diff --git a/src/ezusb.c b/src/ezusb.c
index 034c6c9e..9f40d3b7 100644
--- a/src/ezusb.c
+++ b/src/ezusb.c
@@ -57,7 +57,7 @@ SR_PRIV int ezusb_install_firmware(libusb_device_handle *hdl,
 	unsigned char buf[4096];
 
 	sr_info("Uploading firmware at %s", filename);
-	if ((fw = g_fopen(filename, "rb")) == NULL) {
+	if (!(fw = g_fopen(filename, "rb"))) {
 		sr_err("Unable to open firmware file %s for reading: %s",
 		       filename, strerror(errno));
 		return SR_ERR;
diff --git a/src/hardware/baylibre-acme/api.c b/src/hardware/baylibre-acme/api.c
index 4bcf772d..def373d1 100644
--- a/src/hardware/baylibre-acme/api.c
+++ b/src/hardware/baylibre-acme/api.c
@@ -115,7 +115,7 @@ static GSList *scan(struct sr_dev_driver *di, GSList *options)
 	 * Let's assume there's no ACME device present if no probe
 	 * has been registered.
 	 */
-	if (sdi->channel_groups == NULL)
+	if (!sdi->channel_groups)
 		goto err_out;
 
 	devices = g_slist_append(devices, sdi);
diff --git a/src/hardware/beaglelogic/api.c b/src/hardware/beaglelogic/api.c
index 4fae9b80..5f1d35fc 100644
--- a/src/hardware/beaglelogic/api.c
+++ b/src/hardware/beaglelogic/api.c
@@ -365,7 +365,7 @@ static int dev_acquisition_start(const struct sr_dev_inst *sdi,
 		if (devc->limit_samples > 0)
 			pre_trigger_samples = devc->capture_ratio * devc->limit_samples/100;
 		devc->stl = soft_trigger_logic_new(sdi, trigger, pre_trigger_samples);
-		if (devc->stl == NULL)
+		if (!devc->stl)
 			return SR_ERR_MALLOC;
 		devc->trigger_fired = FALSE;
 	} else
diff --git a/src/hardware/fx2lafw/api.c b/src/hardware/fx2lafw/api.c
index baa1476d..04284e50 100644
--- a/src/hardware/fx2lafw/api.c
+++ b/src/hardware/fx2lafw/api.c
@@ -426,7 +426,7 @@ static int dev_close(struct sr_dev_inst *sdi)
 	struct sr_usb_dev_inst *usb;
 
 	usb = sdi->conn;
-	if (usb->devhdl == NULL)
+	if (!usb->devhdl)
 		return SR_ERR;
 
 	sr_info("fx2lafw: Closing device on %d.%d (logical) / %s (physical) interface %d.",
@@ -629,7 +629,7 @@ static int start_transfers(const struct sr_dev_inst *sdi)
 		if (devc->limit_samples > 0)
 			pre_trigger_samples = devc->capture_ratio * devc->limit_samples/100;
 		devc->stl = soft_trigger_logic_new(sdi, trigger, pre_trigger_samples);
-		if (devc->stl == NULL)
+		if (!devc->stl)
 			return SR_ERR_MALLOC;
 		devc->trigger_fired = FALSE;
 	} else
diff --git a/src/hardware/fx2lafw/dslogic.c b/src/hardware/fx2lafw/dslogic.c
index f0b49c34..715ca8a5 100644
--- a/src/hardware/fx2lafw/dslogic.c
+++ b/src/hardware/fx2lafw/dslogic.c
@@ -57,7 +57,7 @@ int dslogic_fpga_firmware_upload(const struct sr_dev_inst *sdi,
 	}
 	buf = g_malloc(FW_BUFSIZE);
 
-	if ((fw = g_fopen(filename, "rb")) == NULL) {
+	if (!(fw = g_fopen(filename, "rb"))) {
 		sr_err("Unable to open %s for reading: %s.", filename, strerror(errno));
 		return SR_ERR;
 	}
diff --git a/src/hardware/hantek-dso/dso.c b/src/hardware/hantek-dso/dso.c
index 814db598..76615748 100644
--- a/src/hardware/hantek-dso/dso.c
+++ b/src/hardware/hantek-dso/dso.c
@@ -185,7 +185,7 @@ SR_PRIV void dso_close(struct sr_dev_inst *sdi)
 
 	usb = sdi->conn;
 
