[PATCH] ASoC: stm32: sai: Use of_device_get_match_data() to simplify code

[PATCH] ASoC: stm32: sai: Use of_device_get_match_data() to simplify code

[Tang Bin]

Retrieve of match data, it's better and cleaner to use
'of_device_get_match_data' over 'of_match_device'.

Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com>
---
 sound/soc/stm/stm32_sai_sub.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/sound/soc/stm/stm32_sai_sub.c b/sound/soc/stm/stm32_sai_sub.c
index dd636af81..d300605a2 100644
--- a/sound/soc/stm/stm32_sai_sub.c
+++ b/sound/soc/stm/stm32_sai_sub.c
@@ -1500,7 +1500,6 @@ static int stm32_sai_sub_parse_of(struct platform_device *pdev,
 static int stm32_sai_sub_probe(struct platform_device *pdev)
 {
 	struct stm32_sai_sub_data *sai;
-	const struct of_device_id *of_id;
 	const struct snd_dmaengine_pcm_config *conf = &stm32_sai_pcm_config;
 	int ret;
 
@@ -1508,10 +1507,9 @@ static int stm32_sai_sub_probe(struct platform_device *pdev)
 	if (!sai)
 		return -ENOMEM;
 
-	of_id = of_match_device(stm32_sai_sub_ids, &pdev->dev);
-	if (!of_id)
+	sai->id = (uintptr_t)of_device_get_match_data(&pdev->dev);
+	if (!sai->id)
 		return -EINVAL;
-	sai->id = (uintptr_t)of_id->data;
 
 	sai->pdev = pdev;
 	mutex_init(&sai->ctrl_lock);
-- 
2.20.1.windows.1

Re: [PATCH] ASoC: stm32: sai: Use of_device_get_match_data() to simplify code

[Olivier MOYSAN]

Hello Tang,

Thanks for the patch. Unfortunately this patch introduces a regression.

In the SAI driver of_device_id struct the data is a simple enum cast to 
void* pointer.
static const struct of_device_id stm32_sai_sub_ids[] = {
	  .data = (void *)STM_SAI_A_ID},

This data is an ID which can be set to 0x0.
Here we have no way to know to discriminate between an error returned by 
of_device_get_match_data() or a data id set to 0x0.

The current patch requires a change in the driver.
Either changing STM_SAI_x_ID enums, or replacing data by a struct.
For instance:
struct stm32_sai_comp_data {
	unsigned int id;
}
struct stm32_sai_comp_data stm32_sai_comp_data_a = {
	.id = STM_SAI_A_ID;
}
struct of_device_id stm32_sai_sub_ids[] = {
	.data = &stm32_sai_comp_data_a},
}

Regards
Olivier

On 5/19/22 14:42, Tang Bin wrote:
> Retrieve of match data, it's better and cleaner to use
> 'of_device_get_match_data' over 'of_match_device'.
> 
> Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com>
> ---
>   sound/soc/stm/stm32_sai_sub.c | 6 ++----
>   1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/sound/soc/stm/stm32_sai_sub.c b/sound/soc/stm/stm32_sai_sub.c
> index dd636af81..d300605a2 100644
> --- a/sound/soc/stm/stm32_sai_sub.c
> +++ b/sound/soc/stm/stm32_sai_sub.c
> @@ -1500,7 +1500,6 @@ static int stm32_sai_sub_parse_of(struct platform_device *pdev,
>   static int stm32_sai_sub_probe(struct platform_device *pdev)
>   {
>   	struct stm32_sai_sub_data *sai;
> -	const struct of_device_id *of_id;
>   	const struct snd_dmaengine_pcm_config *conf = &stm32_sai_pcm_config;
>   	int ret;
>   
> @@ -1508,10 +1507,9 @@ static int stm32_sai_sub_probe(struct platform_device *pdev)
>   	if (!sai)
>   		return -ENOMEM;
>   
> -	of_id = of_match_device(stm32_sai_sub_ids, &pdev->dev);
> -	if (!of_id)
> +	sai->id = (uintptr_t)of_device_get_match_data(&pdev->dev);
> +	if (!sai->id)
>   		return -EINVAL;
> -	sai->id = (uintptr_t)of_id->data;
>   
>   	sai->pdev = pdev;
>   	mutex_init(&sai->ctrl_lock);

