The imx8mm-venice-gw73xx-0x som+baseboard combination has a multi-protocol
RS-232/RS-485/RS-422 transceiver to an off-board connector which
can be configured in a number of ways via UART and GPIO configuration.
The default configuration per the imx8mm-venice-gw73xx-0x DT is for
UART2 TX/RX and UART4 TX/RX to be available as RS-232:
J15.1 UART2 TX out
J15.2 UART2 RX in
J15.3 UART4 TX out
J15.4 UART4 RX in
J15.5 GND
Add dt overlays to allow additional the modes of operation:
rs232-rts (UART2 RS-232 with RTS/CTS hardware flow control)
J15.1 TX out
J15.2 RX in
J15.3 RTS out
J15.4 CTS in
J15.5 GND
rs485 (UART2 RS-485 half duplex)
J15.1 TXRX-
J15.2 N/C
J15.3 TXRX+
J15.4 N/C
J15.5 GND
rs422 (UART2 RS-422 full duplex)
J15.1 TX-
J15.2 RX+
J15.3 TX+
J15.4 RX-
J15.5 GND
This is an RFC as I am not aware of other dt fragments/overlays being
added to the kernel yet.
I prefer to have this as an overlay vs creating a full dts including this
capability because there are other optional add-on boards for this board
including:
- imx219 camera
- rpidsi touchscreen display
Signed-off-by: Tim Harvey <tharvey@xxxxxxxxxxxxx>
---
arch/arm64/boot/dts/freescale/Makefile | 3 ++
.../imx8mm-venice-gw73xx-0x-rs232-rts.dts | 42 +++++++++++++++++
.../imx8mm-venice-gw73xx-0x-rs422.dts | 45 +++++++++++++++++++
.../imx8mm-venice-gw73xx-0x-rs485.dts | 45 +++++++++++++++++++
4 files changed, 135 insertions(+)
create mode 100644 arch/arm64/boot/dts/freescale/imx8mm-venice-gw73xx-0x-rs232-rts.dts
create mode 100644 arch/arm64/boot/dts/freescale/imx8mm-venice-gw73xx-0x-rs422.dts
create mode 100644 arch/arm64/boot/dts/freescale/imx8mm-venice-gw73xx-0x-rs485.dts
diff --git a/arch/arm64/boot/dts/freescale/Makefile b/arch/arm64/boot/dts/freescale/Makefile
index db9e36ebe932..bcc3c2dcb30b 100644
--- a/arch/arm64/boot/dts/freescale/Makefile
+++ b/arch/arm64/boot/dts/freescale/Makefile
@@ -42,6 +42,9 @@ dtb-$(CONFIG_ARCH_MXC) += imx8mm-var-som-symphony.dtb
dtb-$(CONFIG_ARCH_MXC) += imx8mm-venice-gw71xx-0x.dtb
dtb-$(CONFIG_ARCH_MXC) += imx8mm-venice-gw72xx-0x.dtb
dtb-$(CONFIG_ARCH_MXC) += imx8mm-venice-gw73xx-0x.dtb
+dtb-$(CONFIG_ARCH_MXC) += imx8mm-venice-gw73xx-0x-rs232-rts.dtb
+dtb-$(CONFIG_ARCH_MXC) += imx8mm-venice-gw73xx-0x-rs422.dtb
+dtb-$(CONFIG_ARCH_MXC) += imx8mm-venice-gw73xx-0x-rs485.dtb
dtb-$(CONFIG_ARCH_MXC) += imx8mm-venice-gw7901.dtb
dtb-$(CONFIG_ARCH_MXC) += imx8mm-venice-gw7902.dtb
dtb-$(CONFIG_ARCH_MXC) += imx8mn-beacon-kit.dtb
diff --git a/arch/arm64/boot/dts/freescale/imx8mm-venice-gw73xx-0x-rs232-rts.dts b/arch/arm64/boot/dts/freescale/imx8mm-venice-gw73xx-0x-rs232-rts.dts
new file mode 100644
index 000000000000..18053997efe5
--- /dev/null
+++ b/arch/arm64/boot/dts/freescale/imx8mm-venice-gw73xx-0x-rs232-rts.dts
@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+/*
+ * Copyright 2021 Gateworks Corporation
+ */
+
+#include <dt-bindings/gpio/gpio.h>
+
+#include "imx8mm-pinfunc.h"
+
+/dts-v1/;
+/plugin/;
+
+&{/} {
+ compatible = "gw,imx8mm-gw73xx-0x";
+};
+
+/* For RS232 with CTS_RTS:
+ * - UART4_TX becomes RTS
+ * - UART4_RX becomes CTS
