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ASoC: davinci-mcasp: Add support for FIFO usage caused delay reporting 

McASP have write and read FIFO, each 64 words deep.

From the WFIFOS/RFIFOS registers we can read the amount of data currently
in the FIFO which can be directly reported as delay.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Peter Ujfalusi 2018-08-31 11:24:56 +03:00 committed by Mark Brown
parent 834fe4084d
commit 5fcb457ac2
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GPG Key ID: 24D68B725D5487D0
1 changed files with 37 additions and 0 deletions
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37
sound/soc/davinci/davinci-mcasp.c
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@ -1041,6 +1041,42 @@ static int davinci_mcasp_calc_clk_div(struct davinci_mcasp *mcasp,
return error_ppm;
}
static inline u32 davinci_mcasp_tx_delay(struct davinci_mcasp *mcasp)
{
if (!mcasp->txnumevt)
return 0;
return mcasp_get_reg(mcasp, mcasp->fifo_base + MCASP_WFIFOSTS_OFFSET);
}
static inline u32 davinci_mcasp_rx_delay(struct davinci_mcasp *mcasp)
{
if (!mcasp->rxnumevt)
return 0;
return mcasp_get_reg(mcasp, mcasp->fifo_base + MCASP_RFIFOSTS_OFFSET);
}
static snd_pcm_sframes_t davinci_mcasp_delay(
struct snd_pcm_substream *substream,
struct snd_soc_dai *cpu_dai)
{
struct davinci_mcasp *mcasp = snd_soc_dai_get_drvdata(cpu_dai);
u32 fifo_use;
if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
fifo_use = davinci_mcasp_tx_delay(mcasp);
else
fifo_use = davinci_mcasp_rx_delay(mcasp);
/*
* Divide the used locations with the channel count to get the
* FIFO usage in samples (don't care about partial samples in the
* buffer).
*/
return fifo_use / substream->runtime->channels;
}
static int davinci_mcasp_hw_params(struct snd_pcm_substream *substream,
struct snd_pcm_hw_params *params,
struct snd_soc_dai *cpu_dai)
@ -1365,6 +1401,7 @@ static const struct snd_soc_dai_ops davinci_mcasp_dai_ops = {
.startup = davinci_mcasp_startup,
.shutdown = davinci_mcasp_shutdown,
.trigger = davinci_mcasp_trigger,
.delay = davinci_mcasp_delay,
.hw_params = davinci_mcasp_hw_params,
.set_fmt = davinci_mcasp_set_dai_fmt,
.set_clkdiv = davinci_mcasp_set_clkdiv,