Re: [PATCH] ASoC: stm32: sai: Use of_device_get_match_data() to simplify code

[Mark Brown]

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On Mon, May 23, 2022 at 03:28:48PM +0200, Olivier MOYSAN wrote:

> The current patch requires a change in the driver.
> Either changing STM_SAI_x_ID enums, or replacing data by a struct.
> For instance:
> struct stm32_sai_comp_data {
> 	unsigned int id;
> }
> struct stm32_sai_comp_data stm32_sai_comp_data_a = {
> 	.id = STM_SAI_A_ID;
> }
> struct of_device_id stm32_sai_sub_ids[] = {
> 	.data = &stm32_sai_comp_data_a},
> }

Either approach works for me (or a revert for that matter).

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Re: [PATCH] ASoC: stm32: sai: Use of_device_get_match_data() tosimplify code

[Olivier MOYSAN]

Hi Tang,

On 5/24/22 03:44, tangbin wrote:
> Hi Mark & Olivier：
> 
> On 2022/5/24 2:57, Mark Brown wrote:
>> On Mon, May 23, 2022 at 03:28:48PM +0200, Olivier MOYSAN wrote:
>>
>>> The current patch requires a change in the driver.
>>> Either changing STM_SAI_x_ID enums, or replacing data by a struct.
>>> For instance:
>>> struct stm32_sai_comp_data {
>>>     unsigned int id;
>>> }
>>> struct stm32_sai_comp_data stm32_sai_comp_data_a = {
>>>     .id = STM_SAI_A_ID;
>>> }
>>> struct of_device_id stm32_sai_sub_ids[] = {
>>>     .data = &stm32_sai_comp_data_a},
>>> }
>> Either approach works for me (or a revert for that matter).
> 
>      Thanks for your advice, I was thoughtless.
> 
>      I think change the date of STM_SAI_x_ID maybe simple. But if we 
> don't change the id,
> 
> what about add a "#define" like the line 47:
> 
> #define STM_SAI_IS_SUB(x) ((x)->id == STM_SAI_A_ID || (x)->id == 
> STM_SAI_B_ID)
> 
> then in the judgement, wu use:
> 
>      sai->id = (uintptr_t)of_device_get_match_data(&pdev->dev);
> 
>      if (!STM_SAI_IS_SUB(sai))
> 
>              return -EINVAL;
> 
> 
> if you think that's ok, I will send patch v2 for you .
> 

If we allow null value in STM_SAI_IS_SUB(sai) check, we can miss real 
NULL pointer error from of_device_get_match_data().

The simplest way is to change STM_SAI_x_ID enums I think.
But honnestly, I feel more comfortable to let the driver unchanged.

BRs
Olivier

> Thanks
> 
> Tang Bin
> 
> 

Re: [PATCH] ASoC: stm32: sai: Use of_device_get_match_data()tosimplify code

[tangbin]

Hi Olivier：

On 2022/5/24 22:30, Olivier MOYSAN wrote:
> Hi Tang,
>
> On 5/24/22 03:44, tangbin wrote:
>> Hi Mark & Olivier：
>>
>> On 2022/5/24 2:57, Mark Brown wrote:
>>> On Mon, May 23, 2022 at 03:28:48PM +0200, Olivier MOYSAN wrote:
>>>
>>>> The current patch requires a change in the driver.
>>>> Either changing STM_SAI_x_ID enums, or replacing data by a struct.
>>>> For instance:
>>>> struct stm32_sai_comp_data {
>>>>     unsigned int id;
>>>> }
>>>> struct stm32_sai_comp_data stm32_sai_comp_data_a = {
>>>>     .id = STM_SAI_A_ID;
>>>> }
>>>> struct of_device_id stm32_sai_sub_ids[] = {
>>>>     .data = &stm32_sai_comp_data_a},
>>>> }
>>> Either approach works for me (or a revert for that matter).
>>
>>      Thanks for your advice, I was thoughtless.
>>
>>      I think change the date of STM_SAI_x_ID maybe simple. But if we 
>> don't change the id,
>>
>> what about add a "#define" like the line 47:
>>
>> #define STM_SAI_IS_SUB(x) ((x)->id == STM_SAI_A_ID || (x)->id == 
>> STM_SAI_B_ID)
>>
>> then in the judgement, wu use:
>>
>>      sai->id = (uintptr_t)of_device_get_match_data(&pdev->dev);
>>
>>      if (!STM_SAI_IS_SUB(sai))
>>
>>              return -EINVAL;
>>
>>
>> if you think that's ok, I will send patch v2 for you .
>>
>
> If we allow null value in STM_SAI_IS_SUB(sai) check, we can miss real 
> NULL pointer error from of_device_get_match_data().
>
> The simplest way is to change STM_SAI_x_ID enums I think.
> But honnestly, I feel more comfortable to let the driver unchanged.
>
Oh，you are right, I am sorry.

