From: Alexandre Belloni <alexandre.belloni@free-electrons.com>
To: linux-rtc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org,
Alexandre Belloni <alexandre.belloni@free-electrons.com>
Subject: [PATCH 05/11] rtc: add generic nvmem support
Date: Thu, 6 Jul 2017 11:42:02 +0200 [thread overview]
Message-ID: <20170706094208.16240-6-alexandre.belloni@free-electrons.com> (raw)
In-Reply-To: <20170706094208.16240-1-alexandre.belloni@free-electrons.com>
Many RTCs have an on board non volatile storage. It can be battery backed
RAM or an EEPROM. Use the nvmem subsystem to export it to both userspace
and in-kernel consumers.
This stays compatible with the previous (non documented) ABI that was using
/sys/class/rtc/rtcx/device/nvram to export that memory. But will warn about
the deprecation.
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
---
Documentation/rtc.txt | 2 +
drivers/rtc/Kconfig | 8 ++++
drivers/rtc/Makefile | 1 +
drivers/rtc/class.c | 4 ++
drivers/rtc/nvmem.c | 113 +++++++++++++++++++++++++++++++++++++++++++++++++
drivers/rtc/rtc-core.h | 8 ++++
include/linux/rtc.h | 7 +++
7 files changed, 143 insertions(+)
create mode 100644 drivers/rtc/nvmem.c
diff --git a/Documentation/rtc.txt b/Documentation/rtc.txt
index 47feb4414b7e..c0c977445fb9 100644
--- a/Documentation/rtc.txt
+++ b/Documentation/rtc.txt
@@ -164,6 +164,8 @@ offset The amount which the rtc clock has been adjusted in firmware.
which are added to or removed from the rtc's base clock per
billion ticks. A positive value makes a day pass more slowly,
longer, and a negative value makes a day pass more quickly.
+*/nvmem The non volatile storage exported as a raw file, as described
+ in Documentation/nvmem/nvmem.txt
================ ==============================================================
IOCTL interface
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index d0e4b4a1c2a1..72419ac2c52a 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -77,6 +77,14 @@ config RTC_DEBUG
Say yes here to enable debugging support in the RTC framework
and individual RTC drivers.
+config RTC_NVMEM
+ bool "RTC non volatile storage support"
+ select NVMEM
+ default RTC_CLASS
+ help
+ Say yes here to add support for the non volatile (often battery
+ backed) storage present on RTCs.
+
comment "RTC interfaces"
config RTC_INTF_SYSFS
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 4050fc8b9271..acd366b41c85 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -15,6 +15,7 @@ ifdef CONFIG_RTC_DRV_EFI
rtc-core-y += rtc-efi-platform.o
endif
+rtc-core-$(CONFIG_RTC_NVMEM) += nvmem.o
rtc-core-$(CONFIG_RTC_INTF_DEV) += rtc-dev.o
rtc-core-$(CONFIG_RTC_INTF_PROC) += rtc-proc.o
rtc-core-$(CONFIG_RTC_INTF_SYSFS) += rtc-sysfs.o
diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c
index 58e2a05765bb..2ed970d61da1 100644
--- a/drivers/rtc/class.c
+++ b/drivers/rtc/class.c
@@ -290,6 +290,8 @@ EXPORT_SYMBOL_GPL(rtc_device_register);
*/
void rtc_device_unregister(struct rtc_device *rtc)
{
+ rtc_nvmem_unregister(rtc);
+
mutex_lock(&rtc->ops_lock);
/*
* Remove innards of this RTC, then disable it, before
@@ -448,6 +450,8 @@ int __rtc_register_device(struct module *owner, struct rtc_device *rtc)
rtc_proc_add_device(rtc);
+ rtc_nvmem_register(rtc);
+
rtc->registered = true;
dev_info(rtc->dev.parent, "registered as %s\n",
