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Subject[PATCH v1 3/8] software node: Show properties and their values in sysfs
Date
It's very convenient to see what properties and their values
are currently being assigned in the registered software nodes.

Show properties and their values in sysfs.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
drivers/base/swnode.c | 137 ++++++++++++++++++++++++++++++++++++++++--
1 file changed, 132 insertions(+), 5 deletions(-)

diff --git a/drivers/base/swnode.c b/drivers/base/swnode.c
index 19aa44bc2628..d7fe1a887d2d 100644
--- a/drivers/base/swnode.c
+++ b/drivers/base/swnode.c
@@ -10,6 +10,7 @@
#include <linux/kernel.h>
#include <linux/property.h>
#include <linux/slab.h>
+#include <linux/sysfs.h>

struct swnode {
int id;
@@ -17,6 +18,10 @@ struct swnode {
struct fwnode_handle fwnode;
const struct software_node *node;

+ /* properties in sysfs */
+ struct kobj_attribute *property_attrs;
+ struct attribute_group property_group;
+
/* hierarchy */
struct ida child_ids;
struct list_head entry;
@@ -25,6 +30,7 @@ struct swnode {

unsigned int allocated:1;
unsigned int managed:1;
+ unsigned int properties:1;
};

static DEFINE_IDA(swnode_root_ids);
@@ -299,6 +305,18 @@ static int property_entry_copy_data(struct property_entry *dst,
return 0;
}

+static int property_entries_count(const struct property_entry *properties)
+{
+ int n = 0;
+
+ if (properties) {
+ while (properties[n].name)
+ n++;
+ }
+
+ return n;
+}
+
/**
* property_entries_dup - duplicate array of properties
* @properties: array of properties to copy
@@ -310,15 +328,13 @@ struct property_entry *
property_entries_dup(const struct property_entry *properties)
{
struct property_entry *p;
- int i, n = 0;
+ int i, n;
int ret;

- if (!properties)
+ n = property_entries_count(properties);
+ if (n == 0)
return NULL;

- while (properties[n].name)
- n++;
-
p = kcalloc(n + 1, sizeof(*p), GFP_KERNEL);
if (!p)
return ERR_PTR(-ENOMEM);
@@ -746,6 +762,108 @@ static void software_node_free(const struct software_node *node)
kfree(node);
}

+static ssize_t
+swnode_property_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+ struct swnode *swnode = kobj_to_swnode(kobj);
+ const struct property_entry *prop;
+ const void *pointer;
+ ssize_t len = 0;
+ int i;
+
+ prop = property_entry_get(swnode->node->properties, attr->attr.name);
+ if (!prop)
+ return -EINVAL;
+
+ /* We can't fail here, because it means boolean property */
+ pointer = property_get_pointer(prop);
+ if (!pointer)
+ return sysfs_emit(buf, "\n");
+
+ switch (prop->type) {
+ case DEV_PROP_U8:
+ for (i = 0; i < prop->length / sizeof(u8); i++)
+ len += sysfs_emit_at(buf, len, "%u,", ((u8 *)pointer)[i]);
+ break;
+ case DEV_PROP_U16:
+ for (i = 0; i < prop->length / sizeof(u16); i++)
+ len += sysfs_emit_at(buf, len, "%u,", ((u16 *)pointer)[i]);
+ break;
+ case DEV_PROP_U32:
+ for (i = 0; i < prop->length / sizeof(u32); i++)
+ len += sysfs_emit_at(buf, len, "%u,", ((u32 *)pointer)[i]);
+ break;
+ case DEV_PROP_U64:
+ for (i = 0; i < prop->length / sizeof(u64); i++)
+ len += sysfs_emit_at(buf, len, "%llu,", ((u64 *)pointer)[i]);
+ break;
+ case DEV_PROP_STRING:
+ for (i = 0; i < prop->length / sizeof(const char **); i++)
+ len += sysfs_emit_at(buf, len, "\"%s\",", ((const char **)pointer)[i]);
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ sysfs_emit_at(buf, len ? len - 1 : 0, "\n");
+ return len;
+}
+
+static int swnode_register_properties(struct swnode *swnode)
+{
+ const struct property_entry *props = swnode->node->properties;
+ struct attribute **group_attrs;
+ struct kobj_attribute *attrs;
+ int n;
+ int ret;
+
+ n = property_entries_count(props);
+ if (n == 0)
+ return 0;
+
+ group_attrs = kcalloc(n + 1, sizeof(*group_attrs), GFP_KERNEL);
+ if (!group_attrs)
+ return -ENOMEM;
+
+ attrs = kcalloc(n, sizeof(*attrs), GFP_KERNEL);
+ if (!attrs) {
+ kfree(group_attrs);
+ return -ENOMEM;
+ }
+
+ while (n--) {
+ sysfs_attr_init(&attrs[n]);
+ attrs[n].attr.mode = 0444;
+ attrs[n].attr.name = props[n].name;
+ attrs[n].show = swnode_property_show;
+ group_attrs[n] = &attrs[n].attr;
+ }
+
+ swnode->property_group.name = "properties";
+ swnode->property_group.attrs = group_attrs;
+
+ ret = sysfs_create_group(&swnode->kobj, &swnode->property_group);
+ if (ret) {
+ kfree(attrs);
+ kfree(group_attrs);
+ return ret;
+ }
+
+ swnode->property_attrs = attrs;
+ swnode->properties = true;
+ return 0;
+}
+
+static void swnode_unregister_properties(struct swnode *swnode)
+{
+ /*
+ * Nodes under sysfs are removed by __kobject_del(),
+ * we don't need to call sysfs_remove_group() explicitly.
+ */
+ kfree(swnode->property_group.attrs);
+ kfree(swnode->property_attrs);
+}
+
static void software_node_release(struct kobject *kobj)
{
struct swnode *swnode = kobj_to_swnode(kobj);
@@ -757,6 +875,9 @@ static void software_node_release(struct kobject *kobj)
ida_simple_remove(&swnode_root_ids, swnode->id);
}

+ if (swnode->properties)
+ swnode_unregister_properties(swnode);
+
if (swnode->allocated)
software_node_free(swnode->node);

@@ -810,6 +931,12 @@ swnode_register(const struct software_node *node, struct swnode *parent,
return ERR_PTR(ret);
}

+ ret = swnode_register_properties(swnode);
+ if (ret) {
+ kobject_put(&swnode->kobj);
+ return ERR_PTR(ret);
+ }
+
/*
* Assign the flag only in the successful case, so
* the above kobject_put() won't mess up with properties.
--
2.30.2
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