drivers/nvmem/imx-ocotp.c

   1 /*
   2  * i.MX6 OCOTP fusebox driver
   3  *
   4  * Copyright (c) 2015 Pengutronix, Philipp Zabel <p.zabel@pengutronix.de>
   5  *
   6  * Based on the barebox ocotp driver,
   7  * Copyright (c) 2010 Baruch Siach <baruch@tkos.co.il>,
   8  *      Orex Computed Radiography
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License version 2
  12  * as published by the Free Software Foundation.
  13  *
  14  * http://www.opensource.org/licenses/gpl-license.html
  15  * http://www.gnu.org/copyleft/gpl.html
  16  */
  17
  18 #include <linux/device.h>
  19 #include <linux/io.h>
  20 #include <linux/module.h>
  21 #include <linux/nvmem-provider.h>
  22 #include <linux/of.h>
  23 #include <linux/of_device.h>
  24 #include <linux/platform_device.h>
  25 #include <linux/slab.h>
  26
  27 struct ocotp_priv {
  28         struct device *dev;
  29         void __iomem *base;
  30         unsigned int nregs;
  31 };
  32
  33 static int imx_ocotp_read(void *context, unsigned int offset,
  34                           void *val, size_t bytes)
  35 {
  36         struct ocotp_priv *priv = context;
  37         unsigned int count;
  38         u32 *buf = val;
  39         int i;
  40         u32 index;
  41
  42         index = offset >> 2;
  43         count = bytes >> 2;
  44
  45         if (count > (priv->nregs - index))
  46                 count = priv->nregs - index;
  47
  48         for (i = index; i < (index + count); i++)
  49                 *buf++ = readl(priv->base + 0x400 + i * 0x10);
  50
  51         return 0;
  52 }
  53
  54 static struct nvmem_config imx_ocotp_nvmem_config = {
  55         .name = "imx-ocotp",
  56         .read_only = true,
  57         .word_size = 4,
  58         .stride = 4,
  59         .owner = THIS_MODULE,
  60         .reg_read = imx_ocotp_read,
  61 };
  62
  63 static const struct of_device_id imx_ocotp_dt_ids[] = {
  64         { .compatible = "fsl,imx6q-ocotp",  (void *)128 },
  65         { .compatible = "fsl,imx6sl-ocotp", (void *)32 },
  66         { .compatible = "fsl,imx6sx-ocotp", (void *)128 },
  67         { },
  68 };
  69 MODULE_DEVICE_TABLE(of, imx_ocotp_dt_ids);
  70
  71 static int imx_ocotp_probe(struct platform_device *pdev)
  72 {
  73         const struct of_device_id *of_id;
  74         struct device *dev = &pdev->dev;
  75         struct resource *res;
  76         struct ocotp_priv *priv;
  77         struct nvmem_device *nvmem;
  78
  79         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
  80         if (!priv)
  81                 return -ENOMEM;
  82
  83         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  84         priv->base = devm_ioremap_resource(dev, res);
  85         if (IS_ERR(priv->base))
  86                 return PTR_ERR(priv->base);
  87
  88         of_id = of_match_device(imx_ocotp_dt_ids, dev);
  89         priv->nregs = (unsigned int)of_id->data;
  90         imx_ocotp_nvmem_config.size = 4 * priv->nregs;
  91         imx_ocotp_nvmem_config.dev = dev;
  92         imx_ocotp_nvmem_config.priv = priv;
  93         nvmem = nvmem_register(&imx_ocotp_nvmem_config);
  94         if (IS_ERR(nvmem))
  95                 return PTR_ERR(nvmem);
  96
  97         platform_set_drvdata(pdev, nvmem);
  98
  99         return 0;
 100 }
 101
 102 static int imx_ocotp_remove(struct platform_device *pdev)
 103 {
 104         struct nvmem_device *nvmem = platform_get_drvdata(pdev);
 105
 106         return nvmem_unregister(nvmem);
 107 }
 108
 109 static struct platform_driver imx_ocotp_driver = {
 110         .probe  = imx_ocotp_probe,
 111         .remove = imx_ocotp_remove,
 112         .driver = {
 113                 .name   = "imx_ocotp",
 114                 .of_match_table = imx_ocotp_dt_ids,
 115         },
 116 };
 117 module_platform_driver(imx_ocotp_driver);
 118
 119 MODULE_AUTHOR("Philipp Zabel <p.zabel@pengutronix.de>");
 120 MODULE_DESCRIPTION("i.MX6 OCOTP fuse box driver");
 121 MODULE_LICENSE("GPL v2");