1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Amlogic Meson GX eFuse Driver 4 * 5 * Copyright (c) 2016 Endless Computers, Inc. 6 * Author: Carlo Caione <carlo@endlessm.com> 7 */ 8 9 #include <linux/clk.h> 10 #include <linux/module.h> 11 #include <linux/nvmem-provider.h> 12 #include <linux/of.h> 13 #include <linux/platform_device.h> 14 15 #include <linux/firmware/meson/meson_sm.h> 16 17 static int meson_efuse_read(void *context, unsigned int offset, 18 void *val, size_t bytes) 19 { 20 return meson_sm_call_read((u8 *)val, bytes, SM_EFUSE_READ, offset, 21 bytes, 0, 0, 0); 22 } 23 24 static int meson_efuse_write(void *context, unsigned int offset, 25 void *val, size_t bytes) 26 { 27 return meson_sm_call_write((u8 *)val, bytes, SM_EFUSE_WRITE, offset, 28 bytes, 0, 0, 0); 29 } 30 31 static const struct of_device_id meson_efuse_match[] = { 32 { .compatible = "amlogic,meson-gxbb-efuse", }, 33 { /* sentinel */ }, 34 }; 35 MODULE_DEVICE_TABLE(of, meson_efuse_match); 36 37 static int meson_efuse_probe(struct platform_device *pdev) 38 { 39 struct device *dev = &pdev->dev; 40 struct nvmem_device *nvmem; 41 struct nvmem_config *econfig; 42 struct clk *clk; 43 unsigned int size; 44 int ret; 45 46 clk = devm_clk_get(dev, NULL); 47 if (IS_ERR(clk)) { 48 ret = PTR_ERR(clk); 49 if (ret != -EPROBE_DEFER) 50 dev_err(dev, "failed to get efuse gate"); 51 return ret; 52 } 53 54 ret = clk_prepare_enable(clk); 55 if (ret) { 56 dev_err(dev, "failed to enable gate"); 57 return ret; 58 } 59 60 ret = devm_add_action_or_reset(dev, 61 (void(*)(void *))clk_disable_unprepare, 62 clk); 63 if (ret) { 64 dev_err(dev, "failed to add disable callback"); 65 return ret; 66 } 67 68 if (meson_sm_call(SM_EFUSE_USER_MAX, &size, 0, 0, 0, 0, 0) < 0) { 69 dev_err(dev, "failed to get max user"); 70 return -EINVAL; 71 } 72 73 econfig = devm_kzalloc(dev, sizeof(*econfig), GFP_KERNEL); 74 if (!econfig) 75 return -ENOMEM; 76 77 econfig->dev = dev; 78 econfig->name = dev_name(dev); 79 econfig->stride = 1; 80 econfig->word_size = 1; 81 econfig->reg_read = meson_efuse_read; 82 econfig->reg_write = meson_efuse_write; 83 econfig->size = size; 84 85 nvmem = devm_nvmem_register(&pdev->dev, econfig); 86 87 return PTR_ERR_OR_ZERO(nvmem); 88 } 89 90 static struct platform_driver meson_efuse_driver = { 91 .probe = meson_efuse_probe, 92 .driver = { 93 .name = "meson-efuse", 94 .of_match_table = meson_efuse_match, 95 }, 96 }; 97 98 module_platform_driver(meson_efuse_driver); 99 100 MODULE_AUTHOR("Carlo Caione <carlo@endlessm.com>"); 101 MODULE_DESCRIPTION("Amlogic Meson GX NVMEM driver"); 102 MODULE_LICENSE("GPL v2"); 103