[alsa-devel] [PATCH v6 1/2] ASoC: fsl: Add S/PDIF CPU DAI driver

Nicolin Chen b42378 at freescale.com
Mon Aug 19 08:24:39 CEST 2013

Hi Bhushan,

   I'll revise some as you suggest. Just a few replies here.

On Mon, Aug 19, 2013 at 12:38:11PM +0800, Bhushan Bharat-R65777 wrote:
> > We here suppose the reset bit would be cleared -- "The software reset will last
> > 8 cycles." from RM, so if this happened to be a failure, the whole IP module
> > won't be normally working as well.
> Also add a comment describing this against why cycle = 1000 is selected.

If it is done in 8 cycles, 1000-cycle will be surely a safe value for it.
As long as it finished in 8 cycles, it would quit anyway. Why against?

> > > > +static bool fsl_spdif_volatile_reg(struct device *dev, unsigned int reg)
> > > > +{
> > > > +	/* Sync all registers after reset */
> > >
> > > Where us sync :) ?
> > 
> > The "return true" would do that. For volatile registers, if no "return true"
> > here, the whole regmap would use the value in cache, while for some bits
> > we need to trace its true value from the physical registers not from cache.
> Where will be device registers cached? Do not we program them to be non-cacheable in core?

regmap has a regcache for all the mapped registers. Set the regsiters as
volatile will allow the driver to sync the regcache with physical memory
each time when using regmap_read/write/update_bits().

But I think I can try to use the regcache_bypass instead.

Thank you,
Nicolin Chen

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