drivers/nvmem/uniphier-efuse.c

   1 /*
   2  * UniPhier eFuse driver
   3  *
   4  * Copyright (C) 2017 Socionext Inc.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  */
  15
  16 #include <linux/device.h>
  17 #include <linux/io.h>
  18 #include <linux/module.h>
  19 #include <linux/nvmem-provider.h>
  20 #include <linux/platform_device.h>
  21
  22 struct uniphier_efuse_priv {
  23         void __iomem *base;
  24 };
  25
  26 static int uniphier_reg_read(void *context,
  27                              unsigned int reg, void *_val, size_t bytes)
  28 {
  29         struct uniphier_efuse_priv *priv = context;
  30         u8 *val = _val;
  31         int offs;
  32
  33         for (offs = 0; offs < bytes; offs += sizeof(u8))
  34                 *val++ = readb(priv->base + reg + offs);
  35
  36         return 0;
  37 }
  38
  39 static int uniphier_efuse_probe(struct platform_device *pdev)
  40 {
  41         struct device *dev = &pdev->dev;
  42         struct resource *res;
  43         struct nvmem_device *nvmem;
  44         struct nvmem_config econfig = {};
  45         struct uniphier_efuse_priv *priv;
  46
  47         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
  48         if (!priv)
  49                 return -ENOMEM;
  50
  51         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  52         priv->base = devm_ioremap_resource(dev, res);
  53         if (IS_ERR(priv->base))
  54                 return PTR_ERR(priv->base);
  55
  56         econfig.stride = 1;
  57         econfig.word_size = 1;
  58         econfig.read_only = true;
  59         econfig.reg_read = uniphier_reg_read;
  60         econfig.size = resource_size(res);
  61         econfig.priv = priv;
  62         econfig.dev = dev;
  63         nvmem = devm_nvmem_register(dev, &econfig);
  64
  65         return PTR_ERR_OR_ZERO(nvmem);
  66 }
  67
  68 static const struct of_device_id uniphier_efuse_of_match[] = {
  69         { .compatible = "socionext,uniphier-efuse",},
  70         {/* sentinel */},
  71 };
  72 MODULE_DEVICE_TABLE(of, uniphier_efuse_of_match);
  73
  74 static struct platform_driver uniphier_efuse_driver = {
  75         .probe = uniphier_efuse_probe,
  76         .driver = {
  77                 .name = "uniphier-efuse",
  78                 .of_match_table = uniphier_efuse_of_match,
  79         },
  80 };
  81 module_platform_driver(uniphier_efuse_driver);
  82
  83 MODULE_AUTHOR("Keiji Hayashibara <hayashibara.keiji@socionext.com>");
  84 MODULE_DESCRIPTION("UniPhier eFuse driver");
  85 MODULE_LICENSE("GPL v2");