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Subject: Re: [RFC PATCH v3 9/9] ipu3-cio2: Add functionality allowing
 software_node connections to sensors on platforms designed for Windows
To:     Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc:     linux-kernel@vger.kernel.org, linux-media@vger.kernel.org,
        linus.walleij@linaro.org, prabhakar.mahadev-lad.rj@bp.renesas.com,
        heikki.krogerus@linux.intel.com, dmitry.torokhov@gmail.com,
        laurent.pinchart+renesas@ideasonboard.com,
        kieran.bingham+renesas@ideasonboard.com, jacopo+renesas@jmondi.org,
        robh@kernel.org, davem@davemloft.net, linux@rasmusvillemoes.dk,
        sergey.senozhatsky@gmail.com, rostedt@goodmis.org,
        pmladek@suse.com, mchehab@kernel.org, tian.shu.qiu@intel.com,
        bingbu.cao@intel.com, sakari.ailus@linux.intel.com,
        yong.zhi@intel.com, rafael@kernel.org, gregkh@linuxfoundation.org,
        kitakar@gmail.com
References: <20201019225903.14276-1-djrscally@gmail.com>
 <20201019225903.14276-10-djrscally@gmail.com>
 <20201024012411.GT5979@pendragon.ideasonboard.com>
 <d188f8b5-ed3b-f91b-171a-26afeb7d213e@gmail.com>
 <20201024093702.GA3939@pendragon.ideasonboard.com>
 <748d34c3-a146-12fe-22c0-8dfef9006ea0@gmail.com>
 <20201024223628.GG3943@pendragon.ideasonboard.com>
 <703d5108-5b10-802d-2bac-c719150430af@gmail.com>
 <20201026160549.GO4077@smile.fi.intel.com>
 <20201029201742.GC15024@pendragon.ideasonboard.com>
From:   Dan Scally <djrscally@gmail.com>
Message-ID: <91258d01-7226-880f-1388-02b43a71e0e3@gmail.com>
Date:   Thu, 29 Oct 2020 22:36:43 +0000
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Hi both

On 29/10/2020 20:17, Laurent Pinchart wrote:
> Hi Andy,
>
> On Mon, Oct 26, 2020 at 06:05:49PM +0200, Andy Shevchenko wrote:
>> On Mon, Oct 26, 2020 at 08:20:14AM +0000, Dan Scally wrote:
>>> On 24/10/2020 23:36, Laurent Pinchart wrote:
>>>> On Sat, Oct 24, 2020 at 11:28:06PM +0100, Daniel Scally wrote:
>>>>> On 24/10/2020 10:37, Laurent Pinchart wrote:
>>>>>>>> I wonder if we could avoid depending on the I2C device being created by
>>>>>>>> getting the fwnode from adev, and setting ->secondary manually. adev
>>>>>>>> would need to be passed to get_acpi_ssdb_sensor_data() instead of dev.
>>>>>>> Let me try that; I initially wanted to do
>>>>>>> set_secondary_fwnode(&adev->dev, fwnode) to avoid depending on the I2C
>>>>>>> dev being created but it turns out &adev->dev isn't the same pointer. I
>>>>>>> shall try it and see.
>>>>> Actually, thinking on this further I think maybe we can't avoid that -
>>>>> it's not actually in this patch series but during assigning GPIO
>>>>> resources parsed from PMIC's ACPI node to the sensor, I'm using
>>>>> dev_name() on the i2c dev to pass to .dev_id member of gpiod_lookup_table
>>>> Any chance we can construct the I2C device name from the ACPI device,
>>>> the same way that the ACPI/I2C core does ? It may be a dead end, but if
>>>> we could avoid depending on the I2C device, I think it will make
>>>> initialization easier. I have a feeling that will be difficult though,
>>>> as we'll need the I2C bus number, which won't be readily available.
>>> OK yeah; the i2c core does indeed just prefix "i2c-" onto the acpi
>>> device name, so I will make this change too.
>> This is part of the I²C core and if you go this way, do not home grow the
>> functionality that doesn't belong here.
>>
>> Instead, export a helper function that will do it for you and for I²C core with
>> explanation why it's needed.
> Agreed, I was actually considering suggesting that. Hardcoding the same
> naming scheme in two places is asking for trouble, especially if we
> don't let the I2C maintainers know. It should be easy to do, not
> necessarily the highest priority task, but something that should be
> handled to get this merged.
Understood - I'll have a look at the best way to do this once I'm
through the current to do list