[PATCH v2 0/2] Relax bitclk computation when using PLL

[PATCH v2 0/2] Relax bitclk computation when using PLL

[Daniel Baluta]

Using strict bitclk requirements we cannot support all promised
rates and formats. For this reason we relax bitclk computation
by choosing the best available bitclk.

First patch in the series is based on Arnd's patch:

http://mailman.alsa-project.org/pipermail/alsa-devel/2017-April/119899.html

Second one does the actual bitclk relaxation.

Daniel Baluta (2):
  ASoC: codec: wm9860: avoid maybe-uninitialized warning
  ASoC: codec: wm8960: Relax bit clock computation when using PLL

 sound/soc/codecs/wm8960.c | 36 +++++++++++++++++++++---------------
 1 file changed, 21 insertions(+), 15 deletions(-)

-- 
2.7.4

[PATCH v2 1/2] ASoC: codec: wm9860: avoid maybe-uninitialized warning

[Daniel Baluta]

The new PLL configuration code triggers a harmless warning:

sound/soc/codecs/wm8960.c: In function 'wm8960_configure_clocking':
sound/soc/codecs/wm8960.c:735:3: error: 'best_freq_out' may be used
uninitialized in this function [-Werror=maybe-uninitialized]
   wm8960_set_pll(codec, freq_in, best_freq_out);
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
sound/soc/codecs/wm8960.c:699:12: note: 'best_freq_out' was declared
here

Fix this by reworking the code such that:

1) When there is no PLL freq available return -EINVAL and make
sure *bclk_idx, *dac_idx, *sysclk_idx are initialized with
invalid values.

2) When there is a PLL freq available initialize *bclk_idx,
*dac_idx and *sysclk_idx with correct values and immediately
return the freq available.

Fixes: 84fdc00d519f ("ASoC: codec: wm9860: Refactor PLL out freq search")
Fixes: 303e8954af8d ("ASoC: codec: wm8960: Stop when a matching PLL freq is found")
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Daniel Baluta <daniel.baluta@nxp.com>
---
Changes since v1:
	* use return instead of break
	* update commit message

 sound/soc/codecs/wm8960.c | 26 +++++++++-----------------
 1 file changed, 9 insertions(+), 17 deletions(-)

diff --git a/sound/soc/codecs/wm8960.c b/sound/soc/codecs/wm8960.c
index ace69da..d899623 100644
--- a/sound/soc/codecs/wm8960.c
+++ b/sound/soc/codecs/wm8960.c
@@ -686,7 +686,7 @@ int wm8960_configure_sysclk(struct wm8960_priv *wm8960, int mclk,
  * @bclk_idx: bclk_divs index for found bclk
  *
  * Returns:
- *  -1, in case no PLL frequency out available was found
+ * < 0, in case no PLL frequency out available was found
  * >=0, in case we could derive bclk, lrclk, sysclk from PLL out using
  *      (@sysclk_idx, @dac_idx, @bclk_idx) dividers
  */
@@ -696,13 +696,13 @@ 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;
 	int i, j, k;
 
 	bclk = wm8960->bclk;
 	lrclk = wm8960->lrclk;
 
-	*bclk_idx = -1;
+	*sysclk_idx = *dac_idx = *bclk_idx = -1;
 
 	for (i = 0; i < ARRAY_SIZE(sysclk_divs); ++i) {
 		if (sysclk_divs[i] == -1)
@@ -720,21 +720,12 @@ int wm8960_configure_pll(struct snd_soc_codec *codec, int freq_in,
 					*sysclk_idx = i;
 					*dac_idx = j;
 					*bclk_idx = k;
-					best_freq_out = freq_out;
-					break;
+					return freq_out;
 				}
 			}
-			if (k != ARRAY_SIZE(bclk_divs))
-				break;
 		}
-		if (j != ARRAY_SIZE(dac_divs))
-			break;
 	}
-
-	if (*bclk_idx != -1)
-		wm8960_set_pll(codec, freq_in, best_freq_out);
-
-	return *bclk_idx;
+	return -EINVAL;
 }
 static int wm8960_configure_clocking(struct snd_soc_codec *codec)
 {
@@ -783,11 +774,12 @@ static int wm8960_configure_clocking(struct snd_soc_codec *codec)
 		}
 	}
 
