Hi there,
I was rebasing the Kernel branch of our SAMA5D35 based board from
v5.4.189 to v5.4.238.
I noticed that after the rebase we could _only send, but not receive_
through our RS485 interface.
I could bisect the problem to 77b97ef4908aa917e7b68667ec6b344cc5dc5034
in the v5.4.225 release. If I revert this commit, the tx/rx works just
like before.
Maybe this use-case wasn't considered when this patch was created?
I haven't seen a documentation change regarding this in DT bindings,
but if the config should be something else, please let me know.
Otherwise this commit breaks the RS485 function of atmel_serial at
least in the v5.4.y branch.
Best Regards,
Kristóf Havasi
The relevant device tree nodes:
from sama5d3.dtsi:
usart1: serial@f0020000 {
compatible = "atmel,at91sam9260-usart";
reg = <0xf0020000 0x100>;
interrupts = <13 IRQ_TYPE_LEVEL_HIGH 5>;
dmas = <&dma0 2 AT91_DMA_CFG_PER_ID(5)>,
<&dma0 2 (AT91_DMA_CFG_PER_ID(6) | AT91_DMA_CFG_FIFOCFG_ASAP)>;
dma-names = "tx", "rx";
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_usart1>;
clocks = <&usart1_clk>;
clock-names = "usart";
status = "disabled";
};
pinctrl_usart1: usart1-0 {
atmel,pins =
<AT91_PIOB 28 AT91_PERIPH_A AT91_PINCTRL_PULL_UP
AT91_PIOB 29 AT91_PERIPH_A AT91_PINCTRL_NONE>;
};
pinctrl_usart1_rts_cts: usart1_rts_cts-0 {
atmel,pins =
<AT91_PIOB 26 AT91_PERIPH_A AT91_PINCTRL_NONE /* PB26 periph A,
conflicts with GRX7 */
AT91_PIOB 27 AT91_PERIPH_A AT91_PINCTRL_NONE>; /* PB27 periph A,
conflicts with G125CKO */
};
from our dts:
&usart1 {
pinctrl-0 = <&pinctrl_usart1 &pinctrl_usart1_rts_cts>;
atmel,use-dma-rx;
atmel,use-dma-tx;
rs485-rx-during-tx;
linux,rs485-enabled-at-boot-time;
status = "okay";
};
HW:
The SAMA5D3's PB27 is connected to the |RE+DE of the RS485 transceiver
SP3458EN-L
