[PATCH v2 10/11] ALSA: hda: cs35l41: Add device_link between HDA and cs35l41_hda

[Stefan Binding <sbinding@opensource.cirrus.com>]

To ensure consistency between the HDA core and the CS35L41 HDA
driver, add a device_link between them. This ensures that the
HDA core will suspend first, and resume second, meaning the
amp driver will not miss any events from the playback hook from
the HDA core during system suspend and resume.

Signed-off-by: Stefan Binding <sbinding@opensource.cirrus.com>
---
 sound/pci/hda/cs35l41_hda.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/sound/pci/hda/cs35l41_hda.c b/sound/pci/hda/cs35l41_hda.c
index 70aa819cfbd64..175378cdf9dfa 100644
--- a/sound/pci/hda/cs35l41_hda.c
+++ b/sound/pci/hda/cs35l41_hda.c
@@ -1063,6 +1063,7 @@ static int cs35l41_hda_bind(struct device *dev, struct device *master, void *mas
 {
 	struct cs35l41_hda *cs35l41 = dev_get_drvdata(dev);
 	struct hda_component *comps = master_data;
+	unsigned int sleep_flags;
 	int ret = 0;
 
 	if (!comps || cs35l41->index < 0 || cs35l41->index >= HDA_MAX_COMPONENTS)
@@ -1102,6 +1103,11 @@ static int cs35l41_hda_bind(struct device *dev, struct device *master, void *mas
 
 	mutex_unlock(&cs35l41->fw_mutex);
 
+	sleep_flags = lock_system_sleep();
+	if (!device_link_add(&comps->codec->core.dev, cs35l41->dev, DL_FLAG_STATELESS))
+		dev_warn(dev, "Unable to create device link\n");
+	unlock_system_sleep(sleep_flags);
+
 	pm_runtime_mark_last_busy(dev);
 	pm_runtime_put_autosuspend(dev);
 
@@ -1112,9 +1118,14 @@ static void cs35l41_hda_unbind(struct device *dev, struct device *master, void *
 {
 	struct cs35l41_hda *cs35l41 = dev_get_drvdata(dev);
 	struct hda_component *comps = master_data;
+	unsigned int sleep_flags;
 
-	if (comps[cs35l41->index].dev == dev)
+	if (comps[cs35l41->index].dev == dev) {
 		memset(&comps[cs35l41->index], 0, sizeof(*comps));
+		sleep_flags = lock_system_sleep();
+		device_link_remove(&comps->codec->core.dev, cs35l41->dev);
+		unlock_system_sleep(sleep_flags);
+	}
 }
 
 static const struct component_ops cs35l41_hda_comp_ops = {
-- 
2.34.1