linux-kernel - Re: [RESEND RFC PATCH 0/5] platform drivers for UP Board

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Message-ID: <1473759772.11323.265.camel@linux.intel.com>
Date:   Tue, 13 Sep 2016 12:42:52 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Dan O'Donovan <dan@...tex.com>,
        platform-driver-x86@...r.kernel.org, dvhart@...radead.org
Cc:     lee.jones@...aro.org, mika.westerberg@...ux.intel.com,
        linux-kernel@...r.kernel.org
Subject: Re: [RESEND RFC PATCH 0/5] platform drivers for UP Board

On Mon, 2016-07-04 at 17:07 +0100, Dan O'Donovan wrote:
> [Re-sending to a wider audience suggested by Darren Hart]
> 
> The UP Board is a new SBC based on the Intel Atom X5-Z8350 "Cherry 
> Trail" SoC and features a 40-pin I/O pin header and form-factor 
> inspired by the Raspberry Pi 2.
> 
> It utilises a CPLD between the SoC and the external 40-pin header
> to provide buffered voltage level-shifting of the I/O signals, mux
> switching and LED control, and programmable pin mapping between the
> SoC and the external pin header.
> 
> The gpio, pinctrl and led drivers provided in this patch series 
> enable and manage the functions provided by that CPLD.
> 
> I have some open questions about this patch series:
>  * Is it ok to place all of these various UP board drivers together
>    in drivers/platform/x86/, or would it be preferable to place them
>    in the respective sub-system directories (gpio, pinctrl, etc.)?
>    My rationale for keeping them together here is that they are all
>    specific to this UP Board platform and not expected to be
>    generally useful on any other platforms (except variants of UP).
>  * Is it acceptable to include hard-coded references to ACPI device
>    IDs (representing devices integrated on the SoC devices) for the
>    purpose of pin map and gpio references? Or is it required to
>    use only named gpio pins?
> 
> Any feedback/suggestions on the questions above, and the patch series
> in general, would be greatly appreciated!

Looking closer to this and taking into account what is going on with
ACPI support for open connected boards I think this patch set is not
needed at all.

Basically most (everything?) you are trying to do in C code may and
should be done in ASL.

Mika, can you correct me if I'm wrong?

> 
> Further information on the UP board can be obtained from [1] and [2].
> 
> [1] https://www.up-board.org
> [2] https://up-community.org
> 
> Dan O'Donovan (5):
>   platform: x86: add driver for UP Board I/O CPLD
>   platform: x86: add UP Board I/O pinctrl driver
>   platform: x86: add UP Board I/O gpio driver
>   platform: x86: add UP Board CPLD LED driver
>   platform: x86: add platform driver for UP Board
> 
>  drivers/platform/x86/Kconfig            |  13 +
>  drivers/platform/x86/Makefile           |   5 +
>  drivers/platform/x86/up_board.c         | 167 ++++++++++
>  drivers/platform/x86/up_board_cpld.c    | 560
> ++++++++++++++++++++++++++++++++
>  drivers/platform/x86/up_board_cpld.h    |  38 +++
>  drivers/platform/x86/up_board_gpio.c    | 254 +++++++++++++++
>  drivers/platform/x86/up_board_gpio.h    |  59 ++++
>  drivers/platform/x86/up_board_leds.c    |  85 +++++
>  drivers/platform/x86/up_board_leds.h    |  50 +++
>  drivers/platform/x86/up_board_pinctrl.c | 285 ++++++++++++++++
>  drivers/platform/x86/up_board_pinctrl.h | 102 ++++++
>  11 files changed, 1618 insertions(+)
>  create mode 100644 drivers/platform/x86/up_board.c
>  create mode 100644 drivers/platform/x86/up_board_cpld.c
>  create mode 100644 drivers/platform/x86/up_board_cpld.h
>  create mode 100644 drivers/platform/x86/up_board_gpio.c
>  create mode 100644 drivers/platform/x86/up_board_gpio.h
>  create mode 100644 drivers/platform/x86/up_board_leds.c
>  create mode 100644 drivers/platform/x86/up_board_leds.h
>  create mode 100644 drivers/platform/x86/up_board_pinctrl.c
>  create mode 100644 drivers/platform/x86/up_board_pinctrl.h
> 

-- 
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Intel Finland Oy