[PATCH v2 1/2] regulator: act8945a: add regulator driver for ACT8945A

Yang, Wenyou Wenyou.Yang at atmel.com
Thu Jan 14 04:46:05 PST 2016

Hi Peter,

> -----Original Message-----
> From: Peter Korsgaard [mailto:jacmet at gmail.com] On Behalf Of Peter Korsgaard
> Sent: 2016年1月14日 19:43
> To: Yang, Wenyou <Wenyou.Yang at atmel.com>
> Cc: Liam Girdwood <lgirdwood at gmail.com>; Mark Brown <broonie at kernel.org>;
> Rob Herring <robh+dt at kernel.org>; Pawel Moll <pawel.moll at arm.com>; Mark
> Rutland <mark.rutland at arm.com>; Ian Campbell <ijc+devicetree at hellion.org.uk>;
> Kumar Gala <galak at codeaurora.org>; Krzysztof Kozlowski
> <k.kozlowski at samsung.com>; devicetree at vger.kernel.org; Ferre, Nicolas
> <Nicolas.FERRE at atmel.com>; linux-kernel at vger.kernel.org; Javier Martinez
> Canillas <javier at dowhile0.org>; Lee Jones <lee.jones at linaro.org>; linux-arm-
> kernel at lists.infradead.org
> Subject: Re: [PATCH v2 1/2] regulator: act8945a: add regulator driver for
> ACT8945A
> >>>>> "Yang," == Yang, Wenyou <Wenyou.Yang at atmel.com> writes:
> Hi,
> >>
>  >>> Isn't the regulator part of the act8945a identical to act8865? Can't we just
> use  >>> the existing act8865-regulator.c driver? (E.G. support 8865 variant in the
> mfd  >>> driver, but only register the regulator sub device?)  >>  >> > Yes, the
> regulator part of the act8945a is identical to act8865.
>  >>
>  >> > But the act8865-regulator driver is a struct i2c_driver, and the mfd  > sub-
>   >> device driver is a platform_driver driver, it is not easy to use  > it.
>  >>
>  >> But the mfd driver could support the act8865 variant as well (by only
> registering  >> the regulator mfd cell).
>  > I still don't understand.
>  > The MFD sub device is registered as a platform device, the existing  > act8865
> driver is registered as an i2c_driver. How do they match? :)
>  > Could you point out which exiting driver for me to reference.  Thank you!
> What I'm saying is that it isn't nice that we end up with both act8865-regulator.c
> and act8954-regulator.c doing 95% the same. This can either be fixed by:
> - Adding act8865 support to your mfd driver (but only registering the
>   regulator subdev for act8865) and changing the existing
>   act8865-regulator driver to work as a mfd subdev (platform device)
> - Extending the act8865-regulator driver to register as a platform
>   driver in ADDITION to a i2c driver so it can be used with mfd. The
>   driver already uses regmap so it should only be a matter of adding the
>   pdev probe/remove functions.

Thank you for so detail information, I will do as you said.

Thanks & Best Regards,
Wenyou Yang

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