2024. 03. 13. 19:27 keltezéssel, Konrad Dybcio írta: > > > On 3/13/24 19:25, Gabor Juhos wrote: >> Add device tree source for the TP-Link Archer AX55 v1 [1] >> which is a dual-band WiFi router based on the IPQ5018 SoC. >> >> At the moment, only the UART, the GPIO LEDs and buttons >> are usable, but it makes it possible to boot an initramfs >> image on the device. >> >> The device tree can be extended in the future, once support >> for other periherals will be available for the platform. >> >> 1. https://www.tp-link.com/en/home-networking/wifi-router/archer-ax55/v1/ >> >> Signed-off-by: Gabor Juhos <j4g8y7@xxxxxxxxx> >> --- >> Changes in v3: >> - change pin configuration to use "gpio20" and "gpio21" for UART pins >> - rebase on top of v6.8. > > Did you actually check this? Yes, I have tested this. > And how so? First, I have checked the stock firmware which uses the same pinctrl configuration: root@Archer_AX55:~# uname -a Linux Archer_AX55 4.4.60 #1 SMP PREEMPT Tue Mar 14 18:25:29 CST 2023 armv7l GNU/Linux root@Archer_AX55:~# strings /sys/firmware/devicetree/base/soc/pinctrl@1000000/uart_pins/blsp0_uart_rx_tx/pins gpio20 gpio21 root@Archer_AX55:~# strings /sys/firmware/devicetree/base/soc/pinctrl@1000000/uart_pins/blsp0_uart_rx_tx/function blsp0_uart0 It is also visible in pinctrl-maps: root@Archer_AX55:~# cat /sys/kernel/debug/pinctrl/pinctrl-maps Pinctrl maps: device 1000000.pinctrl state default type MUX_GROUP (2) controlling device 1000000.pinctrl group gpio20 function blsp0_uart0 device 1000000.pinctrl state default type CONFIGS_GROUP (4) controlling device 1000000.pinctrl group gpio20 config 00000001 device 1000000.pinctrl state default type MUX_GROUP (2) controlling device 1000000.pinctrl group gpio21 function blsp0_uart0 device 1000000.pinctrl state default type CONFIGS_GROUP (4) controlling device 1000000.pinctrl group gpio21 config 00000001 ... Additionally, this is what debug/gpio says: root@Archer_AX55:~# grep -E 'gpio2[01]' /sys/kernel/debug/gpio gpio20 : in 1 8mA no pull gpio21 : in 1 8mA no pull Then I have tested the following with v6.8 and with the previous version of the patch. Exported GPIO20 via sysfs ... root@test:/# gpio=$((512+20)); echo $gpio > /sys/class/gpio/export; while true; do for dir in high low; do echo $dir >/sys/class/gpio/gpio$gpio/direction; sleep 3; done; done ... and measured the voltage on the UART pin header. Then I did the same with GPIO21 as well. This revealed that GPIO20 corresponds to RX and GPIO21 to TX. If that matters, the downstream kernel also uses this 'trick' for some boards: https://git.codelinaro.org/clo/qsdk/oss/kernel/linux-ipq-5.4/-/blob/NHSS.QSDK.12.4/arch/arm64/boot/dts/qcom/ipq5018-db-mp03.1.dts?ref_type=heads#L443 https://git.codelinaro.org/clo/qsdk/oss/kernel/linux-ipq-5.4/-/blob/NHSS.QSDK.12.4/arch/arm64/boot/dts/qcom/ipq5018-mp03.1.dts?ref_type=heads#L565 Regards, Gabor
