From 7df8f9a20196072162d9dc8fe99943f2d35f23d5 Mon Sep 17 00:00:00 2001
From: Maxime Ripard <maxime.ripard@bootlin.com>
Date: Mon, 19 Aug 2019 21:25:14 +0200
Subject: [PATCH] ASoC: sun4i-i2s: Don't use the oversample to calculate BCLK
Git-commit: 7df8f9a20196072162d9dc8fe99943f2d35f23d5
Patch-mainline: v5.4-rc1
References: jsc#SLE-16518 bnc#1151927 5.3.4
The BCLK divider should be calculated using the parameters that actually
make the BCLK rate: the number of channels, the sampling rate and the
sample width.
We've been using the oversample_rate previously because in the former SoCs,
the BCLK's parent is MCLK, which in turn is being used to generate the
oversample rate, so we end up with something like this:
oversample = mclk_rate / sampling_rate
bclk_div = oversample / word_size / channels
So, bclk_div = mclk_rate / sampling_rate / word_size / channels.
And this is actually better, since the oversampling ratio only plays a role
because the MCLK is its parent, not because of what BCLK is supposed to be.
Furthermore, that assumption of MCLK being the parent has been broken on
newer SoCs, so let's use the proper formula, and have the parent rate as an
argument.
Fixes: 7d2993811a1e ("ASoC: sun4i-i2s: Add support for H3")
Fixes: 21faaea1343f ("ASoC: sun4i-i2s: Add support for A83T")
Fixes: 66ecce332538 ("ASoC: sun4i-i2s: Add compatibility with A64 codec I2S")
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://lore.kernel.org/r/c3595e3a9788c2ef2dcc30aa3c8c4953bb5cc249.1566242458.git-series.maxime.ripard@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
sound/soc/sunxi/sun4i-i2s.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/sound/soc/sunxi/sun4i-i2s.c b/sound/soc/sunxi/sun4i-i2s.c
index 70608fa30bf2..d879db581073 100644
--- a/sound/soc/sunxi/sun4i-i2s.c
+++ b/sound/soc/sunxi/sun4i-i2s.c
@@ -222,10 +222,11 @@ static const struct sun4i_i2s_clk_div sun4i_i2s_mclk_div[] = {
};
static int sun4i_i2s_get_bclk_div(struct sun4i_i2s *i2s,
- unsigned int oversample_rate,
+ unsigned long parent_rate,
+ unsigned int sampling_rate,
unsigned int word_size)
{
- int div = oversample_rate / word_size / 2;
+ int div = parent_rate / sampling_rate / word_size / 2;
int i;
for (i = 0; i < ARRAY_SIZE(sun4i_i2s_bclk_div); i++) {
@@ -315,8 +316,8 @@ static int sun4i_i2s_set_clk_rate(struct snd_soc_dai *dai,
return -EINVAL;
}
- bclk_div = sun4i_i2s_get_bclk_div(i2s, oversample_rate,
- word_size);
+ bclk_div = sun4i_i2s_get_bclk_div(i2s, i2s->mclk_freq,
+ rate, word_size);
if (bclk_div < 0) {
dev_err(dai->dev, "Unsupported BCLK divider: %d\n", bclk_div);
return -EINVAL;
--
2.16.4