Re: [PATCH v1 0/6] mfd: Make use of software nodes

From: Serge Semin <fancer.lancer@gmail.com>
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: linux-gpio@vger.kernel.org,
	Linus Walleij <linus.walleij@linaro.org>,
	Bartosz Golaszewski <bgolaszewski@baylibre.com>,
	linux-kernel@vger.kernel.org, Lee Jones <lee.jones@linaro.org>
Subject: Re: [PATCH v1 0/6] mfd: Make use of software nodes
Date: Tue, 16 Jun 2020 23:02:25 +0300	[thread overview]
Message-ID: <20200616200225.32mwzew3zw3nuiwh@mobilestation> (raw)
In-Reply-To: <20200608134300.76091-1-andriy.shevchenko@linux.intel.com>

On Mon, Jun 08, 2020 at 04:42:54PM +0300, Andy Shevchenko wrote:
> Some devices would need to have a hierarchy of properties and
> child nodes passed to the child or children of MFD. For such case
> we may utilize software nodes, which is superior on device properties.
> 
> Add support of software nodes to MFD core and convert one driver
> to show how it looks like. This allows to get rid of legacy platform
> data.
> 
> The change has been tested on Intel Galileo Gen 2.

I am wondering whether we could move the {gpio_base, ngpio, irq_shared}
part into the gpio-dwapb.c driver and use either the ACPI-based or
platform_device_id-based matching to get the device-specific resources
info through the driver_data field. By doing so you wouldn't need to
introduce a new "snps,gpio-base"-like property and propagate
software_node-based properties, but still you could get rid of the
dwapb_platform_data structure since all the info would be locally
available.

If ACPI-based matching doesn't uniquely address the Quark GPIO node,
then you could just replace the intel_quark_mfd_cells[0].name with
something like "gpio-dwapb-quark", which then by the MFD core will be
copied to the corresponding platform_device->name due to calling
platform_device_alloc() with cell-name passed. That name will be used
to match a platform_driver with id_table having that new name added.

-Sergey

> 
> Andy Shevchenko (5):
>   gpio: dwapb: Replace irq_shared flag with fwnode type check
>   gpio: dwapb: Read GPIO base from snps,gpio-base property
>   mfd: intel_quark_i2c_gpio: Convert to use software nodes
>   gpio: dwapb: Get rid of legacy platform data
>   gpio: dwapb: Define magic number for IRQ and GPIO lines
> 
> Heikki Krogerus (1):
>   mfd: core: Propagate software node group to the sub devices
> 
>  drivers/gpio/gpio-dwapb.c                | 44 +++++++++-------
>  drivers/mfd/intel_quark_i2c_gpio.c       | 64 +++++++++++-------------
>  drivers/mfd/mfd-core.c                   | 31 ++++++++++--
>  include/linux/mfd/core.h                 |  3 ++
>  include/linux/platform_data/gpio-dwapb.h | 23 ---------
>  5 files changed, 85 insertions(+), 80 deletions(-)
>  delete mode 100644 include/linux/platform_data/gpio-dwapb.h
> 
> -- 
> 2.27.0.rc2
> 