diff --git a/cpu/atmega_common/periph/i2c.c b/cpu/atmega_common/periph/i2c.c
index 30672ba2fe..3b4a0d251e 100644
--- a/cpu/atmega_common/periph/i2c.c
+++ b/cpu/atmega_common/periph/i2c.c
@@ -22,11 +22,12 @@
  * @}
  */
 
+#include <assert.h>
 #include <stdint.h>
 #include <errno.h>
+
 #include "cpu.h"
 #include "mutex.h"
-#include "assert.h"
 #include "periph/i2c.h"
 #include "periph_conf.h"
 
@@ -219,12 +220,11 @@ int i2c_write_bytes(i2c_t dev, uint16_t addr, const void *data, size_t len,
     return 0;
 }
 
-int i2c_acquire(i2c_t dev)
+void i2c_acquire(i2c_t dev)
 {
     assert(dev < I2C_NUMOF);
 
     mutex_lock(&locks[dev]);
-    return 0;
 }
 
 void i2c_release(i2c_t dev)
diff --git a/cpu/atxmega/periph/i2c.c b/cpu/atxmega/periph/i2c.c
index 91195e7876..be43a7f17d 100644
--- a/cpu/atxmega/periph/i2c.c
+++ b/cpu/atxmega/periph/i2c.c
@@ -18,6 +18,7 @@
  *
  * @}
  */
+#include <assert.h>
 #include <errno.h>
 
 #include "cpu.h"
@@ -74,10 +75,7 @@ void i2c_init(i2c_t i2c)
 {
     uint8_t baudrate;
 
-    if (i2c >= I2C_NUMOF) {
-        DEBUG("[i2c] init: dev is invalid.\n");
-        return;
-    }
+    assert((unsigned)i2c < I2C_NUMOF);
 
     baudrate = _i2c_calc_baud(i2c);
     if (baudrate == 0) {
@@ -97,12 +95,14 @@ void i2c_init(i2c_t i2c)
 
 void i2c_init_pins(i2c_t i2c)
 {
+    assert((unsigned)i2c < I2C_NUMOF);
     gpio_init(i2c_config[i2c].sda_pin, GPIO_OPC_WRD_AND_PULL);
     gpio_init(i2c_config[i2c].scl_pin, GPIO_OPC_WRD_AND_PULL);
 }
 
-int i2c_acquire(i2c_t i2c)
+void i2c_acquire(i2c_t i2c)
 {
+    assert((unsigned)i2c < I2C_NUMOF);
     DEBUG("acquire\n");
     pm_block(3);
     mutex_lock(&i2c_ctx[i2c].locks);
@@ -113,12 +113,11 @@ int i2c_acquire(i2c_t i2c)
                            | TWI_MASTER_WIEN_bm
                            | TWI_MASTER_ENABLE_bm;
     dev(i2c)->MASTER.STATUS = TWI_MASTER_BUSSTATE_IDLE_gc;
-
-    return 0;
 }
 
 void i2c_release(i2c_t i2c)
 {
+    assert((unsigned)i2c < I2C_NUMOF);
     dev(i2c)->MASTER.CTRLA = 0;
     pm_periph_disable(i2c_config[i2c].pwr);
     mutex_unlock(&i2c_ctx[i2c].locks);
@@ -129,6 +128,8 @@ void i2c_release(i2c_t i2c)
 static int _i2c_transaction(i2c_t i2c, uint16_t addr, const void *data,
                             size_t len, uint8_t flags, bool is_read)
 {
+    assert((unsigned)i2c < I2C_NUMOF);
+
     if (flags & I2C_ADDR10) {
         DEBUG("[i2c] xfer: no 10 bit address support.\n");
         return -EOPNOTSUPP;
@@ -238,6 +239,8 @@ static inline void _i2c_read_handler(int i2c)
  */
 static inline void isr_handler(int i2c)
 {
+    assert((unsigned)i2c < I2C_NUMOF);
+
     avr8_enter_isr();
 
     int8_t const m_status = dev(i2c)->MASTER.STATUS;
diff --git a/cpu/cc2538/periph/i2c.c b/cpu/cc2538/periph/i2c.c
index 40dbccbdfc..46ced955eb 100644
--- a/cpu/cc2538/periph/i2c.c
+++ b/cpu/cc2538/periph/i2c.c
@@ -231,14 +231,12 @@ void i2c_init(i2c_t dev)
     DEBUG(" - I2C master status (0x%x).\n", _i2c_master_stat_get());
 }
 
