6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Farouk Bouabid <farouk.bouabid@xxxxxxxxxxxxxxxxxxxxx> [ Upstream commit 5963d97aa780619ffb66cf4886c0ca1175ccbd3e ] A hardware switch can set the rs485 transceiver into half or full duplex mode. Switching to the half-duplex mode requires the user to enable em485 on uart5 using ioctl, DE/RE are both connected to GPIO0_B5 which is the RTS signal for uart0. Implement GPIO0_B5 as rts-gpios with RTS_ON_SEND option enabled (default) so that driver mode gets enabled while sending (RTS high) and receiver mode gets enabled while not sending (RTS low). In full-duplex mode (em485 is disabled), DE is connected to GPIO0_B5 and RE is grounded (enabled). Since GPIO0_B5 is implemented as rts-gpios, the driver mode gets enabled whenever we want to send something and RE is not affected (always enabled) in this case by the state of RTS. Signed-off-by: Farouk Bouabid <farouk.bouabid@xxxxxxxxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20240208-dev-rx-enable-v6-2-39e68e17a339@xxxxxxxxxxxxxxxxxxxxx Signed-off-by: Heiko Stuebner <heiko@xxxxxxxxx> Stable-dep-of: 5ae4dca718ea ("arm64: dts: rockchip: Disable DMA for uart5 on px30-ringneck") Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- arch/arm64/boot/dts/rockchip/px30-ringneck-haikou.dts | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm64/boot/dts/rockchip/px30-ringneck-haikou.dts b/arch/arm64/boot/dts/rockchip/px30-ringneck-haikou.dts index de0a1f2af983b..56f73c17363fd 100644 --- a/arch/arm64/boot/dts/rockchip/px30-ringneck-haikou.dts +++ b/arch/arm64/boot/dts/rockchip/px30-ringneck-haikou.dts @@ -226,6 +226,7 @@ &uart0 { &uart5 { pinctrl-0 = <&uart5_xfer>; + rts-gpios = <&gpio0 RK_PB5 GPIO_ACTIVE_HIGH>; status = "okay"; }; -- 2.39.5
