[PATCH v2 1/6] ASoC: rockchip: i2s-tdm: Fix clk_id usage in .set_sysclk()

[Luca Ceresoli <luca.ceresoli@bootlin.com>]

There are two problems with the second parameter of
rockchip_i2s_tdm_set_sysclk():

 1. The second argument to a .set_sysclk() op is a clk_id, not a stream
    index, so it is incorrect to compare it with SNDRV_PCM_STREAM_PLAYBACK.

    Technically this code works correctly anyway because
    SNDRV_PCM_STREAM_PLAYBACK is defined as 0, which is also the clk_id for
    the mclk_tx as enforced by the device tree bindings. So this is a
    formal error, not triggering incorrect behaviour.

 2. The else branch will consider any nonzero value as "rx", while only
    value 1 should be allowed for the mclk_rx clock. This does trigger
    incorrect behaviour if passing clk_id not equal to 0 or 1.

Fix problem 1 by adding a new enum for the clock indexes as enforced in
device tree and replace accordingly:

 * stream -> clk_id
 * SNDRV_PCM_STREAM_PLAYBACK -> CLK_MCLK_TX (value 0)

Fix problem 2 by returning error if clk_id is not 0 or 1.

Also simplify and improve dev_dbg() messages.

Fixes: 081068fd6414 ("ASoC: rockchip: add support for i2s-tdm controller")
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>

---

Changed in v2:
 - use switch statement instead of if/then/else
---
 sound/soc/rockchip/rockchip_i2s_tdm.c | 22 ++++++++++++++++------
 1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/sound/soc/rockchip/rockchip_i2s_tdm.c b/sound/soc/rockchip/rockchip_i2s_tdm.c
index 860e66ec85e8..35b36aa3b970 100644
--- a/sound/soc/rockchip/rockchip_i2s_tdm.c
+++ b/sound/soc/rockchip/rockchip_i2s_tdm.c
@@ -32,6 +32,9 @@
 #define TRCM_TX 1
 #define TRCM_RX 2
 
+/* Clock indexes as enforced by the DT bindings */
+enum { CLK_IDX_MCLK_TX, CLK_IDX_MCLK_RX };
+
 struct txrx_config {
 	u32 addr;
 	u32 reg;
@@ -973,7 +976,7 @@ static int rockchip_i2s_tdm_trigger(struct snd_pcm_substream *substream,
 	return 0;
 }
 
-static int rockchip_i2s_tdm_set_sysclk(struct snd_soc_dai *cpu_dai, int stream,
+static int rockchip_i2s_tdm_set_sysclk(struct snd_soc_dai *cpu_dai, int clk_id,
 				       unsigned int freq, int dir)
 {
 	struct rk_i2s_tdm_dev *i2s_tdm = to_info(cpu_dai);
@@ -982,15 +985,22 @@ static int rockchip_i2s_tdm_set_sysclk(struct snd_soc_dai *cpu_dai, int stream,
 	if (i2s_tdm->clk_trcm) {
 		i2s_tdm->mclk_tx_freq = freq;
 		i2s_tdm->mclk_rx_freq = freq;
+
+		dev_dbg(i2s_tdm->dev, "mclk freq: %u", freq);
 	} else {
-		if (stream == SNDRV_PCM_STREAM_PLAYBACK)
+		switch (clk_id) {
+		case CLK_IDX_MCLK_TX:
 			i2s_tdm->mclk_tx_freq = freq;
-		else
+			break;
+		case CLK_IDX_MCLK_RX:
 			i2s_tdm->mclk_rx_freq = freq;
-	}
+			break;
+		default:
+			return -ENOTSUPP;
+		}
 
-	dev_dbg(i2s_tdm->dev, "The target mclk_%s freq is: %d\n",
-		stream ? "rx" : "tx", freq);
+		dev_dbg(i2s_tdm->dev, "mclk[%d] freq: %u", clk_id, freq);
+	}
 
 	return 0;
 }

-- 
2.34.1