drivers/nvmem/meson-efuse.c

   1 /*
   2  * Amlogic Meson GX eFuse Driver
   3  *
   4  * Copyright (c) 2016 Endless Computers, Inc.
   5  * Author: Carlo Caione <carlo@endlessm.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms of version 2 of the GNU General Public License as
   9  * published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  14  * more details.
  15  */
  16
  17 #include <linux/module.h>
  18 #include <linux/nvmem-provider.h>
  19 #include <linux/of.h>
  20 #include <linux/platform_device.h>
  21
  22 #include <linux/firmware/meson/meson_sm.h>
  23
  24 static int meson_efuse_read(void *context, unsigned int offset,
  25                             void *val, size_t bytes)
  26 {
  27         return meson_sm_call_read((u8 *)val, bytes, SM_EFUSE_READ, offset,
  28                                   bytes, 0, 0, 0);
  29 }
  30
  31 static int meson_efuse_write(void *context, unsigned int offset,
  32                              void *val, size_t bytes)
  33 {
  34         return meson_sm_call_write((u8 *)val, bytes, SM_EFUSE_WRITE, offset,
  35                                    bytes, 0, 0, 0);
  36 }
  37
  38 static const struct of_device_id meson_efuse_match[] = {
  39         { .compatible = "amlogic,meson-gxbb-efuse", },
  40         { /* sentinel */ },
  41 };
  42 MODULE_DEVICE_TABLE(of, meson_efuse_match);
  43
  44 static int meson_efuse_probe(struct platform_device *pdev)
  45 {
  46         struct device *dev = &pdev->dev;
  47         struct nvmem_device *nvmem;
  48         struct nvmem_config *econfig;
  49         unsigned int size;
  50
  51         if (meson_sm_call(SM_EFUSE_USER_MAX, &size, 0, 0, 0, 0, 0) < 0)
  52                 return -EINVAL;
  53
  54         econfig = devm_kzalloc(dev, sizeof(*econfig), GFP_KERNEL);
  55         if (!econfig)
  56                 return -ENOMEM;
  57
  58         econfig->dev = dev;
  59         econfig->name = dev_name(dev);
  60         econfig->stride = 1;
  61         econfig->word_size = 1;
  62         econfig->reg_read = meson_efuse_read;
  63         econfig->reg_write = meson_efuse_write;
  64         econfig->size = size;
  65
  66         nvmem = devm_nvmem_register(&pdev->dev, econfig);
  67
  68         return PTR_ERR_OR_ZERO(nvmem);
  69 }
  70
  71 static struct platform_driver meson_efuse_driver = {
  72         .probe = meson_efuse_probe,
  73         .driver = {
  74                 .name = "meson-efuse",
  75                 .of_match_table = meson_efuse_match,
  76         },
  77 };
  78
  79 module_platform_driver(meson_efuse_driver);
  80
  81 MODULE_AUTHOR("Carlo Caione <carlo@endlessm.com>");
  82 MODULE_DESCRIPTION("Amlogic Meson GX NVMEM driver");
  83 MODULE_LICENSE("GPL v2");