[PATCH 6/7] ASoC: SDCA: Generic interrupt support

[Charles Keepax <ckeepax@opensource.cirrus.com>]

From: Maciej Strozek <mstrozek@opensource.cirrus.com>

Add a library supporting usage of SDCA interrupts, using regmap irq
framework. The library adds functions for parsing ACPI for
interrupt-related information, configuring irq chip and requesting
individual irqs. Calling code (SDCA function code) is expected to also
substitute the library's base irq handler for its own, appropriate
callback.

Signed-off-by: Maciej Strozek <mstrozek@opensource.cirrus.com>
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
---
 include/sound/sdca_interrupts.h  |  74 ++++++++
 sound/soc/sdca/Kconfig           |   7 +
 sound/soc/sdca/Makefile          |   2 +
 sound/soc/sdca/sdca_interrupts.c | 284 +++++++++++++++++++++++++++++++
 4 files changed, 367 insertions(+)
 create mode 100644 include/sound/sdca_interrupts.h
 create mode 100644 sound/soc/sdca/sdca_interrupts.c

diff --git a/include/sound/sdca_interrupts.h b/include/sound/sdca_interrupts.h
new file mode 100644
index 0000000000000..10c14db282bfe
--- /dev/null
+++ b/include/sound/sdca_interrupts.h
@@ -0,0 +1,74 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * The MIPI SDCA specification is available for public downloads at
+ * https://www.mipi.org/mipi-sdca-v1-0-download
+ *
+ * Copyright (C) 2025 Cirrus Logic, Inc. and
+ *                    Cirrus Logic International Semiconductor Ltd.
+ */
+
+#ifndef __SDCA_INTERRUPTS_H__
+#define __SDCA_INTERRUPTS_H__
+
+#include <linux/interrupt.h>
+#include <linux/mutex.h>
+#include <linux/regmap.h>
+
+struct device;
+struct snd_soc_component;
+struct sdca_function_data;
+
+#define SDCA_MAX_INTERRUPTS 31 /* the last bit is reserved for future extensions */
+
+/**
+ * struct sdca_interrupt - contains information about a single SDCA interrupt
+ * @name: The name of the interrupt.
+ * @component: Pointer to the ASoC component owns the interrupt.
+ * @function: Pointer to the Function that the interrupt is associated with.
+ * @entity: Pointer to the Entity that the interrupt is associated with.
+ * @control: Pointer to the Control that the interrupt is associated with.
+ * @externally_requested: Internal flag used to check if something has already
+ * requested the interrupt.
+ */
+struct sdca_interrupt {
+	const char *name;
+
+	struct snd_soc_component *component;
+	struct sdca_function_data *function;
+	struct sdca_entity *entity;
+	struct sdca_control *control;
+
+	bool externally_requested;
+};
+
+/**
+ * struct sdca_interrupt_info - contains top-level SDCA interrupt information
+ * @irq_chip: regmap irq chip structure.
+ * @irq_data: regmap irq chip data structure.
+ * @irqs: Array of data for each individual IRQ.
+ * @irq_lock: Protects access to the list of sdca_interrupt structures.
+ */
+struct sdca_interrupt_info {
+	struct regmap_irq_chip irq_chip;
+	struct regmap_irq_chip_data *irq_data;
+
+	struct sdca_interrupt irqs[SDCA_MAX_INTERRUPTS];
+
+	struct mutex irq_lock; /* Protect accesses to irqs list */
+};
+
+int sdca_irq_request(struct device *dev, struct sdca_interrupt_info *interrupt_info,
+		     int sdca_irq, const char *name, irq_handler_t handler,
+		     void *data);
+int sdca_irq_data_populate(struct snd_soc_component *component,
+			   struct sdca_function_data *function,
+			   struct sdca_entity *entity,
+			   struct sdca_control *control,
+			   struct sdca_interrupt *interrupt);
+int sdca_irq_populate(struct sdca_function_data *function,
+		      struct snd_soc_component *component,
+		      struct sdca_interrupt_info *info);
+struct sdca_interrupt_info *sdca_irq_allocate(struct device *dev,
+					      struct regmap *regmap, int irq);
+
+#endif
diff --git a/sound/soc/sdca/Kconfig b/sound/soc/sdca/Kconfig
index ee20b9914aa1f..d40331cb0a212 100644
--- a/sound/soc/sdca/Kconfig
+++ b/sound/soc/sdca/Kconfig
@@ -9,3 +9,10 @@ config SND_SOC_SDCA
 
 config SND_SOC_SDCA_OPTIONAL
 	def_tristate SND_SOC_SDCA || !SND_SOC_SDCA
+
+config SND_SOC_SDCA_IRQ
+	tristate
+	select REGMAP
+	select REGMAP_IRQ
+	help
+	  This option enables support for SDCA IRQs.
diff --git a/sound/soc/sdca/Makefile b/sound/soc/sdca/Makefile
index 53344f108ca67..d7f9a16790ad8 100644
--- a/sound/soc/sdca/Makefile
+++ b/sound/soc/sdca/Makefile
@@ -1,5 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
 
