counter: Return error code on invalid modes

Only a select set of modes (function, action, etc.) are valid for a given device configuration. This patch ensures that invalid modes result in a return -EINVAL. Such a situation should never occur in reality, but it's good to define a default switch case for the sake of making the intent of the code clear. Cc: Kamel Bouhara <[email protected]> Cc: Maxime Coquelin <[email protected]> Cc: Alexandre Torgue <[email protected]> Acked-by: David Lechner <[email protected]> Acked-by: Syed Nayyar Waris <[email protected]> Reviewed-by: Fabrice Gasnier <[email protected]> Signed-off-by: William Breathitt Gray <[email protected]> Link: https://lore.kernel.org/r/7af82d4e39610da11edce0ee370285fe1cb1eac8.1627990337.git.vilhelm.gray@gmail.com Signed-off-by: Jonathan Cameron <[email protected]>
mrcsosa · Aug 9, 2021 · b11eed1 · b11eed1
1 parent 728246e
commit b11eed1
Show file tree

Hide file tree

Showing 4 changed files with 42 additions and 21 deletions.
diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
@@ -273,6 +273,10 @@ static int quad8_function_set(struct counter_device *counter,
 			*scale = 2;
 			mode_cfg |= QUAD8_CMR_QUADRATURE_X4;
 			break;
+		default:
+			/* should never reach this path */
+			mutex_unlock(&priv->lock);
+			return -EINVAL;
 		}
 	}
 
@@ -349,7 +353,7 @@ static int quad8_action_get(struct counter_device *counter,
 	case QUAD8_COUNT_FUNCTION_PULSE_DIRECTION:
 		if (synapse->signal->id == signal_a_id)
 			*action = QUAD8_SYNAPSE_ACTION_RISING_EDGE;
-		break;
+		return 0;
 	case QUAD8_COUNT_FUNCTION_QUADRATURE_X1:
 		if (synapse->signal->id == signal_a_id) {
 			quad8_direction_get(counter, count, &direction);
@@ -359,17 +363,18 @@ static int quad8_action_get(struct counter_device *counter,
 			else
 				*action = QUAD8_SYNAPSE_ACTION_FALLING_EDGE;
 		}
-		break;
+		return 0;
 	case QUAD8_COUNT_FUNCTION_QUADRATURE_X2:
 		if (synapse->signal->id == signal_a_id)
 			*action = QUAD8_SYNAPSE_ACTION_BOTH_EDGES;
-		break;
+		return 0;
 	case QUAD8_COUNT_FUNCTION_QUADRATURE_X4:
 		*action = QUAD8_SYNAPSE_ACTION_BOTH_EDGES;
-		break;
+		return 0;
+	default:
+		/* should never reach this path */
+		return -EINVAL;
 	}
-
-	return 0;
 }
 
 static const struct counter_ops quad8_ops = {
@@ -529,6 +534,9 @@ static int quad8_count_mode_set(struct counter_device *counter,
 	case COUNTER_COUNT_MODE_MODULO_N:
 		cnt_mode = 3;
 		break;
+	default:
+		/* should never reach this path */
+		return -EINVAL;
 	}
 
 	mutex_lock(&priv->lock);

diff --git a/drivers/counter/microchip-tcb-capture.c b/drivers/counter/microchip-tcb-capture.c
@@ -133,6 +133,9 @@ static int mchp_tc_count_function_set(struct counter_device *counter,
 		bmr |= ATMEL_TC_QDEN | ATMEL_TC_POSEN;
 		cmr |= ATMEL_TC_ETRGEDG_RISING | ATMEL_TC_ABETRG | ATMEL_TC_XC0;
 		break;
+	default:
+		/* should never reach this path */
+		return -EINVAL;
 	}
 
 	regmap_write(priv->regmap, ATMEL_TC_BMR, bmr);
@@ -226,6 +229,9 @@ static int mchp_tc_count_action_set(struct counter_device *counter,
 	case MCHP_TC_SYNAPSE_ACTION_BOTH_EDGE:
 		edge = ATMEL_TC_ETRGEDG_BOTH;
 		break;
+	default:
+		/* should never reach this path */
+		return -EINVAL;
 	}
 
 	return regmap_write_bits(priv->regmap,

diff --git a/drivers/counter/stm32-lptimer-cnt.c b/drivers/counter/stm32-lptimer-cnt.c
@@ -206,9 +206,10 @@ static int stm32_lptim_cnt_function_set(struct counter_device *counter,
 		priv->quadrature_mode = 1;
 		priv->polarity = STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES;
 		return 0;
+	default:
+		/* should never reach this path */
+		return -EINVAL;
 	}
-
-	return -EINVAL;
 }
 
 static ssize_t stm32_lptim_cnt_enable_read(struct counter_device *counter,
@@ -326,9 +327,10 @@ static int stm32_lptim_cnt_action_get(struct counter_device *counter,
 	case STM32_LPTIM_ENCODER_BOTH_EDGE:
 		*action = priv->polarity;
 		return 0;
+	default:
+		/* should never reach this path */
+		return -EINVAL;
 	}
-
-	return -EINVAL;
 }
 
 static int stm32_lptim_cnt_action_set(struct counter_device *counter,

diff --git a/drivers/counter/ti-eqep.c b/drivers/counter/ti-eqep.c
@@ -157,20 +157,22 @@ static int ti_eqep_action_get(struct counter_device *counter,
 		 * QEPA and QEPB trigger QCLK.
 		 */
 		*action = TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES;
-		break;
+		return 0;
 	case TI_EQEP_COUNT_FUNC_DIR_COUNT:
 		/* In direction-count mode only rising edge of QEPA is counted
 		 * and QEPB gives direction.
 		 */
 		switch (synapse->signal->id) {
 		case TI_EQEP_SIGNAL_QEPA:
 			*action = TI_EQEP_SYNAPSE_ACTION_RISING_EDGE;
-			break;
-		default:
+			return 0;
+		case TI_EQEP_SIGNAL_QEPB:
 			*action = TI_EQEP_SYNAPSE_ACTION_NONE;
-			break;
+			return 0;
+		default:
+			/* should never reach this path */
+			return -EINVAL;
 		}
-		break;
 	case TI_EQEP_COUNT_FUNC_UP_COUNT:
 	case TI_EQEP_COUNT_FUNC_DOWN_COUNT:
 		/* In up/down-count modes only QEPA is counted and QEPB is not
@@ -186,15 +188,18 @@ static int ti_eqep_action_get(struct counter_device *counter,
 				*action = TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES;
 			else
 				*action = TI_EQEP_SYNAPSE_ACTION_RISING_EDGE;
-			break;
-		default:
+			return 0;
+		case TI_EQEP_SIGNAL_QEPB:
 			*action = TI_EQEP_SYNAPSE_ACTION_NONE;
-			break;
+			return 0;
+		default:
+			/* should never reach this path */
+			return -EINVAL;
 		}
-		break;
+	default:
+		/* should never reach this path */
+		return -EINVAL;
 	}
-
-	return 0;
 }
 
 static const struct counter_ops ti_eqep_counter_ops = {