-int i2c_acquire(i2c_t dev)
+void i2c_acquire(i2c_t dev)
 {
+    (void)dev;
+    assert(dev < I2C_NUMOF);
     DEBUG("%s\n", __FUNCTION__);
-    if (dev < I2C_NUMOF) {
-        mutex_lock(&lock);
-        return 0;
-    }
-    return -1;
+    mutex_lock(&lock);
 }
 
 void i2c_release(i2c_t dev)
diff --git a/cpu/cc26xx_cc13xx/periph/i2c.c b/cpu/cc26xx_cc13xx/periph/i2c.c
index 830fff0ac5..4e5fc42136 100644
--- a/cpu/cc26xx_cc13xx/periph/i2c.c
+++ b/cpu/cc26xx_cc13xx/periph/i2c.c
@@ -126,12 +126,11 @@ void i2c_init(i2c_t devnum)
     I2C->MTPR = MTPR_TPR_100KHZ;
 }
 
-int i2c_acquire(i2c_t dev)
+void i2c_acquire(i2c_t dev)
 {
     (void)dev;
     assert(dev < I2C_NUMOF);
     mutex_lock(&_lock);
-    return 0;
 }
 
 void i2c_release(i2c_t dev)
diff --git a/cpu/efm32/periph/i2c.c b/cpu/efm32/periph/i2c.c
index cd00033996..c15769cb37 100644
--- a/cpu/efm32/periph/i2c.c
+++ b/cpu/efm32/periph/i2c.c
@@ -142,15 +142,15 @@ void i2c_init(i2c_t dev)
     I2C_Enable(i2c_config[dev].dev, true);
 }
 
-int i2c_acquire(i2c_t dev)
+void i2c_acquire(i2c_t dev)
 {
+    assert(dev < I2C_NUMOF);
+
     /* acquire lock */
     mutex_lock(&i2c_lock[dev]);
 
     /* power peripheral */
     CMU_ClockEnable(i2c_config[dev].cmu, true);
-
-    return 0;
 }
 
 void i2c_release(i2c_t dev)
diff --git a/cpu/esp32/periph/i2c_hw.c b/cpu/esp32/periph/i2c_hw.c
index 1d8df98c22..32ff481e78 100644
--- a/cpu/esp32/periph/i2c_hw.c
+++ b/cpu/esp32/periph/i2c_hw.c
@@ -145,7 +145,7 @@ static inline void _i2c_delay (uint32_t delay);
 
 void i2c_init(i2c_t dev)
 {
-    CHECK_PARAM (dev < I2C_NUMOF)
+    assert(dev < I2C_NUMOF);
 
     if (i2c_config[dev].speed == I2C_SPEED_FAST_PLUS ||
         i2c_config[dev].speed == I2C_SPEED_HIGH) {
@@ -156,7 +156,7 @@ void i2c_init(i2c_t dev)
 
     mutex_init(&_i2c_bus[dev].lock);
 
-    i2c_acquire (dev);
+    i2c_acquire(dev);
 
     _i2c_bus[dev].cmd = 0;
     _i2c_bus[dev].data = 0;
@@ -262,20 +262,17 @@ void i2c_init(i2c_t dev)
     xt_set_interrupt_handler(CPU_INUM_I2C, _i2c_intr_handler, NULL);
     xt_ints_on(BIT(CPU_INUM_I2C));
 
-    i2c_release (dev);
-
-    return;
+    i2c_release(dev);
 }
 
-int i2c_acquire(i2c_t dev)
+void i2c_acquire(i2c_t dev)
 {
     DEBUG ("%s\n", __func__);
 
-    CHECK_PARAM_RET (dev < I2C_NUMOF, -1)
+    assert(dev < I2C_NUMOF);
 
     mutex_lock(&_i2c_bus[dev].lock);
     _i2c_reset_hw(dev);
-    return 0;
 }
 
 void i2c_release(i2c_t dev)
@@ -358,9 +355,9 @@ int i2c_read_bytes(i2c_t dev, uint16_t addr, void *data, size_t len, uint8_t fla
     DEBUG ("%s dev=%u addr=%02x data=%p len=%d flags=%01x\n",
            __func__, dev, addr, data, len, flags);
 
-    CHECK_PARAM_RET (dev < I2C_NUMOF, -EINVAL);
-    CHECK_PARAM_RET (len > 0, -EINVAL);
-    CHECK_PARAM_RET (data != NULL, -EINVAL);
+    assert(dev < I2C_NUMOF);
+    assert(len > 0);
+    assert(data != NULL);
 
