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

-----Original Message-----
From: Chen Guangyu-B42378
Sent: Monday, August 19, 2013 11:55 AM
To: Bhushan Bharat-R65777
Cc: broonie@kernel.org; lars@metafoo.de; p.zabel@pengutronix.de;
s.hauer@pengutronix.de; mark.rutland@arm.com; devicetree@vger.kernel.org;=

 alsa-

devel@alsa-project.org; swarren@wwwdotorg.org; festevam@gmail.com;
timur@tabi.org; rob.herring@calxeda.com; tomasz.figa@gmail.com;
shawn.guo@linaro.org; linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v6 1/2] ASoC: fsl: Add S/PDIF CPU DAI driver
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Hi Bhushan,
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   I'll revise some as you suggest. Just a few replies here.
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On Mon, Aug 19, 2013 at 12:38:11PM +0800, Bhushan Bharat-R65777 wrote:

quoted

quoted

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 =3D 1000 is select=

ed.

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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?

I am not against, I am saying why it was not 200 or 50 or 20 etc. I am sayi=
ng that write a comment saying this much is sufficient as per specification=
 and so keep 1000/etc as preservative.

-Bharat

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quoted

quoted

quoted

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+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 "retur=

n true"

quoted

quoted

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.

quoted

Where will be device registers cached? Do not we program them to be non=

-

cacheable in core?
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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().
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But I think I can try to use the regcache_bypass instead.
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Thank you,
Nicolin Chen