]> git.ipfire.org Git - thirdparty/kernel/linux.git/commitdiff
ASoC: simple-amplifier: gpio-audio-amp: Add support for gain-ranges
authorHerve Codina <herve.codina@bootlin.com>
Wed, 13 May 2026 08:16:58 +0000 (10:16 +0200)
committerMark Brown <broonie@kernel.org>
Mon, 18 May 2026 16:44:13 +0000 (17:44 +0100)
The mapping between physical gain values and gpio values can be
expressed using ranges described in the gain-ranges property.

This gain-ranges property is an array of ranges.

Each range in the array is defined by the first point and last point in
the range. Those points are a pair of values, the gpios value and the
related gain (dB) value.

With that, a given range defines N possible items (from the first point
gpios value to the last point gpios value) in order to set a gain from
the first point gain value to the last point gain value.

Handle this description and the related kcontrol.

Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Link: https://patch.msgid.link/20260513081702.317117-15-herve.codina@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>
sound/soc/codecs/simple-amplifier.c

index 5b172e520dcd0e528d0051976b60ad1f4ae58ba5..5759f9bc2f4ffefba3013fe4a8fffafe9ef48d71 100644 (file)
@@ -7,11 +7,16 @@
 #include <linux/bitmap.h>
 #include <linux/bits.h>
 #include <linux/gpio/consumer.h>
+#include <linux/math.h>
+#include <linux/minmax.h>
 #include <linux/mod_devicetable.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/regulator/consumer.h>
+#include <linux/slab.h>
 #include <sound/soc.h>
+#include <linux/sort.h>
+#include <sound/tlv.h>
 
 struct simple_amp_single {
        struct gpio_desc *gpio;
@@ -20,11 +25,35 @@ struct simple_amp_single {
        const char *control_name;
 };
 
+struct simple_amp_point {
+       u32 gpio_val;
+       int gain_db;
+};
+
+struct simple_amp_range {
+       unsigned int nb_points;
+       struct simple_amp_point min;
+       struct simple_amp_point max;
+};
+
+struct simple_amp_ranges {
+       unsigned int nb_ranges;
+       struct simple_amp_range *tab_ranges;
+};
+
+enum simple_amp_mode {
+       SIMPLE_AMP_MODE_NONE,
+       SIMPLE_AMP_MODE_RANGES,
+};
+
 struct simple_amp_multi {
        struct gpio_descs *gpios;
        u32 kctrl_val;
        u32 kctrl_max;
        const char *control_name;
+       unsigned int *tlv_array;
+       enum simple_amp_mode mode;
+       struct simple_amp_ranges ranges;
 };
 
 struct simple_amp_data {
@@ -195,6 +224,32 @@ static int simple_amp_single_add_kcontrol(struct snd_soc_component *component,
        return snd_soc_add_component_controls(component, &control, 1);
 }
 
+static u32 simple_amp_multi_ranges_kctrl_to_gpio(u32 kctrl_val,
+                                                struct simple_amp_ranges *ranges)
+{
+       struct simple_amp_range *range;
+       u32 index = kctrl_val;
+       unsigned int i;
+
+       for (i = 0; i < ranges->nb_ranges; i++) {
+               range = &ranges->tab_ranges[i];
+
+               if (index < range->nb_points)
+                       return (range->max.gpio_val >= range->min.gpio_val) ?
+                               range->min.gpio_val + index :
+                               range->min.gpio_val - index;
+
+               index -= range->nb_points;
+       }
+
+       /*
+        * Given index out of possible ranges. This is shouldn't happen.
+        * Signal the issue and return the maximum value
+        */
+       WARN(1, "kctrl_val %u out of ranges\n", kctrl_val);
+       return ranges->tab_ranges[ranges->nb_ranges - 1].max.gpio_val;
+}
+
 static int simple_amp_multi_kctrl_write_gpios(struct simple_amp_multi *multi,
                                              u32 kctrl_val)
 {
@@ -204,7 +259,12 @@ static int simple_amp_multi_kctrl_write_gpios(struct simple_amp_multi *multi,
        if (kctrl_val > multi->kctrl_max)
                return -EINVAL;
 
