[PATCH v8 04/12] pinctrl: verify whether gpio chip overlapps range

[Haojian Zhuang]

On 14 February 2013 23:23, Linus Walleij <linus.walleij at linaro.org> wrote:
> On Mon, Feb 11, 2013 at 6:10 PM, Haojian Zhuang
> <haojian.zhuang at linaro.org> wrote:
>
>>  /**
>> + * pinctrl_overlapped_gpio_range() - check if the GPIO chip of a certain GPIO
>> + * pin is overlapped with gpio range.
>> + * @gpio: gpio pin to check taken from the global GPIO pin space
>> + *
>> + * This function is complement of pinctrl_match_gpio_range(). If the return
>> + * value of pinctrl_match_gpio_range() is NULL, this function could be used
>> + * to check whether pinctrl device is ready or not. Maybe some GPIO pins
>> + * don't have back-end pinctrl interface.
>> + * If the return value is true, it means that pinctrl device is ready & the
>> + * certain GPIO pin doesn't have back-end pinctrl device. If the return value
>> + * is false, it means that pinctrl device may not be ready.
>> + */
>> +static bool pinctrl_overlapped_gpio_range(unsigned gpio)
>
> The name of this function confuses me, can we name it something
> like:
>
> pinctrl_gpio_is_in_some_chip_but_no_range()
>
> Which is actually what you test, right?
>
How about pinctrl_match_gpio_range_exclude_some_pins()?

>> +{
>> +       struct pinctrl_dev *pctldev;
>> +       struct pinctrl_gpio_range *range = NULL;
>> +       struct gpio_chip *chip = gpio_to_chip(gpio);
>
> Handle if chip happens to become NULL here.
>
>> +       /* Loop over the pin controllers */
>> +       list_for_each_entry(pctldev, &pinctrldev_list, node) {
>> +               /* Loop over the ranges */
>> +               list_for_each_entry(range, &pctldev->gpio_ranges, node) {
>> +                       /* Check if any gpio range overlapped with gpio chip */
>> +                       if (range->base + range->npins - 1 < chip->base ||
>> +                           range->base > chip->base + chip->ngpio - 1)
>> +                               continue;
>> +                       return true;
>> +               }
>> +       }
>> +       return false;
>> +}
>> +
>> +/**
>>   * pinctrl_get_device_gpio_range() - find device for GPIO range
>>   * @gpio: the pin to locate the pin controller for
>>   * @outdev: the pin control device if found
>> @@ -459,6 +493,8 @@ int pinctrl_request_gpio(unsigned gpio)
>>
>>         ret = pinctrl_get_device_gpio_range(gpio, &pctldev, &range);
>>         if (ret) {
>> +               if (pinctrl_overlapped_gpio_range(gpio))
>> +                       ret = 0;
>
> If you change the name of the function like above this call can be understood,
> but maybe also add a comment above this call explaining the situation.
>
> Yours,
> Linus Walleij