Linux on ARM based TI OMAP SoCs
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From: Dominik Haller <d.haller@phytec.de>
To: <khilman@baylibre.com>, <tony@atomide.com>, <s.hemer@phytec.de>,
	<linux-omap@vger.kernel.org>
Cc: <upstream@phytec.de>, <d.haller@phytec.de>
Subject: [PATCH 1/2] ARM: dts: ti: omap: am335x-regor: Fix RS485 settings
Date: Thu, 25 Jul 2024 16:19:51 +0200	[thread overview]
Message-ID: <20240725141952.81213-1-d.haller@phytec.de> (raw)

From: Steffen Hemer <s.hemer@phytec.de>

RTS pin seems to have inverted behavior on am335x, other than expected
with default "rs485-rts-active-high" (instead of low on idle, high on send,
it is the opposite). Transceiver datasheet also suggests a pulldown.
Add includes to pin definitions that are used.

Signed-off-by: Steffen Hemer <s.hemer@phytec.de>
---
 arch/arm/boot/dts/ti/omap/am335x-regor.dtsi | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/arch/arm/boot/dts/ti/omap/am335x-regor.dtsi b/arch/arm/boot/dts/ti/omap/am335x-regor.dtsi
index 625db3bcd365..287d209a0ea9 100644
--- a/arch/arm/boot/dts/ti/omap/am335x-regor.dtsi
+++ b/arch/arm/boot/dts/ti/omap/am335x-regor.dtsi
@@ -5,6 +5,9 @@
  *
  */
 
+#include <dt-bindings/gpio/gpio.h>
+#include <dt-bindings/pinctrl/am33xx.h>
+
 / {
 	model = "Phytec AM335x phyBOARD-REGOR";
 	compatible = "phytec,am335x-regor", "phytec,am335x-phycore-som", "ti,am33xx";
@@ -188,7 +191,7 @@ uart1_rs485_pins: pinmux-uart1-rs485-pins {
 		pinctrl-single,pins = <
 			AM33XX_PADCONF(AM335X_PIN_UART1_RXD, PIN_INPUT_PULLUP, MUX_MODE0)
 			AM33XX_PADCONF(AM335X_PIN_UART1_TXD, PIN_OUTPUT_PULLDOWN, MUX_MODE0)
-			AM33XX_PADCONF(AM335X_PIN_UART1_RTSN, PIN_OUTPUT_PULLUP, MUX_MODE0)
+			AM33XX_PADCONF(AM335X_PIN_UART1_RTSN, PIN_OUTPUT_PULLDOWN, MUX_MODE0)
 		>;
 	};
 };
@@ -198,4 +201,9 @@ &uart1 {
 	pinctrl-0 = <&uart1_rs485_pins>;
 	status = "okay";
 	linux,rs485-enabled-at-boot-time;
+	/*
+	 * un-intuitively, yet with the default (active-high),
+	 * am335x RTS is high on idle and gets low on active !
+	 */
+	rs485-rts-active-low;
 };
-- 
2.25.1


             reply	other threads:[~2024-07-25 14:20 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-07-25 14:19 Dominik Haller [this message]
2024-07-25 14:19 ` [PATCH 2/2] ARM: dts: ti: omap: am335x-wega: Fix audio clock provider Dominik Haller
2024-07-29 20:14 ` [PATCH 1/2] ARM: dts: ti: omap: am335x-regor: Fix RS485 settings Kevin Hilman
2024-07-30  9:07   ` Dominik Haller

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