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         int ret;
  51
  52         sm_np = of_parse_phandle(pdev->dev.of_node, "secure-monitor", 0);
  53         if (!sm_np) {
  54                 dev_err(&pdev->dev, "no secure-monitor node\n");
  55                 return -ENODEV;
  56         }
  57
  58         fw = meson_sm_get(sm_np);
  59         of_node_put(sm_np);
  60         if (!fw)
  61                 return -EPROBE_DEFER;
  62
  63         clk = devm_clk_get(dev, NULL);
  64         if (IS_ERR(clk)) {
  65                 ret = PTR_ERR(clk);
  66                 if (ret != -EPROBE_DEFER)
  67                         dev_err(dev, "failed to get efuse gate");
  68                 return ret;
  69         }
  70
  71         ret = clk_prepare_enable(clk);
  72         if (ret) {
  73                 dev_err(dev, "failed to enable gate");
  74                 return ret;
  75         }
  76
  77         ret = devm_add_action_or_reset(dev,
  78                                        (void(*)(void *))clk_disable_unprepare,
  79                                        clk);
  80         if (ret) {
  81                 dev_err(dev, "failed to add disable callback");
  82                 return ret;
  83         }
  84
  85         if (meson_sm_call(fw, SM_EFUSE_USER_MAX, &size, 0, 0, 0, 0, 0) < 0) {
  86                 dev_err(dev, "failed to get max user");
  87                 return -EINVAL;
  88         }
  89
  90         econfig = devm_kzalloc(dev, sizeof(*econfig), GFP_KERNEL);
  91         if (!econfig)
  92                 return -ENOMEM;
  93
  94         econfig->dev = dev;
  95         econfig->name = dev_name(dev);
  96         econfig->stride = 1;
  97         econfig->word_size = 1;
  98         econfig->reg_read = meson_efuse_read;
  99         econfig->reg_write = meson_efuse_write;
 100         econfig->size = size;
 101         econfig->priv = fw;
 102
 103         nvmem = devm_nvmem_register(&pdev->dev, econfig);
 104
 105         return PTR_ERR_OR_ZERO(nvmem);
 106 }
 107
 108 static struct platform_driver meson_efuse_driver = {
 109         .probe = meson_efuse_probe,
 110         .driver = {
 111                 .name = "meson-efuse",
 112                 .of_match_table = meson_efuse_match,
 113         },
 114 };
 115
 116 module_platform_driver(meson_efuse_driver);
 117
 118 MODULE_AUTHOR("Carlo Caione <carlo@endlessm.com>");
 119 MODULE_DESCRIPTION("Amlogic Meson GX NVMEM driver");
 120 MODULE_LICENSE("GPL v2");