[alsa-devel] [PATCH] ASoC: nau8825: Add driver for headset chip Nuvoton 8825

[Anatol Pomozov]

Hi

On Thu, Aug 13, 2015 at 3:33 PM, Mark Brown <broonie at kernel.org> wrote:
> On Thu, Aug 13, 2015 at 12:44:33PM -0700, Anatol Pomozov wrote:
>> On Thu, Aug 13, 2015 at 4:26 AM, Mark Brown <broonie at kernel.org> wrote:
>
>> > No, that is not the case at all - what makes you claim that devm_clk_get()
>> > is DT specific?
>
>> clk_dev uses of_clk_get_by_name() that is implemented for DTS only.
>> See include/linux/clk.h.
>
> That means that the clock API can work with DT, not that DT is
> mandatory - notice how there are stubs for the non-DT case.
>
>> ACPI has a compatible API for getting simple properties
>> (strings/numbers), but no API for dealing with clocks.
>
> So ACPI based platforms have to deal with providing clocks in some other
> way, that's something that is abstracted away by the clock API.  There
> are a number of drivers for both board file based and ACPI based systems
> already in tree which manage to make use of the clock API.

What is the best example of driver that uses clk API in both DT and
ACPI friendly way? I will use it as a template for my driver.

>> I am still trying to understand the use-case for NAU8825 without jack
>> detection functionality. Are you talking about a board configuration
>> that does not wire jack to JKDET codec pin and (maybe) statically
>> connects output to speakers?
>
> I'm not specifically familiar with this CODEC, however this sort of
> detection circuitry is all pretty standard.  I'm thinking of the sort of
> straightforward configurations where the detection inputs and any
> outputs required to flip polarity of the jack are just not wired up.

This corresponds to codec's JKDET/GPIO1 pin that is used as a default
source for jack detection interruption. And better place to describe a
board configuration like this is DTS.

Looking at Nuvoton's documentation I see it mentions that jack
detection IRQ source can be set to one of the GPIO pins or its
combination. In DTS it will look something like
  nuvoton,jkdet-source = <N>; // 0 to disable jkdet functionality, 1
for gpio1 (chip default), 2 for gpio2

The chip documentation on jack detection is sparse so I need to
clarify all aspects of configuration with Nuvoton engs.

And I believe this jack detection source configuration can be added
later and should not block the rest of the driver.