+ */
+&uart2 {
+ pinctrl-names = "default";
+ pinctrl-0 = <&pinctrl_uart2>;
+ rts-gpios = <&gpio5 29 GPIO_ACTIVE_LOW>;
+ cts-gpios = <&gpio5 28 GPIO_ACTIVE_LOW>;
+ status = "okay";
+};
+
+&uart4 {
+ status = "disabled";
+};
+
+&iomuxc {
+ pinctrl_uart2: uart2grp {
+ fsl,pins = <
+ MX8MM_IOMUXC_UART2_RXD_UART2_DCE_RX 0x140
+ MX8MM_IOMUXC_UART2_TXD_UART2_DCE_TX 0x140
+ MX8MM_IOMUXC_UART4_TXD_GPIO5_IO29 0x140
+ MX8MM_IOMUXC_UART4_RXD_GPIO5_IO28 0x140
+ >;
+ };
+};
diff --git a/arch/arm64/boot/dts/freescale/imx8mm-venice-gw73xx-0x-rs422.dts b/arch/arm64/boot/dts/freescale/imx8mm-venice-gw73xx-0x-rs422.dts
new file mode 100644
index 000000000000..d23b56ba22e5
--- /dev/null
+++ b/arch/arm64/boot/dts/freescale/imx8mm-venice-gw73xx-0x-rs422.dts
@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+/*
+ * Copyright 2021 Gateworks Corporation
+ */
+
+#include <dt-bindings/gpio/gpio.h>
+
+#include "imx8mm-pinfunc.h"
+
+/dts-v1/;
+/plugin/;
+
+&{/} {
+ compatible = "gw,imx8mm-gw73xx-0x";
+};
+
+/* For RS485 FD:
+ * - UART4_TX is DE for RS485 transmitter
+ * - RS485_EN needs to be pulled high
+ * - RS485_HALF needs to be low
+ */
+&uart2 {
+ pinctrl-names = "default";
+ pinctrl-0 = <&pinctrl_uart2>;
+ rts-gpios = <&gpio5 29 GPIO_ACTIVE_HIGH>;
+ rs485-term-gpios = <&gpio1 0 GPIO_ACTIVE_HIGH>;
+ status = "okay";
+};
+
+&uart4 {
+ status = "disabled";
+};
+
+&iomuxc {
+ pinctrl_uart2: uart2grp {
+ fsl,pins = <
+ MX8MM_IOMUXC_UART2_RXD_UART2_DCE_RX 0x140
+ MX8MM_IOMUXC_UART2_TXD_UART2_DCE_TX 0x140
+ MX8MM_IOMUXC_UART4_TXD_GPIO5_IO29 0x140
+ MX8MM_IOMUXC_GPIO1_IO00_GPIO1_IO0 0x40000104 /* RS485_TERM */
+ MX8MM_IOMUXC_SAI1_RXFS_GPIO4_IO0 0x40000144 /* RS485_EN */
+ MX8MM_IOMUXC_SAI1_RXD0_GPIO4_IO2 0x40000104 /* RS485_HALF */
+ >;
+ };
+};
diff --git a/arch/arm64/boot/dts/freescale/imx8mm-venice-gw73xx-0x-rs485.dts b/arch/arm64/boot/dts/freescale/imx8mm-venice-gw73xx-0x-rs485.dts
new file mode 100644
index 000000000000..f0416af10165
--- /dev/null
+++ b/arch/arm64/boot/dts/freescale/imx8mm-venice-gw73xx-0x-rs485.dts
@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+/*
+ * Copyright 2021 Gateworks Corporation
+ */
+
+#include <dt-bindings/gpio/gpio.h>
+
+#include "imx8mm-pinfunc.h"
+
+/dts-v1/;
+/plugin/;
+
+&{/} {
+ compatible = "gw,imx8mm-gw73xx-0x";
+};
+
+/* For RS485 HD:
+ * - UART4_TX is DE for RS485 transmitter
+ * - RS485_EN needs to be pulled high
+ * - RS485_HALF needs to be pulled high
+ */
+&uart2 {
+ pinctrl-names = "default";
+ pinctrl-0 = <&pinctrl_uart2>;
+ rts-gpios = <&gpio5 29 GPIO_ACTIVE_HIGH>;
+ rs485-term-gpios = <&gpio1 0 GPIO_ACTIVE_HIGH>;
+ status = "okay";
+};
+
+&uart4 {
+ status = "disabled";
+};
+
+&iomuxc {
+ pinctrl_uart2: uart2grp {
+ fsl,pins = <
+ MX8MM_IOMUXC_UART2_RXD_UART2_DCE_RX 0x140
+ MX8MM_IOMUXC_UART2_TXD_UART2_DCE_TX 0x140
+ MX8MM_IOMUXC_UART4_TXD_GPIO5_IO29 0x140
+ MX8MM_IOMUXC_GPIO1_IO00_GPIO1_IO0 0x40000104 /* RS485_TERM */
+ MX8MM_IOMUXC_SAI1_RXFS_GPIO4_IO0 0x40000144 /* RS485_EN */
+ MX8MM_IOMUXC_SAI1_RXD0_GPIO4_IO2 0x40000144 /* RS485_HALF */
+ >;
+ };
+};
--
2.17.1
