drivers/nvmem/mtk-efuse.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2015 MediaTek Inc.
   4  * Author: Andrew-CT Chen <andrew-ct.chen@mediatek.com>
   5  */
   6
   7 #include <linux/device.h>
   8 #include <linux/module.h>
   9 #include <linux/mod_devicetable.h>
  10 #include <linux/io.h>
  11 #include <linux/nvmem-provider.h>
  12 #include <linux/platform_device.h>
  13 #include <linux/property.h>
  14
  15 struct mtk_efuse_pdata {
  16         bool uses_post_processing;
  17 };
  18
  19 struct mtk_efuse_priv {
  20         void __iomem *base;
  21 };
  22
  23 static int mtk_reg_read(void *context,
  24                         unsigned int reg, void *_val, size_t bytes)
  25 {
  26         struct mtk_efuse_priv *priv = context;
  27         void __iomem *addr = priv->base + reg;
  28         u8 *val = _val;
  29         int i;
  30
  31         for (i = 0; i < bytes; i++, val++)
  32                 *val = readb(addr + i);
  33
  34         return 0;
  35 }
  36
  37 static int mtk_efuse_gpu_speedbin_pp(void *context, const char *id, int index,
  38                                      unsigned int offset, void *data, size_t bytes)
  39 {
  40         u8 *val = data;
  41
  42         if (val[0] < 8)
  43                 val[0] = BIT(val[0]);
  44
  45         return 0;
  46 }
  47
  48 static void mtk_efuse_fixup_dt_cell_info(struct nvmem_device *nvmem,
  49                                          struct nvmem_cell_info *cell)
  50 {
  51         size_t sz = strlen(cell->name);
  52
  53         /*
  54          * On some SoCs, the GPU speedbin is not read as bitmask but as
  55          * a number with range [0-7] (max 3 bits): post process to use
  56          * it in OPP tables to describe supported-hw.
  57          */
  58         if (cell->nbits <= 3 &&
  59             strncmp(cell->name, "gpu-speedbin", min(sz, strlen("gpu-speedbin"))) == 0)
  60                 cell->read_post_process = mtk_efuse_gpu_speedbin_pp;
  61 }
  62
  63 static int mtk_efuse_probe(struct platform_device *pdev)
  64 {
  65         struct device *dev = &pdev->dev;
  66         struct resource *res;
  67         struct nvmem_device *nvmem;
  68         struct nvmem_config econfig = {};
  69         struct mtk_efuse_priv *priv;
  70         const struct mtk_efuse_pdata *pdata;
  71
  72         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
  73         if (!priv)
  74                 return -ENOMEM;
  75
  76         priv->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
  77         if (IS_ERR(priv->base))
  78                 return PTR_ERR(priv->base);
  79
  80         pdata = device_get_match_data(dev);
  81         econfig.add_legacy_fixed_of_cells = true;
  82         econfig.stride = 1;
  83         econfig.word_size = 1;
  84         econfig.reg_read = mtk_reg_read;
  85         econfig.size = resource_size(res);
  86         econfig.priv = priv;
  87         econfig.dev = dev;
  88         if (pdata->uses_post_processing)
  89                 econfig.fixup_dt_cell_info = &mtk_efuse_fixup_dt_cell_info;
  90         nvmem = devm_nvmem_register(dev, &econfig);
  91
  92         return PTR_ERR_OR_ZERO(nvmem);
  93 }
  94
  95 static const struct mtk_efuse_pdata mtk_mt8186_efuse_pdata = {
  96         .uses_post_processing = true,
  97 };
  98
  99 static const struct mtk_efuse_pdata mtk_efuse_pdata = {
 100         .uses_post_processing = false,
 101 };
 102
 103 static const struct of_device_id mtk_efuse_of_match[] = {
 104         { .compatible = "mediatek,mt8173-efuse", .data = &mtk_efuse_pdata },
 105         { .compatible = "mediatek,mt8186-efuse", .data = &mtk_mt8186_efuse_pdata },
 106         { .compatible = "mediatek,efuse", .data = &mtk_efuse_pdata },
 107         {/* sentinel */},
 108 };
 109 MODULE_DEVICE_TABLE(of, mtk_efuse_of_match);
 110
 111 static struct platform_driver mtk_efuse_driver = {
 112         .probe = mtk_efuse_probe,
 113         .driver = {
 114                 .name = "mediatek,efuse",
 115                 .of_match_table = mtk_efuse_of_match,
 116         },
 117 };
 118
 119 static int __init mtk_efuse_init(void)
 120 {
 121         int ret;
 122
 123         ret = platform_driver_register(&mtk_efuse_driver);
 124         if (ret) {
 125                 pr_err("Failed to register efuse driver\n");
 126                 return ret;
 127         }
 128
 129         return 0;
 130 }
 131
 132 static void __exit mtk_efuse_exit(void)
 133 {
 134         return platform_driver_unregister(&mtk_efuse_driver);
 135 }
 136
 137 subsys_initcall(mtk_efuse_init);
 138 module_exit(mtk_efuse_exit);
 139
 140 MODULE_AUTHOR("Andrew-CT Chen <andrew-ct.chen@mediatek.com>");
 141 MODULE_DESCRIPTION("Mediatek EFUSE driver");
 142 MODULE_LICENSE("GPL v2");