All of lore.kernel.org
 help / color / mirror / Atom feed
From: Peter Ujfalusi <peter.ujfalusi@ti.com>
To: Mark Brown <broonie@kernel.org>, Liam Girdwood <lgirdwood@gmail.com>
Cc: alsa-devel@alsa-project.org, jsarha@ti.com, zonque@gmail.com
Subject: [PATCH 1/2] ASoC: davinci-mcasp: Correct TX start sequence
Date: Fri, 28 Mar 2014 09:18:29 +0200	[thread overview]
Message-ID: <1395991110-19280-2-git-send-email-peter.ujfalusi@ti.com> (raw)
In-Reply-To: <1395991110-19280-1-git-send-email-peter.ujfalusi@ti.com>

Follow the sequence described in the TRMs when starting TX. This sequence
will make sure that we are not facing with initial channel swap caused by
no data available in McASP for transmit.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
---
 sound/soc/davinci/davinci-mcasp.c | 25 +++++++++----------------
 sound/soc/davinci/davinci-mcasp.h |  6 ++++++
 2 files changed, 15 insertions(+), 16 deletions(-)

diff --git a/sound/soc/davinci/davinci-mcasp.c b/sound/soc/davinci/davinci-mcasp.c
index a01ae97c90aa..c6f2a7b9b6f6 100644
--- a/sound/soc/davinci/davinci-mcasp.c
+++ b/sound/soc/davinci/davinci-mcasp.c
@@ -165,31 +165,24 @@ static void mcasp_start_rx(struct davinci_mcasp *mcasp)
 
 static void mcasp_start_tx(struct davinci_mcasp *mcasp)
 {
-	u8 offset = 0, i;
 	u32 cnt;
 
+	/* Start clocks */
 	mcasp_set_ctl_reg(mcasp, DAVINCI_MCASP_GBLCTLX_REG, TXHCLKRST);
 	mcasp_set_ctl_reg(mcasp, DAVINCI_MCASP_GBLCTLX_REG, TXCLKRST);
+	/* Activate serializer(s) */
 	mcasp_set_ctl_reg(mcasp, DAVINCI_MCASP_GBLCTLX_REG, TXSERCLR);
-	mcasp_set_reg(mcasp, DAVINCI_MCASP_TXBUF_REG, 0);
 
-	mcasp_set_ctl_reg(mcasp, DAVINCI_MCASP_GBLCTLX_REG, TXSMRST);
-	mcasp_set_ctl_reg(mcasp, DAVINCI_MCASP_GBLCTLX_REG, TXFSRST);
-	mcasp_set_reg(mcasp, DAVINCI_MCASP_TXBUF_REG, 0);
-	for (i = 0; i < mcasp->num_serializer; i++) {
-		if (mcasp->serial_dir[i] == TX_MODE) {
-			offset = i;
-			break;
-		}
-	}
-
-	/* wait for TX ready */
+	/* wait for XDATA to be cleared */
 	cnt = 0;
-	while (!(mcasp_get_reg(mcasp, DAVINCI_MCASP_XRSRCTL_REG(offset)) &
-		 TXSTATE) && (cnt < 100000))
+	while (!(mcasp_get_reg(mcasp, DAVINCI_MCASP_TXSTAT_REG) &
+		 ~XRDATA) && (cnt < 100000))
 		cnt++;
 
-	mcasp_set_reg(mcasp, DAVINCI_MCASP_TXBUF_REG, 0);
+	/* Release TX state machine */
+	mcasp_set_ctl_reg(mcasp, DAVINCI_MCASP_GBLCTLX_REG, TXSMRST);
+	/* Release Frame Sync generator */
+	mcasp_set_ctl_reg(mcasp, DAVINCI_MCASP_GBLCTLX_REG, TXFSRST);
 }
 
 static void davinci_mcasp_start(struct davinci_mcasp *mcasp, int stream)
diff --git a/sound/soc/davinci/davinci-mcasp.h b/sound/soc/davinci/davinci-mcasp.h
index 8fed757d6087..53243c22818d 100644
--- a/sound/soc/davinci/davinci-mcasp.h
+++ b/sound/soc/davinci/davinci-mcasp.h
@@ -253,6 +253,12 @@
 #define TXFSRST		BIT(12)	/* Frame Sync Generator Reset */
 
 /*
+ * DAVINCI_MCASP_TXSTAT_REG - Transmitter Status Register Bits
+ * DAVINCI_MCASP_RXSTAT_REG - Receiver Status Register Bits
+ */
+#define XRDATA		BIT(5) /* Transmit/Receive data ready */
+
+/*
  * DAVINCI_MCASP_AMUTE_REG -  Mute Control Register Bits
  */
 #define MUTENA(val)	(val)
-- 
1.9.1

  reply	other threads:[~2014-03-28  7:18 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-03-28  7:18 [PATCH 0/2] ASoC: davinci-mcasp: Correct start sequences for TX/RX Peter Ujfalusi
2014-03-28  7:18 ` Peter Ujfalusi [this message]
2014-03-28  7:18 ` [PATCH 2/2] ASoC: davinci-mcasp: Correct RX start sequence Peter Ujfalusi
2014-03-28  8:24 ` [PATCH 0/2] ASoC: davinci-mcasp: Correct start sequences for TX/RX Peter Ujfalusi

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1395991110-19280-2-git-send-email-peter.ujfalusi@ti.com \
    --to=peter.ujfalusi@ti.com \
    --cc=alsa-devel@alsa-project.org \
    --cc=broonie@kernel.org \
    --cc=jsarha@ti.com \
    --cc=lgirdwood@gmail.com \
    --cc=zonque@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.