[PATCH v3 10/18] HID: steelseries: Add settings poll infrastructure

[Sriman Achanta <srimanachanta@gmail.com>]

Some headset settings (sidetone level, mic volume, etc.) are not
reported spontaneously but must be explicitly requested from the device.
Introduce a separate delayed work item (settings_work) for fetching
these persistent settings, independent of the existing status work.

Settings are requested once at probe time and again whenever the headset
reconnects after being disconnected. Device info structs gain
request_settings and parse_settings hooks for model-specific
implementations. The SS_CAP_EXTERNAL_CONFIG capability flag marks
devices whose writable controls can also be changed from the headset
hardware directly; writable ALSA controls on such devices will be marked
volatile.

The initial implementation adds the Arctis Nova 7 Gen2 audio settings
request (0x00, 0x20).

Signed-off-by: Sriman Achanta <srimanachanta@gmail.com>
---
 drivers/hid/hid-steelseries.c | 37 ++++++++++++++++++++++++++++++++++-
 1 file changed, 36 insertions(+), 1 deletion(-)

diff --git a/drivers/hid/hid-steelseries.c b/drivers/hid/hid-steelseries.c
index 8c6116d02f19..f2423c350154 100644
--- a/drivers/hid/hid-steelseries.c
+++ b/drivers/hid/hid-steelseries.c
@@ -26,6 +26,7 @@
 #define SS_CAP_MIC_MUTE			BIT(2)
 #define SS_CAP_BT_ENABLED		BIT(3)
 #define SS_CAP_BT_DEVICE_CONNECTED	BIT(4)
+#define SS_CAP_EXTERNAL_CONFIG		BIT(5)
 
 #define SS_QUIRK_STATUS_SYNC_POLL	BIT(0)
 
@@ -40,6 +41,9 @@ struct steelseries_device_info {
 
 	int (*request_status)(struct hid_device *hdev);
 	void (*parse_status)(struct steelseries_device *sd, u8 *data, int size);
+
+	int (*request_settings)(struct hid_device *hdev);
+	void (*parse_settings)(struct steelseries_device *sd, u8 *data, int size);
 };
 
 struct steelseries_device {
@@ -49,6 +53,7 @@ struct steelseries_device {
 	bool use_async_protocol;
 
 	struct delayed_work status_work;
+	struct delayed_work settings_work;
 
 	struct power_supply_desc battery_desc;
 	struct power_supply *battery;
@@ -690,6 +695,14 @@ static void steelseries_arctis_nova_7_gen2_parse_status(struct steelseries_devic
 	}
 }
 
+static int steelseries_arctis_nova_7_gen2_request_settings(struct hid_device *hdev)
+{
+	const u8 data[] = { 0x00, 0x20 };
+
+	return steelseries_send_output_report(hdev, data, sizeof(data));
+}
+
+
 static void steelseries_arctis_nova_pro_parse_status(struct steelseries_device *sd,
 						     u8 *data, int size)
 {
@@ -791,9 +804,11 @@ static const struct steelseries_device_info arctis_nova_7_gen2_info = {
 	.sync_interface = 3,
 	.async_interface = 5,
 	.capabilities = SS_CAP_BATTERY | SS_CAP_CHATMIX | SS_CAP_MIC_MUTE |
-			SS_CAP_BT_ENABLED | SS_CAP_BT_DEVICE_CONNECTED,
+			SS_CAP_BT_ENABLED | SS_CAP_BT_DEVICE_CONNECTED |
+			SS_CAP_EXTERNAL_CONFIG,
 	.request_status = steelseries_arctis_nova_request_status,
 	.parse_status = steelseries_arctis_nova_7_gen2_parse_status,
+	.request_settings = steelseries_arctis_nova_7_gen2_request_settings,
 };
 
 static const struct steelseries_device_info arctis_nova_pro_info = {
@@ -901,6 +916,15 @@ static void steelseries_status_timer_work_handler(struct work_struct *work)
 	spin_unlock_irqrestore(&sd->lock, flags);
 }
 
+static void steelseries_settings_work_handler(struct work_struct *work)
+{
+	struct steelseries_device *sd = container_of(
+		work, struct steelseries_device, settings_work.work);
+
+	if (sd->info->request_settings)
+		sd->info->request_settings(sd->hdev);
+}
+
 static int steelseries_battery_register(struct steelseries_device *sd)
 {
 	static atomic_t battery_no = ATOMIC_INIT(0);
@@ -1185,6 +1209,9 @@ static int steelseries_raw_event(struct hid_device *hdev,
 
 	sd->info->parse_status(sd, data, size);
 
+	if (sd->info->parse_settings)
+		sd->info->parse_settings(sd, data, size);
+
 	if (sd->headset_connected != old_connected) {
 		hid_dbg(hdev,
 			"Connected status changed from %sconnected to %sconnected\n",
@@ -1194,6 +1221,9 @@ static int steelseries_raw_event(struct hid_device *hdev,
 		if (sd->headset_connected && !old_connected &&
 		    sd->use_async_protocol && is_async_interface) {
 			schedule_delayed_work(&sd->status_work, 0);
+			if (sd->info->request_settings)
+				schedule_delayed_work(&sd->settings_work,
+						      msecs_to_jiffies(10));
 		}
 
 		if (sd->battery) {
@@ -1329,7 +1359,11 @@ static int steelseries_probe(struct hid_device *hdev,
 #endif
 
 		INIT_DELAYED_WORK(&sd->status_work, steelseries_status_timer_work_handler);
+		INIT_DELAYED_WORK(&sd->settings_work, steelseries_settings_work_handler);
+
 		schedule_delayed_work(&sd->status_work, msecs_to_jiffies(100));
+		if (info->request_settings)
+			schedule_delayed_work(&sd->settings_work, msecs_to_jiffies(200));
 
 		return 0;
 	}
@@ -1415,6 +1449,7 @@ static void steelseries_remove(struct hid_device *hdev)
 		spin_unlock_irqrestore(&sd->lock, flags);
 
 		cancel_delayed_work_sync(&sd->status_work);
+		cancel_delayed_work_sync(&sd->settings_work);
 	}
 
 	hid_hw_close(hdev);
-- 
2.53.0