linux-kernel - Re: [RFC 2/2] mux: mmio-based syscon mux controller

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Date:   Wed, 19 Apr 2017 13:58:44 +0200
From:   Peter Rosin <peda@...ntia.se>
To:     Philipp Zabel <p.zabel@...gutronix.de>,
        Steve Longerbeam <slongerbeam@...il.com>
CC:     Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Sakari Ailus <sakari.ailus@....fi>,
        <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <kernel@...gutronix.de>
Subject: Re: [RFC 2/2] mux: mmio-based syscon mux controller

On 2017-04-19 13:50, Philipp Zabel wrote:
> On Thu, 2017-04-13 at 18:09 -0700, Steve Longerbeam wrote:
>>
>> On 04/13/2017 08:48 AM, Philipp Zabel wrote:
>>> This adds a driver for mmio-based syscon multiplexers controlled by a
>>> single bitfield in a syscon register range.
>>>
>>> Signed-off-by: Philipp Zabel <p.zabel@...gutronix.de>
>>> ---
>>>   drivers/mux/Kconfig      |  13 +++++
>>>   drivers/mux/Makefile     |   1 +
>>>   drivers/mux/mux-syscon.c | 130 +++++++++++++++++++++++++++++++++++++++++++++++
>>>   3 files changed, 144 insertions(+)
>>>   create mode 100644 drivers/mux/mux-syscon.c
>>>
>>> diff --git a/drivers/mux/Kconfig b/drivers/mux/Kconfig
>>> index 86668b4d2fc52..a5e6a3b01ac24 100644
>>> --- a/drivers/mux/Kconfig
>>> +++ b/drivers/mux/Kconfig
>>> @@ -43,4 +43,17 @@ config MUX_GPIO
>>>   	  To compile the driver as a module, choose M here: the module will
>>>   	  be called mux-gpio.
>>>   
>>> +config MUX_SYSCON
>>
>> my preference would be CONFIG_MUX_MMIO.
>>
>>> +	tristate "MMIO bitfield-controlled Multiplexer"
>>
>> "MMIO register bitfield-controlled Multiplexer"
>>
>> The rest looks good to me.
> 
> I'll change those. mux-syscon.c should probably be renamed to
> mux-mmio.c, too.

I think I disagree. But I'm not familiar with syscon so I don't know.
IIUC, syscon uses regmap to do mmio and this driver requires syscon
to get at the regmap, and in the end this driver doesn't know anything
about mmio. All it knows is syscon/regmap. If some warped syscon
thing shows up that wraps something other than mmio in its regmap,
this driver wouldn't care about it. And syscon is something that
is also known in the DT world. Given that, I think everything in this
driver should be named syscon and not mmio.

Or?

Cheers,
peda