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Commit 494dbb64 authored by Jean Delvare's avatar Jean Delvare Committed by Jean Delvare
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i2c-algo-bit: Improve debugging 



Improve the debugging features of the i2c-algo-bit driver:
* Make it possible to compile the driver without debugging support
  at all, making it much smaller.
* Use dev_dbg() for debugging messages where possible, and dev_err()
  for error messages.
* Remove redundant debugging messages.

These changes allowed for minor code cleanups, which are included
as well.

Signed-off-by: default avatarJean Delvare <khali@linux-fr.org>
parent 424ed67c

drivers/i2c/algos/i2c-algo-bit.c

+95 −90
Original line number Diff line number Diff line
@@ -33,19 +33,30 @@ 




/* ----- global defines ----------------------------------------------- */

#define DEB(x) if (i2c_debug>=1) x;

#define DEB2(x) if (i2c_debug>=2) x;

#define DEBSTAT(x) if (i2c_debug>=3) x; /* print several statistical values*/

#define DEBPROTO(x) if (i2c_debug>=9) { x; }

 	/* debug the protocol by showing transferred bits */



#ifdef DEBUG

#define bit_dbg(level, dev, format, args...) \

	do { \

		if (i2c_debug >= level) \

			dev_dbg(dev, format, ##args); \

	} while (0)

#else

#define bit_dbg(level, dev, format, args...) \

	do {} while (0)

#endif /* DEBUG */



/* ----- global variables ---------------------------------------------	*/



/* module parameters:

 */

static int i2c_debug;

static int bit_test;	/* see if the line-setting functions work	*/

module_param(bit_test, bool, 0);

MODULE_PARM_DESC(bit_test, "Test the lines of the bus to see if it is stuck");



#ifdef DEBUG

static int i2c_debug = 1;

module_param(i2c_debug, int, S_IRUGO | S_IWUSR);

MODULE_PARM_DESC(i2c_debug,

		 "debug level - 0 off; 1 normal; 2 verbose; 3 very verbose");

#endif



/* --- setting states on the bus with the right timing: ---------------	*/
@@ -98,7 +109,11 @@ static int sclhi(struct i2c_algo_bit_data *adap) 
		}

		cond_resched();

	}

	DEBSTAT(printk(KERN_DEBUG "needed %ld jiffies\n", jiffies-start));

#ifdef DEBUG

	if (jiffies != start && i2c_debug >= 3)

		pr_debug("i2c-algo-bit: needed %ld jiffies for SCL to go "

			 "high\n", jiffies - start);

#endif



done:

	udelay(adap->udelay);
@@ -110,7 +125,6 @@ done: 
static void i2c_start(struct i2c_algo_bit_data *adap) 

{

	/* assert: scl, sda are high */

	DEBPROTO(printk("S "));

	setsda(adap, 0);

	udelay(adap->udelay);

	scllo(adap);
@@ -119,7 +133,6 @@ static void i2c_start(struct i2c_algo_bit_data *adap) 
static void i2c_repstart(struct i2c_algo_bit_data *adap) 

{

	/* assert: scl is low */

	DEBPROTO(printk(" Sr "));

	sdahi(adap);

	sclhi(adap);

	setsda(adap, 0);
@@ -130,7 +143,6 @@ static void i2c_repstart(struct i2c_algo_bit_data *adap) 


static void i2c_stop(struct i2c_algo_bit_data *adap) 

{

	DEBPROTO(printk("P\n"));

	/* assert: scl is low */

	sdalo(adap);

	sclhi(adap);
@@ -147,7 +159,7 @@ static void i2c_stop(struct i2c_algo_bit_data *adap) 
 * 0 if the device did not ack

 * -ETIMEDOUT if an error occurred (while raising the scl line)

 */

static int i2c_outb(struct i2c_adapter *i2c_adap, char c)

static int i2c_outb(struct i2c_adapter *i2c_adap, unsigned char c)

{

	int i;

	int sb;
@@ -156,12 +168,12 @@ static int i2c_outb(struct i2c_adapter *i2c_adap, char c) 