-	ret = wm8960_configure_pll(codec, freq_in, &i, &j, &k);
-	if (ret < 0) {
+	freq_out = wm8960_configure_pll(codec, freq_in, &i, &j, &k);
+	if (freq_out < 0) {
 		dev_err(codec->dev, "failed to configure clock via PLL\n");
-		return -EINVAL;
+		return freq_out;
 	}
+	wm8960_set_pll(codec, freq_in, freq_out);
 
 configure_clock:
 	/* configure sysclk clock */
-- 
2.7.4

[PATCH v2 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.baluta@nxp.com>
---
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

Re: [PATCH v2 1/2] ASoC: codec: wm9860: avoid maybe-uninitialized warning

[Arnd Bergmann]

On Wed, Apr 26, 2017 at 3:09 PM, Daniel Baluta <daniel.baluta@nxp.com> wrote:
> The new PLL configuration code triggers a harmless warning:
>
> sound/soc/codecs/wm8960.c: In function 'wm8960_configure_clocking':
> sound/soc/codecs/wm8960.c:735:3: error: 'best_freq_out' may be used
> uninitialized in this function [-Werror=maybe-uninitialized]
>    wm8960_set_pll(codec, freq_in, best_freq_out);
>    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> sound/soc/codecs/wm8960.c:699:12: note: 'best_freq_out' was declared
> here
>
> Fix this by reworking the code such that:
>
> 1) When there is no PLL freq available return -EINVAL and make
> sure *bclk_idx, *dac_idx, *sysclk_idx are initialized with
> invalid values.
>
> 2) When there is a PLL freq available initialize *bclk_idx,
> *dac_idx and *sysclk_idx with correct values and immediately
> return the freq available.
>
> Fixes: 84fdc00d519f ("ASoC: codec: wm9860: Refactor PLL out freq search")
> Fixes: 303e8954af8d ("ASoC: codec: wm8960: Stop when a matching PLL freq is found")
> Suggested-by: Arnd Bergmann <arnd@arndb.de>
> Signed-off-by: Daniel Baluta <daniel.baluta@nxp.com>

Looks good to me. Let me know if you need me to test this more thoroughly
with randconfig builds, otherwise I'll assume it's fine and it will
get tested once
it shows up in linux-next.

Acked-by: Arnd Bergmann <arnd@arndb.de>

Thanks for addressing this,

       Arnd

Re: [PATCH v2 1/2] ASoC: codec: wm9860: avoid maybe-uninitialized warning

[Daniel Baluta]

On Jo, 2017-04-27 at 12:07 +0200, Arnd Bergmann wrote:
> On Wed, Apr 26, 2017 at 3:09 PM, Daniel Baluta <daniel.baluta@nxp.com
> > wrote:
> > 
> > The new PLL configuration code triggers a harmless warning:
> > 
> > sound/soc/codecs/wm8960.c: In function 'wm8960_configure_clocking':
> > sound/soc/codecs/wm8960.c:735:3: error: 'best_freq_out' may be used
> > uninitialized in this function [-Werror=maybe-uninitialized]
> >    wm8960_set_pll(codec, freq_in, best_freq_out);
> >    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > sound/soc/codecs/wm8960.c:699:12: note: 'best_freq_out' was
> > declared
> > here
> > 
> > Fix this by reworking the code such that:
> > 
> > 1) When there is no PLL freq available return -EINVAL and make
> > sure *bclk_idx, *dac_idx, *sysclk_idx are initialized with
> > invalid values.
> > 
> > 2) When there is a PLL freq available initialize *bclk_idx,
> > *dac_idx and *sysclk_idx with correct values and immediately
> > return the freq available.
> > 
> > Fixes: 84fdc00d519f ("ASoC: codec: wm9860: Refactor PLL out freq
> > search")
> > Fixes: 303e8954af8d ("ASoC: codec: wm8960: Stop when a matching PLL
> > freq is found")
> > Suggested-by: Arnd Bergmann <arnd@arndb.de>
> > Signed-off-by: Daniel Baluta <daniel.baluta@nxp.com>
> Looks good to me. Let me know if you need me to test this more
> thoroughly
> with randconfig builds, otherwise I'll assume it's fine and it will
> get tested once
> it shows up in linux-next.
> 
> Acked-by: Arnd Bergmann <arnd@arndb.de>
> 

Hi Arnd, 

Thanks for doing this. I wouldn't expect randconfigs builds to show
other issues.

