[alsa-devel] DM365 McBSP as Master

[Appalayagari Sreedhar]

Hi Vladimir,

Thank you very much. i will do the same.
on further probing and testing.

i found that if i open the device O_WRONLY and O_RDONLY mode it works.
if i try to open the device using the O_RDWR mode it fails.

is there any configuration settings i need to check.

-Sreedhar.

On 10/17/11, Vladimir Barinov <Vladimir_Barinov at mentor.com> wrote:
> Hi Sreedhar,
>
> You should always CC the alsa-devel channel list for any alsa related
> questions instead of writing directly to TI support and me. But you can
> CC both me and TI people.
> In that case your questions will not go unanswered.
>
>
> Appalayagari Sreedhar wrote:
>> Hi Vladimir,
>>
>> I need your help to solve one issue.
>>
>> I have developed a audio driver in ALSA model, the audio ic is
>> interfaced with the TI DM365 processor MCBSP ports. I am working with
>> the 2.6.32 kernel.
>>
>> I am able to play the audio using the aplay command.  but when i try
>> to open the device using /dev/dsp i am getting the -ve value. it fails
>> to open the device.
>>
> I believe that you've enabled OSS emulation for alsa drivers:
> CONFIG_SND_PCM_OSS=y
> and read carefully Documentation/sound/alsa/OSS-Emulation.txt guide.
>
> Here you didn't mention how you are trying to open /dev/dsp and the
> error log sample.
> If you'll read the mentioned guide then you'll find some hints about PCM
> mode changes via proc interface. Probably that will shine some light on
> your issue.
>
>> when i check the
>>
>>
>>>> ls /dev/dsp
>>>>
>>
>> it is available in the device directory.
>>
>> I have enabled the Sound OSS related options in the kernel menuconfig.
>> with the same options i am able to open the device for the tlv320aic3x
>> device.
>>
>> Could you please suggest where i am doing wrong? and help to solve
>> this problem.
>>
>> One more observation :
>>
>> after doing aplay i am able to open the device using the /dev/dsp.
>>
>> if try to open the device using the /dev/dsp before aplay i am getting
>> the error.
>>
>> could you please tell me where i am doing.
>>
> It seems that aplay configures the codec and mcbsp interface calling
> it's TRIGGER_START but your own application does not. Once configured
> the pcm streams can pass normally using /dev/dsp. Not usre but seems
> that the problem in inability to call TRIGGER.
>
> Regards,
> Vladimir
>> I have posted the queries in ti e2e website, please check them below.
>> i did not receive any proper response till now so i am contacting you.
>>
>> http://e2e.ti.com/support/embedded/f/354/p/138037/504805.aspx
>>
>> Thank you in advance.
>> Sreedhar.
>>
>> On 9/23/11, Vladimir Barinov <Vladimir_Barinov at mentor.com> wrote:
>>
>>> Hi Sreedhar,
>>>
>>> Appalayagari Sreedhar wrote:
>>>
>>>> Hi Vladimir Barinov,
>>>>
>>>> Now I am able to make it work McBSP as master and also as slave.
>>>> We decided to configure the McBSP as Slave and Codec as Master.
>>>>
>>>> I have one question, Since the Clocks are generated by the Codec.
>>>> will there be any Channel Swap in the audio?
>>>>
>>>> If so how to handle this channel swap mechanism.
>>>>
>>>>
>>> Yes, It possible to get channels swap on any external codec.
>>> Unfortunately I don't know any strong method for this issue. I just
>>> experience similar problem on TI's PMIC audio and get rid from  EVERY
>>> excessive clock in system to be able to fix it. I mean you have to stop
>>> all related clocks in proper sequence during audio pause/stop. When I
>>> did it the channel swap was fixed.
>>>
>>> Regards,
>>> Vladimir
>>>
>>>> Thank you,
>>>> Sreedhar.
>>>>
>>>>
>>>>
>>>>
>>>> On 9/20/11, Appalayagari Sreedhar <sreecha01 at gmail.com> wrote:
>>>>
>>>>
>>>>> Hi Vladimir Barinov,
>>>>>
>>>>> Thank you very much.  I will check as you suggested.
>>>>> Thanks once again you are only person from whom i got the support since
>>>>> 5
>>>>> days.
>>>>>
>>>>> Thanks once again.
>>>>>
>>>>> Thank you,
>>>>> Sreedhar.
>>>>>
>>>>> On 9/20/11, Vladimir Barinov <Vladimir_Barinov at mentor.com> wrote:
>>>>>
>>>>>
>>>>>> Sreedhar,
>>>>>>
>>>>>> 1) verify that mux registers are configured properly
>>>>>> 2) startup with codec as master since the current code tested in this
>>>>>> mode and usually msbsp can't provide variety of clocks to match all
>>>>>> samplerates.
>>>>>> 3) check that you can read/write codec registers with success (i2c
>>>>>> works
>>>>>> find and the codec is not in reset state - check your h/w)
>>>>>> Probe MCLK by scope and find that signal is ON, otherwise you didn't
>>>>>> make codec setup (i2c communication or codec doesn't work)
>>>>>>
>>>>>> After above you can start moving to MCBSP  as master if you really
>>>>>> need
>>>>>> it.
>>>>>>
>>>>>> Regards,
>>>>>> Vladimir
>>>>>>
>>>>>> Appalayagari Sreedhar wrote:
>>>>>>
>>>>>>
>>>>>>> Hi Vladimir Barinov,
>>>>>>>
>>>>>>> I am working with DM365 evm board.  I have interfaced conexant audio
>>>>>>> ic to the McBSP.
>>>>>>>
>>>>>>> I need to do I2S data transfer. I need to program the McBSP as master
>>>>>>> and conexant audio IC as slave.
>>>>>>>
>>>>>>> i did the macro changes in the davinci-evm.c file in AUDIO_FORMAT
>>>>>>> like
>>>>>>> this.
>>>>>>>
>>>>>>> #define AUDIO_FORMAT (SND_SOC_DAIFMT_I2S | \
>>>>>>>                 SND_SOC_DAIFMT_CBS_CFS)
>>>>>>>
>>>>>>> I am using the McBSP internal clock for McBSP. I printed the McBSP
>>>>>>> registers and found that SCLKME - 0 and CLKSM - 1.  by reading the
>>>>>>> registers.
>>>>>>>
>>>>>>> when i run the aplay command i am not viewing any clocks when i probe
>>>>>>> the signals using the CRO.
>>>>>>>
>>>>>>> Could you please tell me where i am doing wrong?
>>>>>>>
>>>>>>> Please find my queries in the following thread in the ti e2e
>>>>>>> comminity.
>>>>>>>
>>>>>>> http://e2e.ti.com/support/embedded/f/354/p/134788/485628.aspx#485628
>>>>>>>
>>>>>>> Thank you, Sreedhar.
>>>>>>>
>>>>>>>
>>>>>>>
>>>
>
>