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cdf7545a | 1 | // SPDX-License-Identifier: GPL-2.0 |
697e5a47 AB |
2 | /* |
3 | * RTC subsystem, nvmem interface | |
4 | * | |
5 | * Copyright (C) 2017 Alexandre Belloni | |
697e5a47 AB |
6 | */ |
7 | ||
8 | #include <linux/err.h> | |
9 | #include <linux/types.h> | |
10 | #include <linux/nvmem-consumer.h> | |
11 | #include <linux/rtc.h> | |
bba3d2da | 12 | #include <linux/slab.h> |
697e5a47 AB |
13 | #include <linux/sysfs.h> |
14 | ||
697e5a47 AB |
15 | /* |
16 | * Deprecated ABI compatibility, this should be removed at some point | |
17 | */ | |
18 | ||
19 | static const char nvram_warning[] = "Deprecated ABI, please use nvmem"; | |
20 | ||
21 | static ssize_t | |
22 | rtc_nvram_read(struct file *filp, struct kobject *kobj, | |
23 | struct bin_attribute *attr, | |
24 | char *buf, loff_t off, size_t count) | |
25 | { | |
697e5a47 AB |
26 | dev_warn_once(kobj_to_dev(kobj), nvram_warning); |
27 | ||
41c9e132 | 28 | return nvmem_device_read(attr->private, off, count, buf); |
697e5a47 AB |
29 | } |
30 | ||
31 | static ssize_t | |
32 | rtc_nvram_write(struct file *filp, struct kobject *kobj, | |
33 | struct bin_attribute *attr, | |
34 | char *buf, loff_t off, size_t count) | |
35 | { | |
697e5a47 AB |
36 | dev_warn_once(kobj_to_dev(kobj), nvram_warning); |
37 | ||
41c9e132 | 38 | return nvmem_device_write(attr->private, off, count, buf); |
697e5a47 AB |
39 | } |
40 | ||
41c9e132 AB |
41 | static int rtc_nvram_register(struct rtc_device *rtc, |
42 | struct nvmem_device *nvmem, size_t size) | |
697e5a47 AB |
43 | { |
44 | int err; | |
45 | ||
606cc43c | 46 | rtc->nvram = kzalloc(sizeof(*rtc->nvram), GFP_KERNEL); |
697e5a47 AB |
47 | if (!rtc->nvram) |
48 | return -ENOMEM; | |
49 | ||
50 | rtc->nvram->attr.name = "nvram"; | |
51 | rtc->nvram->attr.mode = 0644; | |
41c9e132 | 52 | rtc->nvram->private = nvmem; |
697e5a47 AB |
53 | |
54 | sysfs_bin_attr_init(rtc->nvram); | |
55 | ||
56 | rtc->nvram->read = rtc_nvram_read; | |
57 | rtc->nvram->write = rtc_nvram_write; | |
4cce9d39 | 58 | rtc->nvram->size = size; |
697e5a47 AB |
59 | |
60 | err = sysfs_create_bin_file(&rtc->dev.parent->kobj, | |
61 | rtc->nvram); | |
62 | if (err) { | |
bba3d2da | 63 | kfree(rtc->nvram); |
697e5a47 AB |
64 | rtc->nvram = NULL; |
65 | } | |
66 | ||
67 | return err; | |
68 | } | |
69 | ||
70 | static void rtc_nvram_unregister(struct rtc_device *rtc) | |
71 | { | |
72 | sysfs_remove_bin_file(&rtc->dev.parent->kobj, rtc->nvram); | |
bba3d2da AB |
73 | kfree(rtc->nvram); |
74 | rtc->nvram = NULL; | |
697e5a47 AB |
75 | } |
76 | ||
77 | /* | |
78 | * New ABI, uses nvmem | |
79 | */ | |
2cc82121 AB |
80 | int rtc_nvmem_register(struct rtc_device *rtc, |
81 | struct nvmem_config *nvmem_config) | |
697e5a47 | 82 | { |
41c9e132 | 83 | struct nvmem_device *nvmem; |
ab3ea36e | 84 | |
4cce9d39 | 85 | if (!nvmem_config) |
2cc82121 | 86 | return -ENODEV; |
697e5a47 | 87 | |
ac75779b | 88 | nvmem_config->dev = rtc->dev.parent; |
4cce9d39 | 89 | nvmem_config->owner = rtc->owner; |
41c9e132 AB |
90 | nvmem = devm_nvmem_register(rtc->dev.parent, nvmem_config); |
91 | if (IS_ERR(nvmem)) | |
92 | return PTR_ERR(nvmem); | |
697e5a47 AB |
93 | |
94 | /* Register the old ABI */ | |
95 | if (rtc->nvram_old_abi) | |
41c9e132 | 96 | rtc_nvram_register(rtc, nvmem, nvmem_config->size); |
2cc82121 AB |
97 | |
98 | return 0; | |
697e5a47 | 99 | } |
fd5cd21d | 100 | EXPORT_SYMBOL_GPL(rtc_nvmem_register); |
697e5a47 AB |
101 | |
102 | void rtc_nvmem_unregister(struct rtc_device *rtc) | |
103 | { | |
697e5a47 AB |
104 | /* unregister the old ABI */ |
105 | if (rtc->nvram) | |
106 | rtc_nvram_unregister(rtc); | |
697e5a47 | 107 | } |