-       gpio_val = kctrl_val;
+       if (multi->mode == SIMPLE_AMP_MODE_RANGES)
+               gpio_val = simple_amp_multi_ranges_kctrl_to_gpio(kctrl_val,
+                                                                &multi->ranges);
+       else
+               gpio_val = kctrl_val;
+
        bitmap_from_arr32(bm, &gpio_val, multi->gpios->ndescs);
 
        return gpiod_multi_set_value_cansleep(multi->gpios, bm);
@@ -252,6 +312,38 @@ static int simple_amp_multi_kctrl_int_put(struct snd_kcontrol *kcontrol,
        return 1; /* The value changed */
 }
 
+static unsigned int *simple_amp_alloc_tlv_ranges(const struct simple_amp_ranges *ranges)
+{
+       unsigned int index;
+       unsigned int *tlv;
+       unsigned int *t;
+       unsigned int i;
+
+       tlv = kzalloc_objs(*tlv, 2 + ranges->nb_ranges * 6, GFP_KERNEL);
+       if (!tlv)
+               return NULL;
+
+       t = tlv;
+
+       /* Fill first TLV */
+       *t++ = SNDRV_CTL_TLVT_DB_RANGE; /* Tag */
+       *t++ = ranges->nb_ranges * 6 * sizeof(*tlv); /* Len */
+       /* Ranges are sorted from lower to higher value */
+       index = 0;
+       for (i = 0; i < ranges->nb_ranges; i++) {
+               /* Fill range item i */
+               *t++ = index;  /* min */
+               index += ranges->tab_ranges[i].nb_points;
+               *t++ = index - 1;  /* max */
+               *t++ = SNDRV_CTL_TLVT_DB_MINMAX; /* Tag */
+               *t++ = 2 * sizeof(*tlv); /* Len */
+               *t++ = ranges->tab_ranges[i].min.gain_db; /* min_dB */
+               *t++ = ranges->tab_ranges[i].max.gain_db; /* max_dB */
+       }
+
+       return tlv;
+}
+
 static int simple_amp_multi_add_kcontrol(struct snd_soc_component *component,
                                         struct simple_amp_multi *multi)
 {
@@ -265,12 +357,39 @@ static int simple_amp_multi_add_kcontrol(struct snd_soc_component *component,
        };
        int ret;
 
+       switch (multi->mode) {
+       case SIMPLE_AMP_MODE_RANGES:
+               multi->tlv_array = simple_amp_alloc_tlv_ranges(&multi->ranges);
+               if (!multi->tlv_array)
+                       return -ENOMEM;
+
+               control.access = SNDRV_CTL_ELEM_ACCESS_TLV_READ |
+                                SNDRV_CTL_ELEM_ACCESS_READWRITE;
+               control.tlv.p = multi->tlv_array;
+               break;
+
+       case SIMPLE_AMP_MODE_NONE:
+               /* Already set control configuration is enough */
+               break;
+
+       default:
+               return -EINVAL;
+       }
+
        /* Be consistent between multi->kctrl_val value and the GPIOs value */
        ret = simple_amp_multi_kctrl_write_gpios(multi, multi->kctrl_val);
        if (ret)
-               return ret;
+               goto err_free_tlv_array;
 
-       return snd_soc_add_component_controls(component, &control, 1);
+       ret = snd_soc_add_component_controls(component, &control, 1);
+       if (ret)
+               goto err_free_tlv_array;
+
+       return 0;
+
+err_free_tlv_array:
+       kfree(multi->tlv_array);
+       return ret;
 }
 
 static int simple_amp_add_basic_dapm(struct snd_soc_component *component)
@@ -407,8 +526,17 @@ static int simple_amp_component_probe(struct snd_soc_component *component)
        return 0;
 }
 