-	if (usb->devhdl == NULL)
+	if (!usb->devhdl)
 		return;
 
 	sr_info("Closing device on %d.%d (logical) / %s (physical) interface %d.",
diff --git a/src/hardware/ikalogic-scanalogic2/api.c b/src/hardware/ikalogic-scanalogic2/api.c
index 31e1fb1f..a18557cf 100644
--- a/src/hardware/ikalogic-scanalogic2/api.c
+++ b/src/hardware/ikalogic-scanalogic2/api.c
@@ -77,7 +77,7 @@ static GSList *scan(struct sr_dev_driver *di, GSList *options)
 
 	usb_devices = sr_usb_find(drvc->sr_ctx->libusb_ctx, USB_VID_PID);
 
-	if (usb_devices == NULL)
+	if (!usb_devices)
 		return NULL;
 
 	for (l = usb_devices; l; l = l->next) {
diff --git a/src/hardware/link-mso19/api.c b/src/hardware/link-mso19/api.c
index 89718894..dbc66fdd 100644
--- a/src/hardware/link-mso19/api.c
+++ b/src/hardware/link-mso19/api.c
@@ -116,7 +116,7 @@ static GSList *scan(struct sr_dev_driver *di, GSList *options)
 	}
 	if (!conn)
 		conn = SERIALCONN;
-	if (serialcomm == NULL)
+	if (!serialcomm)
 		serialcomm = SERIALCOMM;
 
 	udev = udev_new();
diff --git a/src/hardware/link-mso19/protocol.c b/src/hardware/link-mso19/protocol.c
index 11fa8a61..148f0ba1 100644
--- a/src/hardware/link-mso19/protocol.c
+++ b/src/hardware/link-mso19/protocol.c
@@ -336,7 +336,7 @@ SR_PRIV int mso_check_trigger(struct sr_serial_dev_inst *serial, uint8_t *info)
 
 	sr_dbg("Requesting trigger state.");
 	ret = mso_send_control_message(serial, ARRAY_AND_SIZE(ops));
-	if (info == NULL || ret != SR_OK)
+	if (!info || ret != SR_OK)
 		return ret;
 
 	uint8_t buf = 0;
diff --git a/src/hardware/openbench-logic-sniffer/api.c b/src/hardware/openbench-logic-sniffer/api.c
index c8ddc4be..14437839 100644
--- a/src/hardware/openbench-logic-sniffer/api.c
+++ b/src/hardware/openbench-logic-sniffer/api.c
@@ -123,7 +123,7 @@ static GSList *scan(struct sr_dev_driver *di, GSList *options)
 	if (!conn)
 		return NULL;
 
-	if (serialcomm == NULL)
+	if (!serialcomm)
 		serialcomm = SERIALCOMM;
 
 	serial = sr_serial_dev_inst_new(conn, serialcomm);
diff --git a/src/hardware/saleae-logic16/api.c b/src/hardware/saleae-logic16/api.c
index c82bac80..55e3d752 100644
--- a/src/hardware/saleae-logic16/api.c
+++ b/src/hardware/saleae-logic16/api.c
@@ -398,7 +398,7 @@ static int dev_close(struct sr_dev_inst *sdi)
 	struct sr_usb_dev_inst *usb;
 
 	usb = sdi->conn;
-	if (usb->devhdl == NULL)
+	if (!usb->devhdl)
 		return SR_ERR;
 
 	sr_info("Closing device on %d.%d (logical) / %s (physical) interface %d.",
@@ -738,7 +738,7 @@ static int dev_acquisition_start(const struct sr_dev_inst *sdi, void *cb_data)
 		if (devc->limit_samples > 0)
 			pre_trigger_samples = devc->capture_ratio * devc->limit_samples/100;
 		devc->stl = soft_trigger_logic_new(sdi, trigger, pre_trigger_samples);
-		if (devc->stl == NULL)
+		if (!devc->stl)
 			return SR_ERR_MALLOC;
 		devc->trigger_fired = FALSE;
 	} else
diff --git a/src/hardware/saleae-logic16/protocol.c b/src/hardware/saleae-logic16/protocol.c
index 9e5806e0..3bc7c756 100644
--- a/src/hardware/saleae-logic16/protocol.c
+++ b/src/hardware/saleae-logic16/protocol.c
@@ -107,7 +107,7 @@ static int do_ep1_command(const struct sr_dev_inst *sdi,
 	usb = sdi->conn;
 
