[alsa-devel] [PATCH v2 08/19] soundwire: intel: reset pm_runtime status during system resume

[Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>]

The system resume does the entire bus re-initialization and brings it
to full-power. If the device was pm_runtime suspended, there is no
need to run the pm_runtime resume sequence after the system runtime.

Follow the documentation from runtime_pm.rst, and conditionally
disable, set_active and re-enable the device on system resume.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
---
 drivers/soundwire/intel.c     | 30 ++++++++++++++++++++++++++++++
 include/linux/soundwire/sdw.h |  1 +
 2 files changed, 31 insertions(+)

diff --git a/drivers/soundwire/intel.c b/drivers/soundwire/intel.c
index 650581348732..c3cd7d2d5a34 100644
--- a/drivers/soundwire/intel.c
+++ b/drivers/soundwire/intel.c
@@ -1298,6 +1298,7 @@ static int intel_master_remove(struct sdw_master_device *md)
 
 static int intel_suspend(struct device *dev)
 {
+	struct sdw_master_device *md = to_sdw_master_device(dev);
 	struct sdw_cdns *cdns = dev_get_drvdata(dev);
 	struct sdw_intel *sdw = cdns_to_intel(cdns);
 	int ret;
@@ -1308,6 +1309,20 @@ static int intel_suspend(struct device *dev)
 		return 0;
 	}
 
+	if (pm_runtime_status_suspended(dev)) {
+		dev_dbg(dev,
+			"%s: pm_runtime status: suspended\n",
+			__func__);
+
+		/*
+		 * keep track of the state for the system resume, where
+		 * we will need to reset the pm_runtime status to active
+		 */
+		md->pm_runtime_suspended = true;
+
+		return 0;
+	}
+
 	ret = sdw_cdns_enable_interrupt(cdns, false);
 	if (ret < 0) {
 		dev_err(dev, "cannot disable interrupts on suspend\n");
@@ -1356,6 +1371,7 @@ static int intel_suspend_runtime(struct device *dev)
 
 static int intel_resume(struct device *dev)
 {
+	struct sdw_master_device *md = to_sdw_master_device(dev);
 	struct sdw_cdns *cdns = dev_get_drvdata(dev);
 	struct sdw_intel *sdw = cdns_to_intel(cdns);
 	int ret;
@@ -1366,6 +1382,20 @@ static int intel_resume(struct device *dev)
 		return 0;
 	}
 
+	if (md->pm_runtime_suspended) {
+		dev_dbg(dev,
+			"%s: pm_runtime status was suspended, forcing active\n",
+			__func__);
+
+		/* follow required sequence from runtime_pm.rst */
+		pm_runtime_disable(dev);
+		pm_runtime_set_active(dev);
+		pm_runtime_mark_last_busy(dev);
+		pm_runtime_enable(dev);
+
+		md->pm_runtime_suspended = false;
+	}
+
 	ret = intel_init(sdw);
 	if (ret) {
 		dev_err(dev, "%s failed: %d", __func__, ret);
diff --git a/include/linux/soundwire/sdw.h b/include/linux/soundwire/sdw.h
index 17ec786d3a15..c06c515abad9 100644
--- a/include/linux/soundwire/sdw.h
+++ b/include/linux/soundwire/sdw.h
@@ -583,6 +583,7 @@ struct sdw_master_device {
 	struct device dev;
 	int link_id;
 	struct sdw_md_driver *driver;
+	bool pm_runtime_suspended;
 	void *pdata; /* core does not touch */
 };
 
-- 
2.20.1

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