ACPI: thinkpad-acpi: add infrastructure for the sysfs device attributes

Add infrastructure to deal with sysfs attributes and grouping, and helpers
for common sysfs parsing.  Switch driver attributes to use them.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Signed-off-by: Len Brown <len.brown@intel.com>

2 files changed, 102 insertions, 5 deletions

diff --git a/drivers/misc/thinkpad_acpi.c b/drivers/misc/thinkpad_acpi.c
index a31d00d570cb..ca6d15cdc5f0 100644
--- a/drivers/misc/thinkpad_acpi.c
+++ b/drivers/misc/thinkpad_acpi.c
@@ -520,12 +520,8 @@ static ssize_t tpacpi_driver_debug_store(struct device_driver *drv,
                                                 const char *buf, size_t count)
 {
         unsigned long t;
-        char *endp;
 
-        t = simple_strtoul(buf, &endp, 0);
-        while (*endp && isspace(*endp))
-                endp++;
-        if (*endp)
+        if (parse_strtoul(buf, 0xffff, &t))
                 return -EINVAL;
 
         dbg_level = t;
@@ -575,6 +571,86 @@ static void tpacpi_remove_driver_attributes(struct device_driver *drv)
                 driver_remove_file(drv, tpacpi_driver_attributes[i]);
 }
 
+/*************************************************************************
+ * sysfs support helpers
+ */
+
+struct attribute_set_obj {
+        struct attribute_set s;
+        struct attribute *a;
+} __attribute__((packed));
+
+static struct attribute_set *create_attr_set(unsigned int max_members,
+                                                const char* name)
+{
+        struct attribute_set_obj *sobj;
+
+        if (max_members == 0)
+                return NULL;
+
+        /* Allocates space for implicit NULL at the end too */
+        sobj = kzalloc(sizeof(struct attribute_set_obj) +
+                    max_members * sizeof(struct attribute *),
+                    GFP_KERNEL);
+        if (!sobj)
+                return NULL;
+        sobj->s.max_members = max_members;
+        sobj->s.group.attrs = &sobj->a;
+        sobj->s.group.name = name;
+
+        return &sobj->s;
+}
+
+/* not multi-threaded safe, use it in a single thread per set */
+static int add_to_attr_set(struct attribute_set* s, struct attribute *attr)
+{
+        if (!s || !attr)
+                return -EINVAL;
+
+        if (s->members >= s->max_members)
+                return -ENOMEM;
+
+        s->group.attrs[s->members] = attr;
+        s->members++;
+
+        return 0;
+}
+
+static int add_many_to_attr_set(struct attribute_set* s,
+                        struct attribute **attr,
+                        unsigned int count)
+{
+        int i, res;
+
+        for (i = 0; i < count; i++) {
+                res = add_to_attr_set(s, attr[i]);
+                if (res)
+                        return res;
+        }
+
+        return 0;
+}
+
+static void delete_attr_set(struct attribute_set* s, struct kobject *kobj)
+{
+        sysfs_remove_group(kobj, &s->group);
+        destroy_attr_set(s);
+}
+
+static int parse_strtoul(const char *buf,
+                unsigned long max, unsigned long *value)
+{
+        char *endp;
+
+        *value = simple_strtoul(buf, &endp, 0);
+        while (*endp && isspace(*endp))
+                endp++;
+        if (*endp || *value > max)
+                return -EINVAL;
+
+        return 0;
+}
+
 /****************************************************************************
  ****************************************************************************
  *
diff --git a/drivers/misc/thinkpad_acpi.h b/drivers/misc/thinkpad_acpi.h
index 37860582956f..84fdefe0d200 100644
--- a/drivers/misc/thinkpad_acpi.h
+++ b/drivers/misc/thinkpad_acpi.h
@@ -134,6 +134,27 @@ static int dispatch_procfs_write(struct file *file,
                 unsigned long count, void *data);
 static char *next_cmd(char **cmds);
 
+/* sysfs support */
+struct attribute_set {
+        unsigned int members, max_members;
+        struct attribute_group group;
+};
+
+static struct attribute_set *create_attr_set(unsigned int max_members,
+                                                const char* name);
+#define destroy_attr_set(_set) \
+        kfree(_set);
+static int add_to_attr_set(struct attribute_set* s, struct attribute *attr);
+static int add_many_to_attr_set(struct attribute_set* s,
+                        struct attribute **attr,
+                        unsigned int count);
+#define register_attr_set_with_sysfs(_attr_set, _kobj) \
+        sysfs_create_group(_kobj, &_attr_set->group)
+static void delete_attr_set(struct attribute_set* s, struct kobject *kobj);
+
+static int parse_strtoul(const char *buf, unsigned long max,
+                        unsigned long *value);
+
 /* Device model */
 static struct platform_device *tpacpi_pdev;
 static struct class_device *tpacpi_hwmon;