[PATCH] realtek: ZyXEL GS1900-48: drop gpio-restart
mail at birger-koblitz.de
Tue Feb 22 14:39:38 PST 2022
the information on the external GPIO resetting the board of
the Zyxel GS1900-48 comes from the hardware configuration
reported by the stock firmware. It says:
GS1900# show board
====== Reset =================
Using the rtk gpio commands in u-boot this can be confirmed.
Similarly the information on the XGS1250 comes from the output
of the "show tech-support" command which shows:
Device Pin Direction Default Current Purpose
------- ---- ---------- -------- -------- --------
INT 0 OUT 0 0
INT 1 IN 1 1 FAN_CONTROL
INT 6 IN 1 0 HW_VER_BIT1
INT 7 IN 1 1 HW_VER_BIT0
INT 11 OUT 0 0 FAN_EN
INT 15 OUT 0 0 TX_DIS_P11
INT 16 IN 0 0 SFP_Present_P11
INT 17 IN 0 1 SFP_LOS_P11
INT 20 IN 0 0 TX_FAULT_P11
INT 21 OUT 1 1 RESET_PHY
INT 22 IN 1 1 RST_BTN_OUT
I also tested this in u-boot and toggling that output 21 definitely
only resets the PHYs (port leds turn off), not the entire board.
On 22/02/2022 23:00, Sander Vanheule wrote:
> On Mon, 2022-02-21 at 21:23 +0100, Birger Koblitz wrote:
>>> I just checked with my multimeter, and while the GPIO5 on the RTL8231 does go high/low
>>> when I set the output high/low from Linux, my device certainly doesn't reset. The
>>> GPIO lines on the chip do work, since SFP modules are correctly detected.
>>> Birger, just to be sure, can you confirm that your device does reset with GPIO5 on the
>> Yes, it does.There is a warning, but then it reliably resets. That was why I left it
>> in as is.
> I had another hard look at my board, to check if something may be wrong physically, but I
> cannot find anything. My device's board looks identical to the pictures on the switch wiki
> , which I think you uploaded earlier.
> There is some reset logic on the board , but I cannot figure out how GPIO5 would be
> connected to it electrically. Unless I missed a via connecting to that pin on the RTL8231,
> GPIO5 only appears to lead to TP2. GPIO5/TP2 does not appear to be connected electrically
> to any part of the circuit next to SW1. I could add a bodge wire to connect TP2 to pad
> U25:3, but gpio-restart should really work on unmodified hardware.
> Does my description of the hard reset circuit on the wiki match your board?
> FWIW, the GPIO description reported by the stock firmware on the XGS1250-12 claims that
> internal GPIO21 can be used to reset the board, but you noted in the DTS it actually only
> resets the phy-s. So it wouldn't be the first time the reported board config is partially
>  https://svanheule.net/switches/gs1900-48#board_details
>  https://svanheule.net/switches/gs1900-48#hard_reset_circuit
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