linux-kernel - [PATCH] ASoC: fsl_ssi: call _fsl_ssi_set_dai

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Date:   Mon, 20 Nov 2017 23:13:45 +0100
From:   "Maciej S. Szmigiero" <mail@...iej.szmigiero.name>
To:     Timur Tabi <timur@...i.org>, Nicolin Chen <nicoleotsuka@...il.com>,
        Xiubo Li <Xiubo.Lee@...il.com>
Cc:     Fabio Estevam <fabio.estevam@....com>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>,
        Jaroslav Kysela <perex@...ex.cz>,
        Takashi Iwai <tiwai@...e.com>, alsa-devel@...a-project.org,
        linuxppc-dev@...ts.ozlabs.org,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: [PATCH] ASoC: fsl_ssi: call _fsl_ssi_set_dai_fmt() just once in AC'97
 mode

In AC'97 mode we configure and start SSI RX / TX on probe path via
a call to _fsl_ssi_set_dai_fmt() function.
We don't need to call this function again later and in fact don't want to
do it since this function temporarily sets STCR, SRCR and SCR to some
intermediate values.

We need to make sure, however, that only proper channel slots are enabled
at playback start time since some AC'97 CODECs (like VT1613) were observed
requesting via SLOTREQ (and so enabling at SSI) spurious ones just after
an AC'97 link is started but before the CODEC is configured by its driver.
Theoretically, this should be necessary only for the very first playback
but let's play safe here and make sure that no extra slots are enabled
every time a playback is started.

Signed-off-by: Maciej S. Szmigiero <mail@...iej.szmigiero.name>
---
 sound/soc/fsl/fsl_ssi.c | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/sound/soc/fsl/fsl_ssi.c b/sound/soc/fsl/fsl_ssi.c
index 48bb850a34d9..dad80b4b0cfc 100644
--- a/sound/soc/fsl/fsl_ssi.c
+++ b/sound/soc/fsl/fsl_ssi.c
@@ -630,12 +630,6 @@ static void fsl_ssi_setup_ac97(struct fsl_ssi_private *ssi_private)
 	regmap_write(regs, CCSR_SSI_SACNT,
 			CCSR_SSI_SACNT_AC97EN | CCSR_SSI_SACNT_FV);
 
-	/* no SACC{ST,EN,DIS} regs on imx21-class SSI */
-	if (!ssi_private->soc->imx21regs) {
-		regmap_write(regs, CCSR_SSI_SACCDIS, 0xff);
-		regmap_write(regs, CCSR_SSI_SACCEN, 0x300);
-	}
-
 	/*
 	 * Enable SSI, Transmit and Receive. AC97 has to communicate with the
 	 * codec before a stream is started.
@@ -1076,6 +1070,9 @@ static int fsl_ssi_set_dai_fmt(struct snd_soc_dai *cpu_dai, unsigned int fmt)
 {
 	struct fsl_ssi_private *ssi_private = snd_soc_dai_get_drvdata(cpu_dai);
 
+	if (fsl_ssi_is_ac97(ssi_private))
+		return 0;
+
 	return _fsl_ssi_set_dai_fmt(cpu_dai->dev, ssi_private, fmt);
 }
 
@@ -1149,9 +1146,16 @@ static int fsl_ssi_trigger(struct snd_pcm_substream *substream, int cmd,
 	case SNDRV_PCM_TRIGGER_START:
 	case SNDRV_PCM_TRIGGER_RESUME:
 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
-		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+			/* no SACC{ST,EN,DIS} regs on imx21-class SSI */
+			if (fsl_ssi_is_ac97(ssi_private) &&
+				!ssi_private->soc->imx21regs) {
+				regmap_write(regs, CCSR_SSI_SACCDIS, 0xff);
+				regmap_write(regs, CCSR_SSI_SACCEN, 0x300);
+			}
+
 			fsl_ssi_tx_config(ssi_private, true);
-		else
+		} else
 			fsl_ssi_rx_config(ssi_private, true);
 		break;