From 36bcecd0a73eb4a11c9748bc96c2d254d5364d12 Mon Sep 17 00:00:00 2001 From: Peter Ujfalusi Date: Wed, 29 Oct 2014 13:55:44 +0200 Subject: [PATCH] ASoC: davinci-mcasp: Correct TX start sequence 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 Signed-off-by: Mark Brown --- 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 0eed9b1b24e1..e1c1f40dd77f 100644 --- a/sound/soc/davinci/davinci-mcasp.c +++ b/sound/soc/davinci/davinci-mcasp.c @@ -183,31 +183,24 @@ 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 98fbc451892a..9737108f0305 100644 --- a/sound/soc/davinci/davinci-mcasp.h +++ b/sound/soc/davinci/davinci-mcasp.h @@ -252,6 +252,12 @@ #define TXSMRST BIT(11) /* Transmitter State Machine Reset */ #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 */ -- 2.39.5