[PATCH v10 00/33] Introduce the Counter character device interface

@@ -57,6 +57,7 @@ Description:
 What:		/sys/bus/counter/devices/counterX/countY/count_mode_available
 What:		/sys/bus/counter/devices/counterX/countY/error_noise_available
 What:		/sys/bus/counter/devices/counterX/countY/function_available
+What:		/sys/bus/counter/devices/counterX/countY/prescaler_available
 What:		/sys/bus/counter/devices/counterX/countY/signalZ_action_available
 KernelVersion:	5.2
 Contact:	linux-iio@vger.kernel.org

@@ -154,6 +155,15 @@ Description:
 		Count Y. If possible, this should match the name of the
 		respective channel as it appears in the device datasheet.
 
+What:		/sys/bus/counter/devices/counterX/countY/prescaler
+KernelVersion:	5.2
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Configure the prescaler value associated with Count Y.
+		On the FlexTimer, the counter clock source passes through a
+		prescaler (i.e. a counter). This acts like a clock
+		divider.
+
 What:		/sys/bus/counter/devices/counterX/countY/preset
 KernelVersion:	5.2
 Contact:	linux-iio@vger.kernel.org

@@ -215,11 +225,45 @@ Description:
 		Read-only attribute that indicates the total number of Signals
 		belonging to the Counter.
 
-What:		/sys/bus/counter/devices/counterX/signalY/signal
+What:		/sys/bus/counter/devices/counterX/signalY/cable_fault
+KernelVersion:	5.7
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Read-only attribute that indicates whether a differential
+		encoder cable fault (not connected or loose wires) is detected
+		for the respective channel of Signal Y. Valid attribute values
+		are boolean. Detection must first be enabled via the
+		corresponding cable_fault_enable attribute.
+
+What:		/sys/bus/counter/devices/counterX/signalY/cable_fault_enable
+KernelVersion:	5.7
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Whether detection of differential encoder cable faults for the
+		respective channel of Signal Y is enabled. Valid attribute
+		values are boolean.
+
+What:		/sys/bus/counter/devices/counterX/signalY/filter_clock_prescaler
+KernelVersion:	5.7
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Filter clock factor for input Signal Y. This prescaler value
+		affects the inputs of both quadrature pair signals.
+
+What:		/sys/bus/counter/devices/counterX/signalY/index_polarity
 KernelVersion:	5.2
 Contact:	linux-iio@vger.kernel.org
 Description:
-		Signal data of Signal Y represented as a string.
+		Active level of index input Signal Y; irrelevant in
+		non-synchronous load mode.
+
+What:		/sys/bus/counter/devices/counterX/signalY/index_polarity_available
+What:		/sys/bus/counter/devices/counterX/signalY/synchronous_mode_available
+KernelVersion:	5.2
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Discrete set of available values for the respective Signal Y
+		configuration are listed in this file.
 
 What:		/sys/bus/counter/devices/counterX/signalY/name
 KernelVersion:	5.2

@@ -228,3 +272,31 @@ Description:
 		Read-only attribute that indicates the device-specific name of
 		Signal Y. If possible, this should match the name of the
 		respective signal as it appears in the device datasheet.
+
+What:		/sys/bus/counter/devices/counterX/signalY/signal
+KernelVersion:	5.2
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Signal data of Signal Y represented as a string.
+
+What:		/sys/bus/counter/devices/counterX/signalY/synchronous_mode
+KernelVersion:	5.2
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Configure the counter associated with Signal Y for
+		non-synchronous or synchronous load mode. Synchronous load mode
+		cannot be selected in non-quadrature (Pulse-Direction) clock
+		mode.
+
+		non-synchronous:
+			A logic low level is the active level at this index
+			input. The index function (as enabled via preset_enable)
+			is performed directly on the active level of the index
+			input.
+
+		synchronous:
+			Intended for interfacing with encoder Index output in
+			quadrature clock mode. The active level is configured
+			via index_polarity. The index function (as enabled via
+			preset_enable) is performed synchronously with the
+			quadrature clock on the active level of the index input.

@@ -1,61 +0,0 @@
-What:		/sys/bus/counter/devices/counterX/signalY/cable_fault
-KernelVersion:	5.7
-Contact:	linux-iio@vger.kernel.org
-Description:
-		Read-only attribute that indicates whether a differential
-		encoder cable fault (not connected or loose wires) is detected
-		for the respective channel of Signal Y. Valid attribute values
-		are boolean. Detection must first be enabled via the
-		corresponding cable_fault_enable attribute.
-
-What:		/sys/bus/counter/devices/counterX/signalY/cable_fault_enable
-KernelVersion:	5.7
-Contact:	linux-iio@vger.kernel.org
-Description:
-		Whether detection of differential encoder cable faults for the
-		respective channel of Signal Y is enabled. Valid attribute
-		values are boolean.
-
-What:		/sys/bus/counter/devices/counterX/signalY/filter_clock_prescaler
-KernelVersion:	5.7
-Contact:	linux-iio@vger.kernel.org
-Description:
-		Filter clock factor for input Signal Y. This prescaler value
-		affects the inputs of both quadrature pair signals.
-
-What:		/sys/bus/counter/devices/counterX/signalY/index_polarity
-KernelVersion:	5.2
-Contact:	linux-iio@vger.kernel.org
-Description:
-		Active level of index input Signal Y; irrelevant in
-		non-synchronous load mode.
-
-What:		/sys/bus/counter/devices/counterX/signalY/index_polarity_available
-What:		/sys/bus/counter/devices/counterX/signalY/synchronous_mode_available
-KernelVersion:	5.2
-Contact:	linux-iio@vger.kernel.org
-Description:
-		Discrete set of available values for the respective Signal Y
-		configuration are listed in this file.
-
-What:		/sys/bus/counter/devices/counterX/signalY/synchronous_mode
-KernelVersion:	5.2
-Contact:	linux-iio@vger.kernel.org
-Description:
-		Configure the counter associated with Signal Y for
-		non-synchronous or synchronous load mode. Synchronous load mode
-		cannot be selected in non-quadrature (Pulse-Direction) clock
-		mode.
-
-		non-synchronous:
-			A logic low level is the active level at this index
-			input. The index function (as enabled via preset_enable)
-			is performed directly on the active level of the index
-			input.
-
-		synchronous:
-			Intended for interfacing with encoder Index output in
-			quadrature clock mode. The active level is configured
-			via index_polarity. The index function (as enabled via
-			preset_enable) is performed synchronously with the
-			quadrature clock on the active level of the index input.

