ASoC: core: add TDM slot parsing from DT supports

For some CPU/CODEC DAI devices the TDM slot infomation maybe needed. This
patch adds the slot parsing from DT supports.

TDM slot properties:
    dai-tdm-slot-num : Number of slots in use.
    dai-tdm-slot-width :  Width in bits for each slot.

For instance:
    dai-tdm-slot-num = <2>;
    dai-tdm-slot-width = <8>;

And for each spcified driver, there could be one .of_xlate_tdm_slot_mask()
to specify a explicit mapping of the channels and the slots. If it's absent
the default snd_soc_of_xlate_tdm_slot_mask() will be used to generating the
tx and rx masks.

For snd_soc_of_xlate_tdm_slot_mask(), the tx and rx masks will use a 1 bit
for an active slot as default, and the default active bits are at the LSB of
the masks.
Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

include/sound/soc-dai.h

@@ -142,6 +142,8 @@ struct snd_soc_dai_ops {
 	 * Called by soc_card drivers, normally in their hw_params.
 	 */
 	int (*set_fmt)(struct snd_soc_dai *dai, unsigned int fmt);
+	int (*of_xlate_tdm_slot_mask)(unsigned int slots,
+		unsigned int *tx_mask, unsigned int *rx_mask);
 	int (*set_tdm_slot)(struct snd_soc_dai *dai,
 		unsigned int tx_mask, unsigned int rx_mask,
 		int slots, int slot_width);

include/sound/soc.h

@@ -1175,6 +1175,9 @@ int snd_soc_of_parse_card_name(struct snd_soc_card *card,
 			       const char *propname);
 int snd_soc_of_parse_audio_simple_widgets(struct snd_soc_card *card,
 					  const char *propname);
+int snd_soc_of_parse_tdm_slot(struct device_node *np,
+			      unsigned int *slots,
+			      unsigned int *slot_width);
 int snd_soc_of_parse_audio_routing(struct snd_soc_card *card,
 				   const char *propname);
 unsigned int snd_soc_of_parse_daifmt(struct device_node *np,

sound/soc/soc-core.c

@@ -3608,6 +3608,30 @@ int snd_soc_dai_set_fmt(struct snd_soc_dai *dai, unsigned int fmt)
 }
 EXPORT_SYMBOL_GPL(snd_soc_dai_set_fmt);
 
+/**
+ * snd_soc_of_xlate_tdm_slot - generate tx/rx slot mask.
+ * @slots: Number of slots in use.
+ * @tx_mask: bitmask representing active TX slots.
+ * @rx_mask: bitmask representing active RX slots.
+ *
+ * Generates the TDM tx and rx slot default masks for DAI.
+ */
+static int snd_soc_of_xlate_tdm_slot_mask(unsigned int slots,
+					  unsigned int *tx_mask,
+					  unsigned int *rx_mask)
+{
+	if (*tx_mask || *rx_mask)
+		return 0;
+
+	if (!slots)
+		return -EINVAL;
+
+	*tx_mask = (1 << slots) - 1;
+	*rx_mask = (1 << slots) - 1;
+
+	return 0;
+}
+
 /**
  * snd_soc_dai_set_tdm_slot - configure DAI TDM.
  * @dai: DAI
@@ -3622,6 +3646,12 @@ EXPORT_SYMBOL_GPL(snd_soc_dai_set_fmt);
 int snd_soc_dai_set_tdm_slot(struct snd_soc_dai *dai,
 	unsigned int tx_mask, unsigned int rx_mask, int slots, int slot_width)
 {
+	if (dai->driver && dai->driver->ops->of_xlate_tdm_slot_mask)
+		dai->driver->ops->of_xlate_tdm_slot_mask(slots,
+						&tx_mask, &rx_mask);
+	else
+		snd_soc_of_xlate_tdm_slot_mask(slots, &tx_mask, &rx_mask);
+
 	if (dai->driver && dai->driver->ops->set_tdm_slot)
 		return dai->driver->ops->set_tdm_slot(dai, tx_mask, rx_mask,
 				slots, slot_width);
@@ -4504,6 +4534,35 @@ int snd_soc_of_parse_audio_simple_widgets(struct snd_soc_card *card,
 }
 EXPORT_SYMBOL_GPL(snd_soc_of_parse_audio_simple_widgets);
 
+int snd_soc_of_parse_tdm_slot(struct device_node *np,
+			      unsigned int *slots,
+			      unsigned int *slot_width)
+{
+	u32 val;
+	int ret;
+
+	if (of_property_read_bool(np, "dai-tdm-slot-num")) {
+		ret = of_property_read_u32(np, "dai-tdm-slot-num", &val);
+		if (ret)
+			return ret;
+
+		if (slots)
+			*slots = val;
+	}
+
+	if (of_property_read_bool(np, "dai-tdm-slot-width")) {
+		ret = of_property_read_u32(np, "dai-tdm-slot-width", &val);
+		if (ret)
+			return ret;
+
+		if (slot_width)
+			*slot_width = val;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(snd_soc_of_parse_tdm_slot);
+
 int snd_soc_of_parse_audio_routing(struct snd_soc_card *card,
 				   const char *propname)
 {