Anyhow, would like to see if with your compiler there are no warnings
for the second patch of the series:

http://mailman.alsa-project.org/pipermail/alsa-devel/2017-April/120177.html

thanks,
Daniel.

Re: [PATCH v2 1/2] ASoC: codec: wm9860: avoid maybe-uninitialized warning

[Arnd Bergmann]

On Thu, Apr 27, 2017 at 1:02 PM, Daniel Baluta <daniel.baluta@nxp.com> wrote:
> On Jo, 2017-04-27 at 12:07 +0200, Arnd Bergmann wrote:
>> On Wed, Apr 26, 2017 at 3:09 PM, Daniel Baluta <daniel.baluta@nxp.com
>> > wrote:
>> >
>> > The new PLL configuration code triggers a harmless warning:
>> >
>> > sound/soc/codecs/wm8960.c: In function 'wm8960_configure_clocking':
>> > sound/soc/codecs/wm8960.c:735:3: error: 'best_freq_out' may be used
>> > uninitialized in this function [-Werror=maybe-uninitialized]
>> >    wm8960_set_pll(codec, freq_in, best_freq_out);
>> >    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> > sound/soc/codecs/wm8960.c:699:12: note: 'best_freq_out' was
>> > declared
>> > here
>> >
>> > Fix this by reworking the code such that:
>> >
>> > 1) When there is no PLL freq available return -EINVAL and make
>> > sure *bclk_idx, *dac_idx, *sysclk_idx are initialized with
>> > invalid values.
>> >
>> > 2) When there is a PLL freq available initialize *bclk_idx,
>> > *dac_idx and *sysclk_idx with correct values and immediately
>> > return the freq available.
>> >
>> > Fixes: 84fdc00d519f ("ASoC: codec: wm9860: Refactor PLL out freq
>> > search")
>> > Fixes: 303e8954af8d ("ASoC: codec: wm8960: Stop when a matching PLL
>> > freq is found")
>> > Suggested-by: Arnd Bergmann <arnd@arndb.de>
>> > Signed-off-by: Daniel Baluta <daniel.baluta@nxp.com>
>> Looks good to me. Let me know if you need me to test this more
>> thoroughly
>> with randconfig builds, otherwise I'll assume it's fine and it will
>> get tested once
>> it shows up in linux-next.
>>
>> Acked-by: Arnd Bergmann <arnd@arndb.de>
>>
>
> Hi Arnd,
>
> Thanks for doing this. I wouldn't expect randconfigs builds to show
> other issues.
>
> Anyhow, would like to see if with your compiler there are no warnings
> for the second patch of the series:
>
> http://mailman.alsa-project.org/pipermail/alsa-devel/2017-April/120177.html

I've applied both patches to my randconfig tree now. The configuration
that first showed the problem works fine now, but with -Wmaybe-uninitialized
warnings I try to do additional randconfig tests as sometimes the warnings
come back depending on some other inlining decisions or optimization
flags.

         Arnd

Applied "ASoC: codec: wm8960: Relax bit clock computation when using PLL" to the asoc tree

[Mark Brown]

The patch

   ASoC: codec: wm8960: Relax bit clock computation when using PLL

has been applied to the asoc tree at

   git://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git 

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From 82bab88910ee358305a2f31ab30dad59f1b6421c Mon Sep 17 00:00:00 2001
From: Daniel Baluta <daniel.baluta@nxp.com>
Date: Wed, 26 Apr 2017 16:09:52 +0300
Subject: [PATCH] ASoC: codec: wm8960: Relax bit clock computation when using
 PLL

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>
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 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 d899623fb101..9ed455700954 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)
 {
-- 
2.11.0

Applied "ASoC: codec: wm9860: avoid maybe-uninitialized warning" to the asoc tree

[Mark Brown]

