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    DateMon, 25 Feb 2008 15:10:51 +0900
    FromKohei KaiGai <>
    Subject[PATCH 3/3] a new example to use kobject/kobj_attribute (final#2)
    [PATCH 3/3] a new example to use kobject/kobj_attribute
    
    This patch can provide a new exmple to use kobject and attribute.
    The _show() and _store() method can refer/store the private data field of
    kobj_attribute structure to know what entries are accessed by users.
    It will make easier to share a single _show()/_store() method with several
    entries.
    
    Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com>
    --
     samples/kobject/kobject-example.c |   32 ++++++++++++++++++++++++++++++++
     1 files changed, 32 insertions(+), 0 deletions(-)
    diff --git a/samples/kobject/kobject-example.c b/samples/kobject/kobject-example.c
    index 08d0d3f..5486a14 100644
    --- a/samples/kobject/kobject-example.c
    +++ b/samples/kobject/kobject-example.c
    @@ -77,6 +77,35 @@ static struct kobj_attribute baz_attribute =
     static struct kobj_attribute bar_attribute =
     	__ATTR(bar, 0666, b_show, b_store);
    
    +/*
    + * You can store a private data within 'data' field of kobj_attribute.
    + * It enables to share a single _show() or _store() method with several
    + * entries.
    + */
    +static ssize_t integer_show(struct kobject *kobj,
    +			    struct kobj_attribute *attr,
    +			    char *buf)
    +{
    +	return scnprintf(buf, PAGE_SIZE, "%ld\n", (long) attr->data);
    +}
    +
    +static ssize_t integer_store(struct kobject *kobj,
    +			     struct kobj_attribute *attr,
    +			     const char *buf, size_t count)
    +{
    +	long code;
    +
    +	sscanf(buf, "%ld", &code);
    +	attr->data = (void *) code;
    +	return count;
    +}
    +
    +static struct kobj_attribute hoge_attribute =
    +	__ATTR_DATA(hoge, 0666, integer_show, integer_store, (long) 123);
    +static struct kobj_attribute piyo_attribute =
    +	__ATTR_DATA(piyo, 0666, integer_show, integer_store, (long) 456);
    +static struct kobj_attribute fuga_attribute =
    +	__ATTR_DATA(fuga, 0444, integer_show, NULL, (long) 789);
    
     /*
      * Create a group of attributes so that we can create and destory them all
    @@ -86,6 +115,9 @@ static struct attribute *attrs[] = {
     	&foo_attribute.attr,
     	&baz_attribute.attr,
     	&bar_attribute.attr,
    +	&hoge_attribute.attr,
    +	&piyo_attribute.attr,
    +	&fuga_attribute.attr,
     	NULL,	/* need to NULL terminate the list of attributes */
     };
    
    -- 
    OSS Platform Development Division, NEC
    KaiGai Kohei <kaigai@ak.jp.nec.com>
    
    
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