sensor: icm4568x: Address existing code issues by static analysis

Addressing low-hanging fruits.

Put in a separate commit in order to make it easier to keep track of
changes.

Signed-off-by: Luis Ubieda <[email protected]>

Author: ubieda

drivers/sensor/tdk/icm4268x/icm4268x.h

@@ -200,6 +200,9 @@ static inline void icm4268x_accel_reg_to_hz(uint8_t odr, struct sensor_value *ou
 		out->val1 = 1;
 		out->val2 = 562500;
 		return;
+	default:
+		CODE_UNREACHABLE;
+		return;
 	}
 }
 
@@ -283,6 +286,8 @@ static inline void icm4268x_gyro_reg_to_odr(uint8_t odr, struct sensor_value *ou
 		out->val1 = 12;
 		out->val2 = 500000;
 		return;
+	default:
+		CODE_UNREACHABLE;
 	}
 }
 

drivers/sensor/tdk/icm4268x/icm4268x_common.c

@@ -67,11 +67,19 @@ static uint16_t icm4268x_compute_fifo_wm(const struct icm4268x_cfg *cfg)
 {
 	const bool accel_enabled = cfg->accel_pwr_mode != ICM42688_DT_ACCEL_OFF;
 	const bool gyro_enabled = cfg->gyro_pwr_mode != ICM42688_DT_GYRO_OFF;
-	const int pkt_size = cfg->fifo_hires ? 20 : (accel_enabled && gyro_enabled ? 16 : 8);
 	int accel_modr = 0;
 	int gyro_modr = 0;
+	uint8_t pkt_size;
 	int64_t modr;
 
+	if (cfg->fifo_hires) {
+		pkt_size = 20;
+	} else if (accel_enabled && gyro_enabled) {
+		pkt_size = 16;
+	} else {
+		pkt_size = 8;
+	}
+
 	if (cfg->batch_ticks == 0 || (!accel_enabled && !gyro_enabled)) {
 		return 0;
 	}

drivers/sensor/tdk/icm4268x/icm4268x_decoder.c

@@ -116,7 +116,7 @@ int icm4268x_convert_raw_to_q31(struct icm4268x_cfg *cfg, enum sensor_channel ch
 	if (shift < 0) {
 		intermediate =
 			intermediate * ((int64_t)INT32_MAX + 1) * (1 << -shift) / INT64_C(1000000);
-	} else if (shift > 0) {
+	} else {
 		intermediate =
 			intermediate * ((int64_t)INT32_MAX + 1) / ((1 << shift) * INT64_C(1000000));
 	}
@@ -513,6 +513,8 @@ static int icm4268x_fifo_decode(const uint8_t *buffer, struct sensor_chan_spec c
 				buffer = frame_end;
 				continue;
 			}
+		} else {
+			CODE_UNREACHABLE;
 		}
 		buffer = frame_end;
 		*fit = (uintptr_t)frame_end;

drivers/sensor/tdk/icm4268x/icm4268x_emul.c

@@ -24,8 +24,16 @@ struct icm4268x_emul_data {
 };
 
 struct icm4268x_emul_cfg {
+#if defined(CONFIG_CPP)
+       /* Empty struct has size 0 in C, size 1 in C++. Force them to be the same. */
+	uint8_t unused_cpp_size_compatibility;
+#endif
 };
 
+#if defined(CONFIG_CPP)
+BUILD_ASSERT(sizeof(struct icm4268x_emul_cfg) >= 1);
+#endif
+
 void icm4268x_emul_set_reg(const struct emul *target, uint8_t reg_addr, const uint8_t *val,
 			   size_t count)
 {
@@ -47,17 +55,13 @@ static void icm4268x_emul_handle_write(const struct emul *target, uint8_t regn,
 {
 	struct icm4268x_emul_data *data = target->data;
 
-	switch (regn) {
-	case REG_DEVICE_CONFIG:
-		if (FIELD_GET(BIT_SOFT_RESET_CONFIG, value) == 1) {
-			/* Perform a soft reset */
-			memset(data->reg, 0, NUM_REGS);
-			/* Initialized the who-am-i register */
-			data->reg[REG_WHO_AM_I] = WHO_AM_I_ICM42688;
-			/* Set the bit for the reset being done */
-			data->reg[REG_INT_STATUS] |= BIT_RESET_DONE_INT;
-		}
-		break;
+	if (regn == REG_DEVICE_CONFIG && FIELD_GET(BIT_SOFT_RESET_CONFIG, value) == 1) {
+		/* Perform a soft reset */
+		memset(data->reg, 0, NUM_REGS);
+		/* Initialized the who-am-i register */
+		data->reg[REG_WHO_AM_I] = WHO_AM_I_ICM42688;
+		/* Set the bit for the reset being done */
+		data->reg[REG_INT_STATUS] |= BIT_RESET_DONE_INT;
 	}
 }