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SubjectRe: [PATCH 2/2] ARM: dts: sun8i: enable UART1 for iNet D978 Rev2 board
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HI,

On 25-08-16 16:53, Icenowy Zheng wrote:
>
>
> 25.08.2016, 22:18, "Hans de Goede" <hdegoede@redhat.com>:
>> Hi,
>>
>> On 25-08-16 16:12, Icenowy Zheng wrote:
>>> 25.08.2016, 16:03, "Maxime Ripard" <maxime.ripard@free-electrons.com>:
>>>> Hi,
>>>>
>>>> On Thu, Aug 25, 2016 at 02:57:24PM +0800, Icenowy Zheng wrote:
>>>>> >>>> diff --git a/arch/arm/boot/dts/sun8i-a33-inet-d978-rev2.dts b/arch/arm/boot/dts/sun8i-a33-inet-d978-rev2.dts
>>>>> >>>> index 78823d8..3ac22d4 100644
>>>>> >>>> --- a/arch/arm/boot/dts/sun8i-a33-inet-d978-rev2.dts
>>>>> >>>> +++ b/arch/arm/boot/dts/sun8i-a33-inet-d978-rev2.dts
>>>>> >>>> @@ -48,6 +48,10 @@
>>>>> >>>> model = "INet-D978 Rev 02";
>>>>> >>>> compatible = "primux,inet-d978-rev2", "allwinner,sun8i-a33";
>>>>> >>>>
>>>>> >>>> + aliases {
>>>>> >>>> + serial1 = &uart1;
>>>>> >>>> + };
>>>>> >>>> +
>>>>> >>>
>>>>> >>> Is there any other UART in the system?
>>>>> >>
>>>>> >> serial0 is defined in sun8i-reference-design-tablet.dtsi, as r_uart.
>>>>> >
>>>>> > If your board does not have r_uart pads, then the right thing to do
>>>>> > would be to disable it. You can then have uart1 as serial0.
>>>>>
>>>>> I don't know it. The RX/TX is wired on PF2/PF4 on the board (UART0 muxed with
>>>>> MMC)
>>>>
>>>> Then you don't support it and you need to disable it.
>>>>
>>>>> But many codes will require a ttyS0 as console... So I think the
>>>>> bluetooth should be located at ttyS1...
>>>>
>>>> Most of them would use /dev/console anyway. What do you have in mind?
>>>
>>> As a general configuration, /dev/ttyS0 will be indicated as the default console=
>>> value... (Otherwise more boards will fail)
>>>
>>> Or maybe we can specify uart0 as serial0, and leave it as disabled? (Thus if the
>>> debug port is needed, we can easily apply a overlay with &mmc0 status as disabled,
>>> and &uart0 status as okay)
>>>
>>> On all my A33 boards, the official boot0, u-boot all uses uart0 as debugging port.
>>
>> If no uart is available (and being muxed with the mmc counts as not being available)
>> then you should not have any serial alias in the dts.
>>
>> In u-boot you need to use:
>>
>> # CONFIG_REQUIRE_SERIAL_CONSOLE is not set
>>
>> In the defconfig in this case, otherwise u-boot is going to be unhappy about
>> not having a serial console.
>
> It's not the problem.
>
> Can I have no ttyS0 and just make bluetooth ttyS1?

Ah, yes having a serial1 alias should do that I believe and I agree that it
is probably better to not use ttyS0 for the bluetooth uart.

Regards,

Hans


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