v4.19.13 snapshot.
diff --git a/drivers/rtc/nvmem.c b/drivers/rtc/nvmem.c
new file mode 100644
index 0000000..36ab183
--- /dev/null
+++ b/drivers/rtc/nvmem.c
@@ -0,0 +1,118 @@
+/*
+ * RTC subsystem, nvmem interface
+ *
+ * Copyright (C) 2017 Alexandre Belloni
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/err.h>
+#include <linux/types.h>
+#include <linux/nvmem-consumer.h>
+#include <linux/rtc.h>
+#include <linux/sysfs.h>
+
+/*
+ * Deprecated ABI compatibility, this should be removed at some point
+ */
+
+static const char nvram_warning[] = "Deprecated ABI, please use nvmem";
+
+static ssize_t
+rtc_nvram_read(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *attr,
+ char *buf, loff_t off, size_t count)
+{
+ struct rtc_device *rtc = attr->private;
+
+ dev_warn_once(kobj_to_dev(kobj), nvram_warning);
+
+ return nvmem_device_read(rtc->nvmem, off, count, buf);
+}
+
+static ssize_t
+rtc_nvram_write(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *attr,
+ char *buf, loff_t off, size_t count)
+{
+ struct rtc_device *rtc = attr->private;
+
+ dev_warn_once(kobj_to_dev(kobj), nvram_warning);
+
+ return nvmem_device_write(rtc->nvmem, off, count, buf);
+}
+
+static int rtc_nvram_register(struct rtc_device *rtc, size_t size)
+{
+ int err;
+
+ rtc->nvram = devm_kzalloc(rtc->dev.parent,
+ sizeof(struct bin_attribute),
+ GFP_KERNEL);
+ if (!rtc->nvram)
+ return -ENOMEM;
+
+ rtc->nvram->attr.name = "nvram";
+ rtc->nvram->attr.mode = 0644;
+ rtc->nvram->private = rtc;
+
+ sysfs_bin_attr_init(rtc->nvram);
+
+ rtc->nvram->read = rtc_nvram_read;
+ rtc->nvram->write = rtc_nvram_write;
+ rtc->nvram->size = size;
+
+ err = sysfs_create_bin_file(&rtc->dev.parent->kobj,
+ rtc->nvram);
+ if (err) {
+ devm_kfree(rtc->dev.parent, rtc->nvram);
+ rtc->nvram = NULL;
+ }
+
+ return err;
+}
+
+static void rtc_nvram_unregister(struct rtc_device *rtc)
+{
+ sysfs_remove_bin_file(&rtc->dev.parent->kobj, rtc->nvram);
+}
+
+/*
+ * New ABI, uses nvmem
+ */
+int rtc_nvmem_register(struct rtc_device *rtc,
+ struct nvmem_config *nvmem_config)
+{
+ if (!IS_ERR_OR_NULL(rtc->nvmem))
+ return -EBUSY;
+
+ if (!nvmem_config)
+ return -ENODEV;
+
+ nvmem_config->dev = rtc->dev.parent;
+ nvmem_config->owner = rtc->owner;
+ rtc->nvmem = nvmem_register(nvmem_config);
+ if (IS_ERR(rtc->nvmem))
+ return PTR_ERR(rtc->nvmem);
+
+ /* Register the old ABI */
+ if (rtc->nvram_old_abi)
+ rtc_nvram_register(rtc, nvmem_config->size);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(rtc_nvmem_register);
+
+void rtc_nvmem_unregister(struct rtc_device *rtc)
+{
+ if (IS_ERR_OR_NULL(rtc->nvmem))
+ return;
+
+ /* unregister the old ABI */
+ if (rtc->nvram)
+ rtc_nvram_unregister(rtc);
+
+ nvmem_unregister(rtc->nvmem);
+}