@@ -1,16 +0,0 @@
-What:		/sys/bus/counter/devices/counterX/countY/prescaler_available
-KernelVersion:	5.2
-Contact:	linux-iio@vger.kernel.org
-Description:
-		Discrete set of available values for the respective Count Y
-		configuration are listed in this file. Values are delimited by
-		newline characters.
-
-What:		/sys/bus/counter/devices/counterX/countY/prescaler
-KernelVersion:	5.2
-Contact:	linux-iio@vger.kernel.org
-Description:
-		Configure the prescaler value associated with Count Y.
-		On the FlexTimer, the counter clock source passes through a
-		prescaler (i.e. a counter). This acts like a clock
-		divider.

@@ -299,7 +299,6 @@ M:	William Breathitt Gray <vilhelm.gray@gmail.com>
 M:	Syed Nayyar Waris <syednwaris@gmail.com>
 L:	linux-iio@vger.kernel.org
 S:	Maintained
-F:	Documentation/ABI/testing/sysfs-bus-counter-104-quad-8
 F:	drivers/counter/104-quad-8.c
 
 ACCES PCI-IDIO-16 GPIO DRIVER

@@ -4578,7 +4577,7 @@ COUNTER SUBSYSTEM
 M:	William Breathitt Gray <vilhelm.gray@gmail.com>
 L:	linux-iio@vger.kernel.org
 S:	Maintained
-F:	Documentation/ABI/testing/sysfs-bus-counter*
+F:	Documentation/ABI/testing/sysfs-bus-counter
 F:	Documentation/driver-api/generic-counter.rst
 F:	drivers/counter/
 F:	include/linux/counter.h

@@ -6960,7 +6959,6 @@ FLEXTIMER FTM-QUADDEC DRIVER
 M:	Patrick Havelange <patrick.havelange@essensium.com>
 L:	linux-iio@vger.kernel.org
 S:	Maintained
-F:	Documentation/ABI/testing/sysfs-bus-counter-ftm-quaddec
 F:	Documentation/devicetree/bindings/counter/ftm-quaddec.txt
 F:	drivers/counter/ftm-quaddec.c
 

@@ -307,7 +307,7 @@ Determining the type of extension to create is a matter of scope.
 
 * Device extensions are attributes that expose information/control
   non-specific to a particular Count or Signal. This is where you would
-  put your global features or other miscellanous functionality.
+  put your global features or other miscellaneous functionality.
 
   For example, if your device has an overtemp sensor, you can report the
   chip overheated via a device extension called "error_overtemp":

@@ -1082,7 +1082,6 @@ static int quad8_probe(struct device *dev, unsigned int id)
 	/* Enable all counters */
 	outb(QUAD8_CHAN_OP_ENABLE_COUNTERS, base[id] + QUAD8_REG_CHAN_OP);
 
-	/* Register Counter device */
 	return devm_counter_register(dev, &priv->counter);
 }
 

@@ -714,13 +714,14 @@ static ssize_t quad8_count_ceiling_write(struct counter_device *counter,
 	switch (priv->count_mode[count->id]) {
 	case 1:
 	case 3:
+		mutex_unlock(&priv->lock);
 		quad8_preset_register_set(priv, count->id, ceiling);
-		break;
+		return len;
 	}
 
 	mutex_unlock(&priv->lock);
 
-	return len;
+	return -EINVAL;
 }
 
 static ssize_t quad8_count_preset_enable_read(struct counter_device *counter,

@@ -21,7 +21,7 @@
 
 static unsigned int base[max_num_isa_dev(QUAD8_EXTENT)];
 static unsigned int num_quad8;
-module_param_array(base, uint, &num_quad8, 0);
+module_param_hw_array(base, uint, ioport, &num_quad8, 0);
 MODULE_PARM_DESC(base, "ACCES 104-QUAD-8 base addresses");
 
 #define QUAD8_NUM_COUNTERS 8

@@ -632,8 +632,8 @@ static ssize_t quad8_count_preset_read(struct counter_device *counter,
 	return sprintf(buf, "%u\n", priv->preset[count->id]);
 }
 
-static void quad8_preset_register_set(struct quad8 *priv, int id,
-				      unsigned int preset)
+static void quad8_preset_register_set(struct quad8 *const priv, const int id,
+				      const unsigned int preset)
 {
 	const unsigned int base_offset = priv->base + 2 * id;
 	int i;

@@ -193,7 +193,7 @@ enum quad8_count_function {
 	QUAD8_COUNT_FUNCTION_QUADRATURE_X4
 };
 
