soc: soundwire: Add support to listen for DC detection

Add support to listen for DC detection event.
Shutdown WSA on receiving DC detection event.

CRs-Fixed: 2244131
Change-Id: Ifecab8bb9862976a647a161bad4c202b6e6459c7
Signed-off-by: Vignesh Kulothungan <vigneshk@codeaurora.org>

soc/swr-wcd-ctrl.c

@@ -26,6 +26,7 @@
 #include <linux/uaccess.h>
 #include <soc/soundwire.h>
 #include <soc/swr-wcd.h>
+#include <dsp/msm-audio-event-notify.h>
 #include "swrm_registers.h"
 #include "swr-wcd-ctrl.h"
 
@@ -1393,6 +1394,32 @@ static int swrm_master_init(struct swr_mstr_ctrl *swrm)
 	return ret;
 }
 
+static int swrm_event_notify(struct notifier_block *self,
+				unsigned long action, void *data)
+{
+	struct swr_mstr_ctrl *swrm = container_of(self, struct swr_mstr_ctrl,
+							event_notifier);
+	if (!swrm || !swrm->pdev) {
+		pr_err("%s: swrm or pdev is NULL\n", __func__);
+		return -EINVAL;
+	}
+	if (action != MSM_AUD_DC_EVENT) {
+		dev_err(&swrm->pdev->dev, "%s: invalid event type: %lu\n", __func__, action);
+		return -EINVAL;
+	}
+
+	schedule_work(&(swrm->dc_presence_work));
+
+	return 0;
+}
+
+static void swrm_notify_work_fn(struct work_struct *work)
+{
+	struct swr_mstr_ctrl *swrm = container_of(work, struct swr_mstr_ctrl,
+							dc_presence_work);
+	swrm_wcd_notify(swrm->pdev, SWR_DEVICE_DOWN, NULL);
+}
+
 static int swrm_probe(struct platform_device *pdev)
 {
 	struct swr_mstr_ctrl *swrm;
@@ -1553,6 +1580,10 @@ static int swrm_probe(struct platform_device *pdev)
 	pm_runtime_enable(&pdev->dev);
 	pm_runtime_mark_last_busy(&pdev->dev);
 
+	INIT_WORK(&swrm->dc_presence_work, swrm_notify_work_fn);
+	swrm->event_notifier.notifier_call  = swrm_event_notify;
+	msm_aud_evt_register_client(&swrm->event_notifier);
+
 	return 0;
 err_mstr_fail:
 	swrm->reg_irq(swrm->handle, swr_mstr_interrupt,
@@ -1583,6 +1614,7 @@ static int swrm_remove(struct platform_device *pdev)
 	pm_runtime_disable(&pdev->dev);
 	pm_runtime_set_suspended(&pdev->dev);
 	swr_unregister_master(&swrm->master);
+	msm_aud_evt_unregister_client(&swrm->event_notifier);
 	mutex_destroy(&swrm->mlock);
 	mutex_destroy(&swrm->reslock);
 	mutex_destroy(&swrm->force_down_lock);

soc/swr-wcd-ctrl.h

@@ -108,6 +108,9 @@ struct swr_mstr_ctrl {
 	u8 num_cfg_devs;
 	struct mutex force_down_lock;
 	int force_down_state;
+
+	struct notifier_block event_notifier;
+	struct work_struct dc_presence_work;
 };
 
 #endif /* _SWR_WCD_CTRL_H */