[RFC PATCH 1/3] mfd: AXP22x: add support for APX221 PMIC

[Hans de Goede]

Hi,

On 05/19/2014 07:45 PM, Boris BREZILLON wrote:
> Hello Lee,
> 
> On 19/05/2014 19:28, Lee Jones wrote:
>>> This patch introduces preliminary support for the X-Powers AXP221 PMIC.
>>> The AXP221 is typically used on boards using Allwinner's A31 SoC.
>>>
>>> At the moment, this driver only exposes regulator devices, but other
>>> subdevices.
>>>
>>> Signed-off-by: Boris BREZILLON <boris.brezillon at free-electrons.com>
>>> ---
>>>  drivers/mfd/Kconfig        |  12 +++
>>>  drivers/mfd/Makefile       |   1 +
>>>  drivers/mfd/axp22x.c       | 237 +++++++++++++++++++++++++++++++++++++++++++++
>>>  include/linux/mfd/axp22x.h | 149 ++++++++++++++++++++++++++++
>>>  4 files changed, 399 insertions(+)
>>>  create mode 100644 drivers/mfd/axp22x.c
>>>  create mode 100644 include/linux/mfd/axp22x.h
>> Not a chance.
>>
>> Farrrr, too much common code with axp20x.c - please merge into one file.
>>
> 
> This was one of the questions I asked in my cover letter (could you take
> a look at it and tell me what's your prefered solution ?) ;-).
> 
> I first tried to reuse the axp20x drivers, but ended up copying almost
> all definitions, hence I decided to first do a different driver and ask
> for advices.

I've just taken a good look at this (I'm planning on doing an axp152 driver
myself), and it seems that using a single mfd driver for the 20x and 221 should
be quite feasible:

- axp20x.h would get some new register defines for registers which are
  different (or unique) to the 221 prefixed with aXP221
- An axp20x_writeable_ranges would need
  to be extended with a third range going from AXP221_BAT_CAP1 (0xe0)
  to AXP221_BAT_LOW_THRESH (0xe6)
- axp20x_writeable_table would get .n_yes_ranges set to 2, and a new
  apx22x_writeable_table would be introduced with n_yes_ranges set to 3.
- add a new axp221_supplies array
- add a new axp221_cells array
- and finally use the proper structs in axp20x_i2c_probe depending on the type

Note that this means sharing ie the interrupt table, which is ok since they
are the same, except that the 221 has a couple of interrupts missing, but
the ones which are shared are all at the same place.

Regards,

Hans