1 /* 2 * Amlogic eFuse Driver 3 * 4 * Copyright (c) 2016 Endless Computers, Inc. 5 * Author: Carlo Caione <carlo@endlessm.com> 6 * 7 * This program is free software; you can redistribute it and/or modify it 8 * under the terms of version 2 of the GNU General Public License as 9 * published by the Free Software Foundation. 10 * 11 * This program is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 14 * more details. 15 */ 16 17 #include <linux/module.h> 18 #include <linux/nvmem-provider.h> 19 #include <linux/of.h> 20 #include <linux/platform_device.h> 21 22 #include <linux/firmware/meson/meson_sm.h> 23 24 static int meson_efuse_read(void *context, unsigned int offset, 25 void *val, size_t bytes) 26 { 27 u8 *buf = val; 28 int ret; 29 30 ret = meson_sm_call_read(buf, SM_EFUSE_READ, offset, 31 bytes, 0, 0, 0); 32 if (ret < 0) 33 return ret; 34 35 return 0; 36 } 37 38 static struct nvmem_config econfig = { 39 .name = "meson-efuse", 40 .owner = THIS_MODULE, 41 .stride = 1, 42 .word_size = 1, 43 .read_only = true, 44 }; 45 46 static const struct of_device_id meson_efuse_match[] = { 47 { .compatible = "amlogic,meson-gxbb-efuse", }, 48 { /* sentinel */ }, 49 }; 50 MODULE_DEVICE_TABLE(of, meson_efuse_match); 51 52 static int meson_efuse_probe(struct platform_device *pdev) 53 { 54 struct nvmem_device *nvmem; 55 unsigned int size; 56 57 if (meson_sm_call(SM_EFUSE_USER_MAX, &size, 0, 0, 0, 0, 0) < 0) 58 return -EINVAL; 59 60 econfig.dev = &pdev->dev; 61 econfig.reg_read = meson_efuse_read; 62 econfig.size = size; 63 64 nvmem = nvmem_register(&econfig); 65 if (IS_ERR(nvmem)) 66 return PTR_ERR(nvmem); 67 68 platform_set_drvdata(pdev, nvmem); 69 70 return 0; 71 } 72 73 static int meson_efuse_remove(struct platform_device *pdev) 74 { 75 struct nvmem_device *nvmem = platform_get_drvdata(pdev); 76 77 return nvmem_unregister(nvmem); 78 } 79 80 static struct platform_driver meson_efuse_driver = { 81 .probe = meson_efuse_probe, 82 .remove = meson_efuse_remove, 83 .driver = { 84 .name = "meson-efuse", 85 .of_match_table = meson_efuse_match, 86 }, 87 }; 88 89 module_platform_driver(meson_efuse_driver); 90 91 MODULE_AUTHOR("Carlo Caione <carlo@endlessm.com>"); 92 MODULE_DESCRIPTION("Amlogic Meson NVMEM driver"); 93 MODULE_LICENSE("GPL v2"); 94