2017-07-26 05:46:16

by Arvind Yadav

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Subject: [PATCH v2 01/11] ASoC: samsung: s3c2412: Handle return value of clk_prepare_enable.

clk_prepare_enable() can fail here and we must check its return value.

Signed-off-by: Arvind Yadav <[email protected]>
---
Chnage in v2 :
Error handling for things done in s3c_i2sv2_probe().

sound/soc/samsung/s3c2412-i2s.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/sound/soc/samsung/s3c2412-i2s.c b/sound/soc/samsung/s3c2412-i2s.c
index 0a47182..0b96927 100644
--- a/sound/soc/samsung/s3c2412-i2s.c
+++ b/sound/soc/samsung/s3c2412-i2s.c
@@ -65,13 +65,16 @@ static int s3c2412_i2s_probe(struct snd_soc_dai *dai)
s3c2412_i2s.iis_cclk = devm_clk_get(dai->dev, "i2sclk");
if (IS_ERR(s3c2412_i2s.iis_cclk)) {
pr_err("failed to get i2sclk clock\n");
- return PTR_ERR(s3c2412_i2s.iis_cclk);
+ ret = PTR_ERR(s3c2412_i2s.iis_cclk);
+ goto err;
}

/* Set MPLL as the source for IIS CLK */

clk_set_parent(s3c2412_i2s.iis_cclk, clk_get(NULL, "mpll"));
- clk_prepare_enable(s3c2412_i2s.iis_cclk);
+ ret = clk_prepare_enable(s3c2412_i2s.iis_cclk);
+ if (ret)
+ goto err;

s3c2412_i2s.iis_cclk = s3c2412_i2s.iis_pclk;

@@ -80,6 +83,11 @@ static int s3c2412_i2s_probe(struct snd_soc_dai *dai)
S3C_GPIO_PULL_NONE);

return 0;
+
+err:
+ clk_disable(s3c2412_i2s.iis_pclk);
+ clk_put(s3c2412_i2s.iis_pclk);
+ return ret;
}

static int s3c2412_i2s_remove(struct snd_soc_dai *dai)
--
1.9.1


2017-07-26 11:29:03

by Mark Brown

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Subject: Re: [PATCH v2 01/11] ASoC: samsung: s3c2412: Handle return value of clk_prepare_enable.

On Wed, Jul 26, 2017 at 11:15:25AM +0530, Arvind Yadav wrote:

> --- a/sound/soc/samsung/s3c2412-i2s.c
> +++ b/sound/soc/samsung/s3c2412-i2s.c
> @@ -65,13 +65,16 @@ static int s3c2412_i2s_probe(struct snd_soc_dai *dai)
> s3c2412_i2s.iis_cclk = devm_clk_get(dai->dev, "i2sclk");
> if (IS_ERR(s3c2412_i2s.iis_cclk)) {
> pr_err("failed to get i2sclk clock\n");
> - return PTR_ERR(s3c2412_i2s.iis_cclk);
> + ret = PTR_ERR(s3c2412_i2s.iis_cclk);
> + goto err;
> }
>

Why are we making this unrelated change? None of the error handling we
jump to is relevant if this fails...

> /* Set MPLL as the source for IIS CLK */
>
> clk_set_parent(s3c2412_i2s.iis_cclk, clk_get(NULL, "mpll"));
> - clk_prepare_enable(s3c2412_i2s.iis_cclk);
> + ret = clk_prepare_enable(s3c2412_i2s.iis_cclk);
> + if (ret)
> + goto err;
>
> s3c2412_i2s.iis_cclk = s3c2412_i2s.iis_pclk;
>
> @@ -80,6 +83,11 @@ static int s3c2412_i2s_probe(struct snd_soc_dai *dai)
> S3C_GPIO_PULL_NONE);
>
> return 0;
> +
> +err:
> + clk_disable(s3c2412_i2s.iis_pclk);

This will disable the clock if we failed to enable it which is clearly
not correct. It's also matching a clk_prepare_enable() with a
clk_disable() which is going to leave an unbalanced prepare.


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2017-07-26 12:06:47

by Arvind Yadav

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Subject: Re: [PATCH v2 01/11] ASoC: samsung: s3c2412: Handle return value of clk_prepare_enable.

