I have to use the pins P9_24 TX, P9_26 RX and P8_14 de/re as my beaglebone is mounted on a prewired "IO board".
Tried installing 4.14.71-ti-r80 kernel (8250 driver) and using my UART1-RS485 overlay. But thats not working. Is it possible to use whatever pin for de/re? Tried adding some printk() lines in the omap-serial.c on the modified "stock image" kernel before compiling, but nothing related to RS485 in that code seems to get executed. (Dont see any of the printk() in syslog) tirsdag 19. januar 2021 kl. 09:33:05 UTC+1 skrev [email protected]: > I forget mention the kernel version: 4.14.71-ti-r80 > > On Tue, Jan 19, 2021 at 7:30 PM Atique Rehman <[email protected]> wrote: > >> Hi, >> >> Here is sample of UART4 RS485: >> dts-v1/; >> /plugin/; >> >> #include <dt-bindings/board/am335x-bbw-bbb-base.h> >> #include <dt-bindings/pinctrl/am33xx.h> >> >> / { >> compatible = "ti,beaglebone", "ti,beaglebone-black", >> "ti,beaglebone-green"; >> >> // identification >> part-number = "BB-UART4-COM0"; >> version = "00A0"; >> >> // resources this cape uses >> exclusive-use = >> "P9.13", // uart4_txd >> "P9.11", // uart4_rxd >> "P8.35", // uart4_de/re >> "gpio0_8", >> >> "uart4"; // hardware ip used >> >> /* >> * Free up the pins used by the cape from the pinmux helpers. >> */ >> fragment@0 { >> target = <&ocp>; >> __overlay__ { >> P9_13_pinmux { status = "disabled"; }; /* P9_13: gpmc_wpn.uart4_txd_mux2 >> */ >> P9_11_pinmux { status = "disabled"; }; /* P9_11: >> gpmc_wait0.uart4_rxd_mux2 */ >> P8_35_pinmux { status = "disabled"; }; /* P8_35: PIN_OUTPUT_PULLDOWN | >> MUX_MODE7 (GPIO0_8) */ >> }; >> }; >> >> fragment@1 { >> target = <&am33xx_pinmux>; >> __overlay__ { >> bb_uart4_rs485_pins: pinmux_bb_uart4_rs485_pins { >> pinctrl-single,pins = < >> BONE_P9_13 (PIN_OUTPUT | MUX_MODE6) /* P9_13: gpmc_wpn.uart4_txd_mux2 */ >> BONE_P9_11 (PIN_INPUT | MUX_MODE6) /* P9_11: gpmc_wait0.uart4_rxd_mux2 */ >> BONE_P8_35 0x07 /* P8_35: PIN_OUTPUT_PULLDOWN | MUX_MODE7 (GPIO0_8) */ >> >; >> }; >> }; >> }; >> >> fragment@2 { >> target = <&uart4>; >> __overlay__ { >> status = "okay"; >> pinctrl-names = "default"; >> pinctrl-0 = <&bb_uart4_rs485_pins>; >> rs485-rts-delay = <0 0>; >> >> rts-gpio = <&gpio0 8 1>; /* GPIO_ACTIVE_HIGH>; */ >> rs485-rts-active-high; >> linux,rs485-enabled-at-boot-time; >> }; >> }; >> }; >> >> Regards, >> Atique >> >> On Tue, Jan 19, 2021 at 7:19 PM Jørgen Sirum <[email protected]> wrote: >> >>> Struggling to get RS485 to work with overlays >>> I have been using kernel 3.8.13 (enabling RS485 with python script) with >>> no issues but wanted to upgrade into the modern world. >>> Used default image and did the steps suggested in this post: >>> https://groups.google.com/g/beagleboard/c/nMtRpdWSJu0/m/USjb8sF-AgAJ >>> >>> - Swapped from CONFIG_SERIAL_8250_OMAP to CONFIG_SERIAL_OMAP and rebuild >>> - Used BB-UART4-RS485-00A0.dts but modified it to be for UART1 and the >>> direction pin I am using >>> Everything else is untouched >>> >>> BB-UART1-RS485-00A0.dts: >>> /dts-v1/; >>> /plugin/; >>> >>> #include <dt-bindings/board/am335x-bbw-bbb-base.h> >>> #include <dt-bindings/pinctrl/am33xx.h> >>> >>> / { >>> compatible = "ti,beaglebone", "ti,beaglebone-black", >>> "ti,beaglebone-green"; >>> >>> // identification >>> part-number = "BB-UART1-RS485"; >>> version = "00A0"; >>> >>> // resources this cape uses >>> exclusive-use = >>> "P9.24", // uart1_txd >>> "P9.26", // uart1_rxd >>> "P8.14", // uart1_de/re >>> "gpio0_26", >>> >>> "uart1"; // hardware ip used >>> >>> /* >>> * Helper to show loaded overlays under: >>> /proc/device-tree/chosen/overlays/ >>> */ >>> fragment@0 { >>> target-path="/"; >>> __overlay__ { >>> >>> chosen { >>> overlays { >>> BB-UART1-RS485-00A0 = __TIMESTAMP__; >>> }; >>> }; >>> }; >>> }; >>> >>> /* >>> * Free up the pins used by the cape from the pinmux helpers. >>> */ >>> fragment@1 { >>> target = <&ocp>; >>> __overlay__ { >>> P9_24_pinmux { status = "disabled"; }; >>> P9_26_pinmux { status = "disabled"; }; >>> P8_14_pinmux { status = "disabled"; }; >>> }; >>> }; >>> >>> fragment@2 { >>> target = <&am33xx_pinmux>; >>> __overlay__ { >>> bb_uart1_rs485_pins: pinmux_bb_uart1_rs485_pins { >>> pinctrl-single,pins = < >>> BONE_P9_24 (PIN_OUTPUT | MUX_MODE6) >>> BONE_P9_26 (PIN_INPUT | MUX_MODE6) >>> BONE_P8_14 0x07 >>> >; >>> }; >>> }; >>> }; >>> >>> fragment@3 { >>> target = <&uart1>; >>> __overlay__ { >>> status = "okay"; >>> pinctrl-names = "default"; >>> pinctrl-0 = <&bb_uart1_rs485_pins>; >>> rs485-rts-delay = <0 0>; >>> >>> rts-gpio = <&gpio0 26 1>; /* GPIO_ACTIVE_HIGH>; */ >>> rs485-rts-active-high; >>> linux,rs485-enabled-at-boot-time; >>> }; >>> }; >>> }; >>> >>> /boot/uEnv.txt: >>> >>> enable_uboot_overlays=1 >>> uboot_overlay_addr0=/lib/firmware/BB-UART1-RS485-00A0.dtbo >>> disable_uboot_overlay_video=1 >>> disable_uboot_overlay_audio=1 >>> disable_uboot_overlay_wireless=1 >>> disable_uboot_overlay_adc=1 >>> >>> >>> When I boot: >>> >>> [ 0.460625] 44e09000.serial: ttyO0 at MMIO 0x44e09000 (irq = 30, >>> base_baud = 3000000) is a OMAP UART0 >>> [ 0.472149] 48022000.serial: ttyO1 at MMIO 0x48022000 (irq = 31, >>> base_baud = 3000000) is a OMAP UART1 >>> >>> But it doesnt work. >>> If I use the normal overlay BB-UART1-00A0.dtbo and swap the direction >>> pin manually it works. >>> >>> Any help would be very appreciatied! >>> >>> Jørgen >>> >>> >>> -- >>> For more options, visit http://beagleboard.org/discuss >>> --- >>> You received this message because you are subscribed to the Google >>> Groups "BeagleBoard" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected]. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/beagleboard/cfc7f9c4-2c72-44ff-976e-2ec69db2c7efn%40googlegroups.com >>> >>> <https://groups.google.com/d/msgid/beagleboard/cfc7f9c4-2c72-44ff-976e-2ec69db2c7efn%40googlegroups.com?utm_medium=email&utm_source=footer> >>> . >>> >> >> >> -- >> Regards, >> Atique u Rehman >> > > > -- > Regards, > Atique u Rehman > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/8e094f34-39ee-4ec1-a069-465cadea75f4n%40googlegroups.com.
