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         struct meson_sm_firmware *fw = context;
  21         int ret;
  22
  23         ret = meson_sm_call_read(fw, (u8 *)val, bytes, SM_EFUSE_READ, offset,
  24                                  bytes, 0, 0, 0);
  25
  26         return ret < 0 ? ret : 0;
  27 }
  28
  29 static int meson_efuse_write(void *context, unsigned int offset,
  30                              void *val, size_t bytes)
  31 {
  32         struct meson_sm_firmware *fw = context;
  33         int ret;
  34
  35         ret = meson_sm_call_write(fw, (u8 *)val, bytes, SM_EFUSE_WRITE, offset,
  36                                   bytes, 0, 0, 0);
  37
  38         return ret < 0 ? ret : 0;
  39 }
  40
  41 static const struct of_device_id meson_efuse_match[] = {
  42         { .compatible = "amlogic,meson-gxbb-efuse", },
  43         { /* sentinel */ },
  44 };
  45 MODULE_DEVICE_TABLE(of, meson_efuse_match);
  46
  47 static int meson_efuse_probe(struct platform_device *pdev)
  48 {
  49         struct device *dev = &pdev->dev;
  50         struct meson_sm_firmware *fw;
  51         struct nvmem_device *nvmem;
  52         struct nvmem_config *econfig;
  53         struct clk *clk;
  54         unsigned int size;
  55         struct device_node *sm_np __free(device_node) =
  56                         of_parse_phandle(pdev->dev.of_node, "secure-monitor", 0);
  57
  58         if (!sm_np) {
  59                 dev_err(&pdev->dev, "no secure-monitor node\n");
  60                 return -ENODEV;
  61         }
  62
  63         fw = meson_sm_get(sm_np);
  64         if (!fw)
  65                 return -EPROBE_DEFER;
  66
  67         clk = devm_clk_get_enabled(dev, NULL);
  68         if (IS_ERR(clk))
  69                 return dev_err_probe(dev, PTR_ERR(clk), "failed to get efuse gate");
  70
  71         if (meson_sm_call(fw, SM_EFUSE_USER_MAX, &size, 0, 0, 0, 0, 0) < 0) {
  72                 dev_err(dev, "failed to get max user");
  73                 return -EINVAL;
  74         }
  75
  76         econfig = devm_kzalloc(dev, sizeof(*econfig), GFP_KERNEL);
  77         if (!econfig)
  78                 return -ENOMEM;
  79
  80         econfig->dev = dev;
  81         econfig->name = dev_name(dev);
  82         econfig->add_legacy_fixed_of_cells = true;
  83         econfig->stride = 1;
  84         econfig->word_size = 1;
  85         econfig->reg_read = meson_efuse_read;
  86         econfig->reg_write = meson_efuse_write;
  87         econfig->size = size;
  88         econfig->priv = fw;
  89
  90         nvmem = devm_nvmem_register(&pdev->dev, econfig);
  91
  92         return PTR_ERR_OR_ZERO(nvmem);
  93 }
  94
  95 static struct platform_driver meson_efuse_driver = {
  96         .probe = meson_efuse_probe,
  97         .driver = {
  98                 .name = "meson-efuse",
  99                 .of_match_table = meson_efuse_match,
 100         },
 101 };
 102
 103 module_platform_driver(meson_efuse_driver);
 104
 105 MODULE_AUTHOR("Carlo Caione <carlo@endlessm.com>");
 106 MODULE_DESCRIPTION("Amlogic Meson GX NVMEM driver");
 107 MODULE_LICENSE("GPL v2");