On Tue, Jan 14, 2014 at 3:52 PM, <srinivas.kandagatla@xxxxxx> wrote:
> From: Srinivas Kandagatla <srinivas.kandagatla@xxxxxx>
>
> ST pin controller does not have hardware support for detecting edge
> triggered interrupts, It only has level triggering support.
> This patch attempts to fake up edge triggers from hw level trigger
> support in software. With this facility now the gpios can be easily used
> for keypads, otherwise it would be difficult for drivers like keypads to
> work with level trigger interrupts.
>
> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxx>
Clever! Mostly I like the patch as it is but:
> for_each_set_bit(n, &port_active, BITS_PER_LONG) {
> + /* check if we are detecting fake edges ... */
> + pin_edge_cfg = ST_IRQ_EDGE_CONF(bank_edge_mask, n);
> +
> + if (pin_edge_cfg) {
> + /* edge detection. */
> + val = st_gpio_get(&bank->gpio_chip, n);
> + if (val)
> + writel(BIT(n), bank->base + REG_PIO_SET_PCOMP);
> + else
> + writel(BIT(n), bank->base + REG_PIO_CLR_PCOMP);
> +
> + if (pin_edge_cfg != ST_IRQ_EDGE_BOTH &&
> + !((pin_edge_cfg & ST_IRQ_EDGE_FALLING) ^ val))
> + continue;
> + }
> +
Please insert comments here to explain what you are actually doing
because I sure as hell do not understand this code without comments
describing the trick used.
Yours,
Linus Walleij
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