text: // SPDX-License-Identifier: GPL-2.0-only
  /*
   * UniPhier eFuse driver
   *
   * Copyright (C) 2017 Socionext Inc.
   */
  
  #include <linux/device.h>
  #include <linux/io.h>
  #include <linux/module.h>
  #include <linux/mod_devicetable.h>
  #include <linux/nvmem-provider.h>
  #include <linux/platform_device.h>
  
  struct uniphier_efuse_priv {
  	void __iomem *base;
  };
  
  static int uniphier_reg_read(void *context,
  			     unsigned int reg, void *_val, size_t bytes)
  {
  	struct uniphier_efuse_priv *priv = context;
  	u8 *val = _val;
  	int offs;
  
  	for (offs = 0; offs < bytes; offs += sizeof(u8))
  		*val++ = readb(priv->base + reg + offs);
  
  	return 0;
  }
  
  static int uniphier_efuse_probe(struct platform_device *pdev)
  {
  	struct device *dev = &pdev->dev;
  	struct resource *res;
  	struct nvmem_device *nvmem;
  	struct nvmem_config econfig = {};
  	struct uniphier_efuse_priv *priv;
  
  	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
  	if (!priv)
  		return -ENOMEM;
  
  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	priv->base = devm_ioremap_resource(dev, res);
  	if (IS_ERR(priv->base))
  		return PTR_ERR(priv->base);
  
  	econfig.stride = 1;
  	econfig.word_size = 1;
  	econfig.read_only = true;
  	econfig.reg_read = uniphier_reg_read;
  	econfig.size = resource_size(res);
  	econfig.priv = priv;
  	econfig.dev = dev;
  	nvmem = devm_nvmem_register(dev, &econfig);
  
  	return PTR_ERR_OR_ZERO(nvmem);
  }
  
  static const struct of_device_id uniphier_efuse_of_match[] = {
  	{ .compatible = "socionext,uniphier-efuse",},
  	{/* sentinel */},
  };
  MODULE_DEVICE_TABLE(of, uniphier_efuse_of_match);
  
  static struct platform_driver uniphier_efuse_driver = {
  	.probe = uniphier_efuse_probe,
  	.driver = {
  		.name = "uniphier-efuse",
  		.of_match_table = uniphier_efuse_of_match,
  	},
  };
  module_platform_driver(uniphier_efuse_driver);
  
  MODULE_AUTHOR("Keiji Hayashibara <hayashibara.keiji@socionext.com>");
  MODULE_DESCRIPTION("UniPhier eFuse driver");
  MODULE_LICENSE("GPL v2");
  