diff --git a/devices/bmxx80/bmxx80.go b/devices/bmxx80/bmxx80.go
index 2fe873c..5dc3e00 100644
--- a/devices/bmxx80/bmxx80.go
+++ b/devices/bmxx80/bmxx80.go
@@ -504,4 +504,3 @@ var doSleep = time.Sleep
 
 var _ conn.Resource = &Dev{}
 var _ physic.SenseEnv = &Dev{}
-var _ fmt.Stringer = &Dev{}
diff --git a/devices/ds248x/ds248x.go b/devices/ds248x/ds248x.go
index 24563ad..01a94f4 100644
--- a/devices/ds248x/ds248x.go
+++ b/devices/ds248x/ds248x.go
@@ -313,7 +313,6 @@ func (e busError) BusError() bool { return true }
 var sleep = time.Sleep
 
 var _ conn.Resource = &Dev{}
-var _ fmt.Stringer = &Dev{}
 
 const (
 	cmdReset       = 0xf0 // reset ds248x
diff --git a/devices/lepton/cci/cci.go b/devices/lepton/cci/cci.go
index b1b1694..f420a2f 100644
--- a/devices/lepton/cci/cci.go
+++ b/devices/lepton/cci/cci.go
@@ -160,10 +160,19 @@ type Dev struct {
 	serial uint64
 }
 
+// String implements conn.Resource.
 func (d *Dev) String() string {
 	return d.c.String()
 }
 
+// Halt implements conn.Resource.
+//
+// Halt stops the camera.
+func (d *Dev) Halt() error {
+	// TODO(maruel): Doc says it won't restart. Yo.
+	return d.c.run(oemPowerDown)
+}
+
 // Init initializes the FLIR Lepton in raw 14 bits mode, enables telemetry as
 // header.
 func (d *Dev) Init() error {
@@ -209,12 +218,6 @@ func (d *Dev) WaitIdle() (StatusBit, error) {
 	return d.c.waitIdle()
 }
 
-// Halt stops the camera.
-func (d *Dev) Halt() error {
-	// TODO(maruel): Doc says it won't restart. Yo.
-	return d.c.run(oemPowerDown)
-}
-
 // GetStatus return the status of the camera as known by the camera itself.
 func (d *Dev) GetStatus() (*Status, error) {
 	var v internal.Status
@@ -568,4 +571,3 @@ var sleep = time.Sleep
 
 var _ conn.Resource = &Dev{}
 var _ physic.SenseEnv = &Dev{}
-var _ fmt.Stringer = &cciConn{}
diff --git a/devices/lepton/lepton.go b/devices/lepton/lepton.go
index 0fa92d9..665cba1 100644
--- a/devices/lepton/lepton.go
+++ b/devices/lepton/lepton.go
@@ -447,4 +447,3 @@ func equalUint16(a, b []uint16) bool {
 }
 
 var _ conn.Resource = &Dev{}
-var _ fmt.Stringer = &Dev{}
diff --git a/devices/lirc/lirc.go b/devices/lirc/lirc.go
index 30a1bf8..dc6dfa0 100644
--- a/devices/lirc/lirc.go
+++ b/devices/lirc/lirc.go
@@ -14,6 +14,7 @@ import (
 	"strings"
 	"sync"
 
+	"periph.io/x/periph/conn"
 	"periph.io/x/periph/conn/gpio/gpioreg"
 	"periph.io/x/periph/conn/ir"
 )
@@ -44,10 +45,18 @@ type Conn struct {
 	pendingList map[string][]string // list of remotes and associated keys being created.
 }
 
+// String implements conn.Resource.
 func (c *Conn) String() string {
 	return "lirc"
 }
 