The patch

   ASoC: codec: wm9860: avoid maybe-uninitialized warning

has been applied to the asoc tree at

   git://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git 

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From 66772eda0edbfbbbe7767a6b5d07e09dae84403d Mon Sep 17 00:00:00 2001
From: Daniel Baluta <daniel.baluta@nxp.com>
Date: Wed, 26 Apr 2017 16:09:51 +0300
Subject: [PATCH] ASoC: codec: wm9860: avoid maybe-uninitialized warning

The new PLL configuration code triggers a harmless warning:

sound/soc/codecs/wm8960.c: In function 'wm8960_configure_clocking':
sound/soc/codecs/wm8960.c:735:3: error: 'best_freq_out' may be used
uninitialized in this function [-Werror=maybe-uninitialized]
   wm8960_set_pll(codec, freq_in, best_freq_out);
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
sound/soc/codecs/wm8960.c:699:12: note: 'best_freq_out' was declared
here

Fix this by reworking the code such that:

1) When there is no PLL freq available return -EINVAL and make
sure *bclk_idx, *dac_idx, *sysclk_idx are initialized with
invalid values.

2) When there is a PLL freq available initialize *bclk_idx,
*dac_idx and *sysclk_idx with correct values and immediately
return the freq available.

Fixes: 84fdc00d519f ("ASoC: codec: wm9860: Refactor PLL out freq search")
Fixes: 303e8954af8d ("ASoC: codec: wm8960: Stop when a matching PLL freq is found")
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Daniel Baluta <daniel.baluta@nxp.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 sound/soc/codecs/wm8960.c | 26 +++++++++-----------------
 1 file changed, 9 insertions(+), 17 deletions(-)

diff --git a/sound/soc/codecs/wm8960.c b/sound/soc/codecs/wm8960.c
index ace69da97cb8..d899623fb101 100644
--- a/sound/soc/codecs/wm8960.c
+++ b/sound/soc/codecs/wm8960.c
@@ -686,7 +686,7 @@ int wm8960_configure_sysclk(struct wm8960_priv *wm8960, int mclk,
  * @bclk_idx: bclk_divs index for found bclk
  *
  * Returns:
- *  -1, in case no PLL frequency out available was found
+ * < 0, in case no PLL frequency out available was found
  * >=0, in case we could derive bclk, lrclk, sysclk from PLL out using
  *      (@sysclk_idx, @dac_idx, @bclk_idx) dividers
  */
@@ -696,13 +696,13 @@ 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;
 	int i, j, k;
 
 	bclk = wm8960->bclk;
 	lrclk = wm8960->lrclk;
 
-	*bclk_idx = -1;
+	*sysclk_idx = *dac_idx = *bclk_idx = -1;
 
 	for (i = 0; i < ARRAY_SIZE(sysclk_divs); ++i) {
 		if (sysclk_divs[i] == -1)
@@ -720,21 +720,12 @@ int wm8960_configure_pll(struct snd_soc_codec *codec, int freq_in,
 					*sysclk_idx = i;
 					*dac_idx = j;
 					*bclk_idx = k;
-					best_freq_out = freq_out;
-					break;
+					return freq_out;
 				}
 			}
-			if (k != ARRAY_SIZE(bclk_divs))
-				break;
 		}
-		if (j != ARRAY_SIZE(dac_divs))
-			break;
 	}
-
-	if (*bclk_idx != -1)
-		wm8960_set_pll(codec, freq_in, best_freq_out);
-
-	return *bclk_idx;
+	return -EINVAL;
 }
 static int wm8960_configure_clocking(struct snd_soc_codec *codec)
 {
@@ -783,11 +774,12 @@ static int wm8960_configure_clocking(struct snd_soc_codec *codec)
 		}
 	}
 
-	ret = wm8960_configure_pll(codec, freq_in, &i, &j, &k);
-	if (ret < 0) {
+	freq_out = wm8960_configure_pll(codec, freq_in, &i, &j, &k);
+	if (freq_out < 0) {
 		dev_err(codec->dev, "failed to configure clock via PLL\n");
-		return -EINVAL;
+		return freq_out;
 	}
+	wm8960_set_pll(codec, freq_in, freq_out);
 
 configure_clock:
 	/* configure sysclk clock */
-- 
2.11.0