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/regmap.h>
  26 #include <linux/slab.h>
  27
  28 struct ocotp_priv {
  29         struct device *dev;
  30         void __iomem *base;
  31         unsigned int nregs;
  32 };
  33
  34 static int imx_ocotp_read(void *context, const void *reg, size_t reg_size,
  35                           void *val, size_t val_size)
  36 {
  37         struct ocotp_priv *priv = context;
  38         unsigned int offset = *(u32 *)reg;
  39         unsigned int count;
  40         int i;
  41         u32 index;
  42
  43         index = offset >> 2;
  44         count = val_size >> 2;
  45
  46         if (count > (priv->nregs - index))
  47                 count = priv->nregs - index;
  48
  49         for (i = index; i < (index + count); i++) {
  50                 *(u32 *)val = readl(priv->base + 0x400 + i * 0x10);
  51                 val += 4;
  52         }
  53
  54         return (i - index) * 4;
  55 }
  56
  57 static int imx_ocotp_write(void *context, const void *data, size_t count)
  58 {
  59         /* Not implemented */
  60         return 0;
  61 }
  62
  63 static struct regmap_bus imx_ocotp_bus = {
  64         .read = imx_ocotp_read,
  65         .write = imx_ocotp_write,
  66         .reg_format_endian_default = REGMAP_ENDIAN_NATIVE,
  67         .val_format_endian_default = REGMAP_ENDIAN_NATIVE,
  68 };
  69
  70 static bool imx_ocotp_writeable_reg(struct device *dev, unsigned int reg)
  71 {
  72         return false;
  73 }
  74
  75 static struct regmap_config imx_ocotp_regmap_config = {
  76         .reg_bits = 32,
  77         .val_bits = 32,
  78         .reg_stride = 4,
  79         .writeable_reg = imx_ocotp_writeable_reg,
  80         .name = "imx-ocotp",
  81 };
  82
  83 static struct nvmem_config imx_ocotp_nvmem_config = {
  84         .name = "imx-ocotp",
  85         .read_only = true,
  86         .owner = THIS_MODULE,
  87 };
  88
  89 static const struct of_device_id imx_ocotp_dt_ids[] = {
  90         { .compatible = "fsl,imx6q-ocotp",  (void *)128 },
  91         { .compatible = "fsl,imx6sl-ocotp", (void *)64 },
  92         { .compatible = "fsl,imx6sx-ocotp", (void *)128 },
  93         { },
  94 };
  95 MODULE_DEVICE_TABLE(of, imx_ocotp_dt_ids);
  96
  97 static int imx_ocotp_probe(struct platform_device *pdev)
  98 {
  99         const struct of_device_id *of_id;
 100         struct device *dev = &pdev->dev;
 101         struct resource *res;
 102         struct regmap *regmap;
 103         struct ocotp_priv *priv;
 104         struct nvmem_device *nvmem;
 105
 106         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 107         if (!priv)
 108                 return -ENOMEM;
 109
 110         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 111         priv->base = devm_ioremap_resource(dev, res);
 112         if (IS_ERR(priv->base))
 113                 return PTR_ERR(priv->base);
 114
 115         of_id = of_match_device(imx_ocotp_dt_ids, dev);
 116         priv->nregs = (unsigned int)of_id->data;
 117         imx_ocotp_regmap_config.max_register = 4 * priv->nregs - 4;
 118
 119         regmap = devm_regmap_init(dev, &imx_ocotp_bus, priv,
 120                                   &imx_ocotp_regmap_config);
 121         if (IS_ERR(regmap)) {
 122                 dev_err(dev, "regmap init failed\n");
 123                 return PTR_ERR(regmap);
 124         }
 125         imx_ocotp_nvmem_config.dev = dev;
 126         nvmem = nvmem_register(&imx_ocotp_nvmem_config);
 127         if (IS_ERR(nvmem))
 128                 return PTR_ERR(nvmem);
 129
 130         platform_set_drvdata(pdev, nvmem);
 131
 132         return 0;
 133 }
 134
 135 static int imx_ocotp_remove(struct platform_device *pdev)
 136 {
 137         struct nvmem_device *nvmem = platform_get_drvdata(pdev);
 138
 139         return nvmem_unregister(nvmem);
 140 }
 141
 142 static struct platform_driver imx_ocotp_driver = {
 143         .probe  = imx_ocotp_probe,
 144         .remove = imx_ocotp_remove,
 145         .driver = {
 146                 .name   = "imx_ocotp",
 147                 .of_match_table = imx_ocotp_dt_ids,
 148         },
 149 };
 150 module_platform_driver(imx_ocotp_driver);
 151
 152 MODULE_AUTHOR("Philipp Zabel <p.zabel@pengutronix.de>");
 153 MODULE_DESCRIPTION("i.MX6 OCOTP fuse box driver");
 154 MODULE_LICENSE("GPL v2");