	/* assert: scl is low */

	for ( i=7 ; i>=0 ; i-- ) {

		sb = c & ( 1 << i );

		sb = (c >> i) & 1;

		setsda(adap,sb);

		udelay((adap->udelay + 1) / 2);

		DEBPROTO(printk(KERN_DEBUG "%d",sb!=0));

		if (sclhi(adap)<0) { /* timed out */

			DEB2(printk(KERN_DEBUG " i2c_outb: 0x%02x, timeout at bit #%d\n", c&0xff, i));

			bit_dbg(1, &i2c_adap->dev, "i2c_outb: 0x%02x, "

				"timeout at bit #%d\n", (int)c, i);

			return -ETIMEDOUT;

		};

		/* do arbitration here:
@@ -171,17 +183,17 @@ static int i2c_outb(struct i2c_adapter *i2c_adap, char c) 
	}

	sdahi(adap);

	if (sclhi(adap)<0){ /* timeout */

	    DEB2(printk(KERN_DEBUG " i2c_outb: 0x%02x, timeout at ack\n", c&0xff));

		bit_dbg(1, &i2c_adap->dev, "i2c_outb: 0x%02x, "

			"timeout at ack\n", (int)c);

		return -ETIMEDOUT;

	};

	/* read ack: SDA should be pulled down by slave */

	ack=getsda(adap);	/* ack: sda is pulled low ->success.	 */

	DEB2(printk(KERN_DEBUG " i2c_outb: 0x%02x , getsda() = %d\n", c & 0xff, ack));

	ack = !getsda(adap);    /* ack: sda is pulled low -> success */

	bit_dbg(2, &i2c_adap->dev, "i2c_outb: 0x%02x %s\n", (int)c,

		ack ? "A" : "NA");



	DEBPROTO( printk(KERN_DEBUG "[%2.2x]",c&0xff) );

	DEBPROTO(if (0==ack){ printk(KERN_DEBUG " A ");} else printk(KERN_DEBUG " NA ") );

	scllo(adap);

	return 0==ack;		/* return 1 if device acked	 */

	return ack;

	/* assert: scl is low (sda undef) */

}
@@ -198,7 +210,8 @@ static int i2c_inb(struct i2c_adapter *i2c_adap) 
	sdahi(adap);

	for (i=0;i<8;i++) {

		if (sclhi(adap)<0) { /* timeout */

			DEB2(printk(KERN_DEBUG " i2c_inb: timeout at bit #%d\n", 7-i));

			bit_dbg(1, &i2c_adap->dev, "i2c_inb: timeout at bit "

				"#%d\n", 7 - i);

			return -ETIMEDOUT;

		};

		indata *= 2;
@@ -208,10 +221,7 @@ static int i2c_inb(struct i2c_adapter *i2c_adap) 
		udelay(i == 7 ? adap->udelay / 2 : adap->udelay);

	}

	/* assert: scl is low */

	DEB2(printk(KERN_DEBUG "i2c_inb: 0x%02x\n", indata & 0xff));



	DEBPROTO(printk(KERN_DEBUG " 0x%02x", indata & 0xff));

	return (int) (indata & 0xff);

	return indata;

}



/*
@@ -222,73 +232,67 @@ static int test_bus(struct i2c_algo_bit_data *adap, char* name) { 
	int scl,sda;



	if (adap->getscl==NULL)

		printk(KERN_INFO "i2c-algo-bit.o: Testing SDA only, "

			"SCL is not readable.\n");

		pr_info("%s: Testing SDA only, SCL is not readable\n", name);



	sda=getsda(adap);

	scl=(adap->getscl==NULL?1:getscl(adap));

	printk(KERN_DEBUG "i2c-algo-bit.o: (0) scl=%d, sda=%d\n",scl,sda);

	if (!scl || !sda ) {

		printk(KERN_WARNING "i2c-algo-bit.o: %s seems to be busy.\n", name);

		printk(KERN_WARNING "%s: bus seems to be busy\n", name);

		goto bailout;

