Re: [PATCH 1/3] ASoC Samsung S3C24xx I2S support.

[Ben Dooks <ben-alsa@fluff.org>]

On Fri, Feb 02, 2007 at 07:25:02PM +0100, Takashi Iwai wrote:
> At Fri, 02 Feb 2007 18:03:19 +0000,
> Liam Girdwood wrote:
> > 
> > diff -r 0f9c7c3b7657 soc/s3c24xx/s3c24xx-i2s.c
> > --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
> > +++ b/soc/s3c24xx/s3c24xx-i2s.c	Wed Jan 31 16:43:17 2007 +0000
> (snip)
> > +static void s3c24xx_snd_txctrl(int on)
> > +{
> > +	unsigned long iisfcon;
> > +	unsigned long iiscon;
> > +	unsigned long iismod;
> 
> Should be u32.  unsigned long could be 64bit.
> 
> > +static void s3c24xx_snd_rxctrl(int on)
> > +{
> > +	unsigned long iisfcon;
> > +	unsigned long iiscon;
> > +	unsigned long iismod;
> 
> Ditto.
> > +static int s3c24xx_snd_lrsync()
> > +{
> > +	unsigned long iiscon;
> 
> Ditto.
> 
> > +	int timeout = 10000;
> > +
> > +	DBG("Entered %s\n", __FUNCTION__);
> > +
> > +	while (1) {
> > +		iiscon = readl(s3c24xx_i2s.regs + S3C2410_IISCON);
> > +		if (iiscon & S3C2410_IISCON_LRINDEX)
> > +			break;
> > +
> > +		if (--timeout < 0)
> > +			return -ETIMEDOUT;
> > +	}
> 
> How tolerant should it be?  This style of busy loop depends on the
> machine speed and isn't reliable.

The most this should wait is 1 sample period, as it is to synchronise
the left/right word clock to the system (otherwise you get randon channel
flips when the s3c24xx is the iis slave)... it may be worth using jiffies
for the timeout. 

-- 
Ben

Q:      What's a light-year?
A:      One-third less calories than a regular year.


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