linux-kernel - [PATCH] ASoC: ops: Enforce platform maximum on initial value

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Message-Id: <20250208-asoc-volume-limit-v1-1-b98fcf4cdbad@kernel.org>
Date: Sat, 08 Feb 2025 00:57:22 +0000
From: broonie@...nel.org
To: Liam Girdwood <lgirdwood@...il.com>, 
 Martin Povišer <povik+lin@...ebit.org>
Cc: linux-sound@...r.kernel.org, linux-kernel@...r.kernel.org, 
 Mark Brown <broonie@...nel.orG>
Subject: [PATCH] ASoC: ops: Enforce platform maximum on initial value

From: Martin Povišer <povik+lin@...ebit.org>

Lower the volume if it is violating the platform maximum at its initial
value (i.e. at the time of the 'snd_soc_limit_volume' call).

Signed-off-by: Martin Povišer <povik+lin@...ebit.org>
[Cherry picked from the Asahi kernel with fixups -- broonie]
Signed-off-by: Mark Brown <broonie@...nel.orG>
---
 sound/soc/soc-ops.c | 29 ++++++++++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/sound/soc/soc-ops.c b/sound/soc/soc-ops.c
index 19928f098d8d..4d63dd0b0d0f 100644
--- a/sound/soc/soc-ops.c
+++ b/sound/soc/soc-ops.c
@@ -640,6 +640,33 @@ int snd_soc_get_volsw_range(struct snd_kcontrol *kcontrol,
 }
 EXPORT_SYMBOL_GPL(snd_soc_get_volsw_range);
 
+static int snd_soc_clip_to_platform_max(struct snd_kcontrol *kctl)
+{
+	struct soc_mixer_control *mc = (struct soc_mixer_control *)kctl->private_value;
+	struct snd_ctl_elem_value uctl;
+	int ret;
+
+	if (!mc->platform_max)
+		return 0;
+
+	ret = kctl->get(kctl, &uctl);
+	if (ret < 0)
+		return ret;
+
+	if (uctl.value.integer.value[0] > mc->platform_max)
+		uctl.value.integer.value[0] = mc->platform_max;
+
+	if (snd_soc_volsw_is_stereo(mc) &&
+	    uctl.value.integer.value[1] > mc->platform_max)
+		uctl.value.integer.value[1] = mc->platform_max;
+
+	ret = kctl->put(kctl, &uctl);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
 /**
  * snd_soc_limit_volume - Set new limit to an existing volume control.
  *
@@ -664,7 +691,7 @@ int snd_soc_limit_volume(struct snd_soc_card *card,
 		struct soc_mixer_control *mc = (struct soc_mixer_control *)kctl->private_value;
 		if (max <= mc->max - mc->min) {
 			mc->platform_max = max;
-			ret = 0;
+			ret = snd_soc_clip_to_platform_max(kctl);
 		}
 	}
 	return ret;

---
base-commit: 2014c95afecee3e76ca4a56956a936e23283f05b
change-id: 20250207-asoc-volume-limit-80abec587f6f

Best regards,
-- 
Mark Brown <broonie@...nel.org>