Hi Sjoerd,
On Wed, Apr 6, 2016 at 12:16 PM, Sjoerd Simons
<[email protected]> wrote:
> I've got a Porter board (Revision B) which stopped showing serial
> output since the patch mentioned in the subject. The terrible clearly
> wrong hack below gets serial back (reverting to just the fck clock for
> scif0) on both linux-next and linux master.
Thanks for your report!
I assume something is wrong with the SCIF_CLK input.
Hence I guess the issue is also fixed by removing the "&scif_clk" block in
arch/arm/boot/dts/r8a7791-porter.dts?
> Unfortunately I don't have enough documentation on the board/hardware
> to diagnose this further, but hopefully someone else does ;)
I don't have a Porter, so I based my patch on the documentation, which states:
The SCIF_CLK pin of the R-CarM2 is connected to the crystal oscillator
(X4) on the R-Car M2 Application Development Board, which
supplies a clock frequency of 14.7456 MHz.
which matches r8a7791-porter.dts, if I'm not mistaken.
Perhaps the documentation applies to another version of the board than
Revision B?
Questions:
- Does your board have X4 populated?
X4 seems to be unpopulated on http://elinux.org/R-Car/Boards/Porter
(which is Revision A, look close to the fan, at 10 o'clock).
On Silk, it is populated on http://elinux.org/R-Car/Boards/SILK
(look close to the SoC, at 1 o'clock).
- If X4 is populated, does it help if you change the scif_clk_pins pinctrl
group in arch/arm/boot/dts/r8a7791-porter.dts from "scif_clk" to
"scif_clk_b"?
- Does anyone have schematics?
Thanks!
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected]
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
