changed status form disabled to okay for uart[234]

[umiddelb]

Changed status form disabled to okay for uart@01c28800(uart2) uart@01c28c00(uart3), uart@01c29000(uart4). Credits go to @martinayotte (http://forum.pine64.org/showthread.php?tid=648). I was able to confirm a serial connection for uart2 and uart4(EULER pin 19,21) but failed with uart3(EULER pin 23,24). May be someone with a multimeter might conduct further investigation and find the right pins.

[martinayotte]

Thanks Uli !
You're faster than myself ...
About uart3, I will dig also on my side when I get chance ...
I'm currently setting up my build environment, I should prepare a patch or fixes for getting the I2C ports very soon (in fact, I've just finish building kernel, booted it, and I now see /dev/i2c-*, but not tested with hardware yet).

[martinayotte]

For UART3, I've look quickly the schematic, and it seems that uart3(EULER pin 23,24) is connected with PD0 and PD1, but the DTS, mentioned PH4/PH5 where PH5 is connected to Pi2 header while PH4 is called CTP-INT on TP connector. So, there is big mismatch here : I will have to dig the AllWinner specs to see if the A64 as another alternate pin mux for that, if not, this will means that the Pine64 team make a mistake here in their wiring.

[longsleep]

Thanks folks. For now can you update the PR to keep uart3 disabled unil it is confirmed working please.

[martinayotte]

Hi Simon !
I've investigated the UART3 (EULER pin 23,24) with the AllWinner specs : it has the pin-mux for that !
Strangely, PinA64 team labelled the (EULER pin 19,21) pins as SPI1_MOSI and SPI1_MISO, while they not provided any SPI1_CLK and SPI1_CS, which are the pin 23/24, while 19/21 can also be UART4.
So, it is question of choice : either we prefer defaulting them to UART3 and UART4 and forget about SPI1 (which doesn't work yet anyway, maybe another task for me soon, at least for SPI0 available on PI header). If we go ahead for UART3, then pins only need to be changed in DTS (I will try it out soon).

(BTW, on another subject : I got the I2C working and tested with hardware, an MCP23017, I will prepare a PR in following hours)

[martinayotte]

Ok ! Some more news :
I've changed the TX/RX pin for PD0/PD1 along with "muxsel" value for the UART3, and at first it didn't work !
I've then thought that maybe it still controled my RTS/CTS pins, which where left as PH6/PH7, but those are used by something else on PinA64. So, I decided to remove them completely from UART3 DTS definition, and it worked ! So, all UARTs have RTS/CTS defined except for UART3, and loopback tests are working !

uart3@0 { linux,phandle = <0xa5>; phandle = <0xa5>; allwinner,pins = "PD0", "PD1"; allwinner,function = "uart3"; allwinner,pname = "uart3_tx", "uart3_rx"; allwinner,muxsel = <0x3>; allwinner,pull = <0x1>; allwinner,drive = <0xffffffff>; allwinner,data = <0xffffffff>; };

[umiddelb]

OK. I'll hand over to @martinayotte and close this PR for now.

[martinayotte]

Thanks, Uli !
Here is the continuation : #11

[umiddelb]

Many thanks, Martin!