+// Halt implements conn.Resource.
+//
+// It has no effect.
+func (c *Conn) Halt() error {
+	return nil
+}
+
 // Close closes the socket to lirc. It is not a requirement to close before
 // process termination.
 func (c *Conn) Close() error {
@@ -264,4 +273,4 @@ func getPins() (int, int) {
 }
 
 var _ ir.Conn = &Conn{}
-var _ fmt.Stringer = &Conn{}
+var _ conn.Resource = &Conn{}
diff --git a/devices/tm1637/tm1637.go b/devices/tm1637/tm1637.go
index 8df7f40..d663d2c 100644
--- a/devices/tm1637/tm1637.go
+++ b/devices/tm1637/tm1637.go
@@ -208,4 +208,3 @@ func (d *Dev) sleepHalfCycle() {
 var spin = cpu.Nanospin
 
 var _ conn.Resource = &Dev{}
-var _ fmt.Stringer = &Dev{}
diff --git a/experimental/devices/bitbang/i2c.go b/experimental/devices/bitbang/i2c.go
index 84629a1..3a647f0 100644
--- a/experimental/devices/bitbang/i2c.go
+++ b/experimental/devices/bitbang/i2c.go
@@ -256,4 +256,3 @@ func (i *I2C) sleepHalfCycle() {
 }
 
 var _ i2c.Bus = &I2C{}
-var _ fmt.Stringer = &I2C{}
diff --git a/experimental/devices/bitbang/spi.go b/experimental/devices/bitbang/spi.go
index 750dc49..ec8c7b7 100644
--- a/experimental/devices/bitbang/spi.go
+++ b/experimental/devices/bitbang/spi.go
@@ -279,5 +279,5 @@ func (s *spiConn) unassertCS() error {
 	return nil
 }
 
+var _ spi.Conn = &spiConn{}
 var _ spi.PortCloser = &SPI{}
-var _ fmt.Stringer = &SPI{}
diff --git a/experimental/devices/hd44780/hd44780.go b/experimental/devices/hd44780/hd44780.go
index e27640d..2dcfc14 100644
--- a/experimental/devices/hd44780/hd44780.go
+++ b/experimental/devices/hd44780/hd44780.go
@@ -239,4 +239,3 @@ func delayMs(ms int) {
 }
 
 var _ conn.Resource = &Dev{}
-var _ fmt.Stringer = &Dev{}
diff --git a/experimental/devices/mfrc522/mfrc522.go b/experimental/devices/mfrc522/mfrc522.go
index eb48838..92796e1 100644
--- a/experimental/devices/mfrc522/mfrc522.go
+++ b/experimental/devices/mfrc522/mfrc522.go
@@ -134,11 +134,19 @@ type Dev struct {
 	spiDev           spi.Conn
 }
 
+// String implements conn.Resource.
 func (r *Dev) String() string {
 	return fmt.Sprintf("Mifare MFRC522 [bus: %v, reset pin: %s, irq pin: %s]",
 		r.spiDev, r.resetPin.Name(), r.irqPin.Name())
 }
 
+// Halt implements conn.Resource.
+//
+// It soft-stops the chip - PowerDown bit set, command IDLE
+func (r *Dev) Halt() error {
+	return r.devWrite(commands.CommandReg, 16)
+}
+
 // SetOperationtimeout updates the device timeout for card operations.
 //
 // Effectively that sets the maximum time the RFID device will wait for IRQ
@@ -165,11 +173,6 @@ func (r *Dev) Reset() error {
 	return r.devWrite(commands.CommandReg, commands.PCD_RESETPHASE)
 }
 
-// Halt soft-stops the chip - PowerDown bit set, command IDLE
-func (r *Dev) Halt() error {
-	return r.devWrite(commands.CommandReg, 16)
-}
-
 // SetAntenna configures the antenna state, on/off.
 func (r *Dev) SetAntenna(state bool) error {
 	if state {
@@ -754,10 +757,9 @@ var sequenceCommands = struct {
 	},
 }
 
-var _ conn.Resource = &Dev{}
-var _ fmt.Stringer = &Dev{}
-var _ fmt.Stringer = &BlocksAccess{}
-
 func wrapf(format string, a ...interface{}) error {
 	return fmt.Errorf("mfrc522: "+format, a...)
 }
+
+var _ conn.Resource = &Dev{}
+var _ fmt.Stringer = &BlocksAccess{}