ASoC: max98373-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/20230802153629.53576-17-pierre-louis.bossart@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/sound/soc/codecs/max98373-sdw.c b/sound/soc/codecs/max98373-sdw.c
index 92d2b87..b5cb951 100644 (file)
--- a/sound/soc/codecs/max98373-sdw.c
+++ b/sound/soc/codecs/max98373-sdw.c
@@ -366,22 +366,12 @@ static int max98373_io_init(struct sdw_slave *slave)
                regcache_cache_bypass(max98373->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 (!max98373->first_hw_init) {
-               /* set autosuspend parameters */
-               pm_runtime_set_autosuspend_delay(dev, 3000);
-               pm_runtime_use_autosuspend(dev);
-
+       if (!max98373->first_hw_init)
                /* update count of parent 'active' children */
                pm_runtime_set_active(dev);
 
-               /* make sure the device does not suspend immediately */
-               pm_runtime_mark_last_busy(dev);
-
-               pm_runtime_enable(dev);
-       }
-
        pm_runtime_get_noresume(dev);
 
        /* Software Reset */
@@ -774,10 +764,27 @@ static int max98373_init(struct sdw_slave *slave, struct regmap *regmap)
        ret = devm_snd_soc_register_component(dev, &soc_codec_dev_max98373_sdw,
                                              max98373_sdw_dai,
                                              ARRAY_SIZE(max98373_sdw_dai));
-       if (ret < 0)
+       if (ret < 0) {
                dev_err(dev, "Failed to register codec: %d\n", ret);
+               return ret;
+       }
 
-       return ret;
+       /* set autosuspend parameters */
+       pm_runtime_set_autosuspend_delay(dev, 3000);
+       pm_runtime_use_autosuspend(dev);
+
+       /* 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
+        */
+
+       return 0;
 }
 
 static int max98373_update_status(struct sdw_slave *slave,
@@ -835,10 +842,7 @@ static int max98373_sdw_probe(struct sdw_slave *slave,
 
 static int max98373_sdw_remove(struct sdw_slave *slave)
 {
-       struct max98373_priv *max98373 = dev_get_drvdata(&slave->dev);
-
-       if (max98373->first_hw_init)
-               pm_runtime_disable(&slave->dev);
+       pm_runtime_disable(&slave->dev);
 
        return 0;
 }