-static enum counter_count_function quad8_count_functions_list[] = {
+static const enum counter_count_function quad8_count_functions_list[] = {
 	[QUAD8_COUNT_FUNCTION_PULSE_DIRECTION] = COUNTER_COUNT_FUNCTION_PULSE_DIRECTION,
 	[QUAD8_COUNT_FUNCTION_QUADRATURE_X1] = COUNTER_COUNT_FUNCTION_QUADRATURE_X1_A,
 	[QUAD8_COUNT_FUNCTION_QUADRATURE_X2] = COUNTER_COUNT_FUNCTION_QUADRATURE_X2_A,

@@ -112,7 +112,7 @@ static int interrupt_cnt_write(struct counter_device *counter,
 	return 0;
 }
 
-static enum counter_count_function interrupt_cnt_functions[] = {
+static const enum counter_count_function interrupt_cnt_functions[] = {
 	COUNTER_COUNT_FUNCTION_INCREASE,
 };
 

@@ -37,7 +37,7 @@ enum mchp_tc_count_function {
 	MCHP_TC_FUNCTION_QUADRATURE,
 };
 
-static enum counter_count_function mchp_tc_count_functions[] = {
+static const enum counter_count_function mchp_tc_count_functions[] = {
 	[MCHP_TC_FUNCTION_INCREASE] = COUNTER_COUNT_FUNCTION_INCREASE,
 	[MCHP_TC_FUNCTION_QUADRATURE] = COUNTER_COUNT_FUNCTION_QUADRATURE_X4,
 };

@@ -134,7 +134,7 @@ enum stm32_lptim_cnt_function {
 	STM32_LPTIM_ENCODER_BOTH_EDGE,
 };
 
-static enum counter_count_function stm32_lptim_cnt_functions[] = {
+static const enum counter_count_function stm32_lptim_cnt_functions[] = {
 	[STM32_LPTIM_COUNTER_INCREASE] = COUNTER_COUNT_FUNCTION_INCREASE,
 	[STM32_LPTIM_ENCODER_BOTH_EDGE] = COUNTER_COUNT_FUNCTION_QUADRATURE_X4,
 };

@@ -305,12 +305,12 @@ enum quad8_synapse_action {
 	QUAD8_SYNAPSE_ACTION_BOTH_EDGES
 };
 
-static enum counter_synapse_action quad8_index_actions_list[] = {
+static const enum counter_synapse_action quad8_index_actions_list[] = {
 	[QUAD8_SYNAPSE_ACTION_NONE] = COUNTER_SYNAPSE_ACTION_NONE,
 	[QUAD8_SYNAPSE_ACTION_RISING_EDGE] = COUNTER_SYNAPSE_ACTION_RISING_EDGE
 };
 
-static enum counter_synapse_action quad8_synapse_actions_list[] = {
+static const enum counter_synapse_action quad8_synapse_actions_list[] = {
 	[QUAD8_SYNAPSE_ACTION_NONE] = COUNTER_SYNAPSE_ACTION_NONE,
 	[QUAD8_SYNAPSE_ACTION_RISING_EDGE] = COUNTER_SYNAPSE_ACTION_RISING_EDGE,
 	[QUAD8_SYNAPSE_ACTION_FALLING_EDGE] = COUNTER_SYNAPSE_ACTION_FALLING_EDGE,

@@ -162,7 +162,7 @@ enum ftm_quaddec_synapse_action {
 	FTM_QUADDEC_SYNAPSE_ACTION_BOTH_EDGES,
 };
 
-static enum counter_synapse_action ftm_quaddec_synapse_actions[] = {
+static const enum counter_synapse_action ftm_quaddec_synapse_actions[] = {
 	[FTM_QUADDEC_SYNAPSE_ACTION_BOTH_EDGES] =
 	COUNTER_SYNAPSE_ACTION_BOTH_EDGES
 };

@@ -50,7 +50,7 @@ enum stm32_count_function {
 	STM32_COUNT_ENCODER_MODE_3,
 };
 
-static enum counter_count_function stm32_count_functions[] = {
+static const enum counter_count_function stm32_count_functions[] = {
 	[STM32_COUNT_SLAVE_MODE_DISABLED] = COUNTER_COUNT_FUNCTION_INCREASE,
 	[STM32_COUNT_ENCODER_MODE_1] = COUNTER_COUNT_FUNCTION_QUADRATURE_X2_A,
 	[STM32_COUNT_ENCODER_MODE_2] = COUNTER_COUNT_FUNCTION_QUADRATURE_X2_B,

@@ -77,7 +77,7 @@ static const struct counter_count_ext interrupt_cnt_ext[] = {
 	},
 };
 
-static enum counter_synapse_action interrupt_cnt_synapse_actionss[] = {
+static const enum counter_synapse_action interrupt_cnt_synapse_actionss[] = {
 	COUNTER_SYNAPSE_ACTION_RISING_EDGE,
 };
 

@@ -49,7 +49,7 @@ enum mchp_tc_synapse_action {
 	MCHP_TC_SYNAPSE_ACTION_BOTH_EDGE
 };
 
-static enum counter_synapse_action mchp_tc_synapse_actions[] = {
+static const enum counter_synapse_action mchp_tc_synapse_actions[] = {
 	[MCHP_TC_SYNAPSE_ACTION_NONE] = COUNTER_SYNAPSE_ACTION_NONE,
 	[MCHP_TC_SYNAPSE_ACTION_RISING_EDGE] = COUNTER_SYNAPSE_ACTION_RISING_EDGE,
 	[MCHP_TC_SYNAPSE_ACTION_FALLING_EDGE] = COUNTER_SYNAPSE_ACTION_FALLING_EDGE,