 snd-soc-sdca-y	:= sdca_functions.o sdca_device.o sdca_regmap.o sdca_asoc.o
+snd-soc-sdca-irq-y := sdca_interrupts.o
 
 obj-$(CONFIG_SND_SOC_SDCA)	+= snd-soc-sdca.o
+obj-$(CONFIG_SND_SOC_SDCA_IRQ) += snd-soc-sdca-irq.o
diff --git a/sound/soc/sdca/sdca_interrupts.c b/sound/soc/sdca/sdca_interrupts.c
new file mode 100644
index 0000000000000..1b02d584cb5a3
--- /dev/null
+++ b/sound/soc/sdca/sdca_interrupts.c
@@ -0,0 +1,284 @@
+// 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/bits.h>
+#include <linux/cleanup.h>
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/regmap.h>
+#include <linux/soundwire/sdw.h>
+#include <linux/soundwire/sdw_registers.h>
+#include <sound/sdca.h>
+#include <sound/sdca_function.h>
+#include <sound/sdca_interrupts.h>
+#include <sound/soc-component.h>
+
+#define IRQ_SDCA(number) REGMAP_IRQ_REG(number, ((number) / BITS_PER_BYTE), \
+					SDW_SCP_SDCA_INTMASK_SDCA_##number)
+
+static const struct regmap_irq regmap_irqs[SDCA_MAX_INTERRUPTS] = {
+	IRQ_SDCA(0),
+	IRQ_SDCA(1),
+	IRQ_SDCA(2),
+	IRQ_SDCA(3),
+	IRQ_SDCA(4),
+	IRQ_SDCA(5),
+	IRQ_SDCA(6),
+	IRQ_SDCA(7),
+	IRQ_SDCA(8),
+	IRQ_SDCA(9),
+	IRQ_SDCA(10),
+	IRQ_SDCA(11),
+	IRQ_SDCA(12),
+	IRQ_SDCA(13),
+	IRQ_SDCA(14),
+	IRQ_SDCA(15),
+	IRQ_SDCA(16),
+	IRQ_SDCA(17),
+	IRQ_SDCA(18),
+	IRQ_SDCA(19),
+	IRQ_SDCA(20),
+	IRQ_SDCA(21),
+	IRQ_SDCA(22),
+	IRQ_SDCA(23),
+	IRQ_SDCA(24),
+	IRQ_SDCA(25),
+	IRQ_SDCA(26),
+	IRQ_SDCA(27),
+	IRQ_SDCA(28),
+	IRQ_SDCA(29),
+	IRQ_SDCA(30),
+};
+
+static const struct regmap_irq_chip sdca_irq_chip = {
+	.name = "sdca_irq",
+
+	.status_base = SDW_SCP_SDCA_INT1,
+	.unmask_base = SDW_SCP_SDCA_INTMASK1,
+	.ack_base = SDW_SCP_SDCA_INT1,
+	.num_regs = 4,
+
+	.irqs = regmap_irqs,
+	.num_irqs = SDCA_MAX_INTERRUPTS,
+
+	.runtime_pm = true,
+};
+
+static irqreturn_t base_handler(int irq, void *data)
+{
+	struct sdca_interrupt *interrupt = data;
+	struct device *dev = interrupt->component->dev;
+
+	dev_warn(dev, "%s irq without full handling\n", interrupt->name);
+
+	return IRQ_HANDLED;
+}
+
+static int sdca_irq_request_locked(struct device *dev,
+				   struct sdca_interrupt_info *info,
+				   int sdca_irq, const char *name,
+				   irq_handler_t handler, void *data)
+{
+	int irq;
+	int ret;
+
+	irq = regmap_irq_get_virq(info->irq_data, sdca_irq);
+	if (irq < 0)
+		return irq;
+
+	ret = devm_request_threaded_irq(dev, irq, NULL, handler,
+					IRQF_ONESHOT, name, data);
+	if (ret)
+		return ret;
+
+	dev_dbg(dev, "requested irq %d for %s\n", irq, name);
+
+	return 0;
+}
+
+/**
+ * sdca_request_irq - request an individual SDCA interrupt
+ * @dev: Pointer to the struct device against which things should be allocated.
+ * @interrupt_info: Pointer to the interrupt information structure.
+ * @sdca_irq: SDCA interrupt position.
+ * @name: Name to be given to the IRQ.
+ * @handler: A callback thread function to be called for the IRQ.
+ * @data: Private data pointer that will be passed to the handler.
+ *
+ * Typically this is handled internally by sdca_irq_populate, however if
+ * a device requires custom IRQ handling this can be called manually before
+ * calling sdca_irq_populate, which will then skip that IRQ whilst processing.
+ *
+ * Return: Zero on success, and a negative error code on failure.
+ */
+int sdca_irq_request(struct device *dev, struct sdca_interrupt_info *info,
+		     int sdca_irq, const char *name, irq_handler_t handler,
+		     void *data)
+{
+	int ret;
+
+	if (sdca_irq < 0 || sdca_irq > SDCA_MAX_INTERRUPTS) {
+		dev_err(dev, "bad irq request: %d\n", sdca_irq);
+		return -EINVAL;
+	}
+
+	guard(mutex)(&info->irq_lock);
+
+	ret = sdca_irq_request_locked(dev, info, sdca_irq, name, handler, data);
+	if (ret) {
+		dev_err(dev, "failed to request irq %s: %d\n", name, ret);
+		return ret;
+	}
+
+	info->irqs[sdca_irq].externally_requested = true;
+
+	return 0;
+}
+EXPORT_SYMBOL_NS_GPL(sdca_irq_request, "SND_SOC_SDCA_IRQ");
+
+/**
+ * sdca_irq_data_populate - Populate common interrupt data
