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/clk.h>
  19 #include <linux/device.h>
  20 #include <linux/io.h>
  21 #include <linux/module.h>
  22 #include <linux/nvmem-provider.h>
  23 #include <linux/of.h>
  24 #include <linux/of_device.h>
  25 #include <linux/platform_device.h>
  26 #include <linux/slab.h>
  27
  28 struct ocotp_priv {
  29         struct device *dev;
  30         struct clk *clk;
  31         void __iomem *base;
  32         unsigned int nregs;
  33 };
  34
  35 static int imx_ocotp_read(void *context, unsigned int offset,
  36                           void *val, size_t bytes)
  37 {
  38         struct ocotp_priv *priv = context;
  39         unsigned int count;
  40         u32 *buf = val;
  41         int i, ret;
  42         u32 index;
  43
  44         index = offset >> 2;
  45         count = bytes >> 2;
  46
  47         if (count > (priv->nregs - index))
  48                 count = priv->nregs - index;
  49
  50         ret = clk_prepare_enable(priv->clk);
  51         if (ret < 0) {
  52                 dev_err(priv->dev, "failed to prepare/enable ocotp clk\n");
  53                 return ret;
  54         }
  55         for (i = index; i < (index + count); i++)
  56                 *buf++ = readl(priv->base + 0x400 + i * 0x10);
  57
  58         clk_disable_unprepare(priv->clk);
  59
  60         return 0;
  61 }
  62
  63 static struct nvmem_config imx_ocotp_nvmem_config = {
  64         .name = "imx-ocotp",
  65         .read_only = true,
  66         .word_size = 4,
  67         .stride = 4,
  68         .owner = THIS_MODULE,
  69         .reg_read = imx_ocotp_read,
  70 };
  71
  72 static const struct of_device_id imx_ocotp_dt_ids[] = {
  73         { .compatible = "fsl,imx6q-ocotp",  (void *)128 },
  74         { .compatible = "fsl,imx6sl-ocotp", (void *)64 },
  75         { .compatible = "fsl,imx6sx-ocotp", (void *)128 },
  76         { .compatible = "fsl,imx6ul-ocotp", (void *)128 },
  77         { },
  78 };
  79 MODULE_DEVICE_TABLE(of, imx_ocotp_dt_ids);
  80
  81 static int imx_ocotp_probe(struct platform_device *pdev)
  82 {
  83         const struct of_device_id *of_id;
  84         struct device *dev = &pdev->dev;
  85         struct resource *res;
  86         struct ocotp_priv *priv;
  87         struct nvmem_device *nvmem;
  88
  89         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
  90         if (!priv)
  91                 return -ENOMEM;
  92
  93         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  94         priv->base = devm_ioremap_resource(dev, res);
  95         if (IS_ERR(priv->base))
  96                 return PTR_ERR(priv->base);
  97
  98         priv->clk = devm_clk_get(&pdev->dev, NULL);
  99         if (IS_ERR(priv->clk))
 100                 return PTR_ERR(priv->clk);
 101
 102         of_id = of_match_device(imx_ocotp_dt_ids, dev);
 103         priv->nregs = (unsigned long)of_id->data;
 104         imx_ocotp_nvmem_config.size = 4 * priv->nregs;
 105         imx_ocotp_nvmem_config.dev = dev;
 106         imx_ocotp_nvmem_config.priv = priv;
 107         nvmem = nvmem_register(&imx_ocotp_nvmem_config);
 108         if (IS_ERR(nvmem))
 109                 return PTR_ERR(nvmem);
 110
 111         platform_set_drvdata(pdev, nvmem);
 112
 113         return 0;
 114 }
 115
 116 static int imx_ocotp_remove(struct platform_device *pdev)
 117 {
 118         struct nvmem_device *nvmem = platform_get_drvdata(pdev);
 119
 120         return nvmem_unregister(nvmem);
 121 }
 122
 123 static struct platform_driver imx_ocotp_driver = {
 124         .probe  = imx_ocotp_probe,
 125         .remove = imx_ocotp_remove,
 126         .driver = {
 127                 .name   = "imx_ocotp",
 128                 .of_match_table = imx_ocotp_dt_ids,
 129         },
 130 };
 131 module_platform_driver(imx_ocotp_driver);
 132
 133 MODULE_AUTHOR("Philipp Zabel <p.zabel@pengutronix.de>");
 134 MODULE_DESCRIPTION("i.MX6 OCOTP fuse box driver");
 135 MODULE_LICENSE("GPL v2");