drivers/nvmem/brcm_nvram.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2021 Rafał Miłecki <rafal@milecki.pl>
   4  */
   5
   6 #include <linux/io.h>
   7 #include <linux/mod_devicetable.h>
   8 #include <linux/module.h>
   9 #include <linux/nvmem-provider.h>
  10 #include <linux/platform_device.h>
  11
  12 struct brcm_nvram {
  13         struct device *dev;
  14         void __iomem *base;
  15 };
  16
  17 static int brcm_nvram_read(void *context, unsigned int offset, void *val,
  18                            size_t bytes)
  19 {
  20         struct brcm_nvram *priv = context;
  21         u8 *dst = val;
  22
  23         while (bytes--)
  24                 *dst++ = readb(priv->base + offset++);
  25
  26         return 0;
  27 }
  28
  29 static int brcm_nvram_probe(struct platform_device *pdev)
  30 {
  31         struct nvmem_config config = {
  32                 .name = "brcm-nvram",
  33                 .reg_read = brcm_nvram_read,
  34         };
  35         struct device *dev = &pdev->dev;
  36         struct resource *res;
  37         struct brcm_nvram *priv;
  38
  39         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
  40         if (!priv)
  41                 return -ENOMEM;
  42         priv->dev = dev;
  43
  44         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  45         priv->base = devm_ioremap_resource(dev, res);
  46         if (IS_ERR(priv->base))
  47                 return PTR_ERR(priv->base);
  48
  49         config.dev = dev;
  50         config.priv = priv;
  51         config.size = resource_size(res);
  52
  53         return PTR_ERR_OR_ZERO(devm_nvmem_register(dev, &config));
  54 }
  55
  56 static const struct of_device_id brcm_nvram_of_match_table[] = {
  57         { .compatible = "brcm,nvram", },
  58         {},
  59 };
  60
  61 static struct platform_driver brcm_nvram_driver = {
  62         .probe = brcm_nvram_probe,
  63         .driver = {
  64                 .name = "brcm_nvram",
  65                 .of_match_table = brcm_nvram_of_match_table,
  66         },
  67 };
  68
  69 static int __init brcm_nvram_init(void)
  70 {
  71         return platform_driver_register(&brcm_nvram_driver);
  72 }
  73
  74 subsys_initcall_sync(brcm_nvram_init);
  75
  76 MODULE_AUTHOR("Rafał Miłecki");
  77 MODULE_LICENSE("GPL");
  78 MODULE_DEVICE_TABLE(of, brcm_nvram_of_match_table);