From mboxrd@z Thu Jan  1 00:00:00 1970
From: Troy Kisky <troy.kisky@boundarydevices.com>
Subject: Re: Artifacts present in AIC23 capture for 48
 KHz	sampling rate
Date: Tue, 17 Nov 2009 12:09:21 -0700
Message-ID: <4B02F4E1.3060405@boundarydevices.com>
References: <5A47E75E594F054BAF48C5E4FC4B92AB030A8C9109@dbde02.ent.ti.com>
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To: "Aggarwal, Anuj" <anuj.aggarwal@ti.com>
Cc: "alsa-devel@alsa-project.org" <alsa-devel@alsa-project.org>, "linux-omap@vger.kernel.org" <linux-omap@vger.kernel.org>
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Aggarwal, Anuj wrote:
>> -----Original Message-----
>> From: Aggarwal, Anuj
>> Sent: Friday, November 06, 2009 6:28 PM
>> To: alsa-devel@alsa-project.org; 'linux-omap@vger.kernel.org'
>> Subject: Artifacts present in AIC23 capture for 48 KHz sampling rate
>>
>> Hi,
>>
>> I am observing artifacts (sharp spikes at fixed intervals) while
>> capturing audio on AM3517 EVM and AIC23 codec. They are present only
>> in one of the channels when I am capturing at 48 KHz. All other
>> sampling rates are working fine with the above said combination.
>>
>> I have also attached the screenshot taken with the help of Audacity
>> utility. Here, I tried recording silence but artifacts were observed
>> on one channel.
>>
>> Has anyone also observed the similar behavior with AIC23 codec? Any
>> hints on what could be the root cause?
> [Aggarwal, Anuj] On further debugging, I found that the function
> find_rate() in sound/soc/codecs/tlv320aic23.c is not returning 
> the correct value for capture in 48KHz sample rate. In USB mode
> (MCLK=12MHz), for 48KHz, it returns 0x7D (CLKOUT=0, CLKIN=1, 
> SR[3:0]=0xF, BOSR=1, Normal=1) whereas as per the AIC23B spec, 

0x7D would be BOSR = 0, USB/NORMAL = 1, SR=0xff, div2 = 1

The bug is with sr_valid_mask,

static const unsigned short sr_valid_mask[] = {
	LOWER_GROUP|UPPER_GROUP,	/* Normal, bosr - 0*/
	LOWER_GROUP|UPPER_GROUP,	/* Normal, bosr - 1*/
	LOWER_GROUP,			/* Usb, bosr - 0*/
	UPPER_GROUP,			/* Usb, bosr - 1*/
};

should be

static const unsigned short sr_valid_mask[] = {
	LOWER_GROUP|UPPER_GROUP,	/* Normal, bosr - 0*/
	LOWER_GROUP,			/* Usb, bosr - 0*/
	LOWER_GROUP|UPPER_GROUP,	/* Normal, bosr - 1*/
	UPPER_GROUP,			/* Usb, bosr - 1*/
};


Can you give this a try and let me know?

Thanks
Troy