[PATCH v2 2/2] ASoC: simple-card-utils: support system-clock-id DT property

[Sen Wang]

The generic machine driver never had a mechanism to adjust for various
clk_ids that is tailored for individual codec & cpu peripheral driver.
simple_util_dai_init() has hardcoded 0, thus making non-default clock IDs
unreachable from DTS. Boards needing a specific clk_id have had no choice
but to write dedicated machine drivers.

Add an optional "system-clock-id" u32 property to the cpu/codec
sub-node and use it in all three set_sysclk() call sites. When absent
clk_id stays 0, preserving identical behavior for all existing boards.

And since simple_util_parse_clk() is invoked once per sub-node, per-DAI
independence can be preserved as cpu and codec sub-nodes carry independent
clk_id values.

E.g., the following dts topology would be supported:

  cpu   { system-clock-id = <6>; }
  codec { system-clock-id = <1>; }

Signed-off-by: Sen Wang <sen@xxxxxx>
---

Apologies Morimoto-san, when finalizing the patch I realize a few more
places need to be changed, can you kindly re-review and give your
acked-by?

Changes in v2:
- Adopted sysclk func changes for mclk cases
- Links to v1 (RFC):
https://lore.kernel.org/all/20260514212802.3569643-1-sen@xxxxxx/

diff --git a/include/sound/simple_card_utils.h b/include/sound/simple_card_utils.h
index 915e6ae5f68d..f221fba92e5e 100644
--- a/include/sound/simple_card_utils.h
+++ b/include/sound/simple_card_utils.h
@@ -26,6 +26,7 @@ struct simple_util_dai {
 	const char *name;
 	unsigned int sysclk;
 	int clk_direction;
+	int clk_id;
 	int slots;
 	int slot_width;
 	unsigned int tx_slot_mask;
diff --git a/sound/soc/generic/simple-card-utils.c b/sound/soc/generic/simple-card-utils.c
index 4cf3a5395763..ce7e960db5e9 100644
--- a/sound/soc/generic/simple-card-utils.c
+++ b/sound/soc/generic/simple-card-utils.c
@@ -290,6 +290,9 @@ int simple_util_parse_clk(struct device *dev,
 	if (of_property_read_bool(node, "system-clock-direction-out"))
 		simple_dai->clk_direction = SND_SOC_CLOCK_OUT;
 
+	if (!of_property_read_u32(node, "system-clock-id", &val))
+		simple_dai->clk_id = val;
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(simple_util_parse_clk);
@@ -506,14 +509,16 @@ int simple_util_hw_params(struct snd_pcm_substream *substream,
 			/* CPU first */
 			for_each_rtd_cpu_dais(rtd, i, sdai) {
 				pdai = simple_props_to_dai_cpu(props, i);
-				ret = snd_soc_dai_set_sysclk(sdai, 0, mclk, pdai->clk_direction);
+				ret = snd_soc_dai_set_sysclk(sdai, pdai->clk_id,
+						mclk, pdai->clk_direction);
 				if (ret && ret != -ENOTSUPP)
 					goto end;
 			}
 
 			for_each_rtd_codec_dais(rtd, i, sdai) {
 				pdai = simple_props_to_dai_codec(props, i);
-				ret = snd_soc_dai_set_sysclk(sdai, 0, mclk, pdai->clk_direction);
+				ret = snd_soc_dai_set_sysclk(sdai, pdai->clk_id,
+						mclk, pdai->clk_direction);
 				if (ret && ret != -ENOTSUPP)
 					goto end;
 			}
@@ -521,14 +526,16 @@ int simple_util_hw_params(struct snd_pcm_substream *substream,
 			/* default: codec first */
 			for_each_rtd_codec_dais(rtd, i, sdai) {
 				pdai = simple_props_to_dai_codec(props, i);
-				ret = snd_soc_dai_set_sysclk(sdai, 0, mclk, pdai->clk_direction);
+				ret = snd_soc_dai_set_sysclk(sdai, pdai->clk_id,
+						mclk, pdai->clk_direction);
 				if (ret && ret != -ENOTSUPP)
 					goto end;
 			}
 
 			for_each_rtd_cpu_dais(rtd, i, sdai) {
 				pdai = simple_props_to_dai_cpu(props, i);
-				ret = snd_soc_dai_set_sysclk(sdai, 0, mclk, pdai->clk_direction);
+				ret = snd_soc_dai_set_sysclk(sdai, pdai->clk_id,
+						mclk, pdai->clk_direction);
 				if (ret && ret != -ENOTSUPP)
 					goto end;
 			}
@@ -587,7 +594,8 @@ static int simple_init_dai(struct simple_util_priv *priv,
 		return 0;
 
 	if (simple_dai->sysclk) {
-		ret = snd_soc_dai_set_sysclk(dai, 0, simple_dai->sysclk,
+		ret = snd_soc_dai_set_sysclk(dai, simple_dai->clk_id,
+					     simple_dai->sysclk,
 					     simple_dai->clk_direction);
 		if (ret && ret != -ENOTSUPP) {
 			dev_err(dai->dev, "simple-card: set_sysclk error\n");