2022-08-07 20:32:11

by Christophe JAILLET

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Subject: [PATCH] ASoC: Intel: kbl_rt5663_max98927: Simplify clk_get() usage

If clk_get() returns -ENOENT, there is no need to defer the driver, -ENOENT
will be returned the same for each retries.
So, return the error code directly instead of -EPROBE_DEFER.

Remove this special case and use dev_err_probe() to simplify code. It will
also be less verbose if the clk is really deferred.

Fixes: f7f61e08fe58 ("ASoC: Intel: kbl: Enable mclk and ssp sclk early")
Signed-off-by: Christophe JAILLET <[email protected]>
---
This is based on my understanding of clk_get().
Review with care.

Not sure the Fixes tag is needed. The patch does not fix anything.
If devm_clk_get() returns -ENOENT, it will just loop several time until
the framework gives up.
If it returns -EPROBE_DEFER, this case is already handled by the
"return ret;"

So this patch should be a no-op, just a clean-up.
---
sound/soc/intel/boards/kbl_rt5663_max98927.c | 31 ++++----------------
1 file changed, 6 insertions(+), 25 deletions(-)

diff --git a/sound/soc/intel/boards/kbl_rt5663_max98927.c b/sound/soc/intel/boards/kbl_rt5663_max98927.c
index 2d4224c5b152..07b00af2fa3c 100644
--- a/sound/soc/intel/boards/kbl_rt5663_max98927.c
+++ b/sound/soc/intel/boards/kbl_rt5663_max98927.c
@@ -989,7 +989,6 @@ static int kabylake_audio_probe(struct platform_device *pdev)
{
struct kbl_rt5663_private *ctx;
struct snd_soc_acpi_mach *mach;
- int ret;

ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
if (!ctx)
@@ -1009,32 +1008,14 @@ static int kabylake_audio_probe(struct platform_device *pdev)
&constraints_dmic_2ch : &constraints_dmic_channels;

ctx->mclk = devm_clk_get(&pdev->dev, "ssp1_mclk");
- if (IS_ERR(ctx->mclk)) {
- ret = PTR_ERR(ctx->mclk);
- if (ret == -ENOENT) {
- dev_info(&pdev->dev,
- "Failed to get ssp1_sclk, defer probe\n");
- return -EPROBE_DEFER;
- }
-
- dev_err(&pdev->dev, "Failed to get ssp1_mclk with err:%d\n",
- ret);
- return ret;
- }
+ if (IS_ERR(ctx->mclk))
+ return dev_err_probe(&pdev->dev, PTR_ERR(ctx->mclk),
+ "Failed to get ssp1_mclk\n");

ctx->sclk = devm_clk_get(&pdev->dev, "ssp1_sclk");
- if (IS_ERR(ctx->sclk)) {
- ret = PTR_ERR(ctx->sclk);
- if (ret == -ENOENT) {
- dev_info(&pdev->dev,
- "Failed to get ssp1_sclk, defer probe\n");
- return -EPROBE_DEFER;
- }
-
- dev_err(&pdev->dev, "Failed to get ssp1_sclk with err:%d\n",
- ret);
- return ret;
- }
+ if (IS_ERR(ctx->sclk))
+ return dev_err_probe(&pdev->dev, PTR_ERR(ctx->sclk),
+ "Failed to get ssp1_sclk\n");

return devm_snd_soc_register_card(&pdev->dev, kabylake_audio_card);
}
--
2.34.1


2022-08-08 07:53:38

by Pierre-Louis Bossart

[permalink] [raw]
Subject: Re: [PATCH] ASoC: Intel: kbl_rt5663_max98927: Simplify clk_get() usage



On 8/7/22 22:18, Christophe JAILLET wrote:
> If clk_get() returns -ENOENT, there is no need to defer the driver, -ENOENT
> will be returned the same for each retries.
> So, return the error code directly instead of -EPROBE_DEFER.
>
> Remove this special case and use dev_err_probe() to simplify code. It will
> also be less verbose if the clk is really deferred.
>
> Fixes: f7f61e08fe58 ("ASoC: Intel: kbl: Enable mclk and ssp sclk early")
> Signed-off-by: Christophe JAILLET <[email protected]>
> ---
> This is based on my understanding of clk_get().
> Review with care.
>
> Not sure the Fixes tag is needed. The patch does not fix anything.
> If devm_clk_get() returns -ENOENT, it will just loop several time until
> the framework gives up.
> If it returns -EPROBE_DEFER, this case is already handled by the
> "return ret;"
>
> So this patch should be a no-op, just a clean-up.

I can't pretend understanding the clk framework in depth, but the only
case where -ENOENT is returned seems to be this block in clk_hw_create_clk()

if (!try_module_get(core->owner)) {
free_clk(clk);
return ERR_PTR(-ENOENT);
}

I have no idea why this would be converted to a -EPROBE_DEFER. May to
account for module loading?

