ASoC: rt1308-sdw: enable pm_runtime in probe, keep status as 'suspended'

This patch suggests enabling pm_runtime during the probe, but marking the
device as 'active' only after it is enumerated. That will force a
dependency between the card and the codec, pm_runtime_get_sync() will
have to wait for the codec device to resume and hence implicitly wait
for the enumeration/initialization to be completed. In the nominal
case where the codec device is already active the get_sync() would
only perform a ref-count increase.

The changes are directly inspired by RT711 and RT711-sdca changes.
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@intel.com>
Reviewed-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20230802153629.53576-12-pierre-louis.bossart@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/rt1308-sdw.c

@@ -223,22 +223,12 @@ static int rt1308_io_init(struct device *dev, struct sdw_slave *slave)
 		regcache_cache_bypass(rt1308->regmap, true);
 
 	/*
-	 * PM runtime is only enabled when a Slave reports as Attached
+	 * PM runtime status is marked as 'active' only when a Slave reports as Attached
 	 */
-	if (!rt1308->first_hw_init) {
-		/* set autosuspend parameters */
-		pm_runtime_set_autosuspend_delay(&slave->dev, 3000);
-		pm_runtime_use_autosuspend(&slave->dev);
-
+	if (!rt1308->first_hw_init)
 		/* update count of parent 'active' children */
 		pm_runtime_set_active(&slave->dev);
 
-		/* make sure the device does not suspend immediately */
-		pm_runtime_mark_last_busy(&slave->dev);
-
-		pm_runtime_enable(&slave->dev);
-	}
-
 	pm_runtime_get_noresume(&slave->dev);
 
 	/* sw reset */
@@ -625,6 +615,9 @@ static int rt1308_sdw_component_probe(struct snd_soc_component *component)
 	rt1308->component = component;
 	rt1308_sdw_parse_dt(rt1308, &rt1308->sdw_slave->dev);
 
+	if (!rt1308->first_hw_init)
+		return 0;
+
 	ret = pm_runtime_resume(component->dev);
 	if (ret < 0 && ret != -EACCES)
 		return ret;
@@ -700,10 +693,27 @@ static int rt1308_sdw_init(struct device *dev, struct regmap *regmap,
 				&soc_component_sdw_rt1308,
 				rt1308_sdw_dai,
 				ARRAY_SIZE(rt1308_sdw_dai));
+	if (ret < 0)
+		return ret;
 
-	dev_dbg(&slave->dev, "%s\n", __func__);
+	/* set autosuspend parameters */
+	pm_runtime_set_autosuspend_delay(dev, 3000);
+	pm_runtime_use_autosuspend(dev);
 
-	return ret;
+	/* make sure the device does not suspend immediately */
+	pm_runtime_mark_last_busy(dev);
+
+	pm_runtime_enable(dev);
+
+	/* important note: the device is NOT tagged as 'active' and will remain
+	 * 'suspended' until the hardware is enumerated/initialized. This is required
+	 * to make sure the ASoC framework use of pm_runtime_get_sync() does not silently
+	 * fail with -EACCESS because of race conditions between card creation and enumeration
+	 */
+
+	dev_dbg(dev, "%s\n", __func__);
+
+	return 0;
 }
 
 static int rt1308_sdw_probe(struct sdw_slave *slave,
@@ -721,10 +731,7 @@ static int rt1308_sdw_probe(struct sdw_slave *slave,
 
 static int rt1308_sdw_remove(struct sdw_slave *slave)
 {
-	struct rt1308_sdw_priv *rt1308 = dev_get_drvdata(&slave->dev);
-
-	if (rt1308->first_hw_init)
-		pm_runtime_disable(&slave->dev);
+	pm_runtime_disable(&slave->dev);
 
 	return 0;
 }