diff --git a/drivers/isdn/hardware/avm/b1.c b/drivers/isdn/hardware/avm/b1.c
index 4484a6417235ec3c87de9cbe36313a7b015bfac2..abf05ec31760544b41928a84cb7286b58c6ac95b 100644
--- a/drivers/isdn/hardware/avm/b1.c
+++ b/drivers/isdn/hardware/avm/b1.c
@@ -661,11 +661,11 @@ int b1ctl_read_proc(char *page, char **start, off_t off,
 	len += sprintf(page+len, "%-16s %s\n", "type", s);
 	if (card->cardtype == avm_t1isa)
 	   len += sprintf(page+len, "%-16s %d\n", "cardnr", card->cardnr);
-	if ((s = cinfo->version[VER_DRIVER]) != 0)
+	if ((s = cinfo->version[VER_DRIVER]) != NULL)
 	   len += sprintf(page+len, "%-16s %s\n", "ver_driver", s);
-	if ((s = cinfo->version[VER_CARDTYPE]) != 0)
+	if ((s = cinfo->version[VER_CARDTYPE]) != NULL)
 	   len += sprintf(page+len, "%-16s %s\n", "ver_cardtype", s);
-	if ((s = cinfo->version[VER_SERIAL]) != 0)
+	if ((s = cinfo->version[VER_SERIAL]) != NULL)
 	   len += sprintf(page+len, "%-16s %s\n", "ver_serial", s);
 
 	if (card->cardtype != avm_m1) {
@@ -788,9 +788,9 @@ static int __init b1_init(void)
 	char *p;
 	char rev[32];
 
-	if ((p = strchr(revision, ':')) != 0 && p[1]) {
+	if ((p = strchr(revision, ':')) != NULL && p[1]) {
 		strlcpy(rev, p + 2, 32);
-		if ((p = strchr(rev, '$')) != 0 && p > rev)
+		if ((p = strchr(rev, '$')) != NULL && p > rev)
 		   *(p-1) = 0;
 	} else
 		strcpy(rev, "1.0");
diff --git a/drivers/isdn/hardware/avm/b1dma.c b/drivers/isdn/hardware/avm/b1dma.c
index 669f6f67449c46f26416a27c82939ad734256306..da34b98e3de7425b0ed647a3224e5b1f4d035195 100644
--- a/drivers/isdn/hardware/avm/b1dma.c
+++ b/drivers/isdn/hardware/avm/b1dma.c
@@ -883,11 +883,11 @@ int b1dmactl_read_proc(char *page, char **start, off_t off,
 	default: s = "???"; break;
 	}
 	len += sprintf(page+len, "%-16s %s\n", "type", s);
-	if ((s = cinfo->version[VER_DRIVER]) != 0)
+	if ((s = cinfo->version[VER_DRIVER]) != NULL)
 	   len += sprintf(page+len, "%-16s %s\n", "ver_driver", s);
-	if ((s = cinfo->version[VER_CARDTYPE]) != 0)
+	if ((s = cinfo->version[VER_CARDTYPE]) != NULL)
 	   len += sprintf(page+len, "%-16s %s\n", "ver_cardtype", s);
-	if ((s = cinfo->version[VER_SERIAL]) != 0)
+	if ((s = cinfo->version[VER_SERIAL]) != NULL)
 	   len += sprintf(page+len, "%-16s %s\n", "ver_serial", s);
 
 	if (card->cardtype != avm_m1) {
@@ -970,9 +970,9 @@ static int __init b1dma_init(void)
 	char *p;
 	char rev[32];
 
-	if ((p = strchr(revision, ':')) != 0 && p[1]) {
+	if ((p = strchr(revision, ':')) != NULL && p[1]) {
 		strlcpy(rev, p + 2, sizeof(rev));
-		if ((p = strchr(rev, '$')) != 0 && p > rev)
+		if ((p = strchr(rev, '$')) != NULL && p > rev)
 		   *(p-1) = 0;
 	} else
 		strcpy(rev, "1.0");
diff --git a/drivers/isdn/hardware/avm/b1isa.c b/drivers/isdn/hardware/avm/b1isa.c
index 80fb488848b81ac2cc64e6613e80c21001e5b223..1e288eeb5e2a5679908ca0f9cbf79793b91e18b8 100644
--- a/drivers/isdn/hardware/avm/b1isa.c
+++ b/drivers/isdn/hardware/avm/b1isa.c
@@ -203,9 +203,9 @@ static int __init b1isa_init(void)
 	char rev[32];
 	int i;
 
-	if ((p = strchr(revision, ':')) != 0 && p[1]) {
+	if ((p = strchr(revision, ':')) != NULL && p[1]) {
 		strlcpy(rev, p + 2, 32);
-		if ((p = strchr(rev, '$')) != 0 && p > rev)
+		if ((p = strchr(rev, '$')) != NULL && p > rev)
 		   *(p-1) = 0;
 	} else
 		strcpy(rev, "1.0");
diff --git a/drivers/isdn/hardware/avm/b1pci.c b/drivers/isdn/hardware/avm/b1pci.c
index 90e2e6643d197abd44f499ed83efb4cc8a7eef0b..5b314a2c40493eb7e88441b96fa6f0a523e6933f 100644
--- a/drivers/isdn/hardware/avm/b1pci.c
+++ b/drivers/isdn/hardware/avm/b1pci.c
@@ -382,9 +382,9 @@ static int __init b1pci_init(void)
 	char rev[32];
 	int err;
 
