[Debian 11 - 3.0.11][TinkerBoard 2S] How the change baudrate of uart0 / ttyS0

[Jovan 0]

Hello,

 

When. in /boot/config.txt I enable uart0 and uart4 and define them with different baud rates, both are always initialized with 1500000 baudrate.

intf:fiq_debugger=on
intf:uart0=on
intf:uart4=on
#intf:i2c6=off
#intf:i2c7=off
#intf:i2s0=off
#intf:spdif=on
#intf:spi1=off
#intf:spi5=off
#intf:pwm0=off
#intf:pwm1=off
#intf:pwm3a=off
#intf:test_clkout2=off


uart0 = Serial("/dev/ttyS0", 115200)
uart4 = Serial("/dev/ttyS4", 1000000)

then after the boot I get:

linaro@linaro-alip:~$ sudo dmesg | grep tty
[    4.664967] Kernel command line: storagemedia=emmc androidboot.storagemedia=emmc androidboot.mode=normal  androidboot.verifiedbootstate=orange androidboot.serialno=b6977d7c12b9a2e5 root=/dev/mmcblk0p8 rw rootwait console=tty0 earlycon=uart8250,mmio32,0xff1a0000 console=ttyFIQ0 rootfstype=ext4 coherent_pool=1m
[    5.325828] printk: console [tty0] enabled
[    5.681796] Registered FIQ tty driver
[    6.876158] printk: console [ttyFIQ0] enabled
[    6.890795] Registered fiq debugger ttyFIQ0
[    7.667771] ff180000.serial: ttyS0 at MMIO 0xff180000 (irq = 45, base_baud = 1500000) is a 16550A
[    7.668238] ff370000.serial: ttyS4 at MMIO 0xff370000 (irq = 47, base_baud = 1500000) is a 16550A
[   14.656870] ttyFIQ ttyFIQ0: tty_port_close_start: tty->count = 1 port count = 2

 

How to change baudrate this?

Thanks

[tooz 47]

hello @Jovan, 

modifying /boot/config.txt only allows the function to be enabled

On 12/8/2023 at 10:17 PM, Jovan said:

linaro@linaro-alip:~$ sudo dmesg | grep tty [ 4.664967] Kernel command line: storagemedia=emmc androidboot.storagemedia=emmc androidboot.mode=normal androidboot.verifiedbootstate=orange androidboot.serialno=b6977d7c12b9a2e5 root=/dev/mmcblk0p8 rw rootwait console=tty0 earlycon=uart8250,mmio32,0xff1a0000 console=ttyFIQ0 rootfstype=ext4 coherent_pool=1m [ 5.325828] printk: console [tty0] enabled [ 5.681796] Registered FIQ tty driver [ 6.876158] printk: console [ttyFIQ0] enabled [ 6.890795] Registered fiq debugger ttyFIQ0 [ 7.667771] ff180000.serial: ttyS0 at MMIO 0xff180000 (irq = 45, base_baud = 1500000) is a 16550A [ 7.668238] ff370000.serial: ttyS4 at MMIO 0xff370000 (irq = 47, base_baud = 1500000) is a 16550A [ 14.656870] ttyFIQ ttyFIQ0: tty_port_close_start: tty->count = 1 port count = 2

these are uart driver init loggings 

baud rates can be changed in user space

[Jovan 0]

Yup, my question is kinda pointless... we are changing the baudrate in user space, and it's working properly. 

The issue was somewhere else, not related to TinkerBoard itself (we've resolved that).

 

Thanks