drivers/nvmem/qoriq-efuse.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  Copyright (C) 2023  Westermo Network Technologies AB
   4  */
   5
   6 #include <linux/device.h>
   7 #include <linux/io.h>
   8 #include <linux/module.h>
   9 #include <linux/mod_devicetable.h>
  10 #include <linux/nvmem-provider.h>
  11 #include <linux/platform_device.h>
  12
  13 struct qoriq_efuse_priv {
  14         void __iomem *base;
  15 };
  16
  17 static int qoriq_efuse_read(void *context, unsigned int offset, void *val,
  18                             size_t bytes)
  19 {
  20         struct qoriq_efuse_priv *priv = context;
  21
  22         /* .stride = 4 so offset is guaranteed to be aligned */
  23         __ioread32_copy(val, priv->base + offset, bytes / 4);
  24
  25         /* Ignore trailing bytes (there shouldn't be any) */
  26
  27         return 0;
  28 }
  29
  30 static int qoriq_efuse_probe(struct platform_device *pdev)
  31 {
  32         struct nvmem_config config = {
  33                 .dev = &pdev->dev,
  34                 .read_only = true,
  35                 .reg_read = qoriq_efuse_read,
  36                 .stride = sizeof(u32),
  37                 .word_size = sizeof(u32),
  38                 .name = "qoriq_efuse_read",
  39                 .id = NVMEM_DEVID_AUTO,
  40                 .root_only = true,
  41         };
  42         struct qoriq_efuse_priv *priv;
  43         struct nvmem_device *nvmem;
  44         struct resource *res;
  45
  46         priv = devm_kzalloc(config.dev, sizeof(*priv), GFP_KERNEL);
  47         if (!priv)
  48                 return -ENOMEM;
  49
  50         priv->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
  51         if (IS_ERR(priv->base))
  52                 return PTR_ERR(priv->base);
  53
  54         config.size = resource_size(res);
  55         config.priv = priv;
  56         nvmem = devm_nvmem_register(config.dev, &config);
  57
  58         return PTR_ERR_OR_ZERO(nvmem);
  59 }
  60
  61 static const struct of_device_id qoriq_efuse_of_match[] = {
  62         { .compatible = "fsl,t1023-sfp", },
  63         {/* sentinel */},
  64 };
  65 MODULE_DEVICE_TABLE(of, qoriq_efuse_of_match);
  66
  67 static struct platform_driver qoriq_efuse_driver = {
  68         .probe = qoriq_efuse_probe,
  69         .driver = {
  70                 .name = "qoriq-efuse",
  71                 .of_match_table = qoriq_efuse_of_match,
  72         },
  73 };
  74 module_platform_driver(qoriq_efuse_driver);
  75
  76 MODULE_AUTHOR("Richard Alpe <richard.alpe@bit42.se>");
  77 MODULE_DESCRIPTION("NXP QorIQ Security Fuse Processor (SFP) Reader");
  78 MODULE_LICENSE("GPL");