1 /* 2 * Amlogic Meson GX 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/clk.h> 18 #include <linux/module.h> 19 #include <linux/nvmem-provider.h> 20 #include <linux/of.h> 21 #include <linux/platform_device.h> 22 23 #include <linux/firmware/meson/meson_sm.h> 24 25 static int meson_efuse_read(void *context, unsigned int offset, 26 void *val, size_t bytes) 27 { 28 return meson_sm_call_read((u8 *)val, bytes, SM_EFUSE_READ, offset, 29 bytes, 0, 0, 0); 30 } 31 32 static int meson_efuse_write(void *context, unsigned int offset, 33 void *val, size_t bytes) 34 { 35 return meson_sm_call_write((u8 *)val, bytes, SM_EFUSE_WRITE, offset, 36 bytes, 0, 0, 0); 37 } 38 39 static const struct of_device_id meson_efuse_match[] = { 40 { .compatible = "amlogic,meson-gxbb-efuse", }, 41 { /* sentinel */ }, 42 }; 43 MODULE_DEVICE_TABLE(of, meson_efuse_match); 44 45 static int meson_efuse_probe(struct platform_device *pdev) 46 { 47 struct device *dev = &pdev->dev; 48 struct nvmem_device *nvmem; 49 struct nvmem_config *econfig; 50 struct clk *clk; 51 unsigned int size; 52 int ret; 53 54 clk = devm_clk_get(dev, NULL); 55 if (IS_ERR(clk)) { 56 ret = PTR_ERR(clk); 57 if (ret != -EPROBE_DEFER) 58 dev_err(dev, "failed to get efuse gate"); 59 return ret; 60 } 61 62 ret = clk_prepare_enable(clk); 63 if (ret) { 64 dev_err(dev, "failed to enable gate"); 65 return ret; 66 } 67 68 ret = devm_add_action_or_reset(dev, 69 (void(*)(void *))clk_disable_unprepare, 70 clk); 71 if (ret) { 72 dev_err(dev, "failed to add disable callback"); 73 return ret; 74 } 75 76 if (meson_sm_call(SM_EFUSE_USER_MAX, &size, 0, 0, 0, 0, 0) < 0) { 77 dev_err(dev, "failed to get max user"); 78 return -EINVAL; 79 } 80 81 econfig = devm_kzalloc(dev, sizeof(*econfig), GFP_KERNEL); 82 if (!econfig) 83 return -ENOMEM; 84 85 econfig->dev = dev; 86 econfig->name = dev_name(dev); 87 econfig->stride = 1; 88 econfig->word_size = 1; 89 econfig->reg_read = meson_efuse_read; 90 econfig->reg_write = meson_efuse_write; 91 econfig->size = size; 92 93 nvmem = devm_nvmem_register(&pdev->dev, econfig); 94 95 return PTR_ERR_OR_ZERO(nvmem); 96 } 97 98 static struct platform_driver meson_efuse_driver = { 99 .probe = meson_efuse_probe, 100 .driver = { 101 .name = "meson-efuse", 102 .of_match_table = meson_efuse_match, 103 }, 104 }; 105 106 module_platform_driver(meson_efuse_driver); 107 108 MODULE_AUTHOR("Carlo Caione <carlo@endlessm.com>"); 109 MODULE_DESCRIPTION("Amlogic Meson GX NVMEM driver"); 110 MODULE_LICENSE("GPL v2"); 111