drivers/nvmem/sc27xx-efuse.c

   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 SC2730_MODULE_EN                0x1808
  14 #define SC27XX_EFUSE_EN                 BIT(6)
  15
  16 /* Efuse controller registers definition */
  17 #define SC27XX_EFUSE_GLB_CTRL           0x0
  18 #define SC27XX_EFUSE_DATA_RD            0x4
  19 #define SC27XX_EFUSE_DATA_WR            0x8
  20 #define SC27XX_EFUSE_BLOCK_INDEX        0xc
  21 #define SC27XX_EFUSE_MODE_CTRL          0x10
  22 #define SC27XX_EFUSE_STATUS             0x14
  23 #define SC27XX_EFUSE_WR_TIMING_CTRL     0x20
  24 #define SC27XX_EFUSE_RD_TIMING_CTRL     0x24
  25 #define SC27XX_EFUSE_EFUSE_DEB_CTRL     0x28
  26
  27 /* Mask definition for SC27XX_EFUSE_BLOCK_INDEX register */
  28 #define SC27XX_EFUSE_BLOCK_MASK         GENMASK(4, 0)
  29
  30 /* Bits definitions for SC27XX_EFUSE_MODE_CTRL register */
  31 #define SC27XX_EFUSE_PG_START           BIT(0)
  32 #define SC27XX_EFUSE_RD_START           BIT(1)
  33 #define SC27XX_EFUSE_CLR_RDDONE         BIT(2)
  34
  35 /* Bits definitions for SC27XX_EFUSE_STATUS register */
  36 #define SC27XX_EFUSE_PGM_BUSY           BIT(0)
  37 #define SC27XX_EFUSE_READ_BUSY          BIT(1)
  38 #define SC27XX_EFUSE_STANDBY            BIT(2)
  39 #define SC27XX_EFUSE_GLOBAL_PROT        BIT(3)
  40 #define SC27XX_EFUSE_RD_DONE            BIT(4)
  41
  42 /* Block number and block width (bytes) definitions */
  43 #define SC27XX_EFUSE_BLOCK_MAX          32
  44 #define SC27XX_EFUSE_BLOCK_WIDTH        2
  45
  46 /* Timeout (ms) for the trylock of hardware spinlocks */
  47 #define SC27XX_EFUSE_HWLOCK_TIMEOUT     5000
  48
  49 /* Timeout (us) of polling the status */
  50 #define SC27XX_EFUSE_POLL_TIMEOUT       3000000
  51 #define SC27XX_EFUSE_POLL_DELAY_US      10000
  52
  53 /*
  54  * Since different PMICs of SC27xx series can have different
  55  * address , we should save address in the device data structure.
  56  */
  57 struct sc27xx_efuse_variant_data {
  58         u32 module_en;
  59 };
  60
  61 struct sc27xx_efuse {
  62         struct device *dev;
  63         struct regmap *regmap;
  64         struct hwspinlock *hwlock;
  65         struct mutex mutex;
  66         u32 base;
  67         const struct sc27xx_efuse_variant_data *var_data;
  68 };
  69
  70 static const struct sc27xx_efuse_variant_data sc2731_edata = {
  71         .module_en = SC27XX_MODULE_EN,
  72 };
  73
  74 static const struct sc27xx_efuse_variant_data sc2730_edata = {
  75         .module_en = SC2730_MODULE_EN,
  76 };
  77
  78 /*
  79  * On Spreadtrum platform, we have multi-subsystems will access the unique
  80  * efuse controller, so we need one hardware spinlock to synchronize between
  81  * the multiple subsystems.
