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Message-ID: <b346eb00-fde1-2dc0-e6e3-09dbf1359c20@foss.st.com>
Date:   Wed, 25 May 2022 14:30:13 +0200
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Subject: Re: [PATCH] ASoC: stm32: sai: Use
 of_device_get_match_data()tosimplify code
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To:     tangbin <tangbin@cmss.chinamobile.com>,
        Mark Brown <broonie@kernel.org>
CC:     <arnaud.pouliquen@foss.st.com>, <lgirdwood@gmail.com>,
        <perex@perex.cz>, <tiwai@suse.com>, <mcoquelin.stm32@gmail.com>,
        <alexandre.torgue@foss.st.com>, <alsa-devel@alsa-project.org>,
        <linux-stm32@st-md-mailman.stormreply.com>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>
References: <20220519124235.21100-1-tangbin@cmss.chinamobile.com>
 <69d5cef3-57c0-9bc7-a83b-a85ef1c4cf29@foss.st.com>
 <YovZAf4S0XphBsco@sirena.org.uk>
 <3fb8d7f8-4506-3b28-22cb-863bda1f21c8@cmss.chinamobile.com>
 <d5ab354a-eb10-d31c-d55e-46a4c4d1a4ce@foss.st.com>
 <cd375914-a3e6-37c7-4a16-551937006f92@cmss.chinamobile.com>
From:   Olivier MOYSAN <olivier.moysan@foss.st.com>
In-Reply-To: <cd375914-a3e6-37c7-4a16-551937006f92@cmss.chinamobile.com>
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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
>>>
>>>
> 
>