[RFC PATCHv2 1/2] Export SoC info through sysfs

[Maxime Coquelin]

Common base to export System-on-Chip related informations through sysfs.

Creation of a "socinfo" directory under /sys/.
Creation of SoC information entries.

Signed-off-by: Maxime COQUELIN <maxime.coquelin-nonst at stericsson.com>
---
 Documentation/ABI/testing/sysfs-socinfo |   16 ++++++
 drivers/base/Kconfig                    |    3 +
 drivers/base/Makefile                   |    1 +
 drivers/base/soc.c                      |   79 +++++++++++++++++++++++++++++++
 include/linux/sys_soc.h                 |   50 +++++++++++++++++++
 5 files changed, 149 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/ABI/testing/sysfs-socinfo
 create mode 100644 drivers/base/soc.c
 create mode 100644 include/linux/sys_soc.h

diff --git a/Documentation/ABI/testing/sysfs-socinfo b/Documentation/ABI/testing/sysfs-socinfo
new file mode 100644
index 0000000..afd9da2
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-socinfo
@@ -0,0 +1,16 @@
+What:		/sys/socinfo
+Date:		March 2011
+contact:	Maxime Coquelin <maxime.coquelin-nonst at stericsson.com>
+Description:
+		The /sys/socinfo directory contains information about the
+		System-on-Chip.	It is only available if platform implements it.
+		This directory contains two kind of attributes :
+			- common attributes: 
+				* machine: the name of the machine.
+				* family: the family name of the SoC
+			- SoC-specific attributes: The SoC vendor can declare attributes
+			  to export some strings to user-space, like the serial-number for
+			  example.
+
+Users:
+		User-space applications which needs these kind of attributes.
diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index d57e8d0..372ef3a 100644
--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig
@@ -168,4 +168,7 @@ config SYS_HYPERVISOR
 	bool
 	default n
 
+config SYS_SOC
+	bool
+
 endmenu
diff --git a/drivers/base/Makefile b/drivers/base/Makefile
index 5f51c3b..f3bcfb3 100644
--- a/drivers/base/Makefile
+++ b/drivers/base/Makefile
@@ -18,6 +18,7 @@ ifeq ($(CONFIG_SYSFS),y)
 obj-$(CONFIG_MODULES)	+= module.o
 endif
 obj-$(CONFIG_SYS_HYPERVISOR) += hypervisor.o
+obj-$(CONFIG_SYS_SOC) += soc.o
 
 ccflags-$(CONFIG_DEBUG_DRIVER) := -DDEBUG
 
diff --git a/drivers/base/soc.c b/drivers/base/soc.c
new file mode 100644
index 0000000..046b43b
--- /dev/null
+++ b/drivers/base/soc.c
@@ -0,0 +1,79 @@
+/*
+ * Copyright (C) ST-Ericsson SA 2011
+ * Author: Maxime Coquelin <maxime.coquelin-nonst at stericsson.com> for ST-Ericsson.
+ * License terms:  GNU General Public License (GPL), version 2
+ */
+
+#include <linux/sysfs.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/stat.h>
+#include <linux/slab.h>
+#include <linux/sys_soc.h>
+
+struct kobject *soc_object;
+
+ssize_t show_soc_info(struct kobject *kobj,
+			struct kobj_attribute *attr, char *buf)
+{
+	struct sysfs_soc_info *si = container_of(attr,
+				struct sysfs_soc_info, attr);
+
+	if (si->info)
+		return sprintf(buf, "%s\n", si->info);
+
+	return si->get_info(buf, si);
+}
+
+int __init register_sysfs_soc_info(struct sysfs_soc_info *info, int nb_info)
+{
+	int i, ret;
+
+	for (i = 0; i < nb_info; i++) {
+		ret = sysfs_create_file(soc_object, &info[i].attr.attr);
+		if (ret) {
+			for (i -= 1; i >= 0; i--)
+				sysfs_remove_file(soc_object, &info[i].attr.attr);
+			break;
+		}
+	}
+
+	return ret;
+}
+
+static struct attribute *soc_attrs[] = {
+	NULL,
+};
+
+static struct attribute_group soc_attr_group = {
+	.attrs = soc_attrs,
+};
+
+int __init register_sysfs_soc(struct sysfs_soc_info *info, size_t num)
+{
+	int ret;
+
+	soc_object = kobject_create_and_add("socinfo", NULL);
+	if (!soc_object) {
+		ret = -ENOMEM;
+		goto exit;
+	}
+
+	ret = sysfs_create_group(soc_object, &soc_attr_group);
+	if (ret)
+		goto kset_exit;
+
+	ret = register_sysfs_soc_info(info, num);
+	if (ret)
+		goto group_exit;
+
+	return 0;
+
+group_exit:
+	sysfs_remove_group(soc_object, &soc_attr_group);
+kset_exit:
+	kobject_put(soc_object);
+exit:
+	return ret;
+}
+
diff --git a/include/linux/sys_soc.h b/include/linux/sys_soc.h
new file mode 100644
index 0000000..05e5529
--- /dev/null
+++ b/include/linux/sys_soc.h
@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) ST-Ericsson SA 2011
+ * Author: Maxime Coquelin <maxime.coquelin-nonst at stericsson.com> for ST-Ericsson.
+ * License terms:  GNU General Public License (GPL), version 2
+ */
+#ifndef __SYS_SOC_H
+#define __SYS_SOC_H
+
+#include <linux/kobject.h>
+
+/**
+ * struct sys_soc_info - SoC exports related informations
+ * @name: name of the export
+ * @info: pointer on the key to export
+ * @get_info: callback to retrieve key if info field is NULL
+ * @attr: export's sysdev class attribute
+ */
+struct sysfs_soc_info {
+	const char *info;
+	ssize_t (*get_info)(char *buf, struct sysfs_soc_info *);
+	struct kobj_attribute attr;
+};
+
+ssize_t show_soc_info(struct kobject *, struct kobj_attribute *, char *);
+
+#define SYSFS_SOC_ATTR_VALUE(_name, _value) {		\
+	.attr.attr.name = _name,			\
+	.attr.attr.mode = S_IRUGO,			\
+	.attr.show	= show_soc_info,		\
+	.info           = _value,			\
+}
+
+#define SYSFS_SOC_ATTR_CALLBACK(_name, _callback) {	\
+	.attr.attr.name = _name,			\
+	.attr.attr.mode = S_IRUGO,			\
+	.attr.show	= show_soc_info,		\
+	.get_info       = _callback,			\
+}
+
+/**
+ * register_sys_soc - register the soc information
+ * @name: name of the machine
+ * @info: pointer on the info table to export
+ * @num: number of info to export
+ *
+ * NOTE: This function must only be called once
+ */
+int register_sysfs_soc(struct sysfs_soc_info *info, size_t num);
+
+#endif /* __SYS_SOC_H */
-- 
1.7.1