  82  */
  83 static int sc27xx_efuse_lock(struct sc27xx_efuse *efuse)
  84 {
  85         int ret;
  86
  87         mutex_lock(&efuse->mutex);
  88
  89         ret = hwspin_lock_timeout_raw(efuse->hwlock,
  90                                       SC27XX_EFUSE_HWLOCK_TIMEOUT);
  91         if (ret) {
  92                 dev_err(efuse->dev, "timeout to get the hwspinlock\n");
  93                 mutex_unlock(&efuse->mutex);
  94                 return ret;
  95         }
  96
  97         return 0;
  98 }
  99
 100 static void sc27xx_efuse_unlock(struct sc27xx_efuse *efuse)
 101 {
 102         hwspin_unlock_raw(efuse->hwlock);
 103         mutex_unlock(&efuse->mutex);
 104 }
 105
 106 static int sc27xx_efuse_poll_status(struct sc27xx_efuse *efuse, u32 bits)
 107 {
 108         int ret;
 109         u32 val;
 110
 111         ret = regmap_read_poll_timeout(efuse->regmap,
 112                                        efuse->base + SC27XX_EFUSE_STATUS,
 113                                        val, (val & bits),
 114                                        SC27XX_EFUSE_POLL_DELAY_US,
 115                                        SC27XX_EFUSE_POLL_TIMEOUT);
 116         if (ret) {
 117                 dev_err(efuse->dev, "timeout to update the efuse status\n");
 118                 return ret;
 119         }
 120
 121         return 0;
 122 }
 123
 124 static int sc27xx_efuse_read(void *context, u32 offset, void *val, size_t bytes)
 125 {
 126         struct sc27xx_efuse *efuse = context;
 127         u32 buf, blk_index = offset / SC27XX_EFUSE_BLOCK_WIDTH;
 128         u32 blk_offset = (offset % SC27XX_EFUSE_BLOCK_WIDTH) * BITS_PER_BYTE;
 129         int ret;
 130
 131         if (blk_index > SC27XX_EFUSE_BLOCK_MAX ||
 132             bytes > SC27XX_EFUSE_BLOCK_WIDTH)
 133                 return -EINVAL;
 134
 135         ret = sc27xx_efuse_lock(efuse);
 136         if (ret)
 137                 return ret;
 138
 139         /* Enable the efuse controller. */
 140         ret = regmap_update_bits(efuse->regmap, efuse->var_data->module_en,
 141                                  SC27XX_EFUSE_EN, SC27XX_EFUSE_EN);
 142         if (ret)
 143                 goto unlock_efuse;
 144
 145         /*
 146          * Before reading, we should ensure the efuse controller is in
 147          * standby state.
 148          */
 149         ret = sc27xx_efuse_poll_status(efuse, SC27XX_EFUSE_STANDBY);
 150         if (ret)
 151                 goto disable_efuse;
 152
 153         /* Set the block address to be read. */
 154         ret = regmap_write(efuse->regmap,
 155                            efuse->base + SC27XX_EFUSE_BLOCK_INDEX,
 156                            blk_index & SC27XX_EFUSE_BLOCK_MASK);
 157         if (ret)
 158                 goto disable_efuse;
 159
 160         /* Start reading process from efuse memory. */
 161         ret = regmap_update_bits(efuse->regmap,
 162                                  efuse->base + SC27XX_EFUSE_MODE_CTRL,
 163                                  SC27XX_EFUSE_RD_START,
 164                                  SC27XX_EFUSE_RD_START);
 165         if (ret)
 166                 goto disable_efuse;
 167
 168         /*
 169          * Polling the read done status to make sure the reading process
 170          * is completed, that means the data can be read out now.
