Re: [PATCH] ALSA: ASoC: add codec driver for TI TAS5086

[Daniel Mack <zonque@gmail.com>]

On 22.05.2013 20:33, jonsmirl@gmail.com wrote:
> On Wed, May 22, 2013 at 2:25 PM, Daniel Mack <zonque@gmail.com> wrote:
>> On 22.05.2013 20:01, jonsmirl@gmail.com wrote:
>>> On Wed, May 22, 2013 at 1:55 PM, Daniel Mack <zonque@gmail.com> wrote:
>>>> On 22.05.2013 19:50, jonsmirl@gmail.com wrote:
>>>>> On Fri, Mar 8, 2013 at 6:07 AM, Daniel Mack <zonque@gmail.com> wrote:
>>>>>> This patch adds a driver for TI's TA5086 6-channel PWM processor.
>>>>>>
>>>>>> This chip has a very unusual register layout, specifically because the
>>>>>> registers are of unequal size, and multi-byte registers require bulk
>>>>>> writes to take effect. Regmap does not support these kind of mappings.
>>>>>>
>>>>>> Currently, the driver does not touch any of the registers >= 0x20, so
>>>>>> it doesn't matter, because the register map is mapped to an 8-bit array.
>>>>>> In case more features will be added in the future that require access
>>>>>> to higher registers, the entire regmap H/W I/O routines have to be
>>>>>> open-coded.
>>>>>
>>>>> Check out my tas5504 driver from a long time ago. It dealt with those registers.
>>>>>
>>>>> https://github.com/jonsmirl/mpc5200/blob/master/sound/soc/codecs/tas5504.c
>>>>> https://github.com/jonsmirl/mpc5200/blob/master/sound/soc/codecs/tas5504.h
>>>>
>>>> Sure, without any regmap abstractions, things are somehow manageable.
>>>> Though you lose all the nice things that regmap gives you, such as
>>>> hardware independence and caching. I might have a different solution,
>>>> but I need to get my hands on one of these devices to test.
>>>>
>>>> On a slightly different note: why isn't your driver in the mainline kernel?
>>>
>>> TI doesn't make the chip any more.
>>
>> That might be, but we have tons of drivers for devices in the mainline
>> kernel which aren't in production anymore.
> 
> Yes, but they were added before the chips went out of production.
> 
> Mark/Liam - you can add my TAS5504 driver if you want it. As far as I
> know there is no Linux based hardware using the chip except for a few
> prototypes we built about five years ago.

Ok, I guess that's enough justification to not add it now, at least for
the fact that nobody is able to test this driver now ...


Thanks,
Daniel