Re: [PATCH v6 1/1] gpio: mpfs: add polarfire soc gpio support

[<Lewis.Hanly@xxxxxxxxxxxxx>]

On Mon, 2022-08-22 at 13:28 +0200, Linus Walleij wrote:
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> On Mon, Aug 15, 2022 at 2:08 PM <lewis.hanly@xxxxxxxxxxxxx> wrote:
> 
> > From: Lewis Hanly <lewis.hanly@xxxxxxxxxxxxx>
> > 
> > Add a driver to support the Polarfire SoC gpio controller
> > 
> > Signed-off-by: Lewis Hanly <lewis.hanly@xxxxxxxxxxxxx>
> 
> This looks like  textbook example of a driver that can use
> CONFIG_GPIO_GENERIC
> 
> > +config GPIO_POLARFIRE_SOC
> > +       bool "Microchip FPGA GPIO support"
> > +       depends on OF_GPIO
> > +       select GPIOLIB_IRQCHIP
> 
> select GPIO_GENERIC
> 
> See e.g. drivers/gpio/gpio-ftgpio010.c for an example
> of how to use bgpio_init() to set up the helper library to handle
> the GPIO side of things and combine it with an irqchip.
> You get get/set_multiple() for free with this approach.
> Also see documentation for bgpio_init() in
> drivers/gpio/gpio-mmio.c.
> 
> Yours,
> Linus Walleij

Thank you for the feedback.
We had looked at the bpgpio_init, our controller is not fully memory
mapped to support the bgpio_init() and get all routines for free.
While we have in/out and intr (interrupt state) 32-bit registers, we
would not get as much free as other generic memory mapped controllers.



For details on the gpio controller:
https://onlinedocs.microchip.com/pr/GUID-0E320577-28E6-4365-9BB8-9E1416A0A6E4-en-US-3/index.html?GUID-A0214F3C-C68A-45A9-B81C-4695A58C4A46#GUID-A0214F3C-C68A-45A9-B81C-4695A58C4A46__ID-00000AB0