text: /*
   * i.MX6 OCOTP fusebox driver
   *
   * Copyright (c) 2015 Pengutronix, Philipp Zabel <p.zabel@pengutronix.de>
   *
   * Based on the barebox ocotp driver,
   * Copyright (c) 2010 Baruch Siach <baruch@tkos.co.il>,
   *	Orex Computed Radiography
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2
   * as published by the Free Software Foundation.
   *
   * http://www.opensource.org/licenses/gpl-license.html
   * http://www.gnu.org/copyleft/gpl.html
   */
  
  #include <linux/device.h>
  #include <linux/io.h>
  #include <linux/module.h>
  #include <linux/nvmem-provider.h>
  #include <linux/of.h>
  #include <linux/of_device.h>
  #include <linux/platform_device.h>
  #include <linux/regmap.h>
  #include <linux/slab.h>
  
  struct ocotp_priv {
  	struct device *dev;
  	void __iomem *base;
  	unsigned int nregs;
  };
  
  static int imx_ocotp_read(void *context, const void *reg, size_t reg_size,
  			  void *val, size_t val_size)
  {
  	struct ocotp_priv *priv = context;
  	unsigned int offset = *(u32 *)reg;
  	unsigned int count;
  	int i;
  	u32 index;
  
  	index = offset >> 2;
  	count = val_size >> 2;
  
  	if (count > (priv->nregs - index))
  		count = priv->nregs - index;
  
  	for (i = index; i < (index + count); i++) {
  		*(u32 *)val = readl(priv->base + 0x400 + i * 0x10);
  		val += 4;
  	}
  
  	return (i - index) * 4;
  }
  
  static int imx_ocotp_write(void *context, const void *data, size_t count)
  {
  	/* Not implemented */
  	return 0;
  }
  
  static struct regmap_bus imx_ocotp_bus = {
  	.read = imx_ocotp_read,
  	.write = imx_ocotp_write,
  	.reg_format_endian_default = REGMAP_ENDIAN_NATIVE,
  	.val_format_endian_default = REGMAP_ENDIAN_NATIVE,
  };
  
  static bool imx_ocotp_writeable_reg(struct device *dev, unsigned int reg)
  {
  	return false;
  }
  
  static struct regmap_config imx_ocotp_regmap_config = {
  	.reg_bits = 32,
  	.val_bits = 32,
  	.reg_stride = 4,
  	.writeable_reg = imx_ocotp_writeable_reg,
  	.name = "imx-ocotp",
  };
  
  static struct nvmem_config imx_ocotp_nvmem_config = {
  	.name = "imx-ocotp",
  	.read_only = true,
  	.owner = THIS_MODULE,
  };
  
  static const struct of_device_id imx_ocotp_dt_ids[] = {
  	{ .compatible = "fsl,imx6q-ocotp",  (void *)128 },
  	{ .compatible = "fsl,imx6sl-ocotp", (void *)32 },
  	{ .compatible = "fsl,imx6sx-ocotp", (void *)128 },
  	{ },
  };
  MODULE_DEVICE_TABLE(of, imx_ocotp_dt_ids);
  
  static int imx_ocotp_probe(struct platform_device *pdev)
  {
  	const struct of_device_id *of_id;
  	struct device *dev = &pdev->dev;
  	struct resource *res;
  	struct regmap *regmap;
  	struct ocotp_priv *priv;
  	struct nvmem_device *nvmem;
  
  	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);
  
  	of_id = of_match_device(imx_ocotp_dt_ids, dev);
  	priv->nregs = (unsigned int)of_id->data;
  	imx_ocotp_regmap_config.max_register = 4 * priv->nregs - 4;
  
  	regmap = devm_regmap_init(dev, &imx_ocotp_bus, priv,
  				  &imx_ocotp_regmap_config);
  	if (IS_ERR(regmap)) {
  		dev_err(dev, "regmap init failed\n");
  		return PTR_ERR(regmap);
  	}
  	imx_ocotp_nvmem_config.dev = dev;
  	nvmem = nvmem_register(&imx_ocotp_nvmem_config);
  	if (IS_ERR(nvmem))
  		return PTR_ERR(nvmem);
  
  	platform_set_drvdata(pdev, nvmem);
  
  	return 0;
  }
  
  static int imx_ocotp_remove(struct platform_device *pdev)
  {
  	struct nvmem_device *nvmem = platform_get_drvdata(pdev);
  
  	return nvmem_unregister(nvmem);
  }
  
  static struct platform_driver imx_ocotp_driver = {
  	.probe	= imx_ocotp_probe,
  	.remove	= imx_ocotp_remove,
  	.driver = {
  		.name	= "imx_ocotp",
  		.of_match_table = imx_ocotp_dt_ids,
  	},
  };
  module_platform_driver(imx_ocotp_driver);
  
  MODULE_AUTHOR("Philipp Zabel <p.zabel@pengutronix.de>");
  MODULE_DESCRIPTION("i.MX6 OCOTP fuse box driver");
  MODULE_LICENSE("GPL v2");
  