> ---
> sound/soc/intel/boards/kbl_rt5663_max98927.c | 31 ++++----------------
> 1 file changed, 6 insertions(+), 25 deletions(-)
>
> diff --git a/sound/soc/intel/boards/kbl_rt5663_max98927.c b/sound/soc/intel/boards/kbl_rt5663_max98927.c
> index 2d4224c5b152..07b00af2fa3c 100644
> --- a/sound/soc/intel/boards/kbl_rt5663_max98927.c
> +++ b/sound/soc/intel/boards/kbl_rt5663_max98927.c
> @@ -989,7 +989,6 @@ static int kabylake_audio_probe(struct platform_device *pdev)
> {
> struct kbl_rt5663_private *ctx;
> struct snd_soc_acpi_mach *mach;
> - int ret;
>
> ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
> if (!ctx)
> @@ -1009,32 +1008,14 @@ static int kabylake_audio_probe(struct platform_device *pdev)
> &constraints_dmic_2ch : &constraints_dmic_channels;
>
> ctx->mclk = devm_clk_get(&pdev->dev, "ssp1_mclk");
> - if (IS_ERR(ctx->mclk)) {
> - ret = PTR_ERR(ctx->mclk);
> - if (ret == -ENOENT) {
> - dev_info(&pdev->dev,
> - "Failed to get ssp1_sclk, defer probe\n");
> - return -EPROBE_DEFER;
> - }
> -
> - dev_err(&pdev->dev, "Failed to get ssp1_mclk with err:%d\n",
> - ret);
> - return ret;
> - }
> + if (IS_ERR(ctx->mclk))
> + return dev_err_probe(&pdev->dev, PTR_ERR(ctx->mclk),
> + "Failed to get ssp1_mclk\n");
>
> ctx->sclk = devm_clk_get(&pdev->dev, "ssp1_sclk");
> - if (IS_ERR(ctx->sclk)) {
> - ret = PTR_ERR(ctx->sclk);
> - if (ret == -ENOENT) {
> - dev_info(&pdev->dev,
> - "Failed to get ssp1_sclk, defer probe\n");
> - return -EPROBE_DEFER;
> - }
> -
> - dev_err(&pdev->dev, "Failed to get ssp1_sclk with err:%d\n",
> - ret);
> - return ret;
> - }
> + if (IS_ERR(ctx->sclk))
> + return dev_err_probe(&pdev->dev, PTR_ERR(ctx->sclk),
> + "Failed to get ssp1_sclk\n");
>
> return devm_snd_soc_register_card(&pdev->dev, kabylake_audio_card);
> }

2022-08-08 13:28:29

by Mark Brown

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Subject: Re: [PATCH] ASoC: Intel: kbl_rt5663_max98927: Simplify clk_get() usage

On Sun, Aug 07, 2022 at 10:18:54PM +0200, Christophe JAILLET wrote:

> Not sure the Fixes tag is needed. The patch does not fix anything.

You just answered your own question there...


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2022-08-10 14:19:06

by Mark Brown

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Subject: Re: [PATCH] ASoC: Intel: kbl_rt5663_max98927: Simplify clk_get() usage

On Sun, Aug 07, 2022 at 10:18:54PM +0200, Christophe JAILLET wrote:
> If clk_get() returns -ENOENT, there is no need to defer the driver, -ENOENT
> will be returned the same for each retries.
> So, return the error code directly instead of -EPROBE_DEFER.

Are you *sure* that this is the case on Intel platforms where we don't
have a full firmware description for clocks and therefore can't identify
cases where we expect a clock to at some point to become available.


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2022-08-10 19:10:56

by Christophe JAILLET

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Subject: Re: [PATCH] ASoC: Intel: kbl_rt5663_max98927: Simplify clk_get() usage

Le 10/08/2022 à 15:50, Mark Brown a écrit :
> On Sun, Aug 07, 2022 at 10:18:54PM +0200, Christophe JAILLET wrote:
>> If clk_get() returns -ENOENT, there is no need to defer the driver, -ENOENT
>> will be returned the same for each retries.
>> So, return the error code directly instead of -EPROBE_DEFER.
>
> Are you *sure* that this is the case on Intel platforms where we don't
> have a full firmware description for clocks and therefore can't identify
> cases where we expect a clock to at some point to become available.

No, I'm *not* sure.

This looked odd enough to deserve a patch proposal, that's all.
(based on my grep and coccinelle scripts, this is the only place in the
kernel where the result of a clk_get() is handled that way)

There are many intel.com in cc:.
Would be nice if s.o. could confirm if the patch is valid or not.

CJ