On 01/13/2012 10:03 PM, Sylwester Nawrocki wrote:
> 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);
s/B/A
>
> driver B will end up with configuration of gpioA from nodeA, not from
> nodeB.
ugh, I put it wrong, it should instead read:
"driver A will end up with configuration of gpioA from nodeB, not from
nodeA."
> 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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