counter: Internalize sysfs interface code

This is a reimplementation of the Generic Counter driver interface.
There are no modifications to the Counter subsystem userspace interface,
so existing userspace applications should continue to run seamlessly.

The purpose of this patch is to internalize the sysfs interface code
among the various counter drivers into a shared module. Counter drivers
pass and take data natively (i.e. u8, u64, etc.) and the shared counter
module handles the translation between the sysfs interface and the
device drivers. This guarantees a standard userspace interface for all
counter drivers, and helps generalize the Generic Counter driver ABI in
order to support the Generic Counter chrdev interface (introduced in a
subsequent patch) without significant changes to the existing counter
drivers.

Note, Counter device registration is the same as before: drivers
populate a struct counter_device with components and callbacks, then
pass the structure to the devm_counter_register function. However,
what's different now is how the Counter subsystem code handles this
registration internally.

Whereas before callbacks would interact directly with sysfs data, this
interaction is now abstracted and instead callbacks interact with native
C data types. The counter_comp structure forms the basis for Counter
extensions.

The counter-sysfs.c file contains the code to parse through the
counter_device structure and register the requested components and
extensions. Attributes are created and populated based on type, with
respective translation functions to handle the mapping between sysfs and
the counter driver callbacks.

The translation performed for each attribute is straightforward: the
attribute type and data is parsed from the counter_attribute structure,
the respective counter driver read/write callback is called, and sysfs
I/O is handled before or after the driver read/write function is called.

Cc: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Cc: Patrick Havelange <patrick.havelange@essensium.com>
Cc: Kamel Bouhara <kamel.bouhara@bootlin.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Syed Nayyar Waris <syednwaris@gmail.com>
Reviewed-by: David Lechner <david@lechnology.com>
Tested-by: David Lechner <david@lechnology.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com> # for stm32
Link: https://lore.kernel.org/r/c68b4a1ffb195c1a2f65e8dd5ad7b7c14e79c6ef.1630031207.git.vilhelm.gray@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

1 files changed, 39 insertions, 52 deletions

diff --git a/drivers/counter/microchip-tcb-capture.c b/drivers/counter/microchip-tcb-capture.c
index 1aa70b9c4833..79e0c84a3b81 100644
--- a/drivers/counter/microchip-tcb-capture.c
+++ b/drivers/counter/microchip-tcb-capture.c
@@ -32,28 +32,16 @@ struct mchp_tc_data {
 	bool trig_inverted;
 };
 
-enum mchp_tc_count_function {
-	MCHP_TC_FUNCTION_INCREASE,
-	MCHP_TC_FUNCTION_QUADRATURE,
-};
-
 static const enum counter_function mchp_tc_count_functions[] = {
-	[MCHP_TC_FUNCTION_INCREASE] = COUNTER_FUNCTION_INCREASE,
-	[MCHP_TC_FUNCTION_QUADRATURE] = COUNTER_FUNCTION_QUADRATURE_X4,
-};
-
-enum mchp_tc_synapse_action {
-	MCHP_TC_SYNAPSE_ACTION_NONE = 0,
-	MCHP_TC_SYNAPSE_ACTION_RISING_EDGE,
-	MCHP_TC_SYNAPSE_ACTION_FALLING_EDGE,
-	MCHP_TC_SYNAPSE_ACTION_BOTH_EDGE
+	COUNTER_FUNCTION_INCREASE,
+	COUNTER_FUNCTION_QUADRATURE_X4,
 };
 
 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,
-	[MCHP_TC_SYNAPSE_ACTION_BOTH_EDGE] = COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
+	COUNTER_SYNAPSE_ACTION_NONE,
+	COUNTER_SYNAPSE_ACTION_RISING_EDGE,
+	COUNTER_SYNAPSE_ACTION_FALLING_EDGE,
+	COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
 };
 
 static struct counter_signal mchp_tc_count_signals[] = {
@@ -80,23 +68,23 @@ static struct counter_synapse mchp_tc_count_synapses[] = {
 	}
 };
 
-static int mchp_tc_count_function_get(struct counter_device *counter,
-				      struct counter_count *count,
-				      size_t *function)
+static int mchp_tc_count_function_read(struct counter_device *counter,
+				       struct counter_count *count,
+				       enum counter_function *function)
 {
 	struct mchp_tc_data *const priv = counter->priv;
 
 	if (priv->qdec_mode)
-		*function = MCHP_TC_FUNCTION_QUADRATURE;
+		*function = COUNTER_FUNCTION_QUADRATURE_X4;
 	else
-		*function = MCHP_TC_FUNCTION_INCREASE;
+		*function = COUNTER_FUNCTION_INCREASE;
 
 	return 0;
 }
 
-static int mchp_tc_count_function_set(struct counter_device *counter,
-				      struct counter_count *count,
-				      size_t function)
+static int mchp_tc_count_function_write(struct counter_device *counter,
+					struct counter_count *count,
+					enum counter_function function)
 {
 	struct mchp_tc_data *const priv = counter->priv;
 	u32 bmr, cmr;
@@ -108,7 +96,7 @@ static int mchp_tc_count_function_set(struct counter_device *counter,
 	cmr &= ~ATMEL_TC_WAVE;
 