+ * @component: Pointer to the ASoC component for the Function.
+ * @function: Pointer to the SDCA Function.
+ * @entity: Pointer to the SDCA Entity.
+ * @control: Pointer to the SDCA Control.
+ * @interrupt: Pointer to the SDCA interrupt for this IRQ.
+ *
+ * Return: Zero on success, and a negative error code on failure.
+ */
+int sdca_irq_data_populate(struct snd_soc_component *component,
+			   struct sdca_function_data *function,
+			   struct sdca_entity *entity,
+			   struct sdca_control *control,
+			   struct sdca_interrupt *interrupt)
+{
+	struct device *dev = component->dev;
+	const char *name;
+
+	name = devm_kasprintf(dev, GFP_KERNEL, "%s %s %s", function->desc->name,
+			      entity->label, control->label);
+	if (!name)
+		return -ENOMEM;
+
+	interrupt->name = name;
+	interrupt->component = component;
+	interrupt->function = function;
+	interrupt->entity = entity;
+	interrupt->control = control;
+
+	return 0;
+}
+EXPORT_SYMBOL_NS_GPL(sdca_irq_data_populate, "SND_SOC_SDCA_IRQ");
+
+/**
+ * sdca_irq_populate - Request all the individual IRQs for an SDCA Function
+ * @function: Pointer to the SDCA Function.
+ * @component: Pointer to the ASoC component for the Function.
+ * @info: Pointer to the SDCA interrupt info for this device.
+ *
+ * Typically this would be called from the driver for a single SDCA Function.
+ *
+ * Return: Zero on success, and a negative error code on failure.
+ */
+int sdca_irq_populate(struct sdca_function_data *function,
+		      struct snd_soc_component *component,
+		      struct sdca_interrupt_info *info)
+{
+	struct device *dev = component->dev;
+	int i, j;
+
+	guard(mutex)(&info->irq_lock);
+
+	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 irq = control->interrupt_position;
+			struct sdca_interrupt *interrupt;
+			const char *name;
+			int ret;
+
+			if (irq == SDCA_NO_INTERRUPT) {
+				continue;
+			} else if (irq < 0 || irq >= SDCA_MAX_INTERRUPTS) {
+				dev_err(dev, "bad irq position: %d\n", irq);
+				return -EINVAL;
+			}
+
+			interrupt = &info->irqs[irq];
+
+			if (interrupt->externally_requested) {
+				dev_dbg(dev,
+					"skipping irq %d, externally requested\n",
+					irq);
+				continue;
+			}
+
+			ret = sdca_irq_data_populate(component, function, entity,
+						     control, interrupt);
+			if (ret)
+				return ret;
+
+			ret = sdca_irq_request_locked(dev, info, irq, interrupt->name,
+						      base_handler, interrupt);
+			if (ret) {
+				dev_err(dev, "failed to request irq %s: %d\n",
+					name, ret);
+				return ret;
+			}
+		}
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_NS_GPL(sdca_irq_populate, "SND_SOC_SDCA_IRQ");
+
+/**
+ * sdca_irq_allocate - allocate an SDCA interrupt structure for a device
+ * @dev: Device pointer against which things should be allocated.
+ * @regmap: regmap to be used for accessing the SDCA IRQ registers.
+ * @irq: The interrupt number.
+ *
+ * Typically this would be called from the top level driver for the whole
+ * SDCA device, as only a single instance is required across all Functions
+ * on the device.
+ *
+ * Return: A pointer to the allocated sdca_interrupt_info struct, or an
+ * error code.
+ */
+struct sdca_interrupt_info *sdca_irq_allocate(struct device *dev,
+					      struct regmap *regmap, int irq)
+{
+	struct sdca_interrupt_info *info;
+	int ret;
+
+	info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return ERR_PTR(-ENOMEM);
+
+	info->irq_chip = sdca_irq_chip;
+
+	devm_mutex_init(dev, &info->irq_lock);
+
+	ret = devm_regmap_add_irq_chip(dev, regmap, irq, IRQF_ONESHOT, 0,
+				       &info->irq_chip, &info->irq_data);
+	if (ret) {
+		dev_err(dev, "failed to register irq chip: %d\n", ret);
+		return ERR_PTR(ret);
+	}
+
+	dev_dbg(dev, "registered on irq %d\n", irq);
+
+	return info;
+}
+EXPORT_SYMBOL_NS_GPL(sdca_irq_allocate, "SND_SOC_SDCA_IRQ");
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("SDCA IRQ library");
-- 
2.39.5