• David Howells's avatar
    i2c: Add message transfer tracepoints for SMBUS [ver #2] · 8a325997
    David Howells authored
    The SMBUS tracepoints can be enabled thusly:
    
    	echo 1 >/sys/kernel/debug/tracing/events/i2c/enable
    
    and will dump messages that can be viewed in /sys/kernel/debug/tracing/trace
    that look like:
    
             ... smbus_read: i2c-0 a=051 f=0000 c=fa BYTE_DATA
             ... smbus_reply: i2c-0 a=051 f=0000 c=fa BYTE_DATA l=1 [39]
             ... smbus_result: i2c-0 a=051 f=0000 c=fa BYTE_DATA rd res=0
    
    formatted as:
    
    	i2c-<adapter-nr>
    	a=<addr>
    	f=<flags>
    	c=<command>
    	<protocol-name>
    	<rd|wr>
    	res=<result>
    	l=<data-len>
    	[<data-block>]
    
    The adapters to be traced can be selected by something like:
    
    	echo adapter_nr==1 >/sys/kernel/debug/tracing/events/i2c/filter
    
    Note that this shares the same filter and enablement as i2c.
    Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
    Reviewed-by: default avatarSteven Rostedt <rostedt@goodmis.org>
    Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
    8a325997
i2c-core.c 70.2 KB