@@ -146,7 +146,7 @@ enum stm32_lptim_synapse_action {
 	STM32_LPTIM_SYNAPSE_ACTION_NONE,
 };
 
-static enum counter_synapse_action stm32_lptim_cnt_synapse_actions[] = {
+static const enum counter_synapse_action stm32_lptim_cnt_synapse_actions[] = {
 	/* Index must match with stm32_lptim_cnt_polarity[] (priv->polarity) */
 	[STM32_LPTIM_SYNAPSE_ACTION_RISING_EDGE] = COUNTER_SYNAPSE_ACTION_RISING_EDGE,
 	[STM32_LPTIM_SYNAPSE_ACTION_FALLING_EDGE] = COUNTER_SYNAPSE_ACTION_FALLING_EDGE,

@@ -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);

@@ -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,

@@ -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,

@@ -157,44 +157,39 @@ 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:
+		if (synapse->signal->id == TI_EQEP_SIGNAL_QEPB)
 			*action = TI_EQEP_SYNAPSE_ACTION_NONE;
-			break;
-		}
-		break;
+		else
+			*action = TI_EQEP_SYNAPSE_ACTION_RISING_EDGE;
+		return 0;
 	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
 		 * used.
 		 */
-		switch (synapse->signal->id) {
-		case TI_EQEP_SIGNAL_QEPA:
-			err = regmap_read(priv->regmap16, QDECCTL, &qdecctl);
-			if (err)
-				return err;
-
-			if (qdecctl & QDECCTL_XCR)
-				*action = TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES;
-			else
-				*action = TI_EQEP_SYNAPSE_ACTION_RISING_EDGE;
-			break;
-		default:
+		if (synapse->signal->id == TI_EQEP_SIGNAL_QEPB) {
 			*action = TI_EQEP_SYNAPSE_ACTION_NONE;
-			break;
+			return 0;
 		}
-		break;
-	}
 
-	return 0;
+		err = regmap_read(priv->regmap16, QDECCTL, &qdecctl);
+		if (err)
+			return err;
+
+		if (qdecctl & QDECCTL_XCR)
+			*action = TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES;
+		else
+			*action = TI_EQEP_SYNAPSE_ACTION_RISING_EDGE;
+		return 0;
+	default:
+		/* should never reach this path */
+		return -EINVAL;
+	}
 }
 
 static const struct counter_ops ti_eqep_counter_ops = {

@@ -267,7 +267,7 @@ enum stm32_synapse_action {
 	STM32_SYNAPSE_ACTION_BOTH_EDGES
 };
 
-static enum counter_synapse_action stm32_synapse_actions[] = {
+static const enum counter_synapse_action stm32_synapse_actions[] = {
 	[STM32_SYNAPSE_ACTION_NONE] = COUNTER_SYNAPSE_ACTION_NONE,
 	[STM32_SYNAPSE_ACTION_BOTH_EDGES] = COUNTER_SYNAPSE_ACTION_BOTH_EDGES
 };

@@ -97,7 +97,8 @@ struct quad8 {
 #define QUAD8_CMR_QUADRATURE_X4 0x18
 
 static int quad8_signal_read(struct counter_device *counter,
-	struct counter_signal *signal, enum counter_signal_value *val)
+			     struct counter_signal *signal,
+			     enum counter_signal_level *level)
 {
 	const struct quad8 *const priv = counter->priv;
 	unsigned int state;

@@ -109,7 +110,7 @@ static int quad8_signal_read(struct counter_device *counter,
 	state = inb(priv->base + QUAD8_REG_INDEX_INPUT_LEVELS)
 		& BIT(signal->id - 16);
 
-	*val = (state) ? COUNTER_SIGNAL_HIGH : COUNTER_SIGNAL_LOW;
+	*level = (state) ? COUNTER_SIGNAL_LEVEL_HIGH : COUNTER_SIGNAL_LEVEL_LOW;
 
 	return 0;
 }

@@ -289,9 +289,9 @@ struct counter_signal_unit {
 	struct counter_signal *signal;
 };
 
-static const char *const counter_signal_value_str[] = {
-	[COUNTER_SIGNAL_LOW] = "low",
-	[COUNTER_SIGNAL_HIGH] = "high"
+static const char *const counter_signal_level_str[] = {
+	[COUNTER_SIGNAL_LEVEL_LOW] = "low",
+	[COUNTER_SIGNAL_LEVEL_HIGH] = "high"
 };
 
 static ssize_t counter_signal_show(struct device *dev,

@@ -302,13 +302,13 @@ static ssize_t counter_signal_show(struct device *dev,
 	const struct counter_signal_unit *const component = devattr->component;
 	struct counter_signal *const signal = component->signal;
 	int err;
-	enum counter_signal_value val;
+	enum counter_signal_level level;
 
-	err = counter->ops->signal_read(counter, signal, &val);
+	err = counter->ops->signal_read(counter, signal, &level);
 	if (err)
 		return err;
 
-	return sprintf(buf, "%s\n", counter_signal_value_str[val]);
+	return sprintf(buf, "%s\n", counter_signal_level_str[level]);
 }
 
 struct counter_name_unit {

@@ -130,7 +130,7 @@ static int interrupt_cnt_function_get(struct counter_device *counter,
 
 static int interrupt_cnt_signal_read(struct counter_device *counter,
 				     struct counter_signal *signal,
-				     enum counter_signal_value *val)
+				     enum counter_signal_level *level)
 {
 	struct interrupt_cnt_priv *priv = counter->priv;
 	int ret;

