drivers/nvmem/mtk-efuse.c

   1 /*
   2  * Copyright (c) 2015 MediaTek Inc.
   3  * Author: Andrew-CT Chen <andrew-ct.chen@mediatek.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  */
  14
  15 #include <linux/device.h>
  16 #include <linux/module.h>
  17 #include <linux/io.h>
  18 #include <linux/nvmem-provider.h>
  19 #include <linux/platform_device.h>
  20
  21 struct mtk_efuse_priv {
  22         void __iomem *base;
  23 };
  24
  25 static int mtk_reg_read(void *context,
  26                         unsigned int reg, void *_val, size_t bytes)
  27 {
  28         struct mtk_efuse_priv *priv = context;
  29         u32 *val = _val;
  30         int i = 0, words = bytes / 4;
  31
  32         while (words--)
  33                 *val++ = readl(priv->base + reg + (i++ * 4));
  34
  35         return 0;
  36 }
  37
  38 static int mtk_reg_write(void *context,
  39                          unsigned int reg, void *_val, size_t bytes)
  40 {
  41         struct mtk_efuse_priv *priv = context;
  42         u32 *val = _val;
  43         int i = 0, words = bytes / 4;
  44
  45         while (words--)
  46                 writel(*val++, priv->base + reg + (i++ * 4));
  47
  48         return 0;
  49 }
  50
  51 static int mtk_efuse_probe(struct platform_device *pdev)
  52 {
  53         struct device *dev = &pdev->dev;
  54         struct resource *res;
  55         struct nvmem_device *nvmem;
  56         struct nvmem_config econfig = {};
  57         struct mtk_efuse_priv *priv;
  58
  59         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
  60         if (!priv)
  61                 return -ENOMEM;
  62
  63         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  64         priv->base = devm_ioremap_resource(dev, res);
  65         if (IS_ERR(priv->base))
  66                 return PTR_ERR(priv->base);
  67
  68         econfig.stride = 4;
  69         econfig.word_size = 4;
  70         econfig.reg_read = mtk_reg_read;
  71         econfig.reg_write = mtk_reg_write;
  72         econfig.size = resource_size(res);
  73         econfig.priv = priv;
  74         econfig.dev = dev;
  75         nvmem = nvmem_register(&econfig);
  76         if (IS_ERR(nvmem))
  77                 return PTR_ERR(nvmem);
  78
  79         platform_set_drvdata(pdev, nvmem);
  80
  81         return 0;
  82 }
  83
  84 static int mtk_efuse_remove(struct platform_device *pdev)
  85 {
  86         struct nvmem_device *nvmem = platform_get_drvdata(pdev);
  87
  88         return nvmem_unregister(nvmem);
  89 }
  90
  91 static const struct of_device_id mtk_efuse_of_match[] = {
  92         { .compatible = "mediatek,mt8173-efuse",},
  93         { .compatible = "mediatek,efuse",},
  94         {/* sentinel */},
  95 };
  96 MODULE_DEVICE_TABLE(of, mtk_efuse_of_match);
  97
  98 static struct platform_driver mtk_efuse_driver = {
  99         .probe = mtk_efuse_probe,
 100         .remove = mtk_efuse_remove,
 101         .driver = {
 102                 .name = "mediatek,efuse",
 103                 .of_match_table = mtk_efuse_of_match,
 104         },
 105 };
 106
 107 static int __init mtk_efuse_init(void)
 108 {
 109         int ret;
 110
 111         ret = platform_driver_register(&mtk_efuse_driver);
 112         if (ret) {
 113                 pr_err("Failed to register efuse driver\n");
 114                 return ret;
 115         }
 116
 117         return 0;
 118 }
 119
 120 static void __exit mtk_efuse_exit(void)
 121 {
 122         return platform_driver_unregister(&mtk_efuse_driver);
 123 }
 124
 125 subsys_initcall(mtk_efuse_init);
 126 module_exit(mtk_efuse_exit);
 127
 128 MODULE_AUTHOR("Andrew-CT Chen <andrew-ct.chen@mediatek.com>");
 129 MODULE_DESCRIPTION("Mediatek EFUSE driver");
 130 MODULE_LICENSE("GPL v2");