 171          */
 172         ret = sc27xx_efuse_poll_status(efuse, SC27XX_EFUSE_RD_DONE);
 173         if (ret)
 174                 goto disable_efuse;
 175
 176         /* Read data from efuse memory. */
 177         ret = regmap_read(efuse->regmap, efuse->base + SC27XX_EFUSE_DATA_RD,
 178                           &buf);
 179         if (ret)
 180                 goto disable_efuse;
 181
 182         /* Clear the read done flag. */
 183         ret = regmap_update_bits(efuse->regmap,
 184                                  efuse->base + SC27XX_EFUSE_MODE_CTRL,
 185                                  SC27XX_EFUSE_CLR_RDDONE,
 186                                  SC27XX_EFUSE_CLR_RDDONE);
 187
 188 disable_efuse:
 189         /* Disable the efuse controller after reading. */
 190         regmap_update_bits(efuse->regmap, efuse->var_data->module_en, SC27XX_EFUSE_EN, 0);
 191 unlock_efuse:
 192         sc27xx_efuse_unlock(efuse);
 193
 194         if (!ret) {
 195                 buf >>= blk_offset;
 196                 memcpy(val, &buf, bytes);
 197         }
 198
 199         return ret;
 200 }
 201
 202 static int sc27xx_efuse_probe(struct platform_device *pdev)
 203 {
 204         struct device_node *np = pdev->dev.of_node;
 205         struct nvmem_config econfig = { };
 206         struct nvmem_device *nvmem;
 207         struct sc27xx_efuse *efuse;
 208         int ret;
 209
 210         efuse = devm_kzalloc(&pdev->dev, sizeof(*efuse), GFP_KERNEL);
 211         if (!efuse)
 212                 return -ENOMEM;
 213
 214         efuse->regmap = dev_get_regmap(pdev->dev.parent, NULL);
 215         if (!efuse->regmap) {
 216                 dev_err(&pdev->dev, "failed to get efuse regmap\n");
 217                 return -ENODEV;
 218         }
 219
 220         ret = of_property_read_u32(np, "reg", &efuse->base);
 221         if (ret) {
 222                 dev_err(&pdev->dev, "failed to get efuse base address\n");
 223                 return ret;
 224         }
 225
 226         ret = of_hwspin_lock_get_id(np, 0);
 227         if (ret < 0) {
 228                 dev_err(&pdev->dev, "failed to get hwspinlock id\n");
 229                 return ret;
 230         }
 231
 232         efuse->hwlock = devm_hwspin_lock_request_specific(&pdev->dev, ret);
 233         if (!efuse->hwlock) {
 234                 dev_err(&pdev->dev, "failed to request hwspinlock\n");
 235                 return -ENXIO;
 236         }
 237
 238         mutex_init(&efuse->mutex);
 239         efuse->dev = &pdev->dev;
 240         efuse->var_data = of_device_get_match_data(&pdev->dev);
 241
 242         econfig.stride = 1;
 243         econfig.word_size = 1;
 244         econfig.read_only = true;
 245         econfig.name = "sc27xx-efuse";
 246         econfig.size = SC27XX_EFUSE_BLOCK_MAX * SC27XX_EFUSE_BLOCK_WIDTH;
 247         econfig.reg_read = sc27xx_efuse_read;
 248         econfig.priv = efuse;
 249         econfig.dev = &pdev->dev;
 250         nvmem = devm_nvmem_register(&pdev->dev, &econfig);
 251         if (IS_ERR(nvmem)) {
 252                 dev_err(&pdev->dev, "failed to register nvmem config\n");
 253                 return PTR_ERR(nvmem);
 254         }
 255
 256         return 0;
 257 }
 258
 259 static const struct of_device_id sc27xx_efuse_of_match[] = {
 260         { .compatible = "sprd,sc2731-efuse", .data = &sc2731_edata},
 261         { .compatible = "sprd,sc2730-efuse", .data = &sc2730_edata},
 262         { }
 263 };
 264
 265 static struct platform_driver sc27xx_efuse_driver = {
 266         .probe = sc27xx_efuse_probe,
 267         .driver = {
 268                 .name = "sc27xx-efuse",
 269                 .of_match_table = sc27xx_efuse_of_match,
 270         },
 271 };
 272
 273 module_platform_driver(sc27xx_efuse_driver);
 274
 275 MODULE_AUTHOR("Freeman Liu <freeman.liu@spreadtrum.com>");
 276 MODULE_DESCRIPTION("Spreadtrum SC27xx efuse driver");
 277 MODULE_LICENSE("GPL v2");