Hi,


On Wednesday 26 July 2017 04:58 PM, Mark Brown wrote:
> On Wed, Jul 26, 2017 at 11:15:25AM +0530, Arvind Yadav wrote:
>
>> --- a/sound/soc/samsung/s3c2412-i2s.c
>> +++ b/sound/soc/samsung/s3c2412-i2s.c
>> @@ -65,13 +65,16 @@ static int s3c2412_i2s_probe(struct snd_soc_dai *dai)
>> s3c2412_i2s.iis_cclk = devm_clk_get(dai->dev, "i2sclk");
>> if (IS_ERR(s3c2412_i2s.iis_cclk)) {
>> pr_err("failed to get i2sclk clock\n");
>> - return PTR_ERR(s3c2412_i2s.iis_cclk);
>> + ret = PTR_ERR(s3c2412_i2s.iis_cclk);
>> + goto err;
>> }
>>
> Why are we making this unrelated change? None of the error handling we
> jump to is relevant if this fails...
3c_i2sv2_probe is enabling "iis" clock. If devm_clk_get(, "i2sclk") fails.
we need to disable and free the clock "iis" .
>
>> /* Set MPLL as the source for IIS CLK */
>>
>> clk_set_parent(s3c2412_i2s.iis_cclk, clk_get(NULL, "mpll"));
>> - clk_prepare_enable(s3c2412_i2s.iis_cclk);
>> + ret = clk_prepare_enable(s3c2412_i2s.iis_cclk);
>> + if (ret)
>> + goto err;
>>
>> s3c2412_i2s.iis_cclk = s3c2412_i2s.iis_pclk;
>>
>> @@ -80,6 +83,11 @@ static int s3c2412_i2s_probe(struct snd_soc_dai *dai)
>> S3C_GPIO_PULL_NONE);
>>
>> return 0;
>> +
>> +err:
>> + clk_disable(s3c2412_i2s.iis_pclk);
> This will disable the clock if we failed to enable it which is clearly
> not correct. It's also matching a clk_prepare_enable() with a
> clk_disable() which is going to leave an unbalanced prepare.
s3c_i2sv2_probe is enabling "iis" clock. And s3c2412_i2s_probe is enabling
"i2sclk" and "mpll"clock. If, "mpll" clk_prepare_enable fails. We need
to disable and
free the clock "iis". and devm will handle other clock "i2sclk". In
this code we have used
"s3c2412_i2s.iis_cclk" for all the clock which is more confusing for me.
Please correct me if i am wrong.

~arvind

2017-07-26 14:47:33

by Mark Brown

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Subject: Re: [PATCH v2 01/11] ASoC: samsung: s3c2412: Handle return value of clk_prepare_enable.

On Wed, Jul 26, 2017 at 05:35:32PM +0530, Arvind Yadav wrote:
> On Wednesday 26 July 2017 04:58 PM, Mark Brown wrote:
> > On Wed, Jul 26, 2017 at 11:15:25AM +0530, Arvind Yadav wrote:

> > > +err:
> > > + clk_disable(s3c2412_i2s.iis_pclk);
> > This will disable the clock if we failed to enable it which is clearly
> > not correct. It's also matching a clk_prepare_enable() with a
> > clk_disable() which is going to leave an unbalanced prepare.

> s3c_i2sv2_probe is enabling "iis" clock. And s3c2412_i2s_probe is enabling
> "i2sclk" and "mpll"clock. If, "mpll" clk_prepare_enable fails. We need to
> disable and
> free the clock "iis". and devm will handle other clock "i2sclk". In this
> code we have used
> "s3c2412_i2s.iis_cclk" for all the clock which is more confusing for me.
> Please correct me if i am wrong.

OK, they are different clocks. This inconsistent handling seems like a
big part of the problem though - it's going to be a source of errors.
We're also still only disabling here, not unpreparing, so we're missing
something.


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2017-07-26 15:45:23

by Krzysztof Kozlowski

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Subject: Re: [PATCH v2 01/11] ASoC: samsung: s3c2412: Handle return value of clk_prepare_enable.

On Wed, Jul 26, 2017 at 11:15:25AM +0530, Arvind Yadav wrote:
> clk_prepare_enable() can fail here and we must check its return value.
>
> Signed-off-by: Arvind Yadav <[email protected]>
> ---
> Chnage in v2 :
> Error handling for things done in s3c_i2sv2_probe().
>
> sound/soc/samsung/s3c2412-i2s.c | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/sound/soc/samsung/s3c2412-i2s.c b/sound/soc/samsung/s3c2412-i2s.c
> index 0a47182..0b96927 100644
> --- a/sound/soc/samsung/s3c2412-i2s.c
> +++ b/sound/soc/samsung/s3c2412-i2s.c
> @@ -65,13 +65,16 @@ static int s3c2412_i2s_probe(struct snd_soc_dai *dai)
> s3c2412_i2s.iis_cclk = devm_clk_get(dai->dev, "i2sclk");
> if (IS_ERR(s3c2412_i2s.iis_cclk)) {
> pr_err("failed to get i2sclk clock\n");
> - return PTR_ERR(s3c2412_i2s.iis_cclk);
> + ret = PTR_ERR(s3c2412_i2s.iis_cclk);
> + goto err;

No, this is kind of messy and error-prone. I think that each unit should
rather clean by itself. You should not touch s3c_i2sv2 stuff directly.

Instead define a s3c_i2sv2_cleanup() (or remove() to match the
convention?) and call it here on error-paths.

Best regards,
Krzysztof