1 files changed, 318 insertions, 0 deletions
diff --git a/sound/soc/sdca/sdca_regmap.c b/sound/soc/sdca/sdca_regmap.c
new file mode 100644
index 000000000000..66e7eee7d7f4
--- /dev/null
+++ b/sound/soc/sdca/sdca_regmap.c
@@ -0,0 +1,318 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2025 Cirrus Logic, Inc. and
+//                    Cirrus Logic International Semiconductor Ltd.
+
+/*
+ * The MIPI SDCA specification is available for public downloads at
+ * https://www.mipi.org/mipi-sdca-v1-0-download
+ */
+
+#include <linux/bitops.h>
+#include <linux/minmax.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/soundwire/sdw_registers.h>
+#include <linux/types.h>
+#include <sound/sdca.h>
+#include <sound/sdca_function.h>
+#include <sound/sdca_regmap.h>
+
+static struct sdca_entity *
+function_find_entity(struct sdca_function_data *function, unsigned int reg)
+{
+	int i;
+
+	for (i = 0; i < function->num_entities; i++)
+		if (SDW_SDCA_CTL_ENT(reg) == function->entities[i].id)
+			return &function->entities[i];
+
+	return NULL;
+}
+
+static struct sdca_control *
+entity_find_control(struct sdca_entity *entity, unsigned int reg)
+{
+	int i;
+
+	for (i = 0; i < entity->num_controls; i++) {
+		if (SDW_SDCA_CTL_CSEL(reg) == entity->controls[i].sel)
+			return &entity->controls[i];
+	}
+
+	return NULL;
+}
+
+static struct sdca_control *
+function_find_control(struct sdca_function_data *function, unsigned int reg)
+{
+	struct sdca_entity *entity;
+
+	entity = function_find_entity(function, reg);
+	if (!entity)
+		return NULL;
+
+	return entity_find_control(entity, reg);
+}
+
+/**
+ * sdca_regmap_readable - return if a given SDCA Control is readable
+ * @function: Pointer to the Function information.
+ * @reg: Register address/Control to be processed.
+ *
+ * Return: Returns true if the register is readable.
+ */
+bool sdca_regmap_readable(struct sdca_function_data *function, unsigned int reg)
+{
+	struct sdca_control *control;
+
+	if (!SDW_SDCA_VALID_CTL(reg))
+		return false;
+
+	control = function_find_control(function, reg);
+	if (!control)
+		return false;
+
+	switch (control->mode) {
+	case SDCA_ACCESS_MODE_RW:
+	case SDCA_ACCESS_MODE_RO:
+	case SDCA_ACCESS_MODE_DUAL:
+	case SDCA_ACCESS_MODE_RW1S:
+	case SDCA_ACCESS_MODE_RW1C:
+		/* No access to registers marked solely for device use */
+		return control->layers & ~SDCA_ACCESS_LAYER_DEVICE;
+	default:
+		return false;
+	}
+}
+EXPORT_SYMBOL_NS(sdca_regmap_readable, "SND_SOC_SDCA");
+
+/**
+ * sdca_regmap_writeable - return if a given SDCA Control is writeable
+ * @function: Pointer to the Function information.
+ * @reg: Register address/Control to be processed.
+ *
+ * Return: Returns true if the register is writeable.
+ */
+bool sdca_regmap_writeable(struct sdca_function_data *function, unsigned int reg)
+{
+	struct sdca_control *control;
+
+	if (!SDW_SDCA_VALID_CTL(reg))
+		return false;
+
+	control = function_find_control(function, reg);
+	if (!control)
+		return false;
+
+	switch (control->mode) {
+	case SDCA_ACCESS_MODE_RW:
+	case SDCA_ACCESS_MODE_DUAL:
+	case SDCA_ACCESS_MODE_RW1S:
+	case SDCA_ACCESS_MODE_RW1C:
+		/* No access to registers marked solely for device use */
+		return control->layers & ~SDCA_ACCESS_LAYER_DEVICE;
+	default:
+		return false;
+	}
+}
+EXPORT_SYMBOL_NS(sdca_regmap_writeable, "SND_SOC_SDCA");
+
+/**
+ * sdca_regmap_volatile - return if a given SDCA Control is volatile
+ * @function: Pointer to the Function information.
+ * @reg: Register address/Control to be processed.
+ *
+ * Return: Returns true if the register is volatile.
+ */
+bool sdca_regmap_volatile(struct sdca_function_data *function, unsigned int reg)
+{
+	struct sdca_control *control;
+
+	if (!SDW_SDCA_VALID_CTL(reg))
+		return false;
+
+	control = function_find_control(function, reg);
+	if (!control)
+		return false;
+
+	switch (control->mode) {
+	case SDCA_ACCESS_MODE_RO:
+	case SDCA_ACCESS_MODE_RW1S:
+	case SDCA_ACCESS_MODE_RW1C:
+		return true;
+	default:
+		return false;
+	}
+}
+EXPORT_SYMBOL_NS(sdca_regmap_volatile, "SND_SOC_SDCA");
+
+/**
+ * sdca_regmap_deferrable - return if a given SDCA Control is deferrable
+ * @function: Pointer to the Function information.
+ * @reg: Register address/Control to be processed.
+ *
+ * Return: Returns true if the register is deferrable.
