Re: [PATCH] tty: serial: msm_serial: Use DT aliases

[Kevin Hilman <khilman@kernel.org>]

Stephen Boyd <sboyd@codeaurora.org> writes:

> On 11/10/2014 10:54 AM, Kevin Hilman wrote:
>> On Wed, Oct 22, 2014 at 5:33 PM, Stephen Boyd <sboyd@codeaurora.org> wrote:
>>> We rely on probe order of this driver to determine the line number for
>>> the uart port. This makes it impossible to know the line number
>>> when these devices are populated via DT. Use the DT alias
>>> mechanism to assign the line based on the aliases node.
>>>
>>> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
>> FYI... this patch hit linux-next and caused multiple boot failures on
>> qcom platforms[1] as of next-20141110.  I'm assuming this is because
>> the corresponding DTS changes have not hit linux-next yet.
>>
>> Kevin
>>
>> [1] http://status.armcloud.us/boot/?qcom
>
> Hmm the intention was to make it optional so that dts changes aren't
> necessary unless you want deterministic numbering. I screwed that up
> badly :/ Thanks for finding this.
>
> Greg, can you also apply this patch or squash it into the bad one?
>
> ----8<-----
>
> From: Stephen Boyd <sboyd@codeaurora.org>
> Subject: [PATCH] tty: serial: msm_serial: Don't required DT aliases
>
> If there isn't a DT alias then of_alias_get_id() will return
> -ENODEV. This will cause the msm_serial driver to fail probe,
> when we want to keep the previous behavior where we generated a
> dynamic line number at probe time. Restore this behavior by
> generating a dynamic id if the line number is still negative
> after checking for an alias or (in the non-DT case) looking at the
> .id field of the platform device.
>
> Reported-by: Kevin Hilman <khilman@kernel.org>
> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

Tested-by: Kevin Hilman <khilman@linaro.org>

I confirm that this patch gets things booting again for the
msm8974/xperia-z1 and the apq8064/ifc6410.

Kevin