From: Liam Girdwood <lrg@slimlogic.co.uk>
To: Kuninori Morimoto <morimoto.kuninori@renesas.com>
Cc: Linux-ALSA <alsa-devel@alsa-project.org>,
Mark Brown <broonie@opensource.wolfsonmicro.com>
Subject: Re: [PATCH 2/4] ASoC: fsi: Add FIFO size calculate
Date: Thu, 25 Mar 2010 08:56:14 +0000 [thread overview]
Message-ID: <1269507374.3758.2.camel@odin> (raw)
In-Reply-To: <uk4t1unsy.wl%morimoto.kuninori@renesas.com>
On Thu, 2010-03-25 at 11:39 +0900, Kuninori Morimoto wrote:
>
> > > + dev_dbg(dai->dev, "fifo = %d words\n", fsi->fifo_max);
> > > +
> > > + for (i = 1; i < fsi->chan; i *= 2)
> > > + if (fsi->chan > i)
> > > + fsi->fifo_max >>= 1;
> >
> > Is the if really needed here. You may also want to calculate the shift
> > size rather than looping too.
>
> This calculate number of sample data.
> And it is depend on channel size.
> If chip fifo size is 256, the number of sample data will be...
>
> 1 chan : 256 (256 x 1 = 256)
> 2 chan : 128 (128 x 2 = 256)
> 3 chan : 64 ( 64 x 3 = 192)
> 4 chan : 64 ( 64 x 4 = 256)
> 5 chan : 32 ( 32 x 5 = 160)
> 6 chan : 32 ( 32 x 6 = 192)
> 7 chan : 32 ( 32 x 7 = 224)
> 8 chan : 32 ( 32 x 8 = 256)
>
> Above calculation is needed. but yes un-understandable.
> I don't know a method computable by one line.
> So, I will add tiny comment/document here.
> OK ?
>
Yes, this sounds fine :)
It wasn't understandable from the original code.
Thanks
Liam
--
Freelance Developer, SlimLogic Ltd
ASoC and Voltage Regulator Maintainer.
http://www.slimlogic.co.uk
next prev parent reply other threads:[~2010-03-25 8:56 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-24 6:26 [PATCH 0/4] ASoC: fsi: FSI2 device support Kuninori Morimoto
2010-03-17 5:26 ` [PATCH 2/4] ASoC: fsi: Add FIFO size calculate Kuninori Morimoto
2010-03-24 9:46 ` Liam Girdwood
2010-03-25 2:39 ` Kuninori Morimoto
2010-03-25 8:56 ` Liam Girdwood [this message]
2010-03-23 2:47 ` [PATCH 3/4] ASoC: fsi: IRQ related process had be united Kuninori Morimoto
2010-03-24 9:48 ` Liam Girdwood
2010-03-24 6:27 ` [PATCH 1/4] ASoC: fsi: ensures process inside master lock Kuninori Morimoto
2010-03-24 9:49 ` Liam Girdwood
2010-03-24 6:27 ` [PATCH 4/4] ASoC: fsi: Add FSI2 device support Kuninori Morimoto
2010-03-24 9:50 ` Liam Girdwood
2010-03-24 9:33 ` [PATCH 0/4] ASoC: fsi: " Liam Girdwood
2010-03-24 11:19 ` Mark Brown
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