Subject: Re: [PATCH v5 02/13] mfd: add simple regmap based I2C driver

From: Lee Jones <[email-masked]>
Date: Fri, 17 Jul 2020 10:06:56 +0100

On Mon, 06 Jul 2020, Michael Walle wrote:

> There are I2C devices which contain several different functions but
> doesn't require any special access functions. For these kind of drivers
> an I2C regmap should be enough.
> 
> Create an I2C driver which creates an I2C regmap and enumerates its
> children. If a device wants to use this as its MFD core driver, it has
> to add an individual compatible string. It may provide its own regmap
> configuration.
> 
> Subdevices can use dev_get_regmap() on the parent to get their regmap
> instance.
> 
> Signed-off-by: Michael Walle <[email-masked]>
> ---
> Changes since v4:
>  - new patch. Lee, please bear with me. I didn't want to delay the
>    new version (where a lot of remarks on the other patches were
>    addressed) even more, just because we haven't figured out how
>    to deal with the MFD part. So for now, I've included this one.
> 
>  drivers/mfd/Kconfig          |  9 +++++++
>  drivers/mfd/Makefile         |  1 +
>  drivers/mfd/simple-mfd-i2c.c | 50 ++++++++++++++++++++++++++++++++++++
>  3 files changed, 60 insertions(+)
>  create mode 100644 drivers/mfd/simple-mfd-i2c.c
> 
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index 33df0837ab41..f1536a710aca 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -1162,6 +1162,15 @@ config MFD_SI476X_CORE
>  	  To compile this driver as a module, choose M here: the
>  	  module will be called si476x-core.
>  
> +config MFD_SIMPLE_MFD_I2C
> +	tristate "Simple regmap based I2C devices"

Doesn't look like tristate to me.

Haven't you made this builtin only?

> +	depends on I2C
> +	select MFD_CORE

Why?

> +	select REGMAP_I2C
> +	help
> +	  This is a consolidated driver for all MFD devices which are
> +	  basically just a regmap bus driver.

Please expand on this.  I think it deserves greater explanation.

>  config MFD_SM501
>  	tristate "Silicon Motion SM501"
>  	depends on HAS_DMA

-- 
Lee Jones [李琼斯]
Senior Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
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