 	if (cmd_len < 1 || cmd_len > 64 || reply_len > 64 ||
-	    command == NULL || (reply_len > 0 && reply == NULL))
+	    !command || (reply_len > 0 && !reply))
 		return SR_ERR_ARG;
 
 	encrypt(buf, command, cmd_len);
@@ -165,7 +165,7 @@ static int upload_led_table(const struct sr_dev_inst *sdi,
 	uint8_t chunk, command[64];
 	int ret;
 
-	if (cnt < 1 || cnt + offset > 64 || table == NULL)
+	if (cnt < 1 || cnt + offset > 64 || !table)
 		return SR_ERR_ARG;
 
 	while (cnt > 0) {
@@ -351,7 +351,7 @@ static int upload_fpga_bitstream(const struct sr_dev_inst *sdi,
 		}
 
 		sr_info("Uploading FPGA bitstream at %s.", filename);
-		if ((fw = g_fopen(filename, "rb")) == NULL) {
+		if (!(fw = g_fopen(filename, "rb"))) {
 			sr_err("Unable to open bitstream file %s for reading: %s.",
 			       filename, strerror(errno));
 			return SR_ERR;
diff --git a/src/scpi/scpi_serial.c b/src/scpi/scpi_serial.c
index 7f039bf0..de307989 100644
--- a/src/scpi/scpi_serial.c
+++ b/src/scpi/scpi_serial.c
@@ -54,8 +54,8 @@ static GSList *scpi_serial_scan(struct drv_context *drvc)
 	(void)drvc;
 
 	for (i = 0; i < ARRAY_SIZE(scpi_serial_usb_ids); i++) {
-		if ((l = sr_serial_find_usb(scpi_serial_usb_ids[i].vendor_id,
-		                            scpi_serial_usb_ids[i].product_id)) == NULL)
+		if (!(l = sr_serial_find_usb(scpi_serial_usb_ids[i].vendor_id,
+					scpi_serial_usb_ids[i].product_id)))
 			continue;
 		for (r = l; r; r = r->next) {
 			if (scpi_serial_usb_ids[i].serialcomm)
diff --git a/src/scpi/scpi_vxi.c b/src/scpi/scpi_vxi.c
index e4efbf1d..e7a4b2b5 100644
--- a/src/scpi/scpi_vxi.c
+++ b/src/scpi/scpi_vxi.c
@@ -66,7 +66,7 @@ static int scpi_vxi_open(void *priv)
 	Create_LinkResp *link_resp;
 
 	vxi->client = clnt_create(vxi->address, DEVICE_CORE, DEVICE_CORE_VERSION, "tcp");
-	if (vxi->client == NULL) {
+	if (!vxi->client) {
 		sr_err("Client creation failed for %s", vxi->address);
 		return SR_ERR;
 	}
diff --git a/src/soft-trigger.c b/src/soft-trigger.c
index 27c71b61..9c3963d3 100644
--- a/src/soft-trigger.c
+++ b/src/soft-trigger.c
@@ -40,7 +40,7 @@ SR_PRIV struct soft_trigger_logic *soft_trigger_logic_new(
 	stl->pre_trigger_buffer = g_malloc(stl->pre_trigger_size);
 	stl->pre_trigger_head = stl->pre_trigger_buffer;
 
-	if (stl->pre_trigger_size > 0 && stl->pre_trigger_buffer == NULL) {
+	if (stl->pre_trigger_size > 0 && !stl->pre_trigger_buffer) {
 		soft_trigger_logic_free(stl);
 		return NULL;
 	}
diff --git a/src/strutil.c b/src/strutil.c
index 050f37bf..131126b0 100644
--- a/src/strutil.c
+++ b/src/strutil.c
@@ -246,7 +246,7 @@ SR_API char *sr_si_string_u64(uint64_t x, const char *unit)
 	const char *p, prefix[] = "\0kMGTPE";
 	char fmt[16], fract[20] = "", *f;
 
-	if (unit == NULL)
+	if (!unit)
 		unit = "";
 
 	for (i = 0; (quot = x / divisor[i]) >= 1000; i++);