On 01/09/2012 09:01 PM, Thomas Abraham wrote:
>
> + for (idx = 0; idx< nr_gpios; idx++) {
> + gpio = of_get_gpio(dev->of_node, idx);
> + if (!gpio_is_valid(gpio)) {
> + dev_err(dev, "invalid gpio[%d]: %d\n", idx, gpio);
> + return -EINVAL;
> + }
> +
> + if (!request)
> + continue;
> +
> + ret = gpio_request(gpio, "fimd");
Is it how it normally is supposed to be done, i.e. configuring a gpio
_before_ it has been requested ? of_get_gpio() indirectly touches the
gpio controller and gpio_request() doesn't seem to serve its purpose
in this case, i.e. if there is situation like:
driver A driver B
of_get_gpio(nodeA, gpioA);
of_get_gpio(nodeB, gpioA);
gpio_request(gpioA);
gpio_request(gpioB);
driver B will end up with configuration of gpioA from nodeA, not from
nodeB.
As there are few drivers doing that I must be missing something,
not sure what..
I realize the GPIO number needs to be known in order for a GPIO to be
requested. Shouldn't of_get_gpio() be extended to allow locking gpio
controller's module and marking a GPIO as requested in advance ?
> + if (ret) {
> + dev_err(dev, "gpio [%d] request failed\n", gpio);
> + goto gpio_free;
> + }
> + sfb->gpios[idx] = gpio;
> + }
> + return 0;
> +
> +gpio_free:
> + while (--idx>= 0)
> + gpio_free(sfb->gpios[idx]);
> + return ret;
> +}
> +
> +static void s3c_fb_dt_free_gpios(struct s3c_fb *sfb)
> +{
> + unsigned int idx, nr_gpio;
> +
> + nr_gpio = sfb->pdata->win[0]->max_bpp + 4;
> + for (idx = 0; idx< nr_gpio; idx++)
> + gpio_free(sfb->gpios[idx]);
> +}
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