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

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);

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).