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