dev_name(&rtc->dev));
diff --git a/drivers/rtc/nvmem.c b/drivers/rtc/nvmem.c
new file mode 100644
index 000000000000..8567b4ed9ac6
--- /dev/null
+++ b/drivers/rtc/nvmem.c
@@ -0,0 +1,113 @@
+/*
+ * 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>
+
+#include "rtc-core.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)
+{
+ 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 = rtc->nvmem_config->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
+ */
+void rtc_nvmem_register(struct rtc_device *rtc)
+{
+ if (!rtc->nvmem_config)
+ return;
+
+ rtc->nvmem_config->dev = &rtc->dev;
+ rtc->nvmem_config->owner = rtc->owner;
+ rtc->nvmem = nvmem_register(rtc->nvmem_config);
+ if (IS_ERR_OR_NULL(rtc->nvmem))
+ return;
+
+ /* Register the old ABI */
+ if (rtc->nvram_old_abi)
+ rtc_nvram_register(rtc);
+}
+
+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);
+}
diff --git a/drivers/rtc/rtc-core.h b/drivers/rtc/rtc-core.h
index 7a4ed2f7c7d7..ecab76a3207c 100644
--- a/drivers/rtc/rtc-core.h
+++ b/drivers/rtc/rtc-core.h
@@ -45,3 +45,11 @@ static inline const struct attribute_group **rtc_get_dev_attribute_groups(void)
return NULL;
}
#endif
+
+#ifdef CONFIG_RTC_NVMEM
+void rtc_nvmem_register(struct rtc_device *rtc);
+void rtc_nvmem_unregister(struct rtc_device *rtc);
+#else
+static inline void rtc_nvmem_register(struct rtc_device *rtc) {}
+static inline void rtc_nvmem_unregister(struct rtc_device *rtc) {}
+#endif
diff --git a/include/linux/rtc.h b/include/linux/rtc.h
index 8e4a5f44f59e..d53ecdc060cf 100644
--- a/include/linux/rtc.h
+++ b/include/linux/rtc.h
@@ -14,6 +14,7 @@
#include <linux/types.h>
#include <linux/interrupt.h>
+#include <linux/nvmem-provider.h>
#include <uapi/linux/rtc.h>
extern int rtc_month_days(unsigned int month, unsigned int year);
@@ -144,6 +145,12 @@ struct rtc_device {
bool registered;
+ struct nvmem_config *nvmem_config;
+ struct nvmem_device *nvmem;
+ /* Old ABI support */
+ bool nvram_old_abi;
+ struct bin_attribute *nvram;
+
#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
struct work_struct uie_task;
struct timer_list uie_timer;
--
2.11.0
next prev parent reply other threads:[~2017-07-06 9:42 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-06 9:41 [PATCH 00/11] RTC: rework registration Alexandre Belloni
2017-07-06 9:41 ` [PATCH 01/11] rtc: class separate device allocation from registration Alexandre Belloni
2017-07-06 9:41 ` [PATCH 02/11] rtc: class separate id " Alexandre Belloni
2017-07-06 9:42 ` [PATCH 03/11] rtc: introduce new registration method Alexandre Belloni
2017-07-06 9:42 ` [PATCH 04/11] rtc: at91rm9200: remove race condition Alexandre Belloni
2017-07-06 9:42 ` Alexandre Belloni [this message]
2017-07-06 9:42 ` [PATCH 06/11] rtc: rv8803: switch to rtc_register_device Alexandre Belloni
2017-07-06 9:42 ` [PATCH 07/11] rtc: rv8803: use generic nvmem support Alexandre Belloni
2017-07-06 9:42 ` [PATCH 08/11] rtc: rv8803: remove rv8803_remove Alexandre Belloni
2017-07-06 9:42 ` [PATCH 09/11] rtc: ds1307: switch to rtc_register_device Alexandre Belloni
2017-07-06 9:42 ` [PATCH 10/11] rtc: ds1307: use generic nvmem Alexandre Belloni
2017-07-06 9:42 ` [PATCH 11/11] rtc: ds1307: remove ds1307_remove Alexandre Belloni
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