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90 lines
2.7 KiB
Diff
90 lines
2.7 KiB
Diff
From 425ee76116894c97d5d97ad4883eb2612b8692f3 Mon Sep 17 00:00:00 2001
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From: Giedrius Trainavicius <giedrius@blokas.io>
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Date: Sun, 8 Jan 2017 15:58:54 +0200
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Subject: [PATCH] bcm2835-i2s: Changes for allowing asymmetric sample formats.
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This is achieved by making changes only to the requested
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stream direction format, keeping the other stream direction
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configuration intact.
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Signed-off-by: Giedrius Trainavicius <giedrius@blokas.io>
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---
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sound/soc/bcm/bcm2835-i2s.c | 54 +++++++++++++++++++++++++++++++--------------
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1 file changed, 38 insertions(+), 16 deletions(-)
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--- a/sound/soc/bcm/bcm2835-i2s.c
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+++ b/sound/soc/bcm/bcm2835-i2s.c
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@@ -237,7 +237,9 @@ static int bcm2835_i2s_hw_params(struct
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unsigned int sampling_rate = params_rate(params);
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unsigned int data_length, data_delay, bclk_ratio;
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unsigned int ch1pos, ch2pos, mode, format;
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+ unsigned int previous_ftxp, previous_frxp;
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uint32_t csreg;
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+ bool packed;
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/*
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* If a stream is already enabled,
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@@ -320,26 +322,46 @@ static int bcm2835_i2s_hw_params(struct
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return -EINVAL;
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}
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- /*
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- * Set format for both streams.
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- * We cannot set another frame length
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- * (and therefore word length) anyway,
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- * so the format will be the same.
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- */
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- regmap_write(dev->i2s_regmap, BCM2835_I2S_RXC_A_REG, format);
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- regmap_write(dev->i2s_regmap, BCM2835_I2S_TXC_A_REG, format);
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+ /* Set the format for the matching stream direction. */
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+ switch (substream->stream) {
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+ case SNDRV_PCM_STREAM_PLAYBACK:
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+ regmap_write(dev->i2s_regmap, BCM2835_I2S_TXC_A_REG, format);
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+ break;
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+ case SNDRV_PCM_STREAM_CAPTURE:
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+ regmap_write(dev->i2s_regmap, BCM2835_I2S_RXC_A_REG, format);
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+ break;
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+ default:
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+ return -EINVAL;
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+ }
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/* Setup the I2S mode */
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+ /* Keep existing FTXP and FRXP values. */
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+ regmap_read(dev->i2s_regmap, BCM2835_I2S_MODE_A_REG, &mode);
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+
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+ previous_ftxp = mode & BCM2835_I2S_FTXP;
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+ previous_frxp = mode & BCM2835_I2S_FRXP;
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+
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mode = 0;
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- if (data_length <= 16) {
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- /*
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- * Use frame packed mode (2 channels per 32 bit word)
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- * We cannot set another frame length in the second stream
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- * (and therefore word length) anyway,
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- * so the format will be the same.
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- */
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- mode |= BCM2835_I2S_FTXP | BCM2835_I2S_FRXP;
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+ /*
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+ * Retain the frame packed mode (2 channels per 32 bit word)
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+ * of the other direction stream intact. The formats of each
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+ * direction can be different as long as the frame length is
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+ * shared for both.
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+ */
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+ packed = data_length <= 16;
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+
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+ switch (substream->stream) {
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+ case SNDRV_PCM_STREAM_PLAYBACK:
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+ mode |= previous_frxp;
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+ mode |= packed ? BCM2835_I2S_FTXP : 0;
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+ break;
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+ case SNDRV_PCM_STREAM_CAPTURE:
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+ mode |= previous_ftxp;
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+ mode |= packed ? BCM2835_I2S_FRXP : 0;
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+ break;
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+ default:
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+ return -EINVAL;
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}
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mode |= BCM2835_I2S_FLEN(bclk_ratio - 1);
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