@@ -142,7 +142,7 @@ static int interrupt_cnt_signal_read(struct counter_device *counter,
 	if (ret < 0)
 		return ret;
 
-	*val = ret ? COUNTER_SIGNAL_HIGH : COUNTER_SIGNAL_LOW;
+	*level = ret ? COUNTER_SIGNAL_LEVEL_HIGH : COUNTER_SIGNAL_LEVEL_LOW;
 
 	return 0;
 }

@@ -158,7 +158,7 @@ static int mchp_tc_count_function_set(struct counter_device *counter,
 
 static int mchp_tc_count_signal_read(struct counter_device *counter,
 				     struct counter_signal *signal,
-				     enum counter_signal_value *val)
+				     enum counter_signal_level *lvl)
 {
 	struct mchp_tc_data *const priv = counter->priv;
 	bool sigstatus;

@@ -171,7 +171,7 @@ static int mchp_tc_count_signal_read(struct counter_device *counter,
 	else
 		sigstatus = (sr & ATMEL_TC_MTIOA);
 
-	*val = sigstatus ? COUNTER_SIGNAL_HIGH : COUNTER_SIGNAL_LOW;
+	*lvl = sigstatus ? COUNTER_SIGNAL_LEVEL_HIGH : COUNTER_SIGNAL_LEVEL_LOW;
 
 	return 0;
 }

@@ -290,16 +290,16 @@ struct counter_device_state {
 	const struct attribute_group **groups;
 };
 
-enum counter_signal_value {
-	COUNTER_SIGNAL_LOW = 0,
-	COUNTER_SIGNAL_HIGH
+enum counter_signal_level {
+	COUNTER_SIGNAL_LEVEL_LOW,
+	COUNTER_SIGNAL_LEVEL_HIGH,
 };
 
 /**
  * struct counter_ops - Callbacks from driver
  * @signal_read:	optional read callback for Signal attribute. The read
- *			value of the respective Signal should be passed back via
- *			the val parameter.
+ *			level of the respective Signal should be passed back via
+ *			the level parameter.
  * @count_read:		optional read callback for Count attribute. The read
  *			value of the respective Count should be passed back via
  *			the val parameter.

@@ -324,7 +324,7 @@ enum counter_signal_value {
 struct counter_ops {
 	int (*signal_read)(struct counter_device *counter,
 			   struct counter_signal *signal,
-			   enum counter_signal_value *val);
+			   enum counter_signal_level *level);
 	int (*count_read)(struct counter_device *counter,
 			  struct counter_count *count, unsigned long *val);
 	int (*count_write)(struct counter_device *counter,

@@ -154,7 +154,7 @@ static int quad8_count_write(struct counter_device *counter,
 
 	/* Only 24-bit values are supported */
 	if (val > 0xFFFFFF)
-		return -EINVAL;
+		return -ERANGE;
 
 	mutex_lock(&priv->lock);
 

@@ -669,7 +669,7 @@ static ssize_t quad8_count_preset_write(struct counter_device *counter,
 
 	/* Only 24-bit values are supported */
 	if (preset > 0xFFFFFF)
-		return -EINVAL;
+		return -ERANGE;
 
 	mutex_lock(&priv->lock);
 

@@ -714,7 +714,7 @@ static ssize_t quad8_count_ceiling_write(struct counter_device *counter,
 
 	/* Only 24-bit values are supported */
 	if (ceiling > 0xFFFFFF)
-		return -EINVAL;
+		return -ERANGE;
 
 	mutex_lock(&priv->lock);
 

@@ -107,6 +107,9 @@ static int interrupt_cnt_write(struct counter_device *counter,
 {
 	struct interrupt_cnt_priv *priv = counter->priv;
 
+	if (val != (typeof(priv->count.counter))val)
+		return -ERANGE;
+
 	atomic_set(&priv->count, val);
 
 	return 0;

@@ -283,7 +283,7 @@ static ssize_t stm32_lptim_cnt_ceiling_write(struct counter_device *counter,
 		return ret;
 
 	if (ceiling > STM32_LPTIM_MAX_ARR)
-		return -EINVAL;
+		return -ERANGE;
 
 	priv->ceiling = ceiling;
 

@@ -194,11 +194,11 @@ enum quad8_count_function {
 	QUAD8_COUNT_FUNCTION_QUADRATURE_X4
 };
 
-static const enum counter_count_function quad8_count_functions_list[] = {
-	[QUAD8_COUNT_FUNCTION_PULSE_DIRECTION] = COUNTER_COUNT_FUNCTION_PULSE_DIRECTION,
-	[QUAD8_COUNT_FUNCTION_QUADRATURE_X1] = COUNTER_COUNT_FUNCTION_QUADRATURE_X1_A,
-	[QUAD8_COUNT_FUNCTION_QUADRATURE_X2] = COUNTER_COUNT_FUNCTION_QUADRATURE_X2_A,
-	[QUAD8_COUNT_FUNCTION_QUADRATURE_X4] = COUNTER_COUNT_FUNCTION_QUADRATURE_X4
+static const enum counter_function quad8_count_functions_list[] = {
+	[QUAD8_COUNT_FUNCTION_PULSE_DIRECTION] = COUNTER_FUNCTION_PULSE_DIRECTION,
+	[QUAD8_COUNT_FUNCTION_QUADRATURE_X1] = COUNTER_FUNCTION_QUADRATURE_X1_A,
+	[QUAD8_COUNT_FUNCTION_QUADRATURE_X2] = COUNTER_FUNCTION_QUADRATURE_X2_A,
+	[QUAD8_COUNT_FUNCTION_QUADRATURE_X4] = COUNTER_FUNCTION_QUADRATURE_X4
 };
 
 static int quad8_function_get(struct counter_device *counter,

@@ -744,15 +744,15 @@ static ssize_t counter_count_store(struct device *dev,
 	return len;
 }
 
