1 files changed, 107 insertions, 0 deletions
diff --git a/drivers/rtc/nvmem.c b/drivers/rtc/nvmem.c
new file mode 100644
index 000000000..4312096c7
--- /dev/null
+++ b/drivers/rtc/nvmem.c
@@ -0,0 +1,107 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * RTC subsystem, nvmem interface
+ *
+ * Copyright (C) 2017 Alexandre Belloni
+ */
+
+#include <linux/err.h>
+#include <linux/types.h>
+#include <linux/nvmem-consumer.h>
+#include <linux/rtc.h>
+#include <linux/slab.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)
+{
+	dev_warn_once(kobj_to_dev(kobj), nvram_warning);
+
+	return nvmem_device_read(attr->private, 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)
+{
+	dev_warn_once(kobj_to_dev(kobj), nvram_warning);
+
+	return nvmem_device_write(attr->private, off, count, buf);
+}
+
+static int rtc_nvram_register(struct rtc_device *rtc,
+			      struct nvmem_device *nvmem, size_t size)
+{
+	int err;
+
+	rtc->nvram = kzalloc(sizeof(*rtc->nvram), GFP_KERNEL);
+	if (!rtc->nvram)
+		return -ENOMEM;
+
+	rtc->nvram->attr.name = "nvram";
+	rtc->nvram->attr.mode = 0644;
+	rtc->nvram->private = nvmem;
+
+	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) {
+		kfree(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);
+	kfree(rtc->nvram);
+	rtc->nvram = NULL;
+}
+
+/*
+ * New ABI, uses nvmem
+ */
+int rtc_nvmem_register(struct rtc_device *rtc,
+		       struct nvmem_config *nvmem_config)
+{
+	struct nvmem_device *nvmem;
+
+	if (!nvmem_config)
+		return -ENODEV;
+
+	nvmem_config->dev = rtc->dev.parent;
+	nvmem_config->owner = rtc->owner;
+	nvmem = devm_nvmem_register(rtc->dev.parent, nvmem_config);
+	if (IS_ERR(nvmem))
+		return PTR_ERR(nvmem);
+
+	/* Register the old ABI */
+	if (rtc->nvram_old_abi)
+		rtc_nvram_register(rtc, nvmem, nvmem_config->size);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(rtc_nvmem_register);
+
+void rtc_nvmem_unregister(struct rtc_device *rtc)
+{
+	/* unregister the old ABI */
+	if (rtc->nvram)
+		rtc_nvram_unregister(rtc);
+}