| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.18 024/150] ASoC: dwc: Ensure FIFOs are flushed to prevent channel swap | Date | Tue, 13 Jan 2015 23:21:35 -0800 |
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3.18-stable review patch. If anyone has any objections, please let me know.
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From: Andrew Jackson <Andrew.Jackson@arm.com>
commit 3475c3d034d7f276a474c8bd53f44b48c8bf669d upstream.
Flush the FIFOs when the stream is prepared for use. This avoids an inadvertent swapping of the left/right channels if the FIFOs are not empty at startup.
Signed-off-by: Andrew Jackson <Andrew.Jackson@arm.com> Signed-off-by: Mark Brown <broonie@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- sound/soc/dwc/designware_i2s.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+)
--- a/sound/soc/dwc/designware_i2s.c +++ b/sound/soc/dwc/designware_i2s.c @@ -263,6 +263,19 @@ static void dw_i2s_shutdown(struct snd_p snd_soc_dai_set_dma_data(dai, substream, NULL); } +static int dw_i2s_prepare(struct snd_pcm_substream *substream, + struct snd_soc_dai *dai) +{ + struct dw_i2s_dev *dev = snd_soc_dai_get_drvdata(dai); + + if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) + i2s_write_reg(dev->i2s_base, TXFFR, 1); + else + i2s_write_reg(dev->i2s_base, RXFFR, 1); + + return 0; +} + static int dw_i2s_trigger(struct snd_pcm_substream *substream, int cmd, struct snd_soc_dai *dai) { @@ -294,6 +307,7 @@ static struct snd_soc_dai_ops dw_i2s_dai .startup = dw_i2s_startup, .shutdown = dw_i2s_shutdown, .hw_params = dw_i2s_hw_params, + .prepare = dw_i2s_prepare, .trigger = dw_i2s_trigger, };
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