ASoC: SDCA: Add HID button IRQ

Now full support for the UMP buffers is available, it is possible to
read the SDCA HID descriptors from the device and pass them to
user-space. Add a helper function to process HID events from an SDCA
device.

Reviewed-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.dev>
Link: https://patch.msgid.link/20251020155512.353774-20-ckeepax@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>

include/sound/sdca_hid.h

@@ -8,13 +8,17 @@
 #ifndef __SDCA_HID_H__
 #define __SDCA_HID_H__
 
-#include <linux/types.h>
-#include <linux/hid.h>
+struct device;
+struct sdw_slave;
+
+struct sdca_entity;
+struct sdca_interrupt;
 
 #if IS_ENABLED(CONFIG_SND_SOC_SDCA_HID)
 
 int sdca_add_hid_device(struct device *dev, struct sdw_slave *sdw,
 			struct sdca_entity *entity);
+int sdca_hid_process_report(struct sdca_interrupt *interrupt);
 
 #else
 
@@ -24,6 +28,11 @@ static inline int sdca_add_hid_device(struct device *dev, struct sdw_slave *sdw,
 	return 0;
 }
 
+static inline int sdca_hid_process_report(struct sdca_interrupt *interrupt)
+{
+	return 0;
+}
+
 #endif
 
 #endif /* __SDCA_HID_H__ */

sound/soc/sdca/sdca_hid.c

@@ -10,6 +10,7 @@
 #include <linux/cleanup.h>
 #include <linux/device.h>
 #include <linux/dev_printk.h>
+#include <linux/hid.h>
 #include <linux/module.h>
 #include <linux/property.h>
 #include <linux/soundwire/sdw.h>
@@ -17,6 +18,8 @@
 #include <sound/sdca.h>
 #include <sound/sdca_function.h>
 #include <sound/sdca_hid.h>
+#include <sound/sdca_interrupts.h>
+#include <sound/sdca_ump.h>
 
 static int sdwhid_parse(struct hid_device *hid)
 {
@@ -121,5 +124,48 @@ int sdca_add_hid_device(struct device *dev, struct sdw_slave *sdw,
 }
 EXPORT_SYMBOL_NS(sdca_add_hid_device, "SND_SOC_SDCA");
 
+/**
+ * sdca_hid_process_report - read a HID event from the device and report
+ * @interrupt: Pointer to the SDCA interrupt information structure.
+ *
+ * Return: Zero on success, and a negative error code on failure.
+ */
+int sdca_hid_process_report(struct sdca_interrupt *interrupt)
+{
+	struct device *dev = interrupt->dev;
+	struct hid_device *hid = interrupt->entity->hide.hid;
+	void *val __free(kfree) = NULL;
+	int len, ret;
+
+	ret = sdca_ump_get_owner_host(dev, interrupt->function_regmap,
+				      interrupt->function, interrupt->entity,
+				      interrupt->control);
+	if (ret)
+		return ret;
+
+	len = sdca_ump_read_message(dev, interrupt->device_regmap,
+				    interrupt->function_regmap,
+				    interrupt->function, interrupt->entity,
+				    SDCA_CTL_HIDE_HIDTX_MESSAGEOFFSET,
+				    SDCA_CTL_HIDE_HIDTX_MESSAGELENGTH, &val);
+	if (len < 0)
+		return len;
+
+	ret = sdca_ump_set_owner_device(dev, interrupt->function_regmap,
+					interrupt->function, interrupt->entity,
+					interrupt->control);
+	if (ret)
+		return ret;
+
+	ret = hid_input_report(hid, HID_INPUT_REPORT, val, len, true);
+	if (ret < 0) {
+		dev_err(dev, "failed to report hid event: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_NS(sdca_hid_process_report, "SND_SOC_SDCA");
+
 MODULE_LICENSE("Dual BSD/GPL");
 MODULE_DESCRIPTION("SDCA HID library");

sound/soc/sdca/sdca_interrupts.c

@@ -20,6 +20,7 @@
 #include <sound/sdca.h>
 #include <sound/sdca_fdl.h>
 #include <sound/sdca_function.h>
+#include <sound/sdca_hid.h>
 #include <sound/sdca_interrupts.h>
 #include <sound/sdca_ump.h>
 #include <sound/soc-component.h>
@@ -247,6 +248,29 @@ error:
 	return irqret;
 }
 
+static irqreturn_t hid_handler(int irq, void *data)
+{
+	struct sdca_interrupt *interrupt = data;
+	struct device *dev = interrupt->dev;
+	irqreturn_t irqret = IRQ_NONE;
+	int ret;
+
+	ret = pm_runtime_get_sync(dev);
+	if (ret < 0) {
+		dev_err(dev, "failed to resume for hid: %d\n", ret);
+		goto error;
+	}
+
+	ret = sdca_hid_process_report(interrupt);
+	if (ret)
+		goto error;
+
+	irqret = IRQ_HANDLED;
+error:
+	pm_runtime_put(dev);
+	return irqret;
+}
+
 static irqreturn_t fdl_owner_handler(int irq, void *data)
 {
 	struct sdca_interrupt *interrupt = data;
@@ -528,6 +552,10 @@ int sdca_irq_populate(struct sdca_function_data *function,
 					handler = fdl_owner_handler;
 				}
 				break;
+			case SDCA_ENTITY_TYPE_HIDE:
+				if (control->sel == SDCA_CTL_HIDE_HIDTX_CURRENTOWNER)
+					handler = hid_handler;
+				break;
 			default:
 				break;
 			}