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/mod_devicetable.h>
  20 #include <linux/nvmem-provider.h>
  21 #include <linux/platform_device.h>
  22
  23 struct uniphier_efuse_priv {
  24         void __iomem *base;
  25 };
  26
  27 static int uniphier_reg_read(void *context,
  28                              unsigned int reg, void *_val, size_t bytes)
  29 {
  30         struct uniphier_efuse_priv *priv = context;
  31         u8 *val = _val;
  32         int offs;
  33
  34         for (offs = 0; offs < bytes; offs += sizeof(u8))
  35                 *val++ = readb(priv->base + reg + offs);
  36
  37         return 0;
  38 }
  39
  40 static int uniphier_efuse_probe(struct platform_device *pdev)
  41 {
  42         struct device *dev = &pdev->dev;
  43         struct resource *res;
  44         struct nvmem_device *nvmem;
  45         struct nvmem_config econfig = {};
  46         struct uniphier_efuse_priv *priv;
  47
  48         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
  49         if (!priv)
  50                 return -ENOMEM;
  51
  52         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  53         priv->base = devm_ioremap_resource(dev, res);
  54         if (IS_ERR(priv->base))
  55                 return PTR_ERR(priv->base);
  56
  57         econfig.stride = 1;
  58         econfig.word_size = 1;
  59         econfig.read_only = true;
  60         econfig.reg_read = uniphier_reg_read;
  61         econfig.size = resource_size(res);
  62         econfig.priv = priv;
  63         econfig.dev = dev;
  64         nvmem = devm_nvmem_register(dev, &econfig);
  65
  66         return PTR_ERR_OR_ZERO(nvmem);
  67 }
  68
  69 static const struct of_device_id uniphier_efuse_of_match[] = {
  70         { .compatible = "socionext,uniphier-efuse",},
  71         {/* sentinel */},
  72 };
  73 MODULE_DEVICE_TABLE(of, uniphier_efuse_of_match);
  74
  75 static struct platform_driver uniphier_efuse_driver = {
  76         .probe = uniphier_efuse_probe,
  77         .driver = {
  78                 .name = "uniphier-efuse",
  79                 .of_match_table = uniphier_efuse_of_match,
  80         },
  81 };
  82 module_platform_driver(uniphier_efuse_driver);
  83
  84 MODULE_AUTHOR("Keiji Hayashibara <hayashibara.keiji@socionext.com>");
  85 MODULE_DESCRIPTION("UniPhier eFuse driver");
  86 MODULE_LICENSE("GPL v2");