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 static int mtk_reg_read(void *context,
  22                         unsigned int reg, void *_val, size_t bytes)
  23 {
  24         void __iomem *base = context;
  25         u32 *val = _val;
  26         int i = 0, words = bytes / 4;
  27
  28         while (words--)
  29                 *val++ = readl(base + reg + (i++ * 4));
  30
  31         return 0;
  32 }
  33
  34 static int mtk_reg_write(void *context,
  35                          unsigned int reg, void *_val, size_t bytes)
  36 {
  37         void __iomem *base = context;
  38         u32 *val = _val;
  39         int i = 0, words = bytes / 4;
  40
  41         while (words--)
  42                 writel(*val++, base + reg + (i++ * 4));
  43
  44         return 0;
  45 }
  46
  47 static int mtk_efuse_probe(struct platform_device *pdev)
  48 {
  49         struct device *dev = &pdev->dev;
  50         struct resource *res;
  51         struct nvmem_device *nvmem;
  52         struct nvmem_config *econfig;
  53         void __iomem *base;
  54
  55         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  56         base = devm_ioremap_resource(dev, res);
  57         if (IS_ERR(base))
  58                 return PTR_ERR(base);
  59
  60         econfig = devm_kzalloc(dev, sizeof(*econfig), GFP_KERNEL);
  61         if (!econfig)
  62                 return -ENOMEM;
  63
  64         econfig->stride = 4;
  65         econfig->word_size = 4;
  66         econfig->reg_read = mtk_reg_read;
  67         econfig->reg_write = mtk_reg_write;
  68         econfig->size = resource_size(res);
  69         econfig->priv = base;
  70         econfig->dev = dev;
  71         econfig->owner = THIS_MODULE;
  72         nvmem = nvmem_register(econfig);
  73         if (IS_ERR(nvmem))
  74                 return PTR_ERR(nvmem);
  75
  76         platform_set_drvdata(pdev, nvmem);
  77
  78         return 0;
  79 }
  80
  81 static int mtk_efuse_remove(struct platform_device *pdev)
  82 {
  83         struct nvmem_device *nvmem = platform_get_drvdata(pdev);
  84
  85         return nvmem_unregister(nvmem);
  86 }
  87
  88 static const struct of_device_id mtk_efuse_of_match[] = {
  89         { .compatible = "mediatek,mt8173-efuse",},
  90         { .compatible = "mediatek,efuse",},
  91         {/* sentinel */},
  92 };
  93 MODULE_DEVICE_TABLE(of, mtk_efuse_of_match);
  94
  95 static struct platform_driver mtk_efuse_driver = {
  96         .probe = mtk_efuse_probe,
  97         .remove = mtk_efuse_remove,
  98         .driver = {
  99                 .name = "mediatek,efuse",
 100                 .of_match_table = mtk_efuse_of_match,
 101         },
 102 };
 103
 104 static int __init mtk_efuse_init(void)
 105 {
 106         int ret;
 107
 108         ret = platform_driver_register(&mtk_efuse_driver);
 109         if (ret) {
 110                 pr_err("Failed to register efuse driver\n");
 111                 return ret;
 112         }
 113
 114         return 0;
 115 }
 116
 117 static void __exit mtk_efuse_exit(void)
 118 {
 119         return platform_driver_unregister(&mtk_efuse_driver);
 120 }
 121
 122 subsys_initcall(mtk_efuse_init);
 123 module_exit(mtk_efuse_exit);
 124
 125 MODULE_AUTHOR("Andrew-CT Chen <andrew-ct.chen@mediatek.com>");
 126 MODULE_DESCRIPTION("Mediatek EFUSE driver");
 127 MODULE_LICENSE("GPL v2");