drivers/nvmem/meson-efuse.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Amlogic Meson GX eFuse Driver
   4  *
   5  * Copyright (c) 2016 Endless Computers, Inc.
   6  * Author: Carlo Caione <carlo@endlessm.com>
   7  */
   8
   9 #include <linux/clk.h>
  10 #include <linux/module.h>
  11 #include <linux/nvmem-provider.h>
  12 #include <linux/of.h>
  13 #include <linux/platform_device.h>
  14
  15 #include <linux/firmware/meson/meson_sm.h>
  16
  17 static int meson_efuse_read(void *context, unsigned int offset,
  18                             void *val, size_t bytes)
  19 {
  20         return meson_sm_call_read((u8 *)val, bytes, SM_EFUSE_READ, offset,
  21                                   bytes, 0, 0, 0);
  22 }
  23
  24 static int meson_efuse_write(void *context, unsigned int offset,
  25                              void *val, size_t bytes)
  26 {
  27         return meson_sm_call_write((u8 *)val, bytes, SM_EFUSE_WRITE, offset,
  28                                    bytes, 0, 0, 0);
  29 }
  30
  31 static const struct of_device_id meson_efuse_match[] = {
  32         { .compatible = "amlogic,meson-gxbb-efuse", },
  33         { /* sentinel */ },
  34 };
  35 MODULE_DEVICE_TABLE(of, meson_efuse_match);
  36
  37 static int meson_efuse_probe(struct platform_device *pdev)
  38 {
  39         struct device *dev = &pdev->dev;
  40         struct nvmem_device *nvmem;
  41         struct nvmem_config *econfig;
  42         struct clk *clk;
  43         unsigned int size;
  44         int ret;
  45
  46         clk = devm_clk_get(dev, NULL);
  47         if (IS_ERR(clk)) {
  48                 ret = PTR_ERR(clk);
  49                 if (ret != -EPROBE_DEFER)
  50                         dev_err(dev, "failed to get efuse gate");
  51                 return ret;
  52         }
  53
  54         ret = clk_prepare_enable(clk);
  55         if (ret) {
  56                 dev_err(dev, "failed to enable gate");
  57                 return ret;
  58         }
  59
  60         ret = devm_add_action_or_reset(dev,
  61                                        (void(*)(void *))clk_disable_unprepare,
  62                                        clk);
  63         if (ret) {
  64                 dev_err(dev, "failed to add disable callback");
  65                 return ret;
  66         }
  67
  68         if (meson_sm_call(SM_EFUSE_USER_MAX, &size, 0, 0, 0, 0, 0) < 0) {
  69                 dev_err(dev, "failed to get max user");
  70                 return -EINVAL;
  71         }
  72
  73         econfig = devm_kzalloc(dev, sizeof(*econfig), GFP_KERNEL);
  74         if (!econfig)
  75                 return -ENOMEM;
  76
  77         econfig->dev = dev;
  78         econfig->name = dev_name(dev);
  79         econfig->stride = 1;
  80         econfig->word_size = 1;
  81         econfig->reg_read = meson_efuse_read;
  82         econfig->reg_write = meson_efuse_write;
  83         econfig->size = size;
  84
  85         nvmem = devm_nvmem_register(&pdev->dev, econfig);
  86
  87         return PTR_ERR_OR_ZERO(nvmem);
  88 }
  89
  90 static struct platform_driver meson_efuse_driver = {
  91         .probe = meson_efuse_probe,
  92         .driver = {
  93                 .name = "meson-efuse",
  94                 .of_match_table = meson_efuse_match,
  95         },
  96 };
  97
  98 module_platform_driver(meson_efuse_driver);
  99
 100 MODULE_AUTHOR("Carlo Caione <carlo@endlessm.com>");
 101 MODULE_DESCRIPTION("Amlogic Meson GX NVMEM driver");
 102 MODULE_LICENSE("GPL v2");