drivers/nvmem/meson-efuse.c

   1 /*
   2  * Amlogic 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         u8 *buf = val;
  28         int ret;
  29
  30         ret = meson_sm_call_read(buf, SM_EFUSE_READ, offset,
  31                                  bytes, 0, 0, 0);
  32         if (ret < 0)
  33                 return ret;
  34
  35         return 0;
  36 }
  37
  38 static struct nvmem_config econfig = {
  39         .name = "meson-efuse",
  40         .owner = THIS_MODULE,
  41         .stride = 1,
  42         .word_size = 1,
  43         .read_only = true,
  44 };
  45
  46 static const struct of_device_id meson_efuse_match[] = {
  47         { .compatible = "amlogic,meson-gxbb-efuse", },
  48         { /* sentinel */ },
  49 };
  50 MODULE_DEVICE_TABLE(of, meson_efuse_match);
  51
  52 static int meson_efuse_probe(struct platform_device *pdev)
  53 {
  54         struct nvmem_device *nvmem;
  55         unsigned int size;
  56
  57         if (meson_sm_call(SM_EFUSE_USER_MAX, &size, 0, 0, 0, 0, 0) < 0)
  58                 return -EINVAL;
  59
  60         econfig.dev = &pdev->dev;
  61         econfig.reg_read = meson_efuse_read;
  62         econfig.size = size;
  63
  64         nvmem = nvmem_register(&econfig);
  65         if (IS_ERR(nvmem))
  66                 return PTR_ERR(nvmem);
  67
  68         platform_set_drvdata(pdev, nvmem);
  69
  70         return 0;
  71 }
  72
  73 static int meson_efuse_remove(struct platform_device *pdev)
  74 {
  75         struct nvmem_device *nvmem = platform_get_drvdata(pdev);
  76
  77         return nvmem_unregister(nvmem);
  78 }
  79
  80 static struct platform_driver meson_efuse_driver = {
  81         .probe = meson_efuse_probe,
  82         .remove = meson_efuse_remove,
  83         .driver = {
  84                 .name = "meson-efuse",
  85                 .of_match_table = meson_efuse_match,
  86         },
  87 };
  88
  89 module_platform_driver(meson_efuse_driver);
  90
  91 MODULE_AUTHOR("Carlo Caione <carlo@endlessm.com>");
  92 MODULE_DESCRIPTION("Amlogic Meson NVMEM driver");
  93 MODULE_LICENSE("GPL v2");