	}



	sdalo(adap);

	sda=getsda(adap);

	scl=(adap->getscl==NULL?1:getscl(adap));

	printk(KERN_DEBUG "i2c-algo-bit.o: (1) scl=%d, sda=%d\n",scl,sda);

	if ( 0 != sda ) {

		printk(KERN_WARNING "i2c-algo-bit.o: SDA stuck high!\n");

		printk(KERN_WARNING "%s: SDA stuck high!\n", name);

		goto bailout;

	}

	if ( 0 == scl ) {

		printk(KERN_WARNING "i2c-algo-bit.o: SCL unexpected low "

			"while pulling SDA low!\n");

		printk(KERN_WARNING "%s: SCL unexpected low "

		       "while pulling SDA low!\n", name);

		goto bailout;

	}		



	sdahi(adap);

	sda=getsda(adap);

	scl=(adap->getscl==NULL?1:getscl(adap));

	printk(KERN_DEBUG "i2c-algo-bit.o: (2) scl=%d, sda=%d\n",scl,sda);

	if ( 0 == sda ) {

		printk(KERN_WARNING "i2c-algo-bit.o: SDA stuck low!\n");

		printk(KERN_WARNING "%s: SDA stuck low!\n", name);

		goto bailout;

	}

	if ( 0 == scl ) {

		printk(KERN_WARNING "i2c-algo-bit.o: SCL unexpected low "

			"while pulling SDA high!\n");

		printk(KERN_WARNING "%s: SCL unexpected low "

		       "while pulling SDA high!\n", name);

		goto bailout;

	}



	scllo(adap);

	sda=getsda(adap);

	scl=(adap->getscl==NULL?0:getscl(adap));

	printk(KERN_DEBUG "i2c-algo-bit.o: (3) scl=%d, sda=%d\n",scl,sda);

	if ( 0 != scl ) {

		printk(KERN_WARNING "i2c-algo-bit.o: SCL stuck high!\n");

		printk(KERN_WARNING "%s: SCL stuck high!\n", name);

		goto bailout;

	}

	if ( 0 == sda ) {

		printk(KERN_WARNING "i2c-algo-bit.o: SDA unexpected low "

			"while pulling SCL low!\n");

		printk(KERN_WARNING "%s: SDA unexpected low "

		       "while pulling SCL low!\n", name);

		goto bailout;

	}

	

	sclhi(adap);

	sda=getsda(adap);

	scl=(adap->getscl==NULL?1:getscl(adap));

	printk(KERN_DEBUG "i2c-algo-bit.o: (4) scl=%d, sda=%d\n",scl,sda);

	if ( 0 == scl ) {

		printk(KERN_WARNING "i2c-algo-bit.o: SCL stuck low!\n");

		printk(KERN_WARNING "%s: SCL stuck low!\n", name);

		goto bailout;

	}

	if ( 0 == sda ) {

		printk(KERN_WARNING "i2c-algo-bit.o: SDA unexpected low "

			"while pulling SCL high!\n");

		printk(KERN_WARNING "%s: SDA unexpected low "

		       "while pulling SCL high!\n", name);

		goto bailout;

	}

	printk(KERN_INFO "i2c-algo-bit.o: %s passed test.\n",name);

	pr_info("%s: Test OK\n", name);

	return 0;

bailout:

	sdahi(adap);
@@ -315,32 +319,31 @@ static int try_address(struct i2c_adapter *i2c_adap, 
		ret = i2c_outb(i2c_adap,addr);

		if (ret == 1 || i == retries)

			break;

		bit_dbg(3, &i2c_adap->dev, "emitting stop condition\n");

		i2c_stop(adap);

		udelay(adap->udelay);

		yield();

		bit_dbg(3, &i2c_adap->dev, "emitting start condition\n");

		i2c_start(adap);

	}

	DEB2(if (i)

	     printk(KERN_DEBUG "i2c-algo-bit.o: Used %d tries to %s client at 0x%02x : %s\n",

		    i+1, addr & 1 ? "read" : "write", addr>>1,

		    ret==1 ? "success" : ret==0 ? "no ack" : "failed, timeout?" )

	    );

	if (i && ret)

		bit_dbg(1, &i2c_adap->dev, "Used %d tries to %s client at "

			"0x%02x: %s\n", i + 1,

			addr & 1 ? "read from" : "write to", addr >> 1,

			ret == 1 ? "success" : "failed, timeout?");

	return ret;

