| Alexandre Belloni | 697e5a4 | 2017-07-06 11:42:02 +0200 | [diff] [blame^] | 1 | /* |
| 2 | * RTC subsystem, nvmem interface |
| 3 | * |
| 4 | * Copyright (C) 2017 Alexandre Belloni |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License version 2 as |
| 8 | * published by the Free Software Foundation. |
| 9 | */ |
| 10 | |
| 11 | #include <linux/err.h> |
| 12 | #include <linux/types.h> |
| 13 | #include <linux/nvmem-consumer.h> |
| 14 | #include <linux/rtc.h> |
| 15 | #include <linux/sysfs.h> |
| 16 | |
| 17 | #include "rtc-core.h" |
| 18 | |
| 19 | /* |
| 20 | * Deprecated ABI compatibility, this should be removed at some point |
| 21 | */ |
| 22 | |
| 23 | static const char nvram_warning[] = "Deprecated ABI, please use nvmem"; |
| 24 | |
| 25 | static ssize_t |
| 26 | rtc_nvram_read(struct file *filp, struct kobject *kobj, |
| 27 | struct bin_attribute *attr, |
| 28 | char *buf, loff_t off, size_t count) |
| 29 | { |
| 30 | struct rtc_device *rtc = attr->private; |
| 31 | |
| 32 | dev_warn_once(kobj_to_dev(kobj), nvram_warning); |
| 33 | |
| 34 | return nvmem_device_read(rtc->nvmem, off, count, buf); |
| 35 | } |
| 36 | |
| 37 | static ssize_t |
| 38 | rtc_nvram_write(struct file *filp, struct kobject *kobj, |
| 39 | struct bin_attribute *attr, |
| 40 | char *buf, loff_t off, size_t count) |
| 41 | { |
| 42 | struct rtc_device *rtc = attr->private; |
| 43 | |
| 44 | dev_warn_once(kobj_to_dev(kobj), nvram_warning); |
| 45 | |
| 46 | return nvmem_device_write(rtc->nvmem, off, count, buf); |
| 47 | } |
| 48 | |
| 49 | static int rtc_nvram_register(struct rtc_device *rtc) |
| 50 | { |
| 51 | int err; |
| 52 | |
| 53 | rtc->nvram = devm_kzalloc(rtc->dev.parent, |
| 54 | sizeof(struct bin_attribute), |
| 55 | GFP_KERNEL); |
| 56 | if (!rtc->nvram) |
| 57 | return -ENOMEM; |
| 58 | |
| 59 | rtc->nvram->attr.name = "nvram"; |
| 60 | rtc->nvram->attr.mode = 0644; |
| 61 | rtc->nvram->private = rtc; |
| 62 | |
| 63 | sysfs_bin_attr_init(rtc->nvram); |
| 64 | |
| 65 | rtc->nvram->read = rtc_nvram_read; |
| 66 | rtc->nvram->write = rtc_nvram_write; |
| 67 | rtc->nvram->size = rtc->nvmem_config->size; |
| 68 | |
| 69 | err = sysfs_create_bin_file(&rtc->dev.parent->kobj, |
| 70 | rtc->nvram); |
| 71 | if (err) { |
| 72 | devm_kfree(rtc->dev.parent, rtc->nvram); |
| 73 | rtc->nvram = NULL; |
| 74 | } |
| 75 | |
| 76 | return err; |
| 77 | } |
| 78 | |
| 79 | static void rtc_nvram_unregister(struct rtc_device *rtc) |
| 80 | { |
| 81 | sysfs_remove_bin_file(&rtc->dev.parent->kobj, rtc->nvram); |
| 82 | } |
| 83 | |
| 84 | /* |
| 85 | * New ABI, uses nvmem |
| 86 | */ |
| 87 | void rtc_nvmem_register(struct rtc_device *rtc) |
| 88 | { |
| 89 | if (!rtc->nvmem_config) |
| 90 | return; |
| 91 | |
| 92 | rtc->nvmem_config->dev = &rtc->dev; |
| 93 | rtc->nvmem_config->owner = rtc->owner; |
| 94 | rtc->nvmem = nvmem_register(rtc->nvmem_config); |
| 95 | if (IS_ERR_OR_NULL(rtc->nvmem)) |
| 96 | return; |
| 97 | |
| 98 | /* Register the old ABI */ |
| 99 | if (rtc->nvram_old_abi) |
| 100 | rtc_nvram_register(rtc); |
| 101 | } |
| 102 | |
| 103 | void rtc_nvmem_unregister(struct rtc_device *rtc) |
| 104 | { |
| 105 | if (IS_ERR_OR_NULL(rtc->nvmem)) |
| 106 | return; |
| 107 | |
| 108 | /* unregister the old ABI */ |
| 109 | if (rtc->nvram) |
| 110 | rtc_nvram_unregister(rtc); |
| 111 | |
| 112 | nvmem_unregister(rtc->nvmem); |
| 113 | } |