diff options
Diffstat (limited to 'target/linux/brcm2708/patches-4.4/0015-bcm2835-i2s-add-24bit-support-update-bclk_ratio-to-m.patch')
| -rw-r--r-- | target/linux/brcm2708/patches-4.4/0015-bcm2835-i2s-add-24bit-support-update-bclk_ratio-to-m.patch | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-4.4/0015-bcm2835-i2s-add-24bit-support-update-bclk_ratio-to-m.patch b/target/linux/brcm2708/patches-4.4/0015-bcm2835-i2s-add-24bit-support-update-bclk_ratio-to-m.patch new file mode 100644 index 0000000000..b6273271e1 --- /dev/null +++ b/target/linux/brcm2708/patches-4.4/0015-bcm2835-i2s-add-24bit-support-update-bclk_ratio-to-m.patch @@ -0,0 +1,79 @@ +From 328b2e8b8a38fe62431c2ad5ae22cee31740b10d Mon Sep 17 00:00:00 2001 +From: Matthias Reichl <hias@horus.com> +Date: Sun, 11 Oct 2015 15:21:16 +0200 +Subject: [PATCH 015/127] bcm2835-i2s: add 24bit support, update bclk_ratio to + more correct values + +Code ported from bcm2708-i2s driver in Raspberry Pi tree. + +RPi commit 62c05a0b5328d9376d39c9e74da10b8a2465c234 ("ASoC: BCM2708: +Add 24 bit support") + +This adds 24 bit support to the I2S driver of the BCM2708. +Besides enabling the 24 bit flags, it includes two bug fixes: + +MMAP is not supported. Claiming this leads to strange issues +when the format of driver and file do not match. + +The datasheet states that the width extension bit should be set +for widths greater than 24, but greater or equal would be correct. +This follows from the definition of the width field. + +Signed-off-by: Florian Meier <florian.meier@koalo.de> + +RPi commit 3e8c672bc4e92d457aa4654bbb4cfd79a18a2327 ("bcm2708-i2s: +Update bclk_ratio to more correct values") + +Discussion about blck_ratio affecting sound quality: +https://github.com/raspberrypi/linux/issues/681 + +Signed-off-by: Matthias Reichl <hias@horus.com> +--- + sound/soc/bcm/bcm2835-i2s.c | 12 +++++++++--- + 1 file changed, 9 insertions(+), 3 deletions(-) + +--- a/sound/soc/bcm/bcm2835-i2s.c ++++ b/sound/soc/bcm/bcm2835-i2s.c +@@ -340,11 +340,15 @@ static int bcm2835_i2s_hw_params(struct + switch (params_format(params)) { + case SNDRV_PCM_FORMAT_S16_LE: + data_length = 16; +- bclk_ratio = 40; ++ bclk_ratio = 50; ++ break; ++ case SNDRV_PCM_FORMAT_S24_LE: ++ data_length = 24; ++ bclk_ratio = 50; + break; + case SNDRV_PCM_FORMAT_S32_LE: + data_length = 32; +- bclk_ratio = 80; ++ bclk_ratio = 100; + break; + default: + return -EINVAL; +@@ -420,7 +424,7 @@ static int bcm2835_i2s_hw_params(struct + /* Setup the frame format */ + format = BCM2835_I2S_CHEN; + +- if (data_length > 24) ++ if (data_length >= 24) + format |= BCM2835_I2S_CHWEX; + + format |= BCM2835_I2S_CHWID((data_length-8)&0xf); +@@ -711,6 +715,7 @@ static struct snd_soc_dai_driver bcm2835 + .channels_max = 2, + .rates = SNDRV_PCM_RATE_8000_192000, + .formats = SNDRV_PCM_FMTBIT_S16_LE ++ | SNDRV_PCM_FMTBIT_S24_LE + | SNDRV_PCM_FMTBIT_S32_LE + }, + .capture = { +@@ -718,6 +723,7 @@ static struct snd_soc_dai_driver bcm2835 + .channels_max = 2, + .rates = SNDRV_PCM_RATE_8000_192000, + .formats = SNDRV_PCM_FMTBIT_S16_LE ++ | SNDRV_PCM_FMTBIT_S24_LE + | SNDRV_PCM_FMTBIT_S32_LE + }, + .ops = &bcm2835_i2s_dai_ops, |