// SPDX-License-Identifier: GPL-2.0+
  /*
   * Copyright (C) 2019 Xilinx, Inc.
   */
  
  #include <linux/module.h>
  #include <linux/nvmem-provider.h>
  #include <linux/of.h>
  #include <linux/platform_device.h>
  #include <linux/firmware/xlnx-zynqmp.h>
  
  #define SILICON_REVISION_MASK 0xF
  
  struct zynqmp_nvmem_data {
  	struct device *dev;
  	struct nvmem_device *nvmem;
  };

  static const struct zynqmp_eemi_ops *eemi_ops;

  static int zynqmp_nvmem_read(void *context, unsigned int offset,
  			     void *val, size_t bytes)
  {
  	int ret;
  	int idcode, version;
  	struct zynqmp_nvmem_data *priv = context;

  	if (!eemi_ops->get_chipid)

  		return -ENXIO;
  
  	ret = eemi_ops->get_chipid(&idcode, &version);
  	if (ret < 0)
  		return ret;
  
  	dev_dbg(priv->dev, "Read chipid val %x %x
  ", idcode, version);
  	*(int *)val = version & SILICON_REVISION_MASK;
  
  	return 0;
  }
  
  static struct nvmem_config econfig = {
  	.name = "zynqmp-nvmem",
  	.owner = THIS_MODULE,
  	.word_size = 1,
  	.size = 1,
  	.read_only = true,
  };
  
  static const struct of_device_id zynqmp_nvmem_match[] = {
  	{ .compatible = "xlnx,zynqmp-nvmem-fw", },
  	{ /* sentinel */ },
  };
  MODULE_DEVICE_TABLE(of, zynqmp_nvmem_match);
  
  static int zynqmp_nvmem_probe(struct platform_device *pdev)
  {
  	struct device *dev = &pdev->dev;
  	struct zynqmp_nvmem_data *priv;
  
  	priv = devm_kzalloc(dev, sizeof(struct zynqmp_nvmem_data), GFP_KERNEL);
  	if (!priv)
  		return -ENOMEM;

  	eemi_ops = zynqmp_pm_get_eemi_ops();
  	if (IS_ERR(eemi_ops))
  		return PTR_ERR(eemi_ops);

  	priv->dev = dev;
  	econfig.dev = dev;
  	econfig.reg_read = zynqmp_nvmem_read;
  	econfig.priv = priv;
  
  	priv->nvmem = devm_nvmem_register(dev, &econfig);
  
  	return PTR_ERR_OR_ZERO(priv->nvmem);
  }
  
  static struct platform_driver zynqmp_nvmem_driver = {
  	.probe = zynqmp_nvmem_probe,
  	.driver = {
  		.name = "zynqmp-nvmem",
  		.of_match_table = zynqmp_nvmem_match,
  	},
  };
  
  module_platform_driver(zynqmp_nvmem_driver);
  
  MODULE_AUTHOR("Michal Simek <michal.simek@xilinx.com>, Nava kishore Manne <navam@xilinx.com>");
  MODULE_DESCRIPTION("ZynqMP NVMEM driver");
  MODULE_LICENSE("GPL");