Re: [PATCH v4 2/4] gpiolib: add gpiod_get_array and gpiod_put_array functions

[Alexandre Courbot <gnurou@xxxxxxxxx>]

On Wed, Feb 11, 2015 at 11:00 PM, Rojhalat Ibrahim <imr@xxxxxxxxxxx> wrote:
> On Wednesday 11 February 2015 22:31:12 Alexandre Courbot wrote:
>> On Wed, Feb 11, 2015 at 9:14 PM, Rojhalat Ibrahim <imr@xxxxxxxxxxx> wrote:
>> > On Wednesday 11 February 2015 12:30:01 Mika Westerberg wrote:
>> >> On Tue, Feb 10, 2015 at 02:40:52PM +0100, Rojhalat Ibrahim wrote:
>> >> > +#ifdef CONFIG_ACPI
>> >> > +
>> >> > +static unsigned int acpi_gpio_package_count(const union acpi_object *obj)
>> >> > +{
>> >> > +   const union acpi_object *element = obj->package.elements;
>> >> > +   const union acpi_object *end = element + obj->package.count;
>> >> > +   unsigned int count = 0;
>> >> > +
>> >> > +   while (element < end) {
>> >> > +           if (element->type == ACPI_TYPE_LOCAL_REFERENCE)
>> >> > +                   count++;
>> >> > +
>> >> > +           element++;
>> >> > +   }
>> >> > +   return count;
>> >> > +}
>> >> > +
>> >> > +static int acpi_find_gpio_count(struct acpi_resource *ares, void *data)
>> >> > +{
>> >> > +   unsigned int *count = data;
>> >> > +
>> >> > +   if (ares->type == ACPI_RESOURCE_TYPE_GPIO)
>> >> > +           *count += ares->data.gpio.pin_table_length;
>> >> > +
>> >> > +   return 1;
>> >> > +}
>> >> > +
>> >> > +static int acpi_gpio_count(struct device *dev, const char *con_id)
>> >> > +{
>> >> > +   struct acpi_device *adev = ACPI_COMPANION(dev);
>> >> > +   const union acpi_object *obj;
>> >> > +   const struct acpi_gpio_mapping *gm;
>> >> > +   int count = -ENOENT;
>> >> > +   int ret;
>> >> > +   char propname[32];
>> >> > +   unsigned int i;
>> >> > +
>> >> > +   /* Try first from _DSD */
>> >> > +   for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) {
>> >> > +           if (con_id && strcmp(con_id, "gpios"))
>> >> > +                   snprintf(propname, sizeof(propname), "%s-%s",
>> >> > +                            con_id, gpio_suffixes[i]);
>> >> > +           else
>> >> > +                   snprintf(propname, sizeof(propname), "%s",
>> >> > +                            gpio_suffixes[i]);
>> >> > +
>> >> > +           ret = acpi_dev_get_property(adev, propname, ACPI_TYPE_ANY,
>> >> > +                                       &obj);
>> >> > +           if (ret == 0) {
>> >> > +                   if (obj->type == ACPI_TYPE_LOCAL_REFERENCE)
>> >> > +                           count = 1;
>> >> > +                   else if (obj->type == ACPI_TYPE_PACKAGE)
>> >> > +                           count = acpi_gpio_package_count(obj);
>> >> > +           } else if (adev->driver_gpios) {
>> >> > +                   for (gm = adev->driver_gpios; gm->name; gm++)
>> >> > +                           if (strcmp(propname, gm->name) == 0) {
>> >> > +                                   count = gm->size;
>> >> > +                                   break;
>> >> > +                           }
>> >> > +           }
>> >> > +           if (count >= 0)
>> >> > +                   break;
>> >> > +   }
>> >> > +
>> >> > +   /* Then from plain _CRS GPIOs */
>> >> > +   if (count < 0) {
>> >> > +           struct list_head resource_list;
>> >> > +           unsigned int crs_count = 0;
>> >> > +
>> >> > +           INIT_LIST_HEAD(&resource_list);
>> >> > +           acpi_dev_get_resources(adev, &resource_list,
>> >> > +                                  acpi_find_gpio_count, &crs_count);
>> >> > +           acpi_dev_free_resource_list(&resource_list);
>> >> > +           if (crs_count > 0)
>> >> > +                   count = crs_count;
>> >> > +   }
>> >> > +   return count;
>> >> > +}
>> >> > +
>> >> > +#else
>> >> > +
>> >> > +static int acpi_gpio_count(struct device *dev, const char *con_id)
>> >> > +{
>> >> > +   return -ENODEV;
>> >> > +}
>> >> > +
>> >> > +#endif
>> >>
>> >> It just occured to me that it would be better to put this code to
>> >> gpiolib-acpi.c and declare acpi_gpio_count() in drivers/gpio/gpiolib.h.
>> >>
>> >
>> > Ok. I will also have to move the definition of gpio_suffixes[] (PATCH 1/4)
>> > to drivers/gpio/gpiolib.h since it is needed by both the OF and the ACPI
>> > portions of the code.
>>
>> We will really need to factorize this lookup code. I will give it a
>> look, but first I'd like to merge this good stuff.
>>
>> I am mixed about moving these declarations into gpiolib.h - maybe have
>> one static declaration per file instead, especially since lookup on
>> ACPI is not necessarily the same as lookup on DT. It makes sense to
>> have it that way.
>>
>
> If we do one static declaration per file then acpi_find_gpio() in gpiolib.c
> is going to use potentially different suffixes from acpi_gpio_count() in
> gpiolib-acpi.c. That can't be good.

Yeah it's a bit of a mess, I really need to reorganize that code...

I'm not going to mind how you do it - just do whatever seems good to
you, I will revisit it later anyway. For now I'd like this
well-implemented and tested interface to be merged for everyone to
enjoy.
--
To unsubscribe from this list: send the line "unsubscribe linux-gpio" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html