Please forget this patch, I'm sorry to have wasted your time.

But I saw some codes is useless in the line 48 & line 49, I think we can 
remove it.

If you think so, I will send this patch for you.


Thanks

Tang Bin


> BRs
> Olivier
>
>> Thanks
>>
>> Tang Bin
>>
>>

Re: [PATCH] ASoC: stm32: sai: Use of_device_get_match_data()tosimplify code

[Olivier MOYSAN]

Hi Tang,

On 5/25/22 09:36, tangbin wrote:
> Hi Olivier：
> 
> On 2022/5/24 22:30, Olivier MOYSAN wrote:
>> Hi Tang,
>>
>> On 5/24/22 03:44, tangbin wrote:
>>> Hi Mark & Olivier：
>>>
>>> On 2022/5/24 2:57, Mark Brown wrote:
>>>> On Mon, May 23, 2022 at 03:28:48PM +0200, Olivier MOYSAN wrote:
>>>>
>>>>> The current patch requires a change in the driver.
>>>>> Either changing STM_SAI_x_ID enums, or replacing data by a struct.
>>>>> For instance:
>>>>> struct stm32_sai_comp_data {
>>>>>     unsigned int id;
>>>>> }
>>>>> struct stm32_sai_comp_data stm32_sai_comp_data_a = {
>>>>>     .id = STM_SAI_A_ID;
>>>>> }
>>>>> struct of_device_id stm32_sai_sub_ids[] = {
>>>>>     .data = &stm32_sai_comp_data_a},
>>>>> }
>>>> Either approach works for me (or a revert for that matter).
>>>
>>>      Thanks for your advice, I was thoughtless.
>>>
>>>      I think change the date of STM_SAI_x_ID maybe simple. But if we 
>>> don't change the id,
>>>
>>> what about add a "#define" like the line 47:
>>>
>>> #define STM_SAI_IS_SUB(x) ((x)->id == STM_SAI_A_ID || (x)->id == 
>>> STM_SAI_B_ID)
>>>
>>> then in the judgement, wu use:
>>>
>>>      sai->id = (uintptr_t)of_device_get_match_data(&pdev->dev);
>>>
>>>      if (!STM_SAI_IS_SUB(sai))
>>>
>>>              return -EINVAL;
>>>
>>>
>>> if you think that's ok, I will send patch v2 for you .
>>>
>>
>> If we allow null value in STM_SAI_IS_SUB(sai) check, we can miss real 
>> NULL pointer error from of_device_get_match_data().
>>
>> The simplest way is to change STM_SAI_x_ID enums I think.
>> But honnestly, I feel more comfortable to let the driver unchanged.
>>
> Oh，you are right, I am sorry.
> 
> Please forget this patch, I'm sorry to have wasted your time.
> 
> But I saw some codes is useless in the line 48 & line 49, I think we can 
> remove it.
> 

Yes, these two defines are no more useful.
Feel free to send a cleanup patch.

BRs

Olivier

> If you think so, I will send this patch for you.
> 
> 
> Thanks
> 
> Tang Bin
> 
> 
>> BRs
>> Olivier
>>
>>> Thanks
>>>
>>> Tang Bin
>>>
>>>
> 
>