[PATCH 2/6] ASoC: SDCA: Handle volatile controls correctly

[Charles Keepax <ckeepax@opensource.cirrus.com>]

There are very few volatile controls in SDCA that are exported
as ALSA controls, typically Detected Mode is the only common
one. However, the current code does not resume the device when
these ALSA controls are accessed, which will result in the
read/write failing.

Add a new wrapper specifically for volatile controls that will do
the required pm_runtime operations before accessing the register.

Fixes: c3ca24e3fcb6 ("ASoC: SDCA: Create ALSA controls from DisCo")
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
---
 sound/soc/sdca/sdca_asoc.c | 52 ++++++++++++++++++++++++++++++++++++--
 1 file changed, 50 insertions(+), 2 deletions(-)

diff --git a/sound/soc/sdca/sdca_asoc.c b/sound/soc/sdca/sdca_asoc.c
index 498aba9df5d9b..9685281529e9f 100644
--- a/sound/soc/sdca/sdca_asoc.c
+++ b/sound/soc/sdca/sdca_asoc.c
@@ -16,6 +16,7 @@
 #include <linux/minmax.h>
 #include <linux/module.h>
 #include <linux/overflow.h>
+#include <linux/pm_runtime.h>
 #include <linux/regmap.h>
 #include <linux/soundwire/sdw_registers.h>
 #include <linux/string_helpers.h>
@@ -792,6 +793,48 @@ static int control_limit_kctl(struct device *dev,
 	return 0;
 }
 
+static int volatile_get_volsw(struct snd_kcontrol *kcontrol,
+			      struct snd_ctl_elem_value *ucontrol)
+{
+	struct snd_soc_component *component = snd_kcontrol_chip(kcontrol);
+	struct device *dev = component->dev;
+	int ret;
+
+	ret = pm_runtime_resume_and_get(dev);
+	if (ret < 0) {
+		dev_err(dev, "failed to resume reading %s: %d\n",
+			kcontrol->id.name, ret);
+		return ret;
+	}
+
+	ret = snd_soc_get_volsw(kcontrol, ucontrol);
+
+	pm_runtime_put(dev);
+
+	return ret;
+}
+
+static int volatile_put_volsw(struct snd_kcontrol *kcontrol,
+			      struct snd_ctl_elem_value *ucontrol)
+{
+	struct snd_soc_component *component = snd_kcontrol_chip(kcontrol);
+	struct device *dev = component->dev;
+	int ret;
+
+	ret = pm_runtime_resume_and_get(dev);
+	if (ret < 0) {
+		dev_err(dev, "failed to resume writing %s: %d\n",
+			kcontrol->id.name, ret);
+		return ret;
+	}
+
+	ret = snd_soc_put_volsw(kcontrol, ucontrol);
+
+	pm_runtime_put(dev);
+
+	return ret;
+}
+
 static int populate_control(struct device *dev,
 			    struct sdca_function_data *function,
 			    struct sdca_entity *entity,
@@ -849,8 +892,13 @@ static int populate_control(struct device *dev,
 	(*kctl)->private_value = (unsigned long)mc;
 	(*kctl)->iface = SNDRV_CTL_ELEM_IFACE_MIXER;
 	(*kctl)->info = snd_soc_info_volsw;
-	(*kctl)->get = snd_soc_get_volsw;
-	(*kctl)->put = snd_soc_put_volsw;
+	if (control->is_volatile) {
+		(*kctl)->get = volatile_get_volsw;
+		(*kctl)->put = volatile_put_volsw;
+	} else {
+		(*kctl)->get = snd_soc_get_volsw;
+		(*kctl)->put = snd_soc_put_volsw;
+	}
 
 	if (readonly_control(control))
 		(*kctl)->access = SNDRV_CTL_ELEM_ACCESS_READ;
-- 
2.47.3