[alsa-devel] [PATCH v2 2/3] ARM: mx28evk: set a initial clock rate for saif

[Dong Aisheng-B29396]

> -----Original Message-----
> From: Uwe Kleine-König [mailto:u.kleine-koenig at pengutronix.de]
> Sent: Thursday, September 08, 2011 2:22 AM
> To: Dong Aisheng-B29396
> Cc: alsa-devel at alsa-project.org; s.hauer at pengutronix.de;
> broonie at opensource.wolfsonmicro.com; lrg at ti.com; linux-arm-
> kernel at lists.infradead.org; w.sang at pengutronix.de
> Subject: Re: [PATCH v2 2/3] ARM: mx28evk: set a initial clock rate for
> saif
> 
> On Wed, Sep 07, 2011 at 09:57:37PM +0800, Dong Aisheng wrote:
> > Signed-off-by: Dong Aisheng <b29396 at freescale.com>
> > Cc: Sascha Hauer <s.hauer at pengutronix.de>
> > Cc: Wolfram Sang <w.sang at pengutronix.de>
> > Cc: Mark Brown <broonie at opensource.wolfsonmicro.com>
> > Cc: Liam Girdwood <lrg at ti.com>
> >
> > ---
> > No changes since v1.
> >
> > Note this patch still needs another patch from Wolfram to work.
> > I send out it in this series as
> > [PATCH 3/3] arm: mxs: disable clock-gates when setting saif-clocks
> If your patch 2 depends on patch 3 there is something fishy.
Yes, because the original saif clk setting code has some issues
Which can be fixed in patch 3.
 
> >
> > As discussed with Wolfram, that patch may still have some later work
> > to do. However, we just send out it for testers to work first.
> > ---
> >  arch/arm/mach-mxs/clock-mx28.c |    9 +++++++++
> >  1 files changed, 9 insertions(+), 0 deletions(-)
> >
> > diff --git a/arch/arm/mach-mxs/clock-mx28.c
> > b/arch/arm/mach-mxs/clock-mx28.c index f0c7cb6..33cc2ff 100644
> > --- a/arch/arm/mach-mxs/clock-mx28.c
> > +++ b/arch/arm/mach-mxs/clock-mx28.c
> > @@ -826,6 +826,15 @@ int __init mx28_clocks_init(void)
> >  	clk_set_parent(&saif0_clk, &pll0_clk);
> >  	clk_set_parent(&saif1_clk, &pll0_clk);
> >
> > +	/*
> > +	 * Set an initial clk rate for saif's internal logic to work
> properly,
> > +	 * this is especially for the saif working on EXTMASTER mode that
> who
> > +	 * uses other saif's BITCLK&LRCLK but it still needs a basic clk
> which
> > +	 * should be bigger enough for its internal logic.
> This is not a proper (German) English sentence. Maybe this is better?:
> 
> 	Set an initial clock rate for the saif internal logic to work
> 	properly. This is important when working in EXTMASTER mode that
> 	uses the other saif's BITCLK&LRCLK but it still needs a basic
> 	clock which should be fast enough for the internal logic.
Yes, I think it's better. :)
I will change like that.

> > +	 */
> > +	clk_set_rate(&saif0_clk, 24000000);
> > +	clk_set_rate(&saif1_clk, 24000000);
> > +
> Do you need to check for clk_set_rate returning -ESOMETHING here?
Basically this rate setting will not fail in clock_init.
I noticed arch/arm/mach-mx5/clock-mx51-mx53.c also used like this.
Should I add an error checking here?

Regards
Dong Aisheng