[PATCH v4 1/3] ASoC: fsl_utils: Add snd_kcontrol functions for specific cases

Shengjiu Wang
2026-03-06T09:38:59Z

There are some registers which are volatile, at pm runtime suspend state,
the regmap cache only is enabled, regmap will return -EBUSY when trying to
access these registers.

static int _regmap_read(struct regmap *map, unsigned int reg,
unsigned int *val)
{
int ret;
void *context = _regmap_map_get_context(map);

if (!map->cache_bypass) {
ret = regcache_read(map, reg, val);
if (ret == 0)
return 0;
}

if (map->cache_only)
return -EBUSY;

if (!regmap_readable(map, reg))
return -EIO;

When exporting these registers by amixer interface to user space, there
will be -EBUSY errors in mixer-test when the cpu dai is in idle. In order
to avoid such error, needs to define FSL own functions to take a pm
runtime reference before calling snd_soc_get_xr_sx(),
snd_soc_get_enum_double(), snd_soc_get_volsw(), and so on.

Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
---
sound/soc/fsl/fsl_utils.c | 113 ++++++++++++++++++++++++++++++++++++++
sound/soc/fsl/fsl_utils.h | 30 ++++++++++
2 files changed, 143 insertions(+)

diff --git a/sound/soc/fsl/fsl_utils.c b/sound/soc/fsl/fsl_utils.c
index d69a6b9795bf..b82c2c3bc886 100644
--- a/sound/soc/fsl/fsl_utils.c
+++ b/sound/soc/fsl/fsl_utils.c
@@ -10,6 +10,7 @@
#include <linux/clk-provider.h>
#include <linux/module.h>
#include <linux/of_address.h>
+#include <linux/pm_runtime.h>
#include <sound/soc.h>

#include "fsl_utils.h"
@@ -197,6 +198,118 @@ void fsl_asoc_constrain_rates(struct snd_pcm_hw_constraint_list *target_constr,
}
EXPORT_SYMBOL(fsl_asoc_constrain_rates);

