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From: Troy Kisky <troy.kisky@boundarydevices.com>
To: Raffaele Recalcati <lamiaposta71@gmail.com>
Cc: davinci-linux-open-source@linux.davincidsp.com,
	Russell King <linux@arm.linux.org.uk>,
	Takashi Iwai <tiwai@suse.de>,
	Mark Brown <broonie@opensource.wolfsonmicro.com>,
	alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org,
	Davide Bonfanti <davide.bonfanti@bticino.it>,
	Raffaele Recalcati <raffaele.recalcati@bticino.it>,
	Chaithrika U S <chaithrika@ti.com>,
	linux-arm-kernel@lists.infradead.org,
	Liam Girdwood <lrg@slimlogic.co.uk>
Subject: Re: [PATCH] ASoC: DaVinci: Added support for cpu clocking I2S
Date: Mon, 28 Jun 2010 12:11:13 -0700	[thread overview]
Message-ID: <4C28F3D1.5060806@boundarydevices.com> (raw)
In-Reply-To: <1277707487-3371-1-git-send-email-lamiaposta71@gmail.com>

Raffaele Recalcati wrote:
> +		if (dev->i2s_fast_clock) {
> +			clk_div = 256;
can you have
   f = (freq / params->rate_num) * params->rate_den;
> +			do {
> +				framesize = (freq / (--clk_div)) /
> +					    params->rate_num *
> +					    params->rate_den;
and
				framesize = f / (--clk_div);
> +			} while (((framesize < 33) || (framesize > 4095)) &&
> +				 (clk_div));
> +			clk_div--;
looks like clk_div can go negative here, should the above while say (clk_div > 1)
> +			srgr |= DAVINCI_MCBSP_SRGR_FPER(framesize - 1);
> +		} else {
> +			/* symmetric waveforms */
> +			clk_div = freq / (mcbsp_word_length * 16) /
> +				  params->rate_num * params->rate_den;
> +			srgr |= DAVINCI_MCBSP_SRGR_FPER(mcbsp_word_length *
> +							16 - 1);
> +		}
> +		clk_div &= 0xFF;
> +		srgr |= clk_div;

WARNING: multiple messages have this Message-ID (diff)
From: troy.kisky@boundarydevices.com (Troy Kisky)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] ASoC: DaVinci: Added support for cpu clocking I2S
Date: Mon, 28 Jun 2010 12:11:13 -0700	[thread overview]
Message-ID: <4C28F3D1.5060806@boundarydevices.com> (raw)
In-Reply-To: <1277707487-3371-1-git-send-email-lamiaposta71@gmail.com>

Raffaele Recalcati wrote:
> +		if (dev->i2s_fast_clock) {
> +			clk_div = 256;
can you have
   f = (freq / params->rate_num) * params->rate_den;
> +			do {
> +				framesize = (freq / (--clk_div)) /
> +					    params->rate_num *
> +					    params->rate_den;
and
				framesize = f / (--clk_div);
> +			} while (((framesize < 33) || (framesize > 4095)) &&
> +				 (clk_div));
> +			clk_div--;
looks like clk_div can go negative here, should the above while say (clk_div > 1)
> +			srgr |= DAVINCI_MCBSP_SRGR_FPER(framesize - 1);
> +		} else {
> +			/* symmetric waveforms */
> +			clk_div = freq / (mcbsp_word_length * 16) /
> +				  params->rate_num * params->rate_den;
> +			srgr |= DAVINCI_MCBSP_SRGR_FPER(mcbsp_word_length *
> +							16 - 1);
> +		}
> +		clk_div &= 0xFF;
> +		srgr |= clk_div;

WARNING: multiple messages have this Message-ID (diff)
From: Troy Kisky <troy.kisky@boundarydevices.com>
To: Raffaele Recalcati <lamiaposta71@gmail.com>
Cc: davinci-linux-open-source@linux.davincidsp.com,
	alsa-devel@alsa-project.org,
	Russell King <linux@arm.linux.org.uk>,
	Takashi Iwai <tiwai@suse.de>,
	Mark Brown <broonie@opensource.wolfsonmicro.com>,
	linux-kernel@vger.kernel.org,
	Davide Bonfanti <davide.bonfanti@bticino.it>,
	Raffaele Recalcati <raffaele.recalcati@bticino.it>,
	Chaithrika U S <chaithrika@ti.com>,
	Jaroslav Kysela <perex@perex.cz>,
	linux-arm-kernel@lists.infradead.org,
	Liam Girdwood <lrg@slimlogic.co.uk>
Subject: Re: [PATCH] ASoC: DaVinci: Added support for cpu clocking I2S
Date: Mon, 28 Jun 2010 12:11:13 -0700	[thread overview]
Message-ID: <4C28F3D1.5060806@boundarydevices.com> (raw)
In-Reply-To: <1277707487-3371-1-git-send-email-lamiaposta71@gmail.com>

Raffaele Recalcati wrote:
> +		if (dev->i2s_fast_clock) {
> +			clk_div = 256;
can you have
   f = (freq / params->rate_num) * params->rate_den;
> +			do {
> +				framesize = (freq / (--clk_div)) /
> +					    params->rate_num *
> +					    params->rate_den;
and
				framesize = f / (--clk_div);
> +			} while (((framesize < 33) || (framesize > 4095)) &&
> +				 (clk_div));
> +			clk_div--;
looks like clk_div can go negative here, should the above while say (clk_div > 1)
> +			srgr |= DAVINCI_MCBSP_SRGR_FPER(framesize - 1);
> +		} else {
> +			/* symmetric waveforms */
> +			clk_div = freq / (mcbsp_word_length * 16) /
> +				  params->rate_num * params->rate_den;
> +			srgr |= DAVINCI_MCBSP_SRGR_FPER(mcbsp_word_length *
> +							16 - 1);
> +		}
> +		clk_div &= 0xFF;
> +		srgr |= clk_div;

  parent reply	other threads:[~2010-06-28 19:11 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-06-28  6:44 [PATCH] ASoC: DaVinci: Added support for cpu clocking I2S Raffaele Recalcati
2010-06-28  6:44 ` Raffaele Recalcati
2010-06-28 10:30 ` Mark Brown
2010-06-28 10:30   ` Mark Brown
2010-06-28 10:30   ` Mark Brown
2010-06-30  8:17   ` Raffaele Recalcati
2010-06-30  8:17     ` Raffaele Recalcati
2010-06-30 10:00     ` Raffaele Recalcati
2010-06-30 10:00       ` Raffaele Recalcati
2010-06-30 14:53     ` Mark Brown
2010-06-30 14:53       ` Mark Brown
2010-06-28 19:11 ` Troy Kisky [this message]
2010-06-28 19:11   ` Troy Kisky
2010-06-28 19:11   ` Troy Kisky
2010-06-30  8:52   ` Raffaele Recalcati
2010-06-30  8:52     ` Raffaele Recalcati

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