}



static int sendbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg)

{

	char c;

	const char *temp = msg->buf;

	const unsigned char *temp = msg->buf;

	int count = msg->len;

	unsigned short nak_ok = msg->flags & I2C_M_IGNORE_NAK; 

	int retval;

	int wrcount=0;



	while (count > 0) {

		c = *temp;

		DEB2(dev_dbg(&i2c_adap->dev, "sendbytes: writing %2.2X\n", c&0xff));

		retval = i2c_outb(i2c_adap,c);

		retval = i2c_outb(i2c_adap, *temp);

		if ((retval>0) || (nak_ok && (retval==0)))  { /* ok or ignored NAK */

			count--; 

			temp++;
@@ -359,7 +362,7 @@ static int readbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg) 
	int inval;

	int rdcount=0;   	/* counts bytes read */

	struct i2c_algo_bit_data *adap = i2c_adap->algo_data;

	char *temp = msg->buf;

	unsigned char *temp = msg->buf;

	int count = msg->len;



	while (count > 0) {
@@ -368,28 +371,26 @@ static int readbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg) 
			*temp = inval;

			rdcount++;

		} else {   /* read timed out */

			printk(KERN_ERR "i2c-algo-bit.o: readbytes: i2c_inb timed out.\n");

			break;

		}



		temp++;

		count--;



		if (msg->flags & I2C_M_NO_RD_ACK)

		if (msg->flags & I2C_M_NO_RD_ACK) {

			bit_dbg(2, &i2c_adap->dev, "i2c_inb: 0x%02x\n",

				inval);

			continue;

		}



		/* assert: sda is high */

		if ( count > 0 ) {		/* send ack */

		if (count)		/* send ack */

			setsda(adap, 0);

		udelay((adap->udelay + 1) / 2);

			DEBPROTO(printk(" Am "));

		} else {

			/* neg. ack on last byte */

			udelay((adap->udelay + 1) / 2);

			DEBPROTO(printk(" NAm "));

		}

		bit_dbg(2, &i2c_adap->dev, "i2c_inb: 0x%02x %s\n", inval,

			count ? "A" : "NA");

		if (sclhi(adap)<0) {	/* timeout */

			printk(KERN_ERR "i2c-algo-bit.o: readbytes: Timeout at ack\n");

			dev_err(&i2c_adap->dev, "readbytes: timeout at ack\n");

			return -ETIMEDOUT;

		};

		scllo(adap);
@@ -398,8 +399,8 @@ static int readbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg) 
		   transaction length as the first read byte. */

		if (rdcount == 1 && (msg->flags & I2C_M_RECV_LEN)) {

			if (inval <= 0 || inval > I2C_SMBUS_BLOCK_MAX) {

				printk(KERN_ERR "i2c-algo-bit: readbytes: "

				       "invalid block length (%d)\n", inval);

				dev_err(&i2c_adap->dev, "readbytes: invalid "

					"block length (%d)\n", inval);

				return -EREMOTEIO;

			}

			/* The original count value accounts for the extra
@@ -434,27 +435,31 @@ static int bit_doAddress(struct i2c_adapter *i2c_adap, struct i2c_msg *msg) 
	if ( (flags & I2C_M_TEN)  ) { 

		/* a ten bit address */

		addr = 0xf0 | (( msg->addr >> 7) & 0x03);

		DEB2(printk(KERN_DEBUG "addr0: %d\n",addr));

		bit_dbg(2, &i2c_adap->dev, "addr0: %d\n", addr);

		/* try extended address code...*/

		ret = try_address(i2c_adap, addr, retries);

		if ((ret != 1) && !nak_ok)  {

			printk(KERN_ERR "died at extended address code.\n");

			dev_err(&i2c_adap->dev,

				"died at extended address code\n");

			return -EREMOTEIO;

		}

		/* the remaining 8 bit address */

		ret = i2c_outb(i2c_adap,msg->addr & 0x7f);

		if ((ret != 1) && !nak_ok) {

			/* the chip did not ack / xmission error occurred */

			printk(KERN_ERR "died at 2nd address code.\n");

			dev_err(&i2c_adap->dev, "died at 2nd address code\n");

			return -EREMOTEIO;

