Re: [PATCH 4/4] pinctrl: mcp23s08: work around GPIO line naming

[Linus Walleij <linus.walleij@xxxxxxxxxx>]

On Mon, Jun 4, 2018 at 7:05 PM, Jan Kundrát <jan.kundrat@xxxxxxxxx> wrote:

> This driver is a bit weird because it can hide several gpio_chip
> instances underneath a single SPI slave. One cannot put the
> gpio-line-names DT stanza directly to the SPI slave when the
> spi-present-mask has more than one bit set.
>
> I'm making up the `gpio-bank` DT child name as well as its `address`
> property. We need something to match the DT entries with the SPI
> address.
>
> Signed-off-by: Jan Kundrát <jan.kundrat@xxxxxxxxx>

Ah that was a tricky one.

+ #include "../gpio/gpiolib.h"
(...)
> +                       devprop_gpiochip_set_names(&data->mcp[addr]->chip, of_fwnode_handle(np));

I'm not very happy about reaching into the gpiolib internal API like
this.

As Phil says the function should be moved to <linux/gpio/driver.h>
if we need to use it from drivers.

Also, this symbol is not exported so you would get compile errors
from the test farm quickly becuase a lot of module building
starts failing. This function needs EXPORT_SYMBOL_GPL()
to be used from the outside in drivers.

Mika added this function, I don't know how he feels about
having it externalized?

I also think it would be OK with a device-tree only function,
but maybe that is not as reusable?

Yours,
Linus Walleij
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