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From: Luca Ceresoli <luca.ceresoli@bootlin.com>
Date: Tue, 19 Dec 2023 15:54:16 +0100
Subject: [PATCH v2 1/6] ASoC: rockchip: i2s-tdm: Fix clk_id usage in
 .set_sysclk()
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Message-Id: <20231219-rk3308-audio-codec-v2-1-c70d06021946@bootlin.com>
References: <20231219-rk3308-audio-codec-v2-0-c70d06021946@bootlin.com>
In-Reply-To: <20231219-rk3308-audio-codec-v2-0-c70d06021946@bootlin.com>
To: Nicolas Frattaroli <frattaroli.nicolas@gmail.com>, 
 Liam Girdwood <lgirdwood@gmail.com>, Mark Brown <broonie@kernel.org>, 
 Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.com>, 
 Heiko Stuebner <heiko@sntech.de>, Rob Herring <robh+dt@kernel.org>, 
 Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>, 
 Conor Dooley <conor+dt@kernel.org>, Philipp Zabel <p.zabel@pengutronix.de>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>, 
 linux-rockchip@lists.infradead.org, linux-sound@vger.kernel.org, 
 linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, 
 devicetree@vger.kernel.org, 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