Re: [PATCH 2/2] gpio: dwapb: Call directly into the gpiochip to read value

[Hoan Tran <hotran@apm.com>]

Hi Linus,

On Mon, Feb 12, 2018 at 2:11 AM, Linus Walleij <linus.walleij@linaro.org> wrote:
> We were going out through the (legacy) gpio API to read the value
> of a line to set up polarity inversion. This is abusive. Do something
> less abusive by looking up the actual struct gpio_chip *
> instance and calling .get() directly on it.
>
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
> ---
>  drivers/gpio/gpio-dwapb.c | 37 ++++++++++++++++++++++++++++++-------
>  1 file changed, 30 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpio/gpio-dwapb.c b/drivers/gpio/gpio-dwapb.c
> index 677988f21369..b0704a883513 100644
> --- a/drivers/gpio/gpio-dwapb.c
> +++ b/drivers/gpio/gpio-dwapb.c
> @@ -9,8 +9,6 @@
>   */
>  #include <linux/acpi.h>
>  #include <linux/gpio/driver.h>
> -/* FIXME: for gpio_get_value(), replace this with direct register read */
> -#include <linux/gpio.h>
>  #include <linux/err.h>
>  #include <linux/init.h>
>  #include <linux/interrupt.h>
> @@ -153,16 +151,40 @@ static int dwapb_gpio_to_irq(struct gpio_chip *gc, unsigned offset)
>         return irq_find_mapping(gpio->domain, offset);
>  }
>
> +static struct dwapb_gpio_port *dwapb_offs_to_port(struct dwapb_gpio *gpio, unsigned int offs)
> +{
> +       struct dwapb_gpio_port *port;
> +       int i;
> +
> +       for (i = 0; i < gpio->nr_ports; i++) {
> +               port = &gpio->ports[i];
> +               if (port->idx == offs / 32)
> +                       return port;
> +       }
> +
> +       return NULL;
> +}
> +
>  static void dwapb_toggle_trigger(struct dwapb_gpio *gpio, unsigned int offs)
>  {
> -       u32 v = dwapb_read(gpio, GPIO_INT_POLARITY);
> +       struct dwapb_gpio_port *port = dwapb_offs_to_port(gpio, offs);
> +       struct gpio_chip *gc;
> +       u32 pol;
> +       int val;
> +
> +       if (!port)
> +               return;
> +       gc = &port->gc;
>
> -       if (gpio_get_value(gpio->ports[0].gc.base + offs))
> -               v &= ~BIT(offs);
> +       pol = dwapb_read(gpio, GPIO_INT_POLARITY);
> +       /* Just read the current value right out of the data register */
> +       val = gc->get(gc, offs % 32);
> +       if (val)
> +               pol &= ~BIT(offs);
>         else
> -               v |= BIT(offs);
> +               pol |= BIT(offs);
>
> -       dwapb_write(gpio, GPIO_INT_POLARITY, v);
> +       dwapb_write(gpio, GPIO_INT_POLARITY, pol);
>  }
>
>  static u32 dwapb_do_irq(struct dwapb_gpio *gpio)
> @@ -481,6 +503,7 @@ static int dwapb_gpio_add_port(struct dwapb_gpio *gpio,
>         dirout = gpio->regs + GPIO_SWPORTA_DDR +
>                 (pp->idx * GPIO_SWPORT_DDR_STRIDE);
>
> +       /* This registers 32 GPIO lines per port */
>         err = bgpio_init(&port->gc, gpio->dev, 4, dat, set, NULL, dirout,
>                          NULL, 0);
>         if (err) {
> --
> 2.14.3
>

Acked-by: Hoan Tran <hotran@apm.com>

Thanks
Hoan