[U-Boot] [PATCH v2 2/7] serial: Allow boards to determine whether a serial device is usable

[Simon Glass]

Hi Alex,

On 17 January 2018 at 15:03, Alexander Graf <agraf at suse.de> wrote:
>
>
> On 17.01.18 20:39, Simon Glass wrote:
>> Hi Alex,
>>
>> On 17 January 2018 at 00:54, Alexander Graf <agraf at suse.de> wrote:
>>> On some boards, serial devices may or may not be muxed properly to actual
>>> pins, depending on firmware configuration. To determine whether we should
>>> use a serial device for U-Boot in-/output, we need to check whether it
>>> is muxed properly.
>>>
>>> This is something only the board file can do, so let's expose a weak
>>> function that a board can override to explicitly allow or disallow
>>> usage of certain serial devices.
>>>
>>> Signed-off-by: Alexander Graf <agraf at suse.de>
>>> ---
>>>  drivers/serial/serial-uclass.c | 11 +++++++++++
>>>  include/serial.h               | 11 +++++++++++
>>>  2 files changed, 22 insertions(+)
>>>
>>
>> Can we please figure out how handle this in the serial driver / driver
>> model itself? I want to avoid weak functions with driver model.
>
> I'm very happy to see suggestions :). The reason I went with the weak
> function is really because I couldn't think of anything better.

The serial driver is proprietary so you should be able to put a call
into the pinctrl driver from that. The pinctrl driver can return the
state of a pin - maybe get_gpio_mux() or a new pinmux_get()?

Regards,
Simon