Re: [RFC v7 4/6] gpio: mpfs: add polarfire soc gpio support

[Linus Walleij <linus.walleij@linaro.org>]

On Tue, Jul 23, 2024 at 1:28 PM Conor Dooley <conor.dooley@microchip.com> wrote:


> From: Lewis Hanly <lewis.hanly@microchip.com>
>
> Add a driver to support the Polarfire SoC gpio controller
>
> Signed-off-by: Lewis Hanly <lewis.hanly@microchip.com>
> Signed-off-by: Conor Dooley <conor.dooley@microchip.com>

Just a comment on second thought:

> +config GPIO_POLARFIRE_SOC
> +       bool "Microchip FPGA GPIO support"
> +       depends on OF_GPIO
> +       select GPIOLIB_IRQCHIP

select GPIO_GENERIC?

> +static int mpfs_gpio_direction_input(struct gpio_chip *gc, unsigned int gpio_index)
> +{
> +       struct mpfs_gpio_chip *mpfs_gpio = gpiochip_get_data(gc);
> +       u32 gpio_cfg;
> +       unsigned long flags;
> +
> +       raw_spin_lock_irqsave(&mpfs_gpio->lock, flags);
> +
> +       gpio_cfg = readl(mpfs_gpio->base + MPFS_GPIO_CTRL(gpio_index));
> +       gpio_cfg |= MPFS_GPIO_EN_IN;
> +       gpio_cfg &= ~(MPFS_GPIO_EN_OUT | MPFS_GPIO_EN_OUT_BUF);

OK this part is unique...

> +static int mpfs_gpio_direction_output(struct gpio_chip *gc, unsigned int gpio_index, int value)
> +{
> +       struct mpfs_gpio_chip *mpfs_gpio = gpiochip_get_data(gc);
> +       u32 gpio_cfg;
> +       unsigned long flags;
> +
> +       raw_spin_lock_irqsave(&mpfs_gpio->lock, flags);
> +
> +       gpio_cfg = readl(mpfs_gpio->base + MPFS_GPIO_CTRL(gpio_index));
> +       gpio_cfg |= MPFS_GPIO_EN_OUT | MPFS_GPIO_EN_OUT_BUF;

Also here

> +static int mpfs_gpio_get_direction(struct gpio_chip *gc,
> +                                  unsigned int gpio_index)
> +static int mpfs_gpio_get(struct gpio_chip *gc,
> +                        unsigned int gpio_index)
> +static void mpfs_gpio_set(struct gpio_chip *gc, unsigned int gpio_index, int value)

But these are just MMIO functions.

Is it possible to use augmented generic MMIO, i.e just override these
two functions that
need special handling?

Yours,
Linus Walleij