 	switch (function) {
-	case MCHP_TC_FUNCTION_INCREASE:
+	case COUNTER_FUNCTION_INCREASE:
 		priv->qdec_mode = 0;
 		/* Set highest rate based on whether soc has gclk or not */
 		bmr &= ~(ATMEL_TC_QDEN | ATMEL_TC_POSEN);
@@ -120,7 +108,7 @@ static int mchp_tc_count_function_set(struct counter_device *counter,
 		cmr |=  ATMEL_TC_CMR_MASK;
 		cmr &= ~(ATMEL_TC_ABETRG | ATMEL_TC_XC0);
 		break;
-	case MCHP_TC_FUNCTION_QUADRATURE:
+	case COUNTER_FUNCTION_QUADRATURE_X4:
 		if (!priv->tc_cfg->has_qdec)
 			return -EINVAL;
 		/* In QDEC mode settings both channels 0 and 1 are required */
@@ -176,10 +164,10 @@ static int mchp_tc_count_signal_read(struct counter_device *counter,
 	return 0;
 }
 
-static int mchp_tc_count_action_get(struct counter_device *counter,
-				    struct counter_count *count,
-				    struct counter_synapse *synapse,
-				    size_t *action)
+static int mchp_tc_count_action_read(struct counter_device *counter,
+				     struct counter_count *count,
+				     struct counter_synapse *synapse,
+				     enum counter_synapse_action *action)
 {
 	struct mchp_tc_data *const priv = counter->priv;
 	u32 cmr;
@@ -188,26 +176,26 @@ static int mchp_tc_count_action_get(struct counter_device *counter,
 
 	switch (cmr & ATMEL_TC_ETRGEDG) {
 	default:
-		*action = MCHP_TC_SYNAPSE_ACTION_NONE;
+		*action = COUNTER_SYNAPSE_ACTION_NONE;
 		break;
 	case ATMEL_TC_ETRGEDG_RISING:
-		*action = MCHP_TC_SYNAPSE_ACTION_RISING_EDGE;
+		*action = COUNTER_SYNAPSE_ACTION_RISING_EDGE;
 		break;
 	case ATMEL_TC_ETRGEDG_FALLING:
-		*action = MCHP_TC_SYNAPSE_ACTION_FALLING_EDGE;
+		*action = COUNTER_SYNAPSE_ACTION_FALLING_EDGE;
 		break;
 	case ATMEL_TC_ETRGEDG_BOTH:
-		*action = MCHP_TC_SYNAPSE_ACTION_BOTH_EDGE;
+		*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
 		break;
 	}
 
 	return 0;
 }
 
-static int mchp_tc_count_action_set(struct counter_device *counter,
-				    struct counter_count *count,
-				    struct counter_synapse *synapse,
-				    size_t action)
+static int mchp_tc_count_action_write(struct counter_device *counter,
+				      struct counter_count *count,
+				      struct counter_synapse *synapse,
+				      enum counter_synapse_action action)
 {
 	struct mchp_tc_data *const priv = counter->priv;
 	u32 edge = ATMEL_TC_ETRGEDG_NONE;
@@ -217,16 +205,16 @@ static int mchp_tc_count_action_set(struct counter_device *counter,
 		return -EINVAL;
 
 	switch (action) {
-	case MCHP_TC_SYNAPSE_ACTION_NONE:
+	case COUNTER_SYNAPSE_ACTION_NONE:
 		edge = ATMEL_TC_ETRGEDG_NONE;
 		break;
-	case MCHP_TC_SYNAPSE_ACTION_RISING_EDGE:
+	case COUNTER_SYNAPSE_ACTION_RISING_EDGE:
 		edge = ATMEL_TC_ETRGEDG_RISING;
 		break;
-	case MCHP_TC_SYNAPSE_ACTION_FALLING_EDGE:
+	case COUNTER_SYNAPSE_ACTION_FALLING_EDGE:
 		edge = ATMEL_TC_ETRGEDG_FALLING;
 		break;
-	case MCHP_TC_SYNAPSE_ACTION_BOTH_EDGE:
+	case COUNTER_SYNAPSE_ACTION_BOTH_EDGES:
 		edge = ATMEL_TC_ETRGEDG_BOTH;
 		break;
 	default:
@@ -240,8 +228,7 @@ static int mchp_tc_count_action_set(struct counter_device *counter,
 }
 
 static int mchp_tc_count_read(struct counter_device *counter,
-			      struct counter_count *count,
-			      unsigned long *val)
+			      struct counter_count *count, u64 *val)
 {
 	struct mchp_tc_data *const priv = counter->priv;
 	u32 cnt;
@@ -264,12 +251,12 @@ static struct counter_count mchp_tc_counts[] = {
 };
 
 static const struct counter_ops mchp_tc_ops = {
-	.signal_read  = mchp_tc_count_signal_read,
-	.count_read   = mchp_tc_count_read,
-	.function_get = mchp_tc_count_function_get,
-	.function_set = mchp_tc_count_function_set,
-	.action_get   = mchp_tc_count_action_get,
-	.action_set   = mchp_tc_count_action_set
+	.signal_read    = mchp_tc_count_signal_read,
+	.count_read     = mchp_tc_count_read,
+	.function_read  = mchp_tc_count_function_read,
+	.function_write = mchp_tc_count_function_write,
+	.action_read    = mchp_tc_count_action_read,
+	.action_write   = mchp_tc_count_action_write
 };
 
 static const struct atmel_tcb_config tcb_rm9200_config = {