-	if ((p = strchr(revision, ':')) != 0 && p[1]) {
+	if ((p = strchr(revision, ':')) != NULL && p[1]) {
 		strlcpy(rev, p + 2, 32);
-		if ((p = strchr(rev, '$')) != 0 && p > rev)
+		if ((p = strchr(rev, '$')) != NULL && p > rev)
 		   *(p-1) = 0;
 	} else
 		strcpy(rev, "1.0");
diff --git a/drivers/isdn/hardware/avm/b1pcmcia.c b/drivers/isdn/hardware/avm/b1pcmcia.c
index e479c0aef38d84aad3dc821a45b206b596fd479e..7740403b40e14685638b1d60c5d05a755332e6ae 100644
--- a/drivers/isdn/hardware/avm/b1pcmcia.c
+++ b/drivers/isdn/hardware/avm/b1pcmcia.c
@@ -201,9 +201,9 @@ static int __init b1pcmcia_init(void)
 	char *p;
 	char rev[32];
 
-	if ((p = strchr(revision, ':')) != 0 && p[1]) {
+	if ((p = strchr(revision, ':')) != NULL && p[1]) {
 		strlcpy(rev, p + 2, 32);
-		if ((p = strchr(rev, '$')) != 0 && p > rev)
+		if ((p = strchr(rev, '$')) != NULL && p > rev)
 		   *(p-1) = 0;
 	} else
 		strcpy(rev, "1.0");
diff --git a/drivers/isdn/hardware/avm/c4.c b/drivers/isdn/hardware/avm/c4.c
index 4bbbbe688077558f1793c746e0f95380d8b65f17..9df1d3f66c879e750201e9e16f8d8cbf4d14ccbb 100644
--- a/drivers/isdn/hardware/avm/c4.c
+++ b/drivers/isdn/hardware/avm/c4.c
@@ -1088,11 +1088,11 @@ static int c4_read_proc(char *page, char **start, off_t off,
 	default: s = "???"; break;
 	}
 	len += sprintf(page+len, "%-16s %s\n", "type", s);
-	if ((s = cinfo->version[VER_DRIVER]) != 0)
+	if ((s = cinfo->version[VER_DRIVER]) != NULL)
 	   len += sprintf(page+len, "%-16s %s\n", "ver_driver", s);
-	if ((s = cinfo->version[VER_CARDTYPE]) != 0)
+	if ((s = cinfo->version[VER_CARDTYPE]) != NULL)
 	   len += sprintf(page+len, "%-16s %s\n", "ver_cardtype", s);
-	if ((s = cinfo->version[VER_SERIAL]) != 0)
+	if ((s = cinfo->version[VER_SERIAL]) != NULL)
 	   len += sprintf(page+len, "%-16s %s\n", "ver_serial", s);
 
 	if (card->cardtype != avm_m1) {
@@ -1167,7 +1167,7 @@ static int c4_add_card(struct capicardparams *p, struct pci_dev *dev,
 	}
 
 	card->mbase = ioremap(card->membase, 128);
-	if (card->mbase == 0) {
+	if (card->mbase == NULL) {
 		printk(KERN_NOTICE "c4: can't remap memory at 0x%lx\n",
 		       card->membase);
 		retval = -EIO;
@@ -1291,9 +1291,9 @@ static int __init c4_init(void)
 	char rev[32];
 	int err;
 
-	if ((p = strchr(revision, ':')) != 0 && p[1]) {
+	if ((p = strchr(revision, ':')) != NULL && p[1]) {
 		strlcpy(rev, p + 2, 32);
-		if ((p = strchr(rev, '$')) != 0 && p > rev)
+		if ((p = strchr(rev, '$')) != NULL && p > rev)
 		   *(p-1) = 0;
 	} else
 		strcpy(rev, "1.0");
diff --git a/drivers/isdn/hardware/avm/t1isa.c b/drivers/isdn/hardware/avm/t1isa.c
index 6130724e46e775a98e9f37621d9aa4533eb2c553..e7724493738c4673f14d49c039e94f28c9e3ada8 100644
--- a/drivers/isdn/hardware/avm/t1isa.c
+++ b/drivers/isdn/hardware/avm/t1isa.c
@@ -551,9 +551,9 @@ static int __init t1isa_init(void)
 	char *p;
 	int i;
 
-	if ((p = strchr(revision, ':')) != 0 && p[1]) {
+	if ((p = strchr(revision, ':')) != NULL && p[1]) {
 		strlcpy(rev, p + 2, 32);
-		if ((p = strchr(rev, '$')) != 0 && p > rev)
+		if ((p = strchr(rev, '$')) != NULL && p > rev)
 		   *(p-1) = 0;
 	} else
 		strcpy(rev, "1.0");
diff --git a/drivers/isdn/hardware/avm/t1pci.c b/drivers/isdn/hardware/avm/t1pci.c
index d1e253c94db4b751f353a58587f4378c0adc4666..e6d298d751465af4411143831b7bb4b9d2b3057a 100644
--- a/drivers/isdn/hardware/avm/t1pci.c
+++ b/drivers/isdn/hardware/avm/t1pci.c
@@ -233,9 +233,9 @@ static int __init t1pci_init(void)
 	char rev[32];
 	int err;
 
-	if ((p = strchr(revision, ':')) != 0 && p[1]) {
+	if ((p = strchr(revision, ':')) != NULL && p[1]) {
 		strlcpy(rev, p + 2, 32);
-		if ((p = strchr(rev, '$')) != 0 && p > rev)
+		if ((p = strchr(rev, '$')) != NULL && p > rev)
 		   *(p-1) = 0;
 	} else
 		strcpy(rev, "1.0");