		}

		if ( flags & I2C_M_RD ) {

			bit_dbg(3, &i2c_adap->dev, "emitting repeated "

				"start condition\n");

			i2c_repstart(adap);

			/* okay, now switch into reading mode */

			addr |= 0x01;

			ret = try_address(i2c_adap, addr, retries);

			if ((ret!=1) && !nak_ok) {

				printk(KERN_ERR "died at extended address code.\n");

				dev_err(&i2c_adap->dev,

					"died at repeated address code\n");

				return -EREMOTEIO;

			}

		}
@@ -481,25 +486,31 @@ static int bit_xfer(struct i2c_adapter *i2c_adap, 
	int i,ret;

	unsigned short nak_ok;



	bit_dbg(3, &i2c_adap->dev, "emitting start condition\n");

	i2c_start(adap);

	for (i=0;i<num;i++) {

		pmsg = &msgs[i];

		nak_ok = pmsg->flags & I2C_M_IGNORE_NAK; 

		if (!(pmsg->flags & I2C_M_NOSTART)) {

			if (i) {

				bit_dbg(3, &i2c_adap->dev, "emitting "

					"repeated start condition\n");

				i2c_repstart(adap);

			}

			ret = bit_doAddress(i2c_adap, pmsg);

			if ((ret != 0) && !nak_ok) {

			    DEB2(printk(KERN_DEBUG "i2c-algo-bit.o: NAK from device addr %2.2x msg #%d\n"

					,msgs[i].addr,i));

				bit_dbg(1, &i2c_adap->dev, "NAK from "

					"device addr 0x%02x msg #%d\n",

					msgs[i].addr, i);

				goto bailout;

			}

		}

		if (pmsg->flags & I2C_M_RD ) {

			/* read bytes into buffer*/

			ret = readbytes(i2c_adap, pmsg);

			DEB2(printk(KERN_DEBUG "i2c-algo-bit.o: read %d bytes.\n",ret));

			if (ret >= 1)

				bit_dbg(2, &i2c_adap->dev, "read %d byte%s\n",

					ret, ret == 1 ? "" : "s");

			if (ret < pmsg->len) {

				if (ret >= 0)

					ret = -EREMOTEIO;
@@ -508,7 +519,9 @@ static int bit_xfer(struct i2c_adapter *i2c_adap, 
		} else {

			/* write bytes from buffer */

			ret = sendbytes(i2c_adap, pmsg);

			DEB2(printk(KERN_DEBUG "i2c-algo-bit.o: wrote %d bytes.\n",ret));

			if (ret >= 1)

				bit_dbg(2, &i2c_adap->dev, "wrote %d byte%s\n",

					ret, ret == 1 ? "" : "s");

			if (ret < pmsg->len) {

				if (ret >= 0)

					ret = -EREMOTEIO;
@@ -519,6 +532,7 @@ static int bit_xfer(struct i2c_adapter *i2c_adap, 
	ret = i;



bailout:

	bit_dbg(3, &i2c_adap->dev, "emitting stop condition\n");

	i2c_stop(adap);

	return ret;

}
@@ -552,8 +566,6 @@ static int i2c_bit_prepare_bus(struct i2c_adapter *adap) 
			return -ENODEV;

	}



	DEB2(dev_dbg(&adap->dev, "hw routines registered.\n"));



	/* register new adapter to i2c module... */

	adap->algo = &i2c_bit_algo;
@@ -590,10 +602,3 @@ EXPORT_SYMBOL(i2c_bit_add_numbered_bus); 
MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");

MODULE_DESCRIPTION("I2C-Bus bit-banging algorithm");

MODULE_LICENSE("GPL");
 


module_param(bit_test, bool, 0);

module_param(i2c_debug, int, S_IRUGO | S_IWUSR);



MODULE_PARM_DESC(bit_test, "Test the lines of the bus to see if it is stuck");

MODULE_PARM_DESC(i2c_debug,

		 "debug level - 0 off; 1 normal; 2,3 more verbose; 9 bit-protocol");