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/mod_devicetable.h>
  18 #include <linux/io.h>
  19 #include <linux/nvmem-provider.h>
  20 #include <linux/platform_device.h>
  21
  22 struct mtk_efuse_priv {
  23         void __iomem *base;
  24 };
  25
  26 static int mtk_reg_read(void *context,
  27                         unsigned int reg, void *_val, size_t bytes)
  28 {
  29         struct mtk_efuse_priv *priv = context;
  30         u32 *val = _val;
  31         int i = 0, words = bytes / 4;
  32
  33         while (words--)
  34                 *val++ = readl(priv->base + reg + (i++ * 4));
  35
  36         return 0;
  37 }
  38
  39 static int mtk_reg_write(void *context,
  40                          unsigned int reg, void *_val, size_t bytes)
  41 {
  42         struct mtk_efuse_priv *priv = context;
  43         u32 *val = _val;
  44         int i = 0, words = bytes / 4;
  45
  46         while (words--)
  47                 writel(*val++, priv->base + reg + (i++ * 4));
  48
  49         return 0;
  50 }
  51
  52 static int mtk_efuse_probe(struct platform_device *pdev)
  53 {
  54         struct device *dev = &pdev->dev;
  55         struct resource *res;
  56         struct nvmem_device *nvmem;
  57         struct nvmem_config econfig = {};
  58         struct mtk_efuse_priv *priv;
  59
  60         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
  61         if (!priv)
  62                 return -ENOMEM;
  63
  64         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  65         priv->base = devm_ioremap_resource(dev, res);
  66         if (IS_ERR(priv->base))
  67                 return PTR_ERR(priv->base);
  68
  69         econfig.stride = 4;
  70         econfig.word_size = 4;
  71         econfig.reg_read = mtk_reg_read;
  72         econfig.reg_write = mtk_reg_write;
  73         econfig.size = resource_size(res);
  74         econfig.priv = priv;
  75         econfig.dev = dev;
  76         nvmem = devm_nvmem_register(dev, &econfig);
  77
  78         return PTR_ERR_OR_ZERO(nvmem);
  79 }
  80
  81 static const struct of_device_id mtk_efuse_of_match[] = {
  82         { .compatible = "mediatek,mt8173-efuse",},
  83         { .compatible = "mediatek,efuse",},
  84         {/* sentinel */},
  85 };
  86 MODULE_DEVICE_TABLE(of, mtk_efuse_of_match);
  87
  88 static struct platform_driver mtk_efuse_driver = {
  89         .probe = mtk_efuse_probe,
  90         .driver = {
  91                 .name = "mediatek,efuse",
  92                 .of_match_table = mtk_efuse_of_match,
  93         },
  94 };
  95
  96 static int __init mtk_efuse_init(void)
  97 {
  98         int ret;
  99
 100         ret = platform_driver_register(&mtk_efuse_driver);
 101         if (ret) {
 102                 pr_err("Failed to register efuse driver\n");
 103                 return ret;
 104         }
 105
 106         return 0;
 107 }
 108
 109 static void __exit mtk_efuse_exit(void)
 110 {
 111         return platform_driver_unregister(&mtk_efuse_driver);
 112 }
 113
 114 subsys_initcall(mtk_efuse_init);
 115 module_exit(mtk_efuse_exit);
 116
 117 MODULE_AUTHOR("Andrew-CT Chen <andrew-ct.chen@mediatek.com>");
 118 MODULE_DESCRIPTION("Mediatek EFUSE driver");
 119 MODULE_LICENSE("GPL v2");