ASoC: simple-amplifier: gpio-audio-amp: Add support for gain-labels

The possible gain values can be described using labels instead of gain
values in dB.

Those different labels are attached to a gpio values using the
gain-labels property.

Using the gain-labels description is mutually exclusive with gain-ranges
description used to describe the relationship between gpios values and
gain values.

Handle the gain-labels description and the related kcontrol.

Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Link: https://patch.msgid.link/20260513081702.317117-16-herve.codina@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/sound/soc/codecs/simple-amplifier.c b/sound/soc/codecs/simple-amplifier.c
index 5759f9bc2f4ffefba3013fe4a8fffafe9ef48d71..3785044235bb527ea81bc8ae556af8cdbb537466 100644 (file)
--- a/sound/soc/codecs/simple-amplifier.c
+++ b/sound/soc/codecs/simple-amplifier.c
@@ -41,9 +41,15 @@ struct simple_amp_ranges {
        struct simple_amp_range *tab_ranges;
 };
 
+struct simple_amp_labels {
+       unsigned int nb_labels;
+       const char **tab_labels;
+};
+
 enum simple_amp_mode {
        SIMPLE_AMP_MODE_NONE,
        SIMPLE_AMP_MODE_RANGES,
+       SIMPLE_AMP_MODE_LABELS,
 };
 
 struct simple_amp_multi {
@@ -53,7 +59,10 @@ struct simple_amp_multi {
        const char *control_name;
        unsigned int *tlv_array;
        enum simple_amp_mode mode;
-       struct simple_amp_ranges ranges;
+       union {
+               struct simple_amp_ranges ranges;
+               struct simple_amp_labels labels;
+       };
 };
 
 struct simple_amp_data {
@@ -312,6 +321,45 @@ static int simple_amp_multi_kctrl_int_put(struct snd_kcontrol *kcontrol,
        return 1; /* The value changed */
 }
 
+static int simple_amp_multi_kctrl_enum_info(struct snd_kcontrol *kcontrol,
+                                           struct snd_ctl_elem_info *uinfo)
+{
+       struct simple_amp_multi *multi = (struct simple_amp_multi *)kcontrol->private_value;
+
+       return snd_ctl_enum_info(uinfo, 1, multi->labels.nb_labels,
+                                multi->labels.tab_labels);
+}
+
+static int simple_amp_multi_kctrl_enum_get(struct snd_kcontrol *kcontrol,
+                                          struct snd_ctl_elem_value *ucontrol)
+{
+       struct simple_amp_multi *multi = (struct simple_amp_multi *)kcontrol->private_value;
+
+       ucontrol->value.enumerated.item[0] = multi->kctrl_val;
+       return 0;
+}
+
+static int simple_amp_multi_kctrl_enum_put(struct snd_kcontrol *kcontrol,
+                                          struct snd_ctl_elem_value *ucontrol)
+{
+       struct simple_amp_multi *multi = (struct simple_amp_multi *)kcontrol->private_value;
+       u32 kctrl_val;
+       int ret;
+
+       kctrl_val = ucontrol->value.enumerated.item[0];
+
+       if (kctrl_val == multi->kctrl_val)
+               return 0;
+
+       ret = simple_amp_multi_kctrl_write_gpios(multi, kctrl_val);
+       if (ret)
+               return ret;
+
+       multi->kctrl_val = kctrl_val;
+
+       return 1; /* The value changed */
+}
+
 static unsigned int *simple_amp_alloc_tlv_ranges(const struct simple_amp_ranges *ranges)
 {
        unsigned int index;
@@ -368,6 +416,13 @@ static int simple_amp_multi_add_kcontrol(struct snd_soc_component *component,
                control.tlv.p = multi->tlv_array;
                break;
 
+       case SIMPLE_AMP_MODE_LABELS:
+               /* Use enumerated values */
+               control.info = simple_amp_multi_kctrl_enum_info;
+               control.get = simple_amp_multi_kctrl_enum_get;
+               control.put = simple_amp_multi_kctrl_enum_put;
+               break;
+
        case SIMPLE_AMP_MODE_NONE:
                /* Already set control configuration is enough */
                break;
@@ -719,10 +774,44 @@ static int simple_amp_parse_ranges(struct device *dev,
        return 0;
 }
 
+static int simple_amp_parse_labels(struct device *dev,
+                                  struct simple_amp_multi *multi,
+                                  const char *labels_property)
+{
+       struct simple_amp_labels *labels = &multi->labels;
+       struct device_node *np = dev->of_node;
+       int ret;
+
+       ret = of_property_count_strings(np, labels_property);
+       if (ret < 0)
+               return ret;
+
+       /* The labels array cannot be empty */
+       if (ret == 0)
+               return -EINVAL;
+
+       labels->nb_labels = ret;
+       if (labels->nb_labels > (1 << multi->gpios->ndescs))
+               return -EINVAL;
+
+       labels->tab_labels = devm_kcalloc(dev, labels->nb_labels,
+                                         sizeof(*labels->tab_labels),
+                                         GFP_KERNEL);
+       if (!labels->tab_labels)
+               return -ENOMEM;
+
+       multi->kctrl_max = labels->nb_labels - 1;
+       multi->kctrl_val = 0;
+
+       return of_property_read_string_array(np, labels_property, labels->tab_labels,
+                                            labels->nb_labels);
+}
+
 static int simple_amp_parse_multi_gpio(struct device *dev,
                                       struct simple_amp_multi *multi,
                                       const char *gpios_property,
-                                      const char *ranges_property)
+                                      const char *ranges_property,
+                                      const char *labels_property)
 {
        struct device_node *np = dev->of_node;
        int ret;
@@ -752,6 +841,13 @@ static int simple_amp_parse_multi_gpio(struct device *dev,
                        return dev_err_probe(dev, ret, "Failed to parse '%s'\n",
                                             ranges_property);
                multi->mode = SIMPLE_AMP_MODE_RANGES;
+       } else if (of_property_present(np, labels_property)) {
+               ret = simple_amp_parse_labels(dev, multi, labels_property);
+               if (ret < 0)
+                       return dev_err_probe(dev, ret, "Failed to parse '%s'\n",
+                                            labels_property);
+
+               multi->mode = SIMPLE_AMP_MODE_LABELS;
        }
 
        return 0;
@@ -792,7 +888,7 @@ static int simple_amp_probe(struct platform_device *pdev)
 
        if (simple_amp->data->supports & SIMPLE_AUDIO_SUPPORT_PGA) {
                ret = simple_amp_parse_multi_gpio(dev, &simple_amp->gain, "gain",
-                                                 "gain-ranges");
+                                                 "gain-ranges", "gain-labels");
                if (ret)
                        return ret;
        }
@@ -802,6 +898,20 @@ static int simple_amp_probe(struct platform_device *pdev)
        simple_amp->mute.control_name = "Switch";
        simple_amp->bypass.control_name = "Bypass Switch";
 
+       if (simple_amp->gain.mode == SIMPLE_AMP_MODE_LABELS) {
+               /*
+                * The gain widget control will use enumerated values.
+                *
+                * Having just "Voltage" and "Switch" widget names with
+                * enumerated values and boolean value can confuse ALSA in terms
+                * of possible values (strings).
+                *
+                * Make things clear and avoid the just "Switch" name in that
+                * case.
+                */
+               simple_amp->mute.control_name = "Out Switch";
+       }
+
        return devm_snd_soc_register_component(dev,
                                               &simple_amp_component_driver,
                                               NULL, 0);