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Subject[PATCH 2/2] ASoC: codec: wm8960: Relax bit clock computation when using PLL
Date
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@nxp.com>
---
Here, I forced the following harmless initialization:

*sysclk_idx = *dac_idx = *bclk_idx = -1;

otherwise I would trigger a gcc false positive warning:

sound/soc/codecs/wm8960.c: In function 'wm8960_configure_clocking':
sound/soc/codecs/wm8960.c:810:46: warning: 'j' may be used uninitialized
in this function [-Wmaybe-uninitialized]
snd_soc_update_bits(codec, WM8960_CLOCK1, 0x7 << 6, j << 6);
~~^~~~
sound/soc/codecs/wm8960.c:806:44: warning: 'i' may be used uninitialized
in this function [-Wmaybe-uninitialized]
snd_soc_update_bits(codec, WM8960_CLOCK1, 3 << 1, i << 1);
~~^~~~




sound/soc/codecs/wm8960.c | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/sound/soc/codecs/wm8960.c b/sound/soc/codecs/wm8960.c
index 8c87153..60700d5 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
@@ -696,13 +700,15 @@ 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, best_freq_out;
+ 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) {
if (sysclk_divs[i] == -1)
@@ -723,6 +729,13 @@ int wm8960_configure_pll(struct snd_soc_codec *codec, int freq_in,
best_freq_out = freq_out;
break;
}
+ if (diff > 0 && closest > diff) {
+ *sysclk_idx = i;
+ *dac_idx = j;
+ *bclk_idx = k;
+ closest = diff;
+ best_freq_out = freq_out;
+ }
}
if (k != ARRAY_SIZE(bclk_divs))
break;
--
2.7.4
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