1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * RTC subsystem, nvmem interface
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * Copyright (C) 2017 Alexandre Belloni
6*4882a593Smuzhiyun */
7*4882a593Smuzhiyun
8*4882a593Smuzhiyun #include <linux/err.h>
9*4882a593Smuzhiyun #include <linux/types.h>
10*4882a593Smuzhiyun #include <linux/nvmem-consumer.h>
11*4882a593Smuzhiyun #include <linux/rtc.h>
12*4882a593Smuzhiyun #include <linux/slab.h>
13*4882a593Smuzhiyun #include <linux/sysfs.h>
14*4882a593Smuzhiyun
15*4882a593Smuzhiyun /*
16*4882a593Smuzhiyun * Deprecated ABI compatibility, this should be removed at some point
17*4882a593Smuzhiyun */
18*4882a593Smuzhiyun
19*4882a593Smuzhiyun static const char nvram_warning[] = "Deprecated ABI, please use nvmem";
20*4882a593Smuzhiyun
21*4882a593Smuzhiyun static ssize_t
rtc_nvram_read(struct file * filp,struct kobject * kobj,struct bin_attribute * attr,char * buf,loff_t off,size_t count)22*4882a593Smuzhiyun rtc_nvram_read(struct file *filp, struct kobject *kobj,
23*4882a593Smuzhiyun struct bin_attribute *attr,
24*4882a593Smuzhiyun char *buf, loff_t off, size_t count)
25*4882a593Smuzhiyun {
26*4882a593Smuzhiyun dev_warn_once(kobj_to_dev(kobj), nvram_warning);
27*4882a593Smuzhiyun
28*4882a593Smuzhiyun return nvmem_device_read(attr->private, off, count, buf);
29*4882a593Smuzhiyun }
30*4882a593Smuzhiyun
31*4882a593Smuzhiyun static ssize_t
rtc_nvram_write(struct file * filp,struct kobject * kobj,struct bin_attribute * attr,char * buf,loff_t off,size_t count)32*4882a593Smuzhiyun rtc_nvram_write(struct file *filp, struct kobject *kobj,
33*4882a593Smuzhiyun struct bin_attribute *attr,
34*4882a593Smuzhiyun char *buf, loff_t off, size_t count)
35*4882a593Smuzhiyun {
36*4882a593Smuzhiyun dev_warn_once(kobj_to_dev(kobj), nvram_warning);
37*4882a593Smuzhiyun
38*4882a593Smuzhiyun return nvmem_device_write(attr->private, off, count, buf);
39*4882a593Smuzhiyun }
40*4882a593Smuzhiyun
rtc_nvram_register(struct rtc_device * rtc,struct nvmem_device * nvmem,size_t size)41*4882a593Smuzhiyun static int rtc_nvram_register(struct rtc_device *rtc,
42*4882a593Smuzhiyun struct nvmem_device *nvmem, size_t size)
43*4882a593Smuzhiyun {
44*4882a593Smuzhiyun int err;
45*4882a593Smuzhiyun
46*4882a593Smuzhiyun rtc->nvram = kzalloc(sizeof(*rtc->nvram), GFP_KERNEL);
47*4882a593Smuzhiyun if (!rtc->nvram)
48*4882a593Smuzhiyun return -ENOMEM;
49*4882a593Smuzhiyun
50*4882a593Smuzhiyun rtc->nvram->attr.name = "nvram";
51*4882a593Smuzhiyun rtc->nvram->attr.mode = 0644;
52*4882a593Smuzhiyun rtc->nvram->private = nvmem;
53*4882a593Smuzhiyun
54*4882a593Smuzhiyun sysfs_bin_attr_init(rtc->nvram);
55*4882a593Smuzhiyun
56*4882a593Smuzhiyun rtc->nvram->read = rtc_nvram_read;
57*4882a593Smuzhiyun rtc->nvram->write = rtc_nvram_write;
58*4882a593Smuzhiyun rtc->nvram->size = size;
59*4882a593Smuzhiyun
60*4882a593Smuzhiyun err = sysfs_create_bin_file(&rtc->dev.parent->kobj,
61*4882a593Smuzhiyun rtc->nvram);
62*4882a593Smuzhiyun if (err) {
63*4882a593Smuzhiyun kfree(rtc->nvram);
64*4882a593Smuzhiyun rtc->nvram = NULL;
65*4882a593Smuzhiyun }
66*4882a593Smuzhiyun
67*4882a593Smuzhiyun return err;
68*4882a593Smuzhiyun }
69*4882a593Smuzhiyun
rtc_nvram_unregister(struct rtc_device * rtc)70*4882a593Smuzhiyun static void rtc_nvram_unregister(struct rtc_device *rtc)
71*4882a593Smuzhiyun {
72*4882a593Smuzhiyun sysfs_remove_bin_file(&rtc->dev.parent->kobj, rtc->nvram);
73*4882a593Smuzhiyun kfree(rtc->nvram);
74*4882a593Smuzhiyun rtc->nvram = NULL;
75*4882a593Smuzhiyun }
76*4882a593Smuzhiyun
77*4882a593Smuzhiyun /*
78*4882a593Smuzhiyun * New ABI, uses nvmem
79*4882a593Smuzhiyun */
rtc_nvmem_register(struct rtc_device * rtc,struct nvmem_config * nvmem_config)80*4882a593Smuzhiyun int rtc_nvmem_register(struct rtc_device *rtc,
81*4882a593Smuzhiyun struct nvmem_config *nvmem_config)
82*4882a593Smuzhiyun {
83*4882a593Smuzhiyun struct nvmem_device *nvmem;
84*4882a593Smuzhiyun
85*4882a593Smuzhiyun if (!nvmem_config)
86*4882a593Smuzhiyun return -ENODEV;
87*4882a593Smuzhiyun
88*4882a593Smuzhiyun nvmem_config->dev = rtc->dev.parent;
89*4882a593Smuzhiyun nvmem_config->owner = rtc->owner;
90*4882a593Smuzhiyun nvmem = devm_nvmem_register(rtc->dev.parent, nvmem_config);
91*4882a593Smuzhiyun if (IS_ERR(nvmem))
92*4882a593Smuzhiyun return PTR_ERR(nvmem);
93*4882a593Smuzhiyun
94*4882a593Smuzhiyun /* Register the old ABI */
95*4882a593Smuzhiyun if (rtc->nvram_old_abi)
96*4882a593Smuzhiyun rtc_nvram_register(rtc, nvmem, nvmem_config->size);
97*4882a593Smuzhiyun
98*4882a593Smuzhiyun return 0;
99*4882a593Smuzhiyun }
100*4882a593Smuzhiyun EXPORT_SYMBOL_GPL(rtc_nvmem_register);
101*4882a593Smuzhiyun
rtc_nvmem_unregister(struct rtc_device * rtc)102*4882a593Smuzhiyun void rtc_nvmem_unregister(struct rtc_device *rtc)
103*4882a593Smuzhiyun {
104*4882a593Smuzhiyun /* unregister the old ABI */
105*4882a593Smuzhiyun if (rtc->nvram)
106*4882a593Smuzhiyun rtc_nvram_unregister(rtc);
107*4882a593Smuzhiyun }
108