+static void simple_amp_component_remove(struct snd_soc_component *component)
+{
+       struct simple_amp *simple_amp = snd_soc_component_get_drvdata(component);
+
+       kfree(simple_amp->gain.tlv_array);
+       simple_amp->gain.tlv_array = NULL;
+}
+
 static const struct snd_soc_component_driver simple_amp_component_driver = {
        .probe = simple_amp_component_probe,
+       .remove = simple_amp_component_remove,
 };
 
 static int simple_amp_parse_single_gpio(struct device *dev,
@@ -426,10 +554,179 @@ static int simple_amp_parse_single_gpio(struct device *dev,
        return 0;
 }
 
+static int simple_amp_cmp_ranges(const void *a, const void *b)
+{
+       const struct simple_amp_range *a_range = a;
+       const struct simple_amp_range *b_range = b;
+
+       /* Ranges a and b don't overlap. This has been already checked */
+
+       return a_range->min.gain_db - b_range->max.gain_db;
+}
+
+static int simple_amp_check_new_range(const struct simple_amp_range *new_range,
+                                     const struct simple_amp_range *tab_ranges,
+                                     unsigned int nb_ranges)
+{
+       unsigned int i;
+
+       for (i = 0; i < nb_ranges; i++) {
+               /* Check for range overlaps */
+               if (new_range->min.gain_db >= tab_ranges[i].min.gain_db &&
+                   new_range->min.gain_db <= tab_ranges[i].max.gain_db)
+                       return -EINVAL;
+
+               if (new_range->max.gain_db >= tab_ranges[i].min.gain_db &&
+                   new_range->max.gain_db <= tab_ranges[i].max.gain_db)
+                       return -EINVAL;
+
+               if (new_range->min.gain_db <= tab_ranges[i].min.gain_db &&
+                   new_range->max.gain_db >= tab_ranges[i].max.gain_db)
+                       return -EINVAL;
+       }
+       return 0;
+}
+
+static int simple_amp_parse_ranges(struct device *dev,
+                                  struct simple_amp_multi *multi,
+                                  const char *ranges_property)
+{
+       struct simple_amp_ranges *ranges = &multi->ranges;
+       struct simple_amp_range *range;
+       struct device_node *np = dev->of_node;
+       struct simple_amp_point first_point;
+       unsigned int max_gpio_val;
+       unsigned int i;
+       int ret;
+       u32 u;
+       s32 s;
+
+       max_gpio_val = (1 << multi->gpios->ndescs) - 1;
+
+       ret = of_property_count_u32_elems(np, ranges_property);
+       if (ret < 0)
+               return ret;
+
+       /* The ranges array cannot be empty */
+       if (ret == 0)
+               return -EINVAL;
+       /*
+        * One range item is composed of 2 points and each point is composed of
+        * 2 values.
+        */
+       if (ret % 4)
+               return -EINVAL;
+
+       ranges->nb_ranges = ret / 4;
+
+       /* The worst case is one range per possible gpio value */
+       if (ranges->nb_ranges > max_gpio_val + 1)
+               return -EINVAL;
+
+       ranges->tab_ranges = devm_kcalloc(dev, ranges->nb_ranges,
+                                         sizeof(*ranges->tab_ranges),
+                                         GFP_KERNEL);
+       if (!ranges->tab_ranges)
+               return -ENOMEM;
+
+       multi->kctrl_max = 0;
+       for (i = 0; i < ranges->nb_ranges; i++) {
+               range = &ranges->tab_ranges[i];
+
+               /* First gpios value */
+               ret = of_property_read_u32_index(np, ranges_property, i * 4, &u);
+               if (ret)
+                       return ret;
+               if (u > max_gpio_val)
+                       return -EINVAL;
+
+               range->min.gpio_val = u;
+
+               /* First Gain value */
+               ret = of_property_read_s32_index(np, ranges_property, i * 4 + 1, &s);
+               if (ret)
+                       return ret;
+
+               range->min.gain_db = s;
+
+               /* Second gpios value */
