Commit d714fb25 authored by Jae Hyun Yoo's avatar Jae Hyun Yoo Committed by Wolfram Sang
Browse files

i2c: add tracepoints for I2C slave events 



I2C slave events tracepoints can be enabled by:

	echo 1 > /sys/kernel/tracing/events/i2c_slave/enable

and logs in /sys/kernel/tracing/trace will look like:

	... i2c_slave: i2c-0 a=010 ret=0 WR_REQ []
	... i2c_slave: i2c-0 a=010 ret=0 WR_RCV [02]
	... i2c_slave: i2c-0 a=010 ret=0 WR_RCV [0c]
	... i2c_slave: i2c-0 a=010 ret=0   STOP []
	... i2c_slave: i2c-0 a=010 ret=0 RD_REQ [04]
	... i2c_slave: i2c-0 a=010 ret=0 RD_PRO [b4]
	... i2c_slave: i2c-0 a=010 ret=0  STOP []

formatted as:

	i2c-<adapter_nr>
	a=<addr>
	ret=<ret>	<- callback return value
	<event>
	[<data>]

trace printings can be selected by adding a filter like:

	echo adapter_nr==1 >/sys/kernel/tracing/events/i2c_slave/filter

Signed-off-by: default avatarJae Hyun Yoo <quic_jaehyoo@quicinc.com>
Signed-off-by: default avatarWolfram Sang <wsa@kernel.org>
parent 3364c0ef

drivers/i2c/i2c-core-slave.c

+15 −0
Original line number Diff line number Diff line
@@ -14,6 +14,9 @@ 


#include "i2c-core.h"



#define CREATE_TRACE_POINTS

#include <trace/events/i2c_slave.h>



int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb)

{

	int ret;
@@ -79,6 +82,18 @@ int i2c_slave_unregister(struct i2c_client *client) 
}

EXPORT_SYMBOL_GPL(i2c_slave_unregister);



int i2c_slave_event(struct i2c_client *client,

		    enum i2c_slave_event event, u8 *val)

{

	int ret = client->slave_cb(client, event, val);



	if (trace_i2c_slave_enabled())

		trace_i2c_slave(client, event, val, ret);



	return ret;

}

EXPORT_SYMBOL_GPL(i2c_slave_event);



/**

 * i2c_detect_slave_mode - detect operation mode

 * @dev: The device owning the bus

include/linux/i2c.h

+2 −6
Original line number Diff line number Diff line
@@ -392,12 +392,8 @@ enum i2c_slave_event { 
int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb);

int i2c_slave_unregister(struct i2c_client *client);

bool i2c_detect_slave_mode(struct device *dev);



static inline int i2c_slave_event(struct i2c_client *client,

				  enum i2c_slave_event event, u8 *val)

{

	return client->slave_cb(client, event, val);

}

int i2c_slave_event(struct i2c_client *client,

		    enum i2c_slave_event event, u8 *val);

#else

static inline bool i2c_detect_slave_mode(struct device *dev) { return false; }

#endif

include/trace/events/i2c_slave.h

0 → 100644
+67 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0-or-later */

/*

 * I2C slave tracepoints

 *

 * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.

 */

#undef TRACE_SYSTEM

#define TRACE_SYSTEM i2c_slave



#if !defined(_TRACE_I2C_SLAVE_H) || defined(TRACE_HEADER_MULTI_READ)

#define _TRACE_I2C_SLAVE_H



#include <linux/i2c.h>

#include <linux/tracepoint.h>



TRACE_DEFINE_ENUM(I2C_SLAVE_READ_REQUESTED);

TRACE_DEFINE_ENUM(I2C_SLAVE_WRITE_REQUESTED);

TRACE_DEFINE_ENUM(I2C_SLAVE_READ_PROCESSED);

TRACE_DEFINE_ENUM(I2C_SLAVE_WRITE_RECEIVED);

TRACE_DEFINE_ENUM(I2C_SLAVE_STOP);



#define show_event_type(type)						\

	__print_symbolic(type,						\

		{ I2C_SLAVE_READ_REQUESTED,	"RD_REQ" },		\

		{ I2C_SLAVE_WRITE_REQUESTED,	"WR_REQ" },		\

		{ I2C_SLAVE_READ_PROCESSED,	"RD_PRO" },		\

		{ I2C_SLAVE_WRITE_RECEIVED,	"WR_RCV" },		\

		{ I2C_SLAVE_STOP,		"  STOP" })



TRACE_EVENT(i2c_slave,

	TP_PROTO(const struct i2c_client *client, enum i2c_slave_event event,

		 __u8 *val, int cb_ret),

	TP_ARGS(client, event, val, cb_ret),

	TP_STRUCT__entry(

		__field(int,				adapter_nr	)

		__field(int,				ret		)

		__field(__u16,				addr		)

		__field(__u16,				len		)

		__field(enum i2c_slave_event,		event		)

		__array(__u8,				buf,	1)	),



	TP_fast_assign(

		__entry->adapter_nr = client->adapter->nr;

		__entry->addr = client->addr;

		__entry->event = event;

		__entry->ret = cb_ret;

		switch (event) {

		case I2C_SLAVE_READ_REQUESTED:

		case I2C_SLAVE_READ_PROCESSED:

		case I2C_SLAVE_WRITE_RECEIVED:

			__entry->len = 1;

			memcpy(__entry->buf, val, __entry->len);

			break;

		default:

			__entry->len = 0;

			break;

		}

		),

	TP_printk("i2c-%d a=%03x ret=%d %s [%*phD]",

		__entry->adapter_nr, __entry->addr, __entry->ret,

		show_event_type(__entry->event), __entry->len, __entry->buf

		));



#endif /* _TRACE_I2C_SLAVE_H */



/* This part must be outside protection */

#include <trace/define_trace.h>