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