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SubjectRe: [PATCH] ASoC: cs42888: Add codec driver support
On Mon, Feb 24, 2014 at 08:30:11PM +0900, Mark Brown wrote:
> On Mon, Feb 24, 2014 at 02:55:29PM +0800, Nicolin Chen wrote:
> > This patch adds support for the Cirrus Logic CS42888 Audio CODEC that
> > has four 24-bit A/D and eight 24-bit D/A converters.
>
> Looks generally good, some fairly small nits below.

I'll revise all of them.

Thank you.
Nicolin

----

>
> > [ CS42888 supports both I2C and SPI control ports. As initial patch,
> > this patch only adds the support for I2C. ]
>
> > 5 files changed, 795 insertions(+)
> > create mode 100644 Documentation/devicetree/bindings/sound/cs42888.txt
> > create mode 100644 sound/soc/codecs/cs42888.c
> > create mode 100644 sound/soc/codecs/cs42888.h
>
> Given that we're starting to split out separate bus drivers for the I2C
> and SPI CODECs (look at the recent submissions from Lars-Peter) it'd be
> good to start this off with a separate bus driver for I2C even if the
> SPI one is still to be done - that way the Kconfig stuff for machine
> drivers is all in place and doesn't need updating.
>
> > + - clocks : phandle to the clock source for MCLK
> > +
> > + - clock-names : must contain "mclk".
>
> These should really be lists though there's only one documented element
> so it's purely a documentation update.
>
> > + /* Disable auto-mute */
> > + regmap_update_bits(cs42888->regmap, CS42888_TXCTL,
> > + CS42888_TXCTL_AMUTE | CS42888_TXCTL_DAC_SZC_MASK,
> > + CS42888_TXCTL_DAC_SZC_SR);
>
> Does this interfere with the manual mute controls or is it a separate
> thing? If it plays nicely with the manual controls it's probably better
> to leave it enabled since it improves performance in some benchmarks
> (that's why hardware tends to have the feature).
>
> > + /*
> > + * We haven't marked the chip revision as volatile due to
> > + * sharing a register with the right input volume; explicitly
> > + * bypass the cache to read it.
> > + */
> > + regcache_cache_bypass(cs42888->regmap, true);
>
> The other option here is to just not provide a default so that the first
> time it's read it goes to hardware. It doesn't make much difference
> either way though.
>
> > +static int cs42888_i2c_remove(struct i2c_client *i2c_client)
> > +{
> > + snd_soc_unregister_codec(&i2c_client->dev);
> > + return 0;
> > +}
>
> The driver ought to disable runtime PM, the clock and the regulators here.
>
> > + /*
> > + * In case the device was put to hard reset during sleep,
> > + * we need to wait 500ns here before any I2C communication
> > + */
> > + mdelay(5);
>
> Do we need 500ns or 5ms?
>
> > + regcache_sync(cs42888->regmap);
>
> Should really check the return value here.
>
> > + if (!IS_ERR(cs42888->clk))
> > + clk_disable_unprepare(cs42888->clk);
>
> Does the device work without MCLK?






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