+ */
+bool sdca_regmap_deferrable(struct sdca_function_data *function, unsigned int reg)
+{
+	struct sdca_control *control;
+
+	if (!SDW_SDCA_VALID_CTL(reg))
+		return false;
+
+	control = function_find_control(function, reg);
+	if (!control)
+		return false;
+
+	return control->deferrable;
+}
+EXPORT_SYMBOL_NS(sdca_regmap_deferrable, "SND_SOC_SDCA");
+
+/**
+ * sdca_regmap_mbq_size - return size in bytes of a given SDCA Control
+ * @function: Pointer to the Function information.
+ * @reg: Register address/Control to be processed.
+ *
+ * Return: Returns the size in bytes of the Control.
+ */
+int sdca_regmap_mbq_size(struct sdca_function_data *function, unsigned int reg)
+{
+	struct sdca_control *control;
+
+	if (!SDW_SDCA_VALID_CTL(reg))
+		return -EINVAL;
+
+	control = function_find_control(function, reg);
+	if (!control)
+		return false;
+
+	return clamp_val(control->nbits / BITS_PER_BYTE, sizeof(u8), sizeof(u32));
+}
+EXPORT_SYMBOL_NS(sdca_regmap_mbq_size, "SND_SOC_SDCA");
+
+/**
+ * sdca_regmap_count_constants - count the number of DisCo constant Controls
+ * @dev: Pointer to the device.
+ * @function: Pointer to the Function information, to be parsed.
+ *
+ * This function returns the number of DisCo constant Controls present
+ * in a function. Typically this information will be used to populate
+ * the regmap defaults array, allowing drivers to access the values of
+ * DisCo constants as any other physical register.
+ *
+ * Return: Returns number of DisCo constant controls, or a negative error
+ * code on failure.
+ */
+int sdca_regmap_count_constants(struct device *dev,
+				struct sdca_function_data *function)
+{
+	int nconsts = 0;
+	int i, j;
+
+	for (i = 0; i < function->num_entities; i++) {
+		struct sdca_entity *entity = &function->entities[i];
+
+		for (j = 0; j < entity->num_controls; j++) {
+			if (entity->controls[j].mode == SDCA_ACCESS_MODE_DC)
+				nconsts += hweight64(entity->controls[j].cn_list);
+		}
+	}
+
+	return nconsts;
+}
+EXPORT_SYMBOL_NS(sdca_regmap_count_constants, "SND_SOC_SDCA");
+
+/**
+ * sdca_regmap_populate_constants - fill an array with DisCo constant values
+ * @dev: Pointer to the device.
+ * @function: Pointer to the Function information, to be parsed.
+ * @consts: Pointer to the array which should be filled with the DisCo
+ * constant values.
+ *
+ * This function will populate a regmap struct reg_default array with
+ * the values of the DisCo constants for a given Function. This
+ * allows to access the values of DisCo constants the same as any
+ * other physical register.
+ *
+ * Return: Returns the number of constants populated on success, a negative
+ * error code on failure.
+ */
+int sdca_regmap_populate_constants(struct device *dev,
+				   struct sdca_function_data *function,
+				   struct reg_default *consts)
+{
+	int i, j, k;
+
+	for (i = 0, k = 0; i < function->num_entities; i++) {
+		struct sdca_entity *entity = &function->entities[i];
+
+		for (j = 0; j < entity->num_controls; j++) {
+			struct sdca_control *control = &entity->controls[j];
+			int cn;
+
+			if (control->mode != SDCA_ACCESS_MODE_DC)
+				continue;
+
+			for_each_set_bit(cn, (unsigned long *)&control->cn_list,
+					 BITS_PER_TYPE(control->cn_list)) {
+				consts[k].reg = SDW_SDCA_CTL(function->desc->adr,
+							     entity->id,
+							     control->sel, cn);
+				consts[k].def = control->value;
+				k++;
+			}
+		}
+	}
+
+	return k;
+}
+EXPORT_SYMBOL_NS(sdca_regmap_populate_constants, "SND_SOC_SDCA");
+
+/**
+ * sdca_regmap_write_defaults - write out DisCo defaults to device
+ * @dev: Pointer to the device.
+ * @regmap: Pointer to the Function register map.
+ * @function: Pointer to the Function information, to be parsed.
+ *
+ * This function will write out to the hardware all the DisCo default and
+ * fixed value controls. This will cause them to be populated into the cache,
+ * and subsequent handling can be done through a cache sync.
+ *
+ * Return: Returns zero on success, and a negative error code on failure.
+ */
+int sdca_regmap_write_defaults(struct device *dev, struct regmap *regmap,
+			       struct sdca_function_data *function)
+{
+	int i, j;
+	int ret;
+
+	for (i = 0; i < function->num_entities; i++) {
+		struct sdca_entity *entity = &function->entities[i];
+
+		for (j = 0; j < entity->num_controls; j++) {
+			struct sdca_control *control = &entity->controls[j];
+			int cn;
+
+			if (control->mode == SDCA_ACCESS_MODE_DC)
+				continue;
+
+			if (!control->has_default && !control->has_fixed)
+				continue;
+
+			for_each_set_bit(cn, (unsigned long *)&control->cn_list,
+					 BITS_PER_TYPE(control->cn_list)) {
+				unsigned int reg;
+
+				reg = SDW_SDCA_CTL(function->desc->adr, entity->id,
+						   control->sel, cn);
+
+				ret = regmap_write(regmap, reg, control->value);
+				if (ret)
+					return ret;
+			}
+		}
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_NS(sdca_regmap_write_defaults, "SND_SOC_SDCA");