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: Jean Delvare <khali@linux-fr.org>

1 files changed, 95 insertions, 90 deletions

diff --git a/drivers/i2c/algos/i2c-algo-bit.c b/drivers/i2c/algos/i2c-algo-bit.c
index d9d0ec49e60d..8a5f5825bb72 100644
--- a/drivers/i2c/algos/i2c-algo-bit.c
+++ b/drivers/i2c/algos/i2c-algo-bit.c
@@ -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));
-            return -ETIMEDOUT;
+                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 "));
-                }
+                udelay((adap->udelay + 1) / 2);
+                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");