     /*  if I2C_NOSTART is not set, START condition and ADDR is used */
     if (!(flags & I2C_NOSTART)) {
@@ -445,9 +442,9 @@ int i2c_write_bytes(i2c_t dev, uint16_t addr, const void *data, size_t len, uint
     DEBUG ("%s dev=%u addr=%02x data=%p len=%d flags=%01x\n",
            __func__, dev, addr, data, len, flags);
 
-    CHECK_PARAM_RET (dev < I2C_NUMOF, -EINVAL);
-    CHECK_PARAM_RET (len > 0, -EINVAL);
-    CHECK_PARAM_RET (data != NULL, -EINVAL);
+    assert(dev < I2C_NUMOF);
+    assert(len > 0);
+    assert(data != NULL);
 
     /*  if I2C_NOSTART is not set, START condition and ADDR is used */
     if (!(flags & I2C_NOSTART)) {
diff --git a/cpu/esp_common/periph/i2c_sw.c b/cpu/esp_common/periph/i2c_sw.c
index efb45e26f9..4a75efd3df 100644
--- a/cpu/esp_common/periph/i2c_sw.c
+++ b/cpu/esp_common/periph/i2c_sw.c
@@ -246,12 +246,11 @@ void i2c_init(i2c_t dev)
     return;
 }
 
-int i2c_acquire(i2c_t dev)
+void i2c_acquire(i2c_t dev)
 {
     assert(dev < I2C_NUMOF);
 
     mutex_lock(&_i2c_bus[dev].lock);
-    return 0;
 }
 
 void i2c_release(i2c_t dev)
diff --git a/cpu/fe310/periph/i2c.c b/cpu/fe310/periph/i2c.c
index 76029585c8..f3b2f4b9a2 100644
--- a/cpu/fe310/periph/i2c.c
+++ b/cpu/fe310/periph/i2c.c
@@ -90,11 +90,10 @@ void i2c_init(i2c_t dev)
     DEBUG("[i2c] initialization done\n");
 }
 
-int i2c_acquire(i2c_t dev)
+void i2c_acquire(i2c_t dev)
 {
     assert(dev < I2C_NUMOF);
     mutex_lock(&locks[dev]);
-    return 0;
 }
 
 void i2c_release(i2c_t dev)
diff --git a/cpu/kinetis/periph/i2c.c b/cpu/kinetis/periph/i2c.c
index 12d503308a..20e7bc2134 100644
--- a/cpu/kinetis/periph/i2c.c
+++ b/cpu/kinetis/periph/i2c.c
@@ -106,12 +106,11 @@ typedef struct {
 
 static i2c_state_t i2c_state[I2C_NUMOF];
 
-int i2c_acquire(i2c_t dev)
+void i2c_acquire(i2c_t dev)
 {
     assert((unsigned)dev < I2C_NUMOF);
     mutex_lock(&i2c_state[dev].mtx);
     i2c_state[dev].pid = thread_getpid();
-    return 0;
 }
 
 void i2c_release(i2c_t dev)
diff --git a/cpu/lpc23xx/periph/i2c.c b/cpu/lpc23xx/periph/i2c.c
index 592b26467a..190e3b680f 100644
--- a/cpu/lpc23xx/periph/i2c.c
+++ b/cpu/lpc23xx/periph/i2c.c
@@ -103,14 +103,12 @@ static void poweroff(lpc23xx_i2c_t *i2c)
     }
 }
 
-int i2c_acquire(i2c_t dev)
+void i2c_acquire(i2c_t dev)
 {
     assert(dev < I2C_NUMOF);
 
     mutex_lock(&ctx[dev].lock);
     poweron(i2c_config[dev].dev);
-
-    return 0;
 }
 
 void i2c_release(i2c_t dev)
@@ -332,6 +330,8 @@ static void irq_handler(i2c_t dev)
     }
 
     /* clear interrupt flag */
+    /* cppcheck-suppress redundantAssignment
+     * (reason: writing 1 to volatile register to clear the interrupt) */
     i2c->CONCLR = I2CONCLR_SIC;
 }
 
diff --git a/cpu/nrf51/periph/i2c.c b/cpu/nrf51/periph/i2c.c
index 5f6bcc10fe..cd2efd09e9 100644
--- a/cpu/nrf51/periph/i2c.c
+++ b/cpu/nrf51/periph/i2c.c
@@ -132,12 +132,11 @@ void i2c_init(i2c_t dev)
     i2c(dev)->ENABLE = TWI_ENABLE_ENABLE_Enabled;
 }
 
