linux-kernel - [PATCH RFC] ASoC: core: ensure component names are unique

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Date:   Fri, 14 Feb 2020 14:47:04 +0100
From:   Jerome Brunet <jbrunet@...libre.com>
To:     Mark Brown <broonie@...nel.org>,
        Liam Girdwood <lgirdwood@...il.com>
Cc:     Jerome Brunet <jbrunet@...libre.com>, alsa-devel@...a-project.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH RFC] ASoC: core: ensure component names are unique

Make sure each ASoC component is registered with a unique name.
The component is derived from the device name. If a device registers more
than one component, the component names will be the same.

This usually brings up a warning about the debugfs directory creation of
the component since directory already exists.

In such case, start numbering the component of the device so the names
don't collide anymore.

Signed-off-by: Jerome Brunet <jbrunet@...libre.com>
---

* Here is an example of /sys/kernel/debug/asoc/components before the change:
hdmi-audio-codec.3.auto
c1105400.audio-controller
c1105400.audio-controller
c1105400.audio-controller
c8832000.audio-controller
analog-amplifier
snd-soc-dummy
snd-soc-dummy

* and after:
hdmi-audio-codec.3.auto
c1105400.audio-controller-2
c1105400.audio-controller-1
c1105400.audio-controller
c8832000.audio-controller
analog-amplifier
snd-soc-dummy-1
snd-soc-dummy

I wanted to keep the name as they were for the devices registering
only one component but we could also start the numbering from the first
component instead of the second.

 sound/soc/soc-core.c | 29 ++++++++++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
index 03b87427faa7..6a58a8f6e3c4 100644
--- a/sound/soc/soc-core.c
+++ b/sound/soc/soc-core.c
@@ -2446,6 +2446,33 @@ static int snd_soc_register_dais(struct snd_soc_component *component,
 	return ret;
 }
 
+static char *snd_soc_component_unique_name(struct device *dev,
+					   struct snd_soc_component *component)
+{
+	struct snd_soc_component *pos;
+	int count = 0;
+	char *name, *unique;
+
+	name = fmt_single_name(dev, &component->id);
+	if (!name)
+		return name;
+
+	/* Count the number of components registred by the device */
+	for_each_component(pos) {
+		if (dev == pos->dev)
+			count++;
+	}
+
+	/* Keep naming as it is for the 1st component */
+	if (!count)
+		return name;
+
+	unique = devm_kasprintf(dev, GFP_KERNEL, "%s-%d", name, count);
+	devm_kfree(dev, name);
+
+	return unique;
+}
+
 static int snd_soc_component_initialize(struct snd_soc_component *component,
 	const struct snd_soc_component_driver *driver, struct device *dev)
 {
@@ -2454,7 +2481,7 @@ static int snd_soc_component_initialize(struct snd_soc_component *component,
 	INIT_LIST_HEAD(&component->card_list);
 	mutex_init(&component->io_mutex);
 
-	component->name = fmt_single_name(dev, &component->id);
+	component->name = snd_soc_component_unique_name(dev, component);
 	if (!component->name) {
 		dev_err(dev, "ASoC: Failed to allocate name\n");
 		return -ENOMEM;
-- 
2.24.1