linux-kernel - Re: [PATCH v4 02/15] gpio: regmap: set gpio_chip of

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Date:   Thu, 4 Mar 2021 16:24:55 +0100
From:   Álvaro Fernández Rojas <noltari@...il.com>
To:     Andy Shevchenko <andy.shevchenko@...il.com>
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Michael Walle <michael@...le.cc>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        bcm-kernel-feedback-list <bcm-kernel-feedback-list@...adcom.com>,
        Jonas Gorski <jonas.gorski@...il.com>,
        Necip Fazil Yildiran <fazilyildiran@...il.com>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        devicetree <devicetree@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-arm Mailing List <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v4 02/15] gpio: regmap: set gpio_chip of_node

Hi Andy,

> El 4 mar 2021, a las 16:17, Andy Shevchenko <andy.shevchenko@...il.com> escribió:
> 
> On Thu, Mar 4, 2021 at 5:06 PM Álvaro Fernández Rojas <noltari@...il.com> wrote:
>>> El 4 mar 2021, a las 11:35, Andy Shevchenko <andy.shevchenko@...il.com> escribió:
>>> On Thu, Mar 4, 2021 at 10:57 AM Álvaro Fernández Rojas
>>> <noltari@...il.com> wrote:
> 
>>>> + * @of_node:           (Optional) The device node
>>> 
>>>> +       struct device_node *of_node;
>>> 
>>> Can we use fwnode from day 1, please?
>> 
>> Could you explain this? I haven’t dealt with fwnode never :$
>> BTW, this is done to fix this check when parsing gpio ranges:
>> https://github.com/torvalds/linux/blob/f69d02e37a85645aa90d18cacfff36dba370f797/drivers/gpio/gpiolib-of.c#L933-L934
> 
> Use struct fwnode_handle pointer instead of OF-specific one.

But is that compatible with the current gpiolib-of code? :$

> 
> Also here is the question, why do you need to have that field in the
> regmap config structure and can't simply use the parent's fwnode?
> Also I'm puzzled why it's not working w/o this patch: GPIO library
> effectively assigns parent's fwnode (okay, of_node right now).

Because gpio regmap a child node of the pin controller, which is the one probed (gpio regmap is probed from the pin controller).
Therefore the parent’s fwnode is useless, since the correct gpio_chip node is the child's one (we have pin-ranges declared in the child node, referencing the parent pinctrl node).

> 
> -- 
> With Best Regards,
> Andy Shevchenko

Best regards,
Álvaro.