status = "disabled";
in the Device Tree?/dts-v1/;
/plugin/;
/ {
compatible = "rockchip,rk3328";
fragment@0 {
target-path = "/serial@ff120000";
__overlay__ {
status = "okay";
};
};
fragment@1 {
target = <&pinctrl>;
__overlay__ {
uart1_pins: uart1_pins {
rockchip,pins = <
3 4 5 /* TX -> GPIO3_A4, mode 5 */
3 6 5 /* RX -> GPIO3_A6, mode 5 */
>;
function = "uart";
};
};
};
};
dtc -@ -I dts -O dtb -o /boot/dtb/rockchip/rk3328-uart1-olimex.dtbo rk3328-uart1-olimex.dts
fdt_overlays=rockchip-rk3328-uart1-olimex
fdt_overlays=rockchip-rk3328-uart1
ls /sys/firmware/devicetree/base | grep serial@
serial@ff110000
serial@ff120000
serial@ff130000
cat /sys/firmware/devicetree/base/serial@ff120000/status
cat /sys/firmware/devicetree/base/serial@ff130000/status
dmesg | grep ttyS
[ 0.000000] Kernel command line: root=UUID=3440d0ff-bb26-49a0-92cb-65352124c942 rootwait rootfstype=ext4 splash=verbose console=ttyS2,1500000 consoleblank=0 loglevel=1 ubootpart=ec32f700-01 usb-storage.quirks=0x2537:0x1066:u,0x2537:0x1068:u cgroup_enable=cpuset cgroup_memory=1 cgroup_enable=memory
[ 0.865993] printk: console [ttyS2] disabled
[ 0.866687] ff130000.serial: ttyS2 at MMIO 0xff130000 (irq = 21, base_baud = 1500000) is a 16550A
[ 0.866814] printk: console [ttyS2] enabled
[ 6.976456] systemd[1]: Expecting device dev-ttyS2.device - /dev/ttyS2...
[ 9.592381] systemd[1]: Found device dev-ttyS2.device - /dev/ttyS2.