+               ret = of_property_read_u32_index(np, ranges_property, i * 4 + 2, &u);
+               if (ret)
+                       return ret;
+               if (u > max_gpio_val)
+                       return -EINVAL;
+
+               range->max.gpio_val = u;
+
+               /* Second Gain value */
+               ret = of_property_read_s32_index(np, ranges_property, i * 4 + 3, &s);
+               if (ret)
+                       return ret;
+
+               range->max.gain_db = s;
+
+               /* Save the first point for later usage */
+               if (i == 0)
+                       first_point = range->min;
+
+               /* Fix min and max if needed */
+               if (range->min.gain_db > range->max.gain_db)
+                       swap(range->min, range->max);
+
+               ret = simple_amp_check_new_range(range, ranges->tab_ranges, i);
+               if (ret)
+                       return ret;
+
+               range->nb_points = abs_diff(range->min.gpio_val,
+                                           range->max.gpio_val) + 1;
+
+               multi->kctrl_max += range->nb_points;
+       }
+
+       multi->kctrl_max -= 1;
+
+       /* Sort the tab_range array by gain_db value */
+       sort(ranges->tab_ranges, ranges->nb_ranges, sizeof(*ranges->tab_ranges),
+            simple_amp_cmp_ranges, NULL);
+
+       /*
+        * multi->kctrl_val is the index in tab_ranges.
+        *
+        * Choose to have the initial amplification value set to the first point
+        * available in the first range available in the tab_ranges array before
+        * sorting.
+        *
+        * This first point has been identified before sorting. Search for it in
+        * the sorted array in order to set the multi->kctrl_val initial value.
+        */
+       multi->kctrl_val = 0;
+       for (i = 0; i < ranges->nb_ranges; i++) {
+               range = &ranges->tab_ranges[i];
+
+               if (range->min.gpio_val == first_point.gpio_val &&
+                   range->min.gain_db == first_point.gain_db)
+                       break;
+
+               multi->kctrl_val += range->nb_points;
+
+               if (range->max.gpio_val == first_point.gpio_val &&
+                   range->max.gain_db == first_point.gain_db) {
+                       multi->kctrl_val--;
+                       break;
+               }
+       }
+
+       return 0;
+}
+
 static int simple_amp_parse_multi_gpio(struct device *dev,
                                       struct simple_amp_multi *multi,
-                                      const char *gpios_property)
+                                      const char *gpios_property,
+                                      const char *ranges_property)
 {
+       struct device_node *np = dev->of_node;
+       int ret;
+
        /* Start with the value 0 (GPIO inactive). Can be changed later */
        multi->kctrl_val = 0;
        multi->gpios = devm_gpiod_get_array_optional(dev, gpios_property, GPIOD_OUT_LOW);
@@ -448,6 +745,15 @@ static int simple_amp_parse_multi_gpio(struct device *dev,
        /* Set default value for the kctrl_max. Can be changed later */
        multi->kctrl_max = (1 << multi->gpios->ndescs) - 1;
 
+       multi->mode = SIMPLE_AMP_MODE_NONE;
+       if (of_property_present(np, ranges_property)) {
+               ret = simple_amp_parse_ranges(dev, multi, ranges_property);
+               if (ret < 0)
+                       return dev_err_probe(dev, ret, "Failed to parse '%s'\n",
+                                            ranges_property);
+               multi->mode = SIMPLE_AMP_MODE_RANGES;
+       }
+
        return 0;
 }
 
@@ -485,7 +791,8 @@ 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");
+               ret = simple_amp_parse_multi_gpio(dev, &simple_amp->gain, "gain",
+                                                 "gain-ranges");
                if (ret)
                        return ret;
        }