[PATCH v2 2/2] ASoC: codec: wm8960: Relax bit clock computation when using PLL

From: Daniel Baluta
Date: Wed Apr 26 2017 - 09:10:47 EST


Bitclk is derived from sysclk using bclk_divs.
Sysclk can be derived in two ways:
(1) directly from MLCK
(2) MCLK via PLL

Commit 3c01b9ee2ab9d0d ("ASoC: codec: wm8960: Relax bit clock
computation")
relaxed bitclk computation when sysclk is directly derived from MCLK.

Lets do the same thing when sysclk is derived via PLL.

Signed-off-by: Daniel Baluta <daniel.baluta@xxxxxxx>
---
Changes since v2:
* rebase after changes in first patch in the series

sound/soc/codecs/wm8960.c | 18 ++++++++++++++++--
1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/sound/soc/codecs/wm8960.c b/sound/soc/codecs/wm8960.c
index d899623..9ed4557 100644
--- a/sound/soc/codecs/wm8960.c
+++ b/sound/soc/codecs/wm8960.c
@@ -679,6 +679,10 @@ int wm8960_configure_sysclk(struct wm8960_priv *wm8960, int mclk,
* - freq_out = sysclk * sysclk_divs
* - 10 * sysclk = bclk * bclk_divs
*
+ * If we cannot find an exact match for (sysclk, lrclk, bclk)
+ * triplet, we relax the bclk such that bclk is chosen as the
+ * closest available frequency greater than expected bclk.
+ *
* @codec: codec structure
* @freq_in: input frequency used to derive freq out via PLL
* @sysclk_idx: sysclk_divs index for found sysclk
@@ -696,12 +700,14 @@ int wm8960_configure_pll(struct snd_soc_codec *codec, int freq_in,
{
struct wm8960_priv *wm8960 = snd_soc_codec_get_drvdata(codec);
int sysclk, bclk, lrclk, freq_out;
- int diff;
+ int diff, closest, best_freq_out;
int i, j, k;

bclk = wm8960->bclk;
lrclk = wm8960->lrclk;
+ closest = freq_in;

+ best_freq_out = -EINVAL;
*sysclk_idx = *dac_idx = *bclk_idx = -1;

for (i = 0; i < ARRAY_SIZE(sysclk_divs); ++i) {
@@ -722,10 +728,18 @@ int wm8960_configure_pll(struct snd_soc_codec *codec, int freq_in,
*bclk_idx = k;
return freq_out;
}
+ if (diff > 0 && closest > diff) {
+ *sysclk_idx = i;
+ *dac_idx = j;
+ *bclk_idx = k;
+ closest = diff;
+ best_freq_out = freq_out;
+ }
}
}
}
- return -EINVAL;
+
+ return best_freq_out;
}
static int wm8960_configure_clocking(struct snd_soc_codec *codec)
{
--
2.7.4