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 <[email protected]>
   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_cell_info(struct nvmem_device *nvmem,
  49                                       struct nvmem_layout *layout,
  50                                       struct nvmem_cell_info *cell)
  51 {
  52         size_t sz = strlen(cell->name);
  53
  54         /*
  55          * On some SoCs, the GPU speedbin is not read as bitmask but as
  56          * a number with range [0-7] (max 3 bits): post process to use
  57          * it in OPP tables to describe supported-hw.
  58          */
  59         if (cell->nbits <= 3 &&
  60             strncmp(cell->name, "gpu-speedbin", min(sz, strlen("gpu-speedbin"))) == 0)
  61                 cell->read_post_process = mtk_efuse_gpu_speedbin_pp;
  62 }
  63
  64 static struct nvmem_layout mtk_efuse_layout = {
  65         .fixup_cell_info = mtk_efuse_fixup_cell_info,
  66 };
  67
  68 static int mtk_efuse_probe(struct platform_device *pdev)
  69 {
  70         struct device *dev = &pdev->dev;
  71         struct resource *res;
  72         struct nvmem_device *nvmem;
  73         struct nvmem_config econfig = {};
  74         struct mtk_efuse_priv *priv;
  75         const struct mtk_efuse_pdata *pdata;
  76
  77         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
  78         if (!priv)
  79                 return -ENOMEM;
  80
  81         priv->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
  82         if (IS_ERR(priv->base))
  83                 return PTR_ERR(priv->base);
  84
  85         pdata = device_get_match_data(dev);
  86         econfig.add_legacy_fixed_of_cells = true;
  87         econfig.stride = 1;
  88         econfig.word_size = 1;
  89         econfig.reg_read = mtk_reg_read;
  90         econfig.size = resource_size(res);
  91         econfig.priv = priv;
  92         econfig.dev = dev;
  93         if (pdata->uses_post_processing)
  94                 econfig.layout = &mtk_efuse_layout;
  95         nvmem = devm_nvmem_register(dev, &econfig);
  96
  97         return PTR_ERR_OR_ZERO(nvmem);
  98 }
  99
 100 static const struct mtk_efuse_pdata mtk_mt8186_efuse_pdata = {
 101         .uses_post_processing = true,
 102 };
 103
 104 static const struct mtk_efuse_pdata mtk_efuse_pdata = {
 105         .uses_post_processing = false,
 106 };
 107
 108 static const struct of_device_id mtk_efuse_of_match[] = {
 109         { .compatible = "mediatek,mt8173-efuse", .data = &mtk_efuse_pdata },
 110         { .compatible = "mediatek,mt8186-efuse", .data = &mtk_mt8186_efuse_pdata },
 111         { .compatible = "mediatek,efuse", .data = &mtk_efuse_pdata },
 112         {/* sentinel */},
 113 };
 114 MODULE_DEVICE_TABLE(of, mtk_efuse_of_match);
 115
 116 static struct platform_driver mtk_efuse_driver = {
 117         .probe = mtk_efuse_probe,
 118         .driver = {
 119                 .name = "mediatek,efuse",
 120                 .of_match_table = mtk_efuse_of_match,
 121         },
 122 };
 123
 124 static int __init mtk_efuse_init(void)
 125 {
 126         int ret;
 127
 128         ret = platform_driver_register(&mtk_efuse_driver);
 129         if (ret) {
 130                 pr_err("Failed to register efuse driver\n");
 131                 return ret;
 132         }
 133
 134         return 0;
 135 }
 136
 137 static void __exit mtk_efuse_exit(void)
 138 {
 139         return platform_driver_unregister(&mtk_efuse_driver);
 140 }
 141
 142 subsys_initcall(mtk_efuse_init);
 143 module_exit(mtk_efuse_exit);
 144
 145 MODULE_AUTHOR("Andrew-CT Chen <[email protected]>");
 146 MODULE_DESCRIPTION("Mediatek EFUSE driver");
 147 MODULE_LICENSE("GPL v2");