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

[Daniel Baluta]

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.bal...@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