[PATCH] arm: mx28: check for gated clocks when setting saif divider

[w.sang@pengutronix.de (Wolfram Sang)]

On Wed, Nov 16, 2011 at 01:35:04PM +0000, Dong Aisheng-B29396 wrote:
> > -----Original Message-----
> > From: Wolfram Sang [mailto:w.sang at pengutronix.de]
> > Sent: Wednesday, November 16, 2011 9:22 PM
> > To: linux-arm-kernel at lists.infradead.org
> > Cc: Sascha Hauer; Guo Shawn-R65073; Dong Aisheng-B29396
> > Subject: Re: [PATCH] arm: mx28: check for gated clocks when setting saif
> > divider
> > 
> > On Sat, Sep 10, 2011 at 12:29:43PM +0200, Wolfram Sang wrote:
> > > Like with all other clocks, the divider for the SAIF devices should
> > > not be altered when the clock is gated. Bail out when this is the case
> > > like the other clocks do.
> > >
> > > Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
> > > Cc: Sascha Hauer <s.hauer@pengutronix.de>
> > > Cc: Shawn Guo <shawn.guo@freescale.com>
> > > Cc: Dong Aisheng-B29396 <B29396@freescale.com>
> > > ---
> > >
> > > Aisheng: I think this is the correct solution for clock-mx28.c. If
> > > setting the rate of the saif clocks hit the error path, it should be
> > fixed in the driver?
> > 
> > Ping. Trying to catch up, has this been resolved meanwhile?
> > 
> Sorry, I missed this patch.
> 
> If I understand right, the convention way is to clk_set_rate() then
> clk_enable().I f that, is it reasonable for driver to do something like:
> Clk_enable -> clk_set_rate->clk_disable to set a proper rate,
> then when needs the clock on, do clk_enable again?

Confused, do you really mean enable -> set_rate -> disable? Because you
can't set clocks when they are enabled?

Well, to be honest, this is all is not very nice due to mxs
restrictions. I chose this approach because this is the common pattern
in all other clocks. There might be a better way of handling this, but
then we'd need to adapt all other clocks as well. What we definately
should not have is one kind of handling the 'already enabled' case for a
few clocks and another kind for others.

Regards,

   Wolfram

-- 
Pengutronix e.K.                           | Wolfram Sang                |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
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