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

[Simon Glass]

Hi Paul,

On 30 September 2016 at 12:12, Paul Burton <paul.burton at imgtec.com> wrote:
> On Monday, 26 September 2016 18:35:25 BST Simon Glass wrote:
>
>> 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
>
>
>
> Hi Simon,
>
>
>
> For the MIPS Boston system I already enable DM_GPIO, I went with this
> approach so that it wouldn't necessarily need to be enabled for the Crown
> Bay x86 system which is the other user of the pch_gbe driver.
>
>
>
> Would having pch_gbe depend on CONFIG_DM_GPIO be ok with you Bin? I see
> crownbay_defconfig enables CONFIG_CMD_GPIO but couldn't find any GPIO-using
> code at a glance. So hopefully it would just work without needing to change
> any existing crownbay code?

It seems OK to me, but in any case, DM_GPIO should be enabled for x86.

Regards,
Simon