[U-Boot] [RFC] Merge all ns16550 dm serial drivers into one

[Stephen Warren <swarren@wwwdotorg.org>]

On 08/14/2015 10:50 AM, Simon Glass wrote:
> Hi Bin,
>
> On 14 August 2015 at 03:18, Bin Meng <bmeng.cn@gmail.com> wrote:
>> Hi,
>>
>> Currently there are 5 dm serial drivers, all of which are ns16550
>> compatible drivers. They are:
>>
>>    serial_omap.c
>>    serial_dw.c
>>    serial_tegra.c
>>    serial_x86.c
>>    serial_ppc.c
>>
>> All these drivers are pretty much similar. I think we can justmerge
>> these into one ns16550 driver.
>>
>> If you think this is necessary, I will send a patch series to do this.
>
> The tegra one is there because it needs an input clock and Stephen
> didn't want to add this to the device tree binding (the kernel has a
> clock framework which gets around this problem).
>
> After that I followed the same pattern. I would support updating the
> binding to support an input clock. Even with the new clock framework
> in U-Boot it might be painful to fit it into SPL in some cases.

The clock is already in the DT, in both Linux and U-Boot's copy, at 
least for Tegra DTs:

         uarta: serial at 0,70006000 {
                 compatible = "nvidia,tegra124-uart", ...
...
                 clocks = <&tegra_car TEGRA124_CLK_UARTA>;