-static const char *const counter_count_function_str[] = {
-	[COUNTER_COUNT_FUNCTION_INCREASE] = "increase",
-	[COUNTER_COUNT_FUNCTION_DECREASE] = "decrease",
-	[COUNTER_COUNT_FUNCTION_PULSE_DIRECTION] = "pulse-direction",
-	[COUNTER_COUNT_FUNCTION_QUADRATURE_X1_A] = "quadrature x1 a",
-	[COUNTER_COUNT_FUNCTION_QUADRATURE_X1_B] = "quadrature x1 b",
-	[COUNTER_COUNT_FUNCTION_QUADRATURE_X2_A] = "quadrature x2 a",
-	[COUNTER_COUNT_FUNCTION_QUADRATURE_X2_B] = "quadrature x2 b",
-	[COUNTER_COUNT_FUNCTION_QUADRATURE_X4] = "quadrature x4"
+static const char *const counter_function_str[] = {
+	[COUNTER_FUNCTION_INCREASE] = "increase",
+	[COUNTER_FUNCTION_DECREASE] = "decrease",
+	[COUNTER_FUNCTION_PULSE_DIRECTION] = "pulse-direction",
+	[COUNTER_FUNCTION_QUADRATURE_X1_A] = "quadrature x1 a",
+	[COUNTER_FUNCTION_QUADRATURE_X1_B] = "quadrature x1 b",
+	[COUNTER_FUNCTION_QUADRATURE_X2_A] = "quadrature x2 a",
+	[COUNTER_FUNCTION_QUADRATURE_X2_B] = "quadrature x2 b",
+	[COUNTER_FUNCTION_QUADRATURE_X4] = "quadrature x4"
 };
 
 static ssize_t counter_function_show(struct device *dev,

@@ -764,7 +764,7 @@ static ssize_t counter_function_show(struct device *dev,
 	const struct counter_count_unit *const component = devattr->component;
 	struct counter_count *const count = component->count;
 	size_t func_index;
-	enum counter_count_function function;
+	enum counter_function function;
 
 	err = counter->ops->function_get(counter, count, &func_index);
 	if (err)

@@ -773,7 +773,7 @@ static ssize_t counter_function_show(struct device *dev,
 	count->function = func_index;
 
 	function = count->functions_list[func_index];
-	return sprintf(buf, "%s\n", counter_count_function_str[function]);
+	return sprintf(buf, "%s\n", counter_function_str[function]);
 }
 
 static ssize_t counter_function_store(struct device *dev,

@@ -785,14 +785,14 @@ static ssize_t counter_function_store(struct device *dev,
 	struct counter_count *const count = component->count;
 	const size_t num_functions = count->num_functions;
 	size_t func_index;
-	enum counter_count_function function;
+	enum counter_function function;
 	int err;
 	struct counter_device *const counter = dev_get_drvdata(dev);
 
 	/* Find requested Count function mode */
 	for (func_index = 0; func_index < num_functions; func_index++) {
 		function = count->functions_list[func_index];
-		if (sysfs_streq(buf, counter_count_function_str[function]))
+		if (sysfs_streq(buf, counter_function_str[function]))
 			break;
 	}
 	/* Return error if requested Count function mode not found */

@@ -880,25 +880,25 @@ static int counter_count_ext_register(
 }
 
 struct counter_func_avail_unit {
-	const enum counter_count_function *functions_list;
+	const enum counter_function *functions_list;
 	size_t num_functions;
 };
 
-static ssize_t counter_count_function_available_show(struct device *dev,
+static ssize_t counter_function_available_show(struct device *dev,
 	struct device_attribute *attr, char *buf)
 {
 	const struct counter_device_attr *const devattr = to_counter_attr(attr);
 	const struct counter_func_avail_unit *const component = devattr->component;
-	const enum counter_count_function *const func_list = component->functions_list;
+	const enum counter_function *const func_list = component->functions_list;
 	const size_t num_functions = component->num_functions;
 	size_t i;
-	enum counter_count_function function;
+	enum counter_function function;
 	ssize_t len = 0;
 
 	for (i = 0; i < num_functions; i++) {
 		function = func_list[i];
 		len += sprintf(buf + len, "%s\n",
-			       counter_count_function_str[function]);
+			       counter_function_str[function]);
 	}
 
 	return len;

@@ -968,7 +968,7 @@ static int counter_count_attributes_create(
 	parm.group = group;
 	parm.prefix = "";
 	parm.name = "function_available";
-	parm.show = counter_count_function_available_show;
+	parm.show = counter_function_available_show;
 	parm.store = NULL;
 	parm.component = avail_comp;
 	err = counter_attribute_create(&parm);

@@ -171,9 +171,8 @@ enum ftm_quaddec_count_function {
 	FTM_QUADDEC_COUNT_ENCODER_MODE_1,
 };
 
-static const enum counter_count_function ftm_quaddec_count_functions[] = {
-	[FTM_QUADDEC_COUNT_ENCODER_MODE_1] =
-	COUNTER_COUNT_FUNCTION_QUADRATURE_X4
+static const enum counter_function ftm_quaddec_count_functions[] = {
+	[FTM_QUADDEC_COUNT_ENCODER_MODE_1] = COUNTER_FUNCTION_QUADRATURE_X4
 };
 
 static int ftm_quaddec_count_read(struct counter_device *counter,

@@ -115,8 +115,8 @@ static int interrupt_cnt_write(struct counter_device *counter,
 	return 0;
 }
 
