[U-Boot] [PATCH 14/23] gpio: Provide dummy get/request & is_valid functions

[Simon Glass]

Hi Paul,

On 26 September 2016 at 12:29, Paul Burton <paul.burton at imgtec.com> wrote:
> Allow for drivers to make use of driver model GPIOs when they're enabled
> & available without needing to #ifdef on CONFIG_DM_GPIO by providing
> dummy functions covering GPIO requests. Each will simply return -ENODEV
> or -EINVAL, depending upon which the real implementation returns when a
> GPIO isn't found. Only the driver model versions of the GPIO request
> functions are covered & dm_gpio_request is excluded since it's
> documented as only being of use for debugging, so drivers shouldn't be
> calling it anyway.
>
> Also provide a dummy dm_gpio_is_valid, with the idea that all other GPIO
> functions called would be within an if (dm_gpio_is_valid(...)) statement
> and have been optimised out in cases where that returns a compile-time
> constant false.
>
> This parallels the clock API, keeping the #ifdefs & checks in a single
> location allowing drivers or other code to use GPIOs without needing to
> perform such checks themselves.
>
> Signed-off-by: Paul Burton <paul.burton at imgtec.com>
>
> ---
>
>  include/asm-generic/gpio.h | 38 ++++++++++++++++++++++++++++++++++++++
>  1 file changed, 38 insertions(+)

Ick - why not just define DM_GPIO? I don't think we want to provide
special support for legacy things. It is just confusing.

- Simon