Communications Inc. 3 4 #include <linux/hwspinlock.h> 5 #include <linux/module.h> 6 #include <linux/of.h> 7 #include <linux/platform_device.h> 8 #include <linux/regmap.h> 9 #include <linux/nvmem-provider.h> 10 11 /* PMIC global registers definition */ 12 #define SC27XX_MODULE_EN 0xc08 13 #define SC27XX_EFUSE_EN BIT(6) 14 15 /* Efuse controller registers definition */ 16 #define SC27XX_EFUSE_GLB_CTRL 0x0 17 #define SC27XX_EFUSE_DATA_RD 0x4 18 #define SC27XX_EFUSE_DATA_WR 0x8 19 #define SC27XX_EFUSE_BLOCK_INDEX 0xc 20 #define SC27XX_EFUSE_MODE_CTRL 0x10 21 #define SC27XX_EFUSE_STATUS 0x14 22 #define SC27XX_EFUSE_WR_TIMING_CTRL 0x20 23 #define SC27XX_EFUSE_RD_TIMING_CTRL 0x24 24 #define SC27XX_EFUSE_EFUSE_DEB_CTRL 0x28 25 26 /* Mask definition for SC27XX_EFUSE_BLOCK_INDEX register */ 27 #define SC27XX_EFUSE_BLOCK_MASK GENMASK(4, 0) 28 29 /* Bits definitions for SC27XX_EFUSE_MODE_CTRL register */ 30 #define SC27XX_EFUSE_PG_START BIT(0) 31 #define SC27XX_EFUSE_RD_START BIT(1) 32 #define SC27XX_EFUSE_CLR_RDDONE BIT(2) 33 34 /* Bits definitions for SC27XX_EFUSE_STATUS register */ 35 #define SC27XX_EFUSE_PGM_BUSY BIT(0) 36 #define SC27XX_EFUSE_READ_BUSY BIT(1) 37 #define SC27XX_EFUSE_STANDBY BIT(2) 38 #define SC27XX_EFUSE_GLOBAL_PROT BIT(3) 39 #define SC27XX_EFUSE_RD_DONE BIT(4) 40 41 /* Block number and block width (bytes) definitions */ 42 #define SC27XX_EFUSE_BLOCK_MAX 32 43 #define SC27XX_EFUSE_BLOCK_WIDTH 2 44 45 /* Timeout (ms) for the trylock of hardware spinlocks */ 46 #define SC27XX_EFUSE_HWLOCK_TIMEOUT 5000 47 48 /* Timeout (us) of polling the status */ 49 #define SC27XX_EFUSE_POLL_TIMEOUT 3000000 50 #define SC27XX_EFUSE_POLL_DELAY_US 10000 51 52 struct sc27xx_efuse { 53 struct device *dev; 54 struct regmap *regmap; 55 struct hwspinlock *hwlock; 56 struct mutex mutex; 57 u32 base; 58 }; 59 60 /* 61 * On Spreadtrum platform, we have multi-subsystems will access the unique 62 * efuse controller, so we need one hardware spinlock to synchronize between 63 * the multiple subsystems. 64 */ 65 static int sc27xx_efuse_lock(struct sc27xx_efuse *efuse) 66 { 67 int ret; 68 69 mutex_lock(&efuse->mutex); 70 71 ret = hwspin_lock_timeout_raw(efuse->hwlock, 72 SC27XX_EFUSE_HWLOCK_TIMEOUT); 73 if (ret) { 74 dev_err(efuse->dev, "timeout to get the hwspinlock\n"); 75 mutex_unlock(&efuse->mutex); 76 return ret; 77 } 78 79 return 0; 80 } 81 82 static void sc27xx_efuse_unlock(struct sc27xx_efuse *efuse) 83 { 84 hwspin_unlock_raw(efuse->hwlock); 85 mutex_unlock(&efuse->mutex); 86 } 87 88 static int sc27xx_efuse_poll_status(struct sc27xx_efuse *efuse, u32 bits) 89 { 90 int ret; 91 u32 val; 92 93 ret = regmap_read_poll_timeout(efuse->regmap, 94 efuse->base + SC27XX_EFUSE_STATUS, 95 val, (val & bits), 96 SC27XX_EFUSE_POLL_DELAY_US, 97 SC27XX_EFUSE_POLL_TIMEOUT); 98 if (ret) { 99 dev_err(efuse->dev, "timeout to update the efuse status\n"); 100 return ret; 101 } 102 103 return 0; 104 } 105 106 static int sc27xx_efuse_read(void *context, u32 offset, void *val, size_t bytes) 107 { 108 struct sc27xx_efuse *efuse = context; 109 u32 buf; 110 int ret; 111 112 if (offset > SC27XX_EFUSE_BLOCK_MAX || bytes > SC27XX_EFUSE_BLOCK_WIDTH) 113 return -EINVAL; 114 115 ret = sc27xx_efuse_lock(efuse); 116 if (ret) 117 return ret; 118 119 /* Enable the efuse controller. */ 120 ret = regmap_update_bits(efuse->regmap, SC27XX_MODULE_EN, 121 SC27XX_EFUSE_EN, SC27XX_EFUSE_EN); 122 if (ret) 123 goto unlock_efuse; 124 125 /* 126 * Before reading, we should ensure the efuse controller is in 127 * standby state. 