[alsa-devel] [PATCH] ASoC: core: Configure pin muxing via pinctrl when registering a DAI

[Peter Ujfalusi]

On 09/21/2012 02:13 PM, Mark Brown wrote:
> On Fri, Sep 21, 2012 at 10:54:26AM +0300, Peter Ujfalusi wrote:
>> pinctrl framework now becoming widely available for SoCs to configure pin
>> multiplexing.
>> Instead of adding the same code to all dai drivers the core can take care
>> of this transparently.
>> Do not make too much noise if pinctrl is not provided via DT for the dai
>> but just use dev_info().
> 
> Please fix your word wrapping, I've mentioned this to you before...

I'll reformat it. BTW: The text is edited so it fits in the 'Commit Message'
part of git gui.

>> +/*
>> + * Simple function to be used in snd_soc_dai_register_dai/s to set the default
>> + * pinmuxing for the dai.
> 
> I would be more inclined to do this on card init time, doing it at
> registration seems wrong as systems typically have interfaces that
> aren't used and share pins with other functions.  By the time we are
> setting up a card we've got a good idea we actually want to use the IP
> but at probe time that's not the case.

Make sense. My first candidate to do this is the soc_probe_link_dais()
function and to call snd_soc_configure_dai_pins() for both the cpu_dai and
codec_dai.

> It also seems bad that we're ignoring errors, does the pinctl API not
> stub itself out well enough.

pinctrl_get_select() returns with a pointer to struct pinctrl. If the platform
does not have CONFIG_PINCTRL enabled it will return with NULL.
If no pinctrl has been specified for the device it will return with error
(-ENODEV).
Neither of these cases should be considered as error. We do print out with
dev_info() to notify the developer, but having pinctrl mux should not be
mandatory.

-- 
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