ASoC: rsnd: add rsnd_ssi_clk_query()

Current Renesas sound driver is assuming that all Sampling rate and
channles are possible to use, but these are depends on inputed clock
and SSI connection situation.
For example, if it is using 1 SSI, enabled TDM mode and has 12288000
input clock, 2ch output can support until 192000Hz, but 6ch output can
support until 64000Hz, 8ch can support 48000Hz.
To control these situation correctly, it needs to support
hw_constraints / refine feature.

To support such feature, this patch adds new rsnd_ssi_clk_query().

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Tested-by: Hiroyuki Yokoyama <hiroyuki.yokoyama.vx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sh/rcar/rsnd.h

@@ -679,6 +679,8 @@ int __rsnd_ssi_is_pin_sharing(struct rsnd_mod *mod);
 void rsnd_parse_connect_ssi(struct rsnd_dai *rdai,
 			    struct device_node *playback,
 			    struct device_node *capture);
+int rsnd_ssi_clk_query(struct rsnd_priv *priv,
+		       int param1, int param2, int *idx);
 
 /*
  *	R-Car SSIU

sound/soc/sh/rcar/ssi.c

@@ -208,6 +208,46 @@ u32 rsnd_ssi_multi_slaves_runtime(struct rsnd_dai_stream *io)
 	return 0;
 }
 
+int rsnd_ssi_clk_query(struct rsnd_priv *priv,
+		       int param1, int param2, int *idx)
+{
+	int ssi_clk_mul_table[] = {
+		1, 2, 4, 8, 16, 6, 12,
+	};
+	int j, ret;
+	int main_rate;
+
+	for (j = 0; j < ARRAY_SIZE(ssi_clk_mul_table); j++) {
+
+		/*
+		 * It will set SSIWSR.CONT here, but SSICR.CKDV = 000
+		 * with it is not allowed. (SSIWSR.WS_MODE with
+		 * SSICR.CKDV = 000 is not allowed either).
+		 * Skip it. See SSICR.CKDV
+		 */
+		if (j == 0)
+			continue;
+
+		/*
+		 * this driver is assuming that
+		 * system word is 32bit x chan
+		 * see rsnd_ssi_init()
+		 */
+		main_rate = 32 * param1 * param2 * ssi_clk_mul_table[j];
+
+		ret = rsnd_adg_clk_query(priv, main_rate);
+		if (ret < 0)
+			continue;
+
+		if (idx)
+			*idx = j;
+
+		return main_rate;
+	}
+
+	return -EINVAL;
+}
+
 static int rsnd_ssi_master_clk_start(struct rsnd_mod *mod,
 				     struct rsnd_dai_stream *io)
 {
@@ -217,10 +257,7 @@ static int rsnd_ssi_master_clk_start(struct rsnd_mod *mod,
 	struct rsnd_ssi *ssi = rsnd_mod_to_ssi(mod);
 	struct rsnd_mod *ssi_parent_mod = rsnd_io_to_mod_ssip(io);
 	int chan = rsnd_runtime_channel_for_ssi(io);
-	int j, ret;
-	int ssi_clk_mul_table[] = {
-		1, 2, 4, 8, 16, 6, 12,
-	};
+	int idx, ret;
 	unsigned int main_rate;
 	unsigned int rate = rsnd_io_is_play(io) ?
 		rsnd_src_get_out_rate(priv, io) :
@@ -244,45 +281,25 @@ static int rsnd_ssi_master_clk_start(struct rsnd_mod *mod,
 		return 0;
 	}
 
-	/*
-	 * Find best clock, and try to start ADG
-	 */
-	for (j = 0; j < ARRAY_SIZE(ssi_clk_mul_table); j++) {
-
-		/*
-		 * It will set SSIWSR.CONT here, but SSICR.CKDV = 000
-		 * with it is not allowed. (SSIWSR.WS_MODE with
-		 * SSICR.CKDV = 000 is not allowed either).
-		 * Skip it. See SSICR.CKDV
-		 */
-		if (j == 0)
-			continue;
-
-		/*
-		 * this driver is assuming that
-		 * system word is 32bit x chan
-		 * see rsnd_ssi_init()
-		 */
-		main_rate = rate * 32 * chan * ssi_clk_mul_table[j];
-
-		ret = rsnd_adg_ssi_clk_try_start(mod, main_rate);
-		if (0 == ret) {
-			ssi->cr_clk	= FORCE | SWL_32 |
-				SCKD | SWSD | CKDV(j);
-			ssi->wsr = CONT;
-
-			ssi->rate = rate;
-
-			dev_dbg(dev, "%s[%d] outputs %u Hz\n",
-				rsnd_mod_name(mod),
-				rsnd_mod_id(mod), rate);
-
-			return 0;
-		}
+	main_rate = rsnd_ssi_clk_query(priv, rate, chan, &idx);
+	if (main_rate < 0) {
+		dev_err(dev, "unsupported clock rate\n");
+		return -EIO;
 	}
 
-	dev_err(dev, "unsupported clock rate\n");
-	return -EIO;
+	ret = rsnd_adg_ssi_clk_try_start(mod, main_rate);
+	if (ret < 0)
+		return ret;
+
+	ssi->cr_clk = FORCE | SWL_32 | SCKD | SWSD | CKDV(idx);
+	ssi->wsr = CONT;
+	ssi->rate = rate;
+
+	dev_dbg(dev, "%s[%d] outputs %u Hz\n",
+		rsnd_mod_name(mod),
+		rsnd_mod_id(mod), rate);
+
+	return 0;
 }
 
 static void rsnd_ssi_master_clk_stop(struct rsnd_mod *mod,