128 */ 129 ret = sc27xx_efuse_poll_status(efuse, SC27XX_EFUSE_STANDBY); 130 if (ret) 131 goto disable_efuse; 132 133 /* Set the block address to be read. */ 134 ret = regmap_write(efuse->regmap, 135 efuse->base + SC27XX_EFUSE_BLOCK_INDEX, 136 offset & SC27XX_EFUSE_BLOCK_MASK); 137 if (ret) 138 goto disable_efuse; 139 140 /* Start reading process from efuse memory. */ 141 ret = regmap_update_bits(efuse->regmap, 142 efuse->base + SC27XX_EFUSE_MODE_CTRL, 143 SC27XX_EFUSE_RD_START, 144 SC27XX_EFUSE_RD_START); 145 if (ret) 146 goto disable_efuse; 147 148 /* 149 * Polling the read done status to make sure the reading process 150 * is completed, that means the data can be read out now. 151 */ 152 ret = sc27xx_efuse_poll_status(efuse, SC27XX_EFUSE_RD_DONE); 153 if (ret) 154 goto disable_efuse; 155 156 /* Read data from efuse memory. */ 157 ret = regmap_read(efuse->regmap, efuse->base + SC27XX_EFUSE_DATA_RD, 158 &buf); 159 if (ret) 160 goto disable_efuse; 161 162 /* Clear the read done flag. */ 163 ret = regmap_update_bits(efuse->regmap, 164 efuse->base + SC27XX_EFUSE_MODE_CTRL, 165 SC27XX_EFUSE_CLR_RDDONE, 166 SC27XX_EFUSE_CLR_RDDONE); 167 168 disable_efuse: 169 /* Disable the efuse controller after reading. */ 170 regmap_update_bits(efuse->regmap, SC27XX_MODULE_EN, SC27XX_EFUSE_EN, 0); 171 unlock_efuse: 172 sc27xx_efuse_unlock(efuse); 173 174 if (!ret) 175 memcpy(val, &buf, bytes); 176 177 return ret; 178 } 179 180 static int sc27xx_efuse_probe(struct platform_device *pdev) 181 { 182 struct device_node *np = pdev->dev.of_node; 183 struct nvmem_config econfig = { }; 184 struct nvmem_device *nvmem; 185 struct sc27xx_efuse *efuse; 186 int ret; 187 188 efuse = devm_kzalloc(&pdev->dev, sizeof(*efuse), GFP_KERNEL); 189 if (!efuse) 190 return -ENOMEM; 191 192 efuse->regmap = dev_get_regmap(pdev->dev.parent, NULL); 193 if (!efuse->regmap) { 194 dev_err(&pdev->dev, "failed to get efuse regmap\n"); 195 return -ENODEV; 196 } 197 198 ret = of_property_read_u32(np, "reg", &efuse->base); 199 if (ret) { 200 dev_err(&pdev->dev, "failed to get efuse base address\n"); 201 return ret; 202 } 203 204 ret = of_hwspin_lock_get_id(np, 0); 205 if (ret < 0) { 206 dev_err(&pdev->dev, "failed to get hwspinlock id\n"); 207 return ret; 208 } 209 210 efuse->hwlock = hwspin_lock_request_specific(ret); 211 if (!efuse->hwlock) { 212 dev_err(&pdev->dev, "failed to request hwspinlock\n"); 213 return -ENXIO; 214 } 215 216 mutex_init(&efuse->mutex); 217 efuse->dev = &pdev->dev; 218 platform_set_drvdata(pdev, efuse); 219 220 econfig.stride = 1; 221 econfig.word_size = 1; 222 econfig.read_only = true; 223 econfig.name = "sc27xx-efuse"; 224 econfig.size = SC27XX_EFUSE_BLOCK_MAX * SC27XX_EFUSE_BLOCK_WIDTH; 225 econfig.reg_read = sc27xx_efuse_read; 226 econfig.priv = efuse; 227 econfig.dev = &pdev->dev; 228 nvmem = devm_nvmem_register(&pdev->dev, &econfig); 229 if (IS_ERR(nvmem)) { 230 dev_err(&pdev->dev, "failed to register nvmem config\n"); 231 hwspin_lock_free(efuse->hwlock); 232 return PTR_ERR(nvmem); 233 } 234 235 return 0; 236 } 237 238 static int sc27xx_efuse_remove(struct platform_device *pdev) 239 { 240 struct sc27xx_efuse *efuse = platform_get_drvdata(pdev); 241 242 hwspin_lock_free(efuse->hwlock); 243 return 0; 244 } 245 246 static const struct of_device_id sc27xx_efuse_of_match[] = { 247 { .compatible = "sprd,sc2731-efuse" }, 248 { } 249 }; 250 251 static struct platform_driver sc27xx_efuse_driver = { 252 .probe = sc27xx_efuse_probe, 253 .remove = sc27xx_efuse_remove, 254 .driver = { 255 .name = "sc27xx-efuse", 256 .of_match_table = sc27xx_efuse_of_match, 257 }, 258 }; 259 260 module_platform_driver(sc27xx_efuse_driver); 261 262 MODULE_AUTHOR("Freeman Liu <freeman.liu@spreadtrum.com>"); 263 MODULE_DESCRIPTION("Spreadtrum SC27xx efuse driver"); 264 MODULE_LICENSE("GPL v2"); 265