-int i2c_acquire(i2c_t dev)
+void i2c_acquire(i2c_t dev)
 {
     assert(dev < I2C_NUMOF);
 
     mutex_lock(&locks[dev]);
-    return 0;
 }
 
 void i2c_release(i2c_t dev)
diff --git a/cpu/nrf5x_common/periph/i2c_nrf52_nrf9160.c b/cpu/nrf5x_common/periph/i2c_nrf52_nrf9160.c
index 516acedcfc..8069051535 100644
--- a/cpu/nrf5x_common/periph/i2c_nrf52_nrf9160.c
+++ b/cpu/nrf5x_common/periph/i2c_nrf52_nrf9160.c
@@ -154,7 +154,7 @@ void i2c_deinit_pins(i2c_t dev)
 }
 #endif /* MODULE_PERIPH_I2C_RECONFIGURE */
 
-int i2c_acquire(i2c_t dev)
+void i2c_acquire(i2c_t dev)
 {
     assert(dev < I2C_NUMOF);
 
@@ -162,7 +162,6 @@ int i2c_acquire(i2c_t dev)
     bus(dev)->ENABLE = TWIM_ENABLE_ENABLE_Enabled;
 
     DEBUG("[i2c] acquired dev %i\n", (int)dev);
-    return 0;
 }
 
 void i2c_release(i2c_t dev)
diff --git a/cpu/qn908x/periph/i2c.c b/cpu/qn908x/periph/i2c.c
index 08a3d0bc85..faf2f690dc 100644
--- a/cpu/qn908x/periph/i2c.c
+++ b/cpu/qn908x/periph/i2c.c
@@ -153,11 +153,10 @@ void i2c_deinit_pins(i2c_t dev)
 }
 #endif /* MODULE_PERIPH_I2C_RECONFIGURE */
 
-int i2c_acquire(i2c_t dev)
+void i2c_acquire(i2c_t dev)
 {
     assert(dev < I2C_NUMOF);
     mutex_lock(&locks[dev]);
-    return 0;
 }
 
 void i2c_release(i2c_t dev)
diff --git a/cpu/sam0_common/periph/i2c.c b/cpu/sam0_common/periph/i2c.c
index 176f9e0af6..df8bfb2b0d 100644
--- a/cpu/sam0_common/periph/i2c.c
+++ b/cpu/sam0_common/periph/i2c.c
@@ -194,11 +194,10 @@ void i2c_init(i2c_t dev)
     }
 }
 
-int i2c_acquire(i2c_t dev)
+void i2c_acquire(i2c_t dev)
 {
     assert(dev < I2C_NUMOF);
     mutex_lock(&locks[dev]);
-    return 0;
 }
 
 void i2c_release(i2c_t dev)
diff --git a/cpu/stm32/periph/i2c_1.c b/cpu/stm32/periph/i2c_1.c
index 4af801fed6..464c584bef 100644
--- a/cpu/stm32/periph/i2c_1.c
+++ b/cpu/stm32/periph/i2c_1.c
@@ -135,7 +135,7 @@ static void _i2c_init(I2C_TypeDef *i2c, uint32_t timing)
     i2c->CR1 |= I2C_CR1_PE;
 }
 
-int i2c_acquire(i2c_t dev)
+void i2c_acquire(i2c_t dev)
 {
     assert(dev < I2C_NUMOF);
 
@@ -145,8 +145,6 @@ int i2c_acquire(i2c_t dev)
 
     /* enable device */
     i2c_config[dev].dev->CR1 |= I2C_CR1_PE;
-
-    return 0;
 }
 
 void i2c_release(i2c_t dev)
diff --git a/cpu/stm32/periph/i2c_2.c b/cpu/stm32/periph/i2c_2.c
index c130abaa13..ebfb2dae53 100644
--- a/cpu/stm32/periph/i2c_2.c
+++ b/cpu/stm32/periph/i2c_2.c
@@ -180,7 +180,7 @@ static void _init(i2c_t dev)
     _i2c_init(i2c, i2c_config[dev].clk, ccr);
 }
 
-int i2c_acquire(i2c_t dev)
+void i2c_acquire(i2c_t dev)
 {
     assert(dev < I2C_NUMOF);
 
@@ -195,8 +195,6 @@ int i2c_acquire(i2c_t dev)
 
     /* enable device */
     i2c_config[dev].dev->CR1 |= I2C_CR1_PE;
-
-    return 0;
 }
 
 void i2c_release(i2c_t dev)