Hi Linus,
On Wed, Jun 22, 2016 at 11:25 PM, Linus Walleij
<linus.walleij@xxxxxxxxxx> wrote:
> The generic IRQ helper library just checks if the IRQ line is
> set as input before activating it for interrupts. As we
> recently started to check things better with .get_dir() it
> turns out that it's good to try to convince the line to become
> an input before attempting to lock it as IRQ.
>
> Cc: Björn Andersson <bjorn.andersson@xxxxxxxxxx>
> Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
> ---
> ChangeLog v1->v2:
> - Propagate the error from .direction_input() so we can rely on
> it being used.
This patch (commit 7e7c059cb50c7c72 in gpio/for-next) breaks Ethernet on
r8a7795/salvator-x:
libphy: ravb_mii: probed
[1] gpio_rcar e6052000.gpio: sense irq = 11, type = 8
ravb e6800000.ethernet eth0: Base address at 0xe6800000,
2e:09:0a:00:83:1e, IRQ 131.
...
[2] gpiochip_irq_reqres: gpiochip e6052000.gpio
[3] gpio_rcar e6052000.gpio: gpio_rcar_direction_input: 11
[4] gpiochip_irq_reqres: desc->flags = 0x0
ravb e6800000.ethernet eth0: limited PHY to 100Mbit/s
Micrel KSZ9031 Gigabit PHY e6800000.etherne:00: attached PHY
driver [Micrel KSZ9031 Gigabit PHY]
(mii_bus:phy_addr=e6800000.etherne:00, irq=206)
Waiting up to 110 more seconds for network.
Waiting up to 100 more seconds for network.
...
Reverting it fixes the issue.
phy0 in arch/arm64/boot/dts/renesas/r8a7795-salvator-x.dts
phy0: ethernet-phy@0 {
...
interrupt-parent = <&gpio2>;
interrupts = <11 IRQ_TYPE_LEVEL_LOW>;
};
sets up the GPIO for interrupt mode, cfr. [1] in the kernel output above.
> ---
> drivers/gpio/gpiolib.c | 19 +++++++++++++++++++
> 1 file changed, 19 insertions(+)
>
> diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> index 5a21a6acf8af..b195ec406ff4 100644
> --- a/drivers/gpio/gpiolib.c
> +++ b/drivers/gpio/gpiolib.c
> @@ -1505,6 +1505,25 @@ static int gpiochip_irq_reqres(struct irq_data *d)
> if (!try_module_get(chip->gpiodev->owner))
> return -ENODEV;
>
> + /*
> + * If it is possible to switch this GPIO to an input
> + * this is a good time to do it.
> + */
> + if (chip->direction_input) {
> + struct gpio_desc *desc;
> + int ret;
> +
> + desc = gpiochip_get_desc(chip, d->hwirq);
> + if (IS_ERR(desc))
> + return PTR_ERR(desc);
> +
> + ret = chip->direction_input(chip, d->hwirq);
This configures the GPIO for plain input mode, cfr. [3] above, basically
undoing the configuration from [1]. Hence interrupts no longer come through,
and Ethernet fails.
> + if (ret)
> + return ret;
> +
> + clear_bit(FLAG_IS_OUT, &desc->flags);
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
