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Date:   Mon, 12 Aug 2019 08:24:31 +0100
From:   Lee Jones <lee.jones@linaro.org>
To:     Enric Balletbo i Serra <enric.balletbo@collabora.com>
Cc:     linux-kernel@vger.kernel.org, Jonathan Corbet <corbet@lwn.net>,
        Krzysztof Kozlowski <krzk@kernel.org>,
        Will Deacon <will.deacon@arm.com>,
        MyungJoo Ham <myungjoo.ham@samsung.com>,
        Chanwoo Choi <cw00.choi@samsung.com>,
        Benson Leung <bleung@chromium.org>,
        Guenter Roeck <groeck@chromium.org>,
        Jonathan Cameron <jic23@kernel.org>,
        Dmitry Torokhov <dmitry.torokhov@gmail.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Sebastian Reichel <sre@kernel.org>,
        Thierry Reding <thierry.reding@gmail.com>,
        Alexandre Belloni <alexandre.belloni@bootlin.com>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Mark Brown <broonie@kernel.org>,
        Neil Armstrong <narmstrong@baylibre.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Collabora kernel ML <kernel@collabora.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Gwendal Grignou <gwendal@chromium.org>
Subject: Re: [PATCH v5 01/11] mfd / platform: cros_ec: Handle chained ECs as
 platform devices
Message-ID: <20190812072431.GE4594@dell>
References: <20190722133257.9336-1-enric.balletbo@collabora.com>
 <20190722133257.9336-2-enric.balletbo@collabora.com>
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On Mon, 22 Jul 2019, Enric Balletbo i Serra wrote:

> An MFD is a device that contains several sub-devices (cells). For instance,
> the ChromeOS EC fits in this description as usually contains a charger and
> can have other devices with different functions like a Real-Time Clock,
> an Audio codec, a Real-Time Clock, ...
> 
> If you look at the driver, though, we're doing something odd. We have
> two MFD cros-ec drivers where one of them (cros-ec-core) instantiates
> another MFD driver as sub-driver (cros-ec-dev), and the latest
> instantiates the different sub-devices (Real-Time Clock, Audio codec,
> etc).
> 
>                   MFD
> ------------------------------------------
>    cros-ec-core
>        |___ mfd-cellA (cros-ec-dev)
>        |       |__ mfd-cell0
>        |       |__ mfd-cell1
>        |       |__ ...
>        |
>        |___ mfd-cellB (cros-ec-dev)
>                |__ mfd-cell0
>                |__ mfd-cell1
>                |__ ...
> 
> The problem that was trying to solve is to describe some kind of topology for
> the case where we have an EC (cros-ec) chained with another EC
> (cros-pd). Apart from that this extends the bounds of what MFD was
> designed to do we might be interested on have other kinds of topology that
> can't be implemented in that way.
> 
> Let's prepare the code to move the cros-ec-core part from MFD to
> platform/chrome as this is clearly a platform specific thing non-related
> to a MFD device.
> 
>   platform/chrome  |         MFD
> ------------------------------------------
>                    |
>    cros-ec ________|___ cros-ec-dev
>                    |       |__ mfd-cell0
>                    |       |__ mfd-cell1
>                    |       |__ ...
>                    |
>    cros-pd ________|___ cros-ec-dev
>                    |        |__ mfd-cell0
>                    |        |__ mfd-cell1
>                    |        |__ ...
> 
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
> Tested-by: Gwendal Grignou <gwendal@chromium.org>
> ---
> 
> Changes in v5:
> - Rebased on top of 5.3-rc1
> 
> Changes in v4:
> - Rebase again on top of for-mfd-next to avoid conflicts.
> 
> Changes in v3:
> - Collect more acks an tested-by
> 
> Changes in v2:
> - Collect acks received.
> - Remove '[PATCH 07/10] mfd: cros_ec: Update with SPDX Licence identifier
>   and fix description' to avoid conflicts with some tree-wide patches
>   that actually updates the Licence identifier.
> - Add '[PATCH 10/10] arm/arm64: defconfig: Update configs to use the new
>   CROS_EC options' to update the defconfigs after change some config
>   symbols.
> 
>  drivers/mfd/cros_ec.c                   | 61 +++++++++++++------------
>  drivers/platform/chrome/cros_ec_i2c.c   |  8 ++++
>  drivers/platform/chrome/cros_ec_lpc.c   |  3 +-
>  drivers/platform/chrome/cros_ec_rpmsg.c |  2 +
>  drivers/platform/chrome/cros_ec_spi.c   |  8 ++++
>  include/linux/mfd/cros_ec.h             | 18 ++++++++
>  6 files changed, 69 insertions(+), 31 deletions(-)

For my own reference:
  Acked-for-MFD-by: Lee Jones <lee.jones@linaro.org>

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