[PATCH 1/4] ASoC: davinci-mcasp: Clear TXSTAT register before activating serializers

From: Peter Ujfalusi <peter.ujfalusi@ti.com>
To: Mark Brown <broonie@kernel.org>, Liam Girdwood <lgirdwood@gmail.com>
Cc: <alsa-devel@alsa-project.org>, <misael.lopez@ti.com>,
	<jsarha@ti.com>, <robh+dt@kernel.org>,
	<devicetree@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: [PATCH 1/4] ASoC: davinci-mcasp: Clear TXSTAT register before activating serializers
Date: Fri, 16 Nov 2018 15:41:38 +0200	[thread overview]
Message-ID: <20181116134141.17396-2-peter.ujfalusi@ti.com> (raw)
In-Reply-To: <20181116134141.17396-1-peter.ujfalusi@ti.com>

Follow the guideline from the TRM:
Before starting, clear the respective transmitter and receiver status
registers

To avoid stale state stored in the status registers.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
---
 sound/soc/davinci/davinci-mcasp.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/sound/soc/davinci/davinci-mcasp.c b/sound/soc/davinci/davinci-mcasp.c
index 267aee776b2d..740030b4d37a 100644
--- a/sound/soc/davinci/davinci-mcasp.c
+++ b/sound/soc/davinci/davinci-mcasp.c
@@ -192,6 +192,7 @@ static void mcasp_start_rx(struct davinci_mcasp *mcasp)
 	}
 
 	/* Activate serializer(s) */
+	mcasp_set_reg(mcasp, DAVINCI_MCASP_RXSTAT_REG, 0xFFFFFFFF);
 	mcasp_set_ctl_reg(mcasp, DAVINCI_MCASP_GBLCTLR_REG, RXSERCLR);
 	/* Release RX state machine */
 	mcasp_set_ctl_reg(mcasp, DAVINCI_MCASP_GBLCTLR_REG, RXSMRST);
@@ -220,6 +221,7 @@ static void mcasp_start_tx(struct davinci_mcasp *mcasp)
 	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_reg(mcasp, DAVINCI_MCASP_TXSTAT_REG, 0xFFFFFFFF);
 	mcasp_set_ctl_reg(mcasp, DAVINCI_MCASP_GBLCTLX_REG, TXSERCLR);
 
 	/* wait for XDATA to be cleared */
-- 
Peter

Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
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