+/*
+ * Below functions are used by mixer interface to avoid accessing registers
+ * which are volatile at pm runtime suspend state (cache_only is enabled).
+ */
+int fsl_asoc_get_xr_sx(struct snd_kcontrol *kcontrol,
+ struct snd_ctl_elem_value *ucontrol)
+{
+ struct snd_soc_component *component = snd_kcontrol_chip(kcontrol);
+ int ret = 0;
+
+ ret = pm_runtime_resume_and_get(component->dev);
+ if (ret)
+ return ret;
+
+ ret = snd_soc_get_xr_sx(kcontrol, ucontrol);
+
+ pm_runtime_put_autosuspend(component->dev);
+
+ return ret;
+}
+EXPORT_SYMBOL(fsl_asoc_get_xr_sx);
+
+int fsl_asoc_put_xr_sx(struct snd_kcontrol *kcontrol,
+ struct snd_ctl_elem_value *ucontrol)
+{
+ struct snd_soc_component *component = snd_kcontrol_chip(kcontrol);
+ int ret = 0;
+
+ ret = pm_runtime_resume_and_get(component->dev);
+ if (ret)
+ return ret;
+
+ ret = snd_soc_put_xr_sx(kcontrol, ucontrol);
+
+ pm_runtime_put_autosuspend(component->dev);
+
+ return ret;
+}
+EXPORT_SYMBOL(fsl_asoc_put_xr_sx);
+
+int fsl_asoc_get_enum_double(struct snd_kcontrol *kcontrol,
+ struct snd_ctl_elem_value *ucontrol)
+{
+ struct snd_soc_component *component = snd_kcontrol_chip(kcontrol);
+ int ret = 0;
+
+ ret = pm_runtime_resume_and_get(component->dev);
+ if (ret)
+ return ret;
+
+ ret = snd_soc_get_enum_double(kcontrol, ucontrol);
+
+ pm_runtime_put_autosuspend(component->dev);
+
+ return ret;
+}
+EXPORT_SYMBOL(fsl_asoc_get_enum_double);
+
+int fsl_asoc_put_enum_double(struct snd_kcontrol *kcontrol,
+ struct snd_ctl_elem_value *ucontrol)
+{
+ struct snd_soc_component *component = snd_kcontrol_chip(kcontrol);
+ int ret = 0;
+
+ ret = pm_runtime_resume_and_get(component->dev);
+ if (ret)
+ return ret;
+
+ ret = snd_soc_put_enum_double(kcontrol, ucontrol);
+
+ pm_runtime_put_autosuspend(component->dev);
+
+ return ret;
+}
+EXPORT_SYMBOL(fsl_asoc_put_enum_double);
+
+int fsl_asoc_get_volsw(struct snd_kcontrol *kcontrol,
+ struct snd_ctl_elem_value *ucontrol)
+{
+ struct snd_soc_component *component = snd_kcontrol_chip(kcontrol);
+ int ret = 0;
+
+ ret = pm_runtime_resume_and_get(component->dev);
+ if (ret)
+ return ret;
+
+ ret = snd_soc_get_volsw(kcontrol, ucontrol);
+
+ pm_runtime_put_autosuspend(component->dev);
+
+ return ret;
+}
+EXPORT_SYMBOL(fsl_asoc_get_volsw);
+
+int fsl_asoc_put_volsw(struct snd_kcontrol *kcontrol,
+ struct snd_ctl_elem_value *ucontrol)
+{
+ struct snd_soc_component *component = snd_kcontrol_chip(kcontrol);
+ int ret = 0;
+
+ ret = pm_runtime_resume_and_get(component->dev);
+ if (ret)
+ return ret;
+
+ ret = snd_soc_put_volsw(kcontrol, ucontrol);
+
+ pm_runtime_put_autosuspend(component->dev);
+
+ return ret;
+}
+EXPORT_SYMBOL(fsl_asoc_put_volsw);
+
MODULE_AUTHOR("Timur Tabi <timur@freescale.com>");
MODULE_DESCRIPTION("Freescale ASoC utility code");
MODULE_LICENSE("GPL v2");
diff --git a/sound/soc/fsl/fsl_utils.h b/sound/soc/fsl/fsl_utils.h
index 21b25a11ecda..0cf9d1e7fb14 100644
--- a/sound/soc/fsl/fsl_utils.h
+++ b/sound/soc/fsl/fsl_utils.h
@@ -31,4 +31,34 @@ void fsl_asoc_constrain_rates(struct snd_pcm_hw_constraint_list *target_constr,
const struct snd_pcm_hw_constraint_list *original_constr,
struct clk *pll8k_clk, struct clk *pll11k_clk,
struct clk *ext_clk, int *target_rates);
+
+/* Similar to SOC_SINGLE_XR_SX, but it is for read only registers. */
+#define FSL_ASOC_SINGLE_XR_SX_EXT_RO(xname, xregbase, xregcount, xnbits, \
+ xmin, xmax, xinvert, xhandler_get) \
+{ .iface = SNDRV_CTL_ELEM_IFACE_MIXER, .name = (xname), \
+ .access = SNDRV_CTL_ELEM_ACCESS_READ | \
+ SNDRV_CTL_ELEM_ACCESS_VOLATILE, \
+ .info = snd_soc_info_xr_sx, .get = xhandler_get, \
+ .private_value = (unsigned long)&(struct soc_mreg_control) \
+ {.regbase = xregbase, .regcount = xregcount, .nbits = xnbits, \
+ .invert = xinvert, .min = xmin, .max = xmax} }
+
+int fsl_asoc_get_xr_sx(struct snd_kcontrol *kcontrol,
+ struct snd_ctl_elem_value *ucontrol);
+
+int fsl_asoc_put_xr_sx(struct snd_kcontrol *kcontrol,
+ struct snd_ctl_elem_value *ucontrol);
+
+int fsl_asoc_get_enum_double(struct snd_kcontrol *kcontrol,
+ struct snd_ctl_elem_value *ucontrol);
+
+int fsl_asoc_put_enum_double(struct snd_kcontrol *kcontrol,
+ struct snd_ctl_elem_value *ucontrol);
+
+int fsl_asoc_get_volsw(struct snd_kcontrol *kcontrol,
+ struct snd_ctl_elem_value *ucontrol);
+
+int fsl_asoc_put_volsw(struct snd_kcontrol *kcontrol,
+ struct snd_ctl_elem_value *ucontrol);
+
#endif /* _FSL_UTILS_H */
--
2.34.1