-static const enum counter_count_function interrupt_cnt_functions[] = {
-	COUNTER_COUNT_FUNCTION_INCREASE,
+static const enum counter_function interrupt_cnt_functions[] = {
+	COUNTER_FUNCTION_INCREASE,
 };
 
 static int interrupt_cnt_function_get(struct counter_device *counter,

@@ -38,8 +38,8 @@ enum mchp_tc_count_function {
 };
 
 static const enum counter_count_function mchp_tc_count_functions[] = {
-	[MCHP_TC_FUNCTION_INCREASE] = COUNTER_COUNT_FUNCTION_INCREASE,
-	[MCHP_TC_FUNCTION_QUADRATURE] = COUNTER_COUNT_FUNCTION_QUADRATURE_X4,
+	[MCHP_TC_FUNCTION_INCREASE] = COUNTER_FUNCTION_INCREASE,
+	[MCHP_TC_FUNCTION_QUADRATURE] = COUNTER_FUNCTION_QUADRATURE_X4,
 };
 
 enum mchp_tc_synapse_action {

@@ -134,9 +134,9 @@ enum stm32_lptim_cnt_function {
 	STM32_LPTIM_ENCODER_BOTH_EDGE,
 };
 
-static const enum counter_count_function stm32_lptim_cnt_functions[] = {
-	[STM32_LPTIM_COUNTER_INCREASE] = COUNTER_COUNT_FUNCTION_INCREASE,
-	[STM32_LPTIM_ENCODER_BOTH_EDGE] = COUNTER_COUNT_FUNCTION_QUADRATURE_X4,
+static const enum counter_function stm32_lptim_cnt_functions[] = {
+	[STM32_LPTIM_COUNTER_INCREASE] = COUNTER_FUNCTION_INCREASE,
+	[STM32_LPTIM_ENCODER_BOTH_EDGE] = COUNTER_FUNCTION_QUADRATURE_X4,
 };
 
 enum stm32_lptim_synapse_action {

@@ -50,11 +50,11 @@ enum stm32_count_function {
 	STM32_COUNT_ENCODER_MODE_3,
 };
 
-static const enum counter_count_function stm32_count_functions[] = {
-	[STM32_COUNT_SLAVE_MODE_DISABLED] = COUNTER_COUNT_FUNCTION_INCREASE,
-	[STM32_COUNT_ENCODER_MODE_1] = COUNTER_COUNT_FUNCTION_QUADRATURE_X2_A,
-	[STM32_COUNT_ENCODER_MODE_2] = COUNTER_COUNT_FUNCTION_QUADRATURE_X2_B,
-	[STM32_COUNT_ENCODER_MODE_3] = COUNTER_COUNT_FUNCTION_QUADRATURE_X4,
+static const enum counter_function stm32_count_functions[] = {
+	[STM32_COUNT_SLAVE_MODE_DISABLED] = COUNTER_FUNCTION_INCREASE,
+	[STM32_COUNT_ENCODER_MODE_1] = COUNTER_FUNCTION_QUADRATURE_X2_A,
+	[STM32_COUNT_ENCODER_MODE_2] = COUNTER_FUNCTION_QUADRATURE_X2_B,
+	[STM32_COUNT_ENCODER_MODE_3] = COUNTER_FUNCTION_QUADRATURE_X4,
 };
 
 static int stm32_count_read(struct counter_device *counter,

@@ -284,11 +284,11 @@ static struct counter_signal ti_eqep_signals[] = {
 	},
 };
 
-static const enum counter_count_function ti_eqep_position_functions[] = {
-	[TI_EQEP_COUNT_FUNC_QUAD_COUNT]	= COUNTER_COUNT_FUNCTION_QUADRATURE_X4,
-	[TI_EQEP_COUNT_FUNC_DIR_COUNT]	= COUNTER_COUNT_FUNCTION_PULSE_DIRECTION,
-	[TI_EQEP_COUNT_FUNC_UP_COUNT]	= COUNTER_COUNT_FUNCTION_INCREASE,
-	[TI_EQEP_COUNT_FUNC_DOWN_COUNT]	= COUNTER_COUNT_FUNCTION_DECREASE,
+static const enum counter_function ti_eqep_position_functions[] = {
+	[TI_EQEP_COUNT_FUNC_QUAD_COUNT]	= COUNTER_FUNCTION_QUADRATURE_X4,
+	[TI_EQEP_COUNT_FUNC_DIR_COUNT]	= COUNTER_FUNCTION_PULSE_DIRECTION,
+	[TI_EQEP_COUNT_FUNC_UP_COUNT]	= COUNTER_FUNCTION_INCREASE,
+	[TI_EQEP_COUNT_FUNC_DOWN_COUNT]	= COUNTER_FUNCTION_DECREASE,
 };
 
 static const enum counter_synapse_action ti_eqep_position_synapse_actions[] = {

@@ -162,15 +162,15 @@ struct counter_count_ext {
 	void *priv;
 };
 
