realtek: hog the GS1900-24E external IC reset line

The GPIO line connecting to the reset signals of the GS1900-24E(A1)'s
external ICs (RTL8218B phys and RTL8231 expander) cannot be asserted by
the MDIO subsystem, as the reset is shared between busses.

To prevent users from accidentally asserting the reset line, a GPIO hog
is created to permanently de-assert the signal, reliably keeping the
phys and GPIO expanders on.

Tested-by: Simon Fischer <simi.fischa@gmail.com>
Signed-off-by: Sander Vanheule <sander@svanheule.net>

diff --git a/target/linux/realtek/dts/rtl8382_zyxel_gs1900-24e-a1.dts b/target/linux/realtek/dts/rtl8382_zyxel_gs1900-24e-a1.dts
index c54648cc3205f39296334d558e0add664ba4fe14..4cffc040ed93c0cb8bc2cde7274c85d33dca81b9 100644 (file)
--- a/target/linux/realtek/dts/rtl8382_zyxel_gs1900-24e-a1.dts
+++ b/target/linux/realtek/dts/rtl8382_zyxel_gs1900-24e-a1.dts
@@ -8,6 +8,16 @@
        model = "Zyxel GS1900-24E A1";
 };
 
+&gpio0 {
+       /* Shared between the main and aux MDIO busses */
+       mdio_reset {
+               gpio-hog;
+               gpios = <1 GPIO_ACTIVE_LOW>;
+               output-low;
+               line-name = "mdio-reset";
+       };
+};
+
 &mdio_bus0 {
        EXTERNAL_PHY(0)
        EXTERNAL_PHY(1)