ASoC: core: Add support for masking out parts of coefficient blocks

Chip designers frequently include things like the enable and disable
controls for algorithms in the register blocks which also hold the
coefficients. Since it's desirable to split out the enable/disable
control from userspace the plain SND_SOC_BYTES() isn't optimal for
these devices.

Add a SND_SOC_BYTES_MASK() which allows a bitmask from the first word
of the block to be excluded from the control. This supports the needs
of devices I've looked at and lets us have a reasonably simple API.
Further controls can be added in future if that's needed.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Liam Girdwood <lrg@ti.com>

include/sound/soc.h

@@ -192,6 +192,14 @@
 		((unsigned long)&(struct soc_bytes)           \
 		{.base = xbase, .num_regs = xregs }) }
 
+#define SND_SOC_BYTES_MASK(xname, xbase, xregs, xmask)	      \
+{	.iface = SNDRV_CTL_ELEM_IFACE_MIXER, .name = xname,   \
+	.info = snd_soc_bytes_info, .get = snd_soc_bytes_get, \
+	.put = snd_soc_bytes_put, .private_value =	      \
+		((unsigned long)&(struct soc_bytes)           \
+		{.base = xbase, .num_regs = xregs,	      \
+		 .mask = xmask }) }
+
 /*
  * Simplified versions of above macros, declaring a struct and calculating
  * ARRAY_SIZE internally
@@ -904,6 +912,7 @@ struct soc_mixer_control {
 struct soc_bytes {
 	int base;
 	int num_regs;
+	u32 mask;
 };
 
 /* enumerated kcontrol */

sound/soc/soc-core.c

@@ -2763,6 +2763,25 @@ int snd_soc_bytes_get(struct snd_kcontrol *kcontrol,
 	else
 		ret = -EINVAL;
 
+	/* Hide any masked bytes to ensure consistent data reporting */
+	if (ret == 0 && params->mask) {
+		switch (codec->val_bytes) {
+		case 1:
+			ucontrol->value.bytes.data[0] &= ~params->mask;
+			break;
+		case 2:
+			((u16 *)(&ucontrol->value.bytes.data))[0]
+				&= ~params->mask;
+			break;
+		case 4:
+			((u32 *)(&ucontrol->value.bytes.data))[0]
+				&= ~params->mask;
+			break;
+		default:
+			return -EINVAL;
+		}
+	}
+
 	return ret;
 }
 EXPORT_SYMBOL_GPL(snd_soc_bytes_get);
@@ -2772,14 +2791,55 @@ int snd_soc_bytes_put(struct snd_kcontrol *kcontrol,
 {
 	struct soc_bytes *params = (void *)kcontrol->private_value;
 	struct snd_soc_codec *codec = snd_kcontrol_chip(kcontrol);
-	int ret;
+	int ret, len;
+	unsigned int val;
+	void *data;
 
-	if (codec->using_regmap)
-		ret = regmap_raw_write(codec->control_data, params->base,
-				       ucontrol->value.bytes.data,
-				       params->num_regs * codec->val_bytes);
-	else
-		ret = -EINVAL;
+	if (!codec->using_regmap)
+		return -EINVAL;
+
+	data = ucontrol->value.bytes.data;
+	len = params->num_regs * codec->val_bytes;
+
+	/*
+	 * If we've got a mask then we need to preserve the register
+	 * bits.  We shouldn't modify the incoming data so take a
+	 * copy.
+	 */
+	if (params->mask) {
+		ret = regmap_read(codec->control_data, params->base, &val);
+		if (ret != 0)
+			return ret;
+
+		val &= params->mask;
+
+		data = kmemdup(data, len, GFP_KERNEL);
+		if (!data)
+			return -ENOMEM;
+
+		switch (codec->val_bytes) {
+		case 1:
+			((u8 *)data)[0] &= ~params->mask;
+			((u8 *)data)[0] |= val;
+			break;
+		case 2:
+			((u16 *)data)[0] &= cpu_to_be16(~params->mask);
+			((u16 *)data)[0] |= cpu_to_be16(val);
+			break;
+		case 4:
+			((u32 *)data)[0] &= cpu_to_be32(~params->mask);
+			((u32 *)data)[0] |= cpu_to_be32(val);
+			break;
+		default:
+			return -EINVAL;
+		}
+	}
+
+	ret = regmap_raw_write(codec->control_data, params->base,
+			       data, len);
+
+	if (params->mask)
+		kfree(data);
 
 	return ret;
 }