-enum counter_count_function {
-	COUNTER_COUNT_FUNCTION_INCREASE = 0,
-	COUNTER_COUNT_FUNCTION_DECREASE,
-	COUNTER_COUNT_FUNCTION_PULSE_DIRECTION,
-	COUNTER_COUNT_FUNCTION_QUADRATURE_X1_A,
-	COUNTER_COUNT_FUNCTION_QUADRATURE_X1_B,
-	COUNTER_COUNT_FUNCTION_QUADRATURE_X2_A,
-	COUNTER_COUNT_FUNCTION_QUADRATURE_X2_B,
-	COUNTER_COUNT_FUNCTION_QUADRATURE_X4
+enum counter_function {
+	COUNTER_FUNCTION_INCREASE = 0,
+	COUNTER_FUNCTION_DECREASE,
+	COUNTER_FUNCTION_PULSE_DIRECTION,
+	COUNTER_FUNCTION_QUADRATURE_X1_A,
+	COUNTER_FUNCTION_QUADRATURE_X1_B,
+	COUNTER_FUNCTION_QUADRATURE_X2_A,
+	COUNTER_FUNCTION_QUADRATURE_X2_B,
+	COUNTER_FUNCTION_QUADRATURE_X4
 };
 
 /**

@@ -192,7 +192,7 @@ struct counter_count {
 	const char *name;
 
 	size_t function;
-	const enum counter_count_function *functions_list;
+	const enum counter_function *functions_list;
 	size_t num_functions;
 
 	struct counter_synapse *synapses;

@@ -41,6 +41,9 @@ static struct bus_type counter_bus_type = {
  * This function registers a Counter to the system. A sysfs "counter" directory
  * will be created and populated with sysfs attributes correlating with the
  * Counter Signals, Synapses, and Counts respectively.
+ *
+ * RETURNS:
+ * 0 on success, negative error number on failure.
  */
 int counter_register(struct counter_device *const counter)
 {

@@ -188,12 +188,10 @@ struct counter_comp {
 
 /**
  * struct counter_signal - Counter Signal node
- * @id:		unique ID used to identify signal
- * @name:	device-specific Signal name; ideally, this should match the name
- *		as it appears in the datasheet documentation
- * @ext:	optional array of Counter Signal extensions
- * @num_ext:	number of Counter Signal extensions specified in @ext
- * @priv:	optional private data supplied by driver
+ * @id:		unique ID used to identify the Signal
+ * @name:	device-specific Signal name
+ * @ext:	optional array of Signal extensions
+ * @num_ext:	number of Signal extensions specified in @ext
  */
 struct counter_signal {
 	int id;

@@ -207,7 +205,7 @@ struct counter_signal {
  * struct counter_synapse - Counter Synapse node
  * @actions_list:	array of available action modes
  * @num_actions:	number of action modes specified in @actions_list
- * @signal:		pointer to associated signal
+ * @signal:		pointer to the associated Signal
  */
 struct counter_synapse {
 	const enum counter_synapse_action *actions_list;

@@ -218,17 +216,14 @@ struct counter_synapse {
 
 /**
  * struct counter_count - Counter Count node
- * @id:			unique ID used to identify Count
- * @name:		device-specific Count name; ideally, this should match
- *			the name as it appears in the datasheet documentation
- * @function:		index of current function mode
- * @functions_list:	array available function modes
+ * @id:			unique ID used to identify the Count
+ * @name:		device-specific Count name
+ * @functions_list:	array of available function modes
  * @num_functions:	number of function modes specified in @functions_list
- * @synapses:		array of synapses for initialization
- * @num_synapses:	number of synapses specified in @synapses
- * @ext:		optional array of Counter Count extensions
- * @num_ext:		number of Counter Count extensions specified in @ext
- * @priv:		optional private data supplied by driver
+ * @synapses:		array of Synapses for initialization
+ * @num_synapses:	number of Synapses specified in @synapses
+ * @ext:		optional array of Count extensions
+ * @num_ext:		number of Count extensions specified in @ext
  */
 struct counter_count {
 	int id;

@@ -246,29 +241,26 @@ struct counter_count {
 
 /**
  * struct counter_ops - Callbacks from driver
- * @signal_read:	optional read callback for Signal attribute. The read
- *			level of the respective Signal should be passed back via
- *			the level parameter.
- * @count_read:		optional read callback for Count attribute. The read
- *			value of the respective Count should be passed back via
- *			the val parameter.
- * @count_write:	optional write callback for Count attribute. The write
- *			value for the respective Count is passed in via the val
+ * @signal_read:	read callback for Signals. The read level of the
+ *			respective Signal should be passed back via the level
+ *			parameter.
+ * @count_read:		read callback for Counts. The read value of the
+ *			respective Count should be passed back via the value
  *			parameter.
- * @function_get:	function to get the current count function mode. Returns
- *			0 on success and negative error code on error. The index
- *			of the respective Count's returned function mode should
- *			be passed back via the function parameter.
- * @function_set:	function to set the count function mode. function is the
- *			index of the requested function mode from the respective
- *			Count's functions_list array.
- * @action_get:		function to get the current action mode. Returns 0 on
- *			success and negative error code on error. The index of
- *			the respective Synapse's returned action mode should be
- *			passed back via the action parameter.
- * @action_set:		function to set the action mode. action is the index of
- *			the requested action mode from the respective Synapse's
- *			actions_list array.
+ * @count_write:	write callback for Counts. The write value for the
+ *			respective Count is passed in via the value parameter.
+ * @function_read:	read callback the Count function modes. The read
+ *			function mode of the respective Count should be passed
+ *			back via the function parameter.
+ * @function_write:	write callback for Count function modes. The function
+ *			mode to write for the respective Count is passed in via
+ *			the function parameter.
+ * @action_read:	read callback the Synapse action modes. The read action
+ *			mode of the respective Synapse should be passed back via
+ *			the action parameter.
+ * @action_write:	write callback for Synapse action modes. The action mode
+ *			to write for the respective Synapse is passed in via the
+ *			action parameter.
  */
 struct counter_ops {
 	int (*signal_read)(struct counter_device *counter,