From 3cd66593725a234662955baaf78d2ce5333de56d Mon Sep 17 00:00:00 2001 From: Martin Devera Date: Sun, 28 Mar 2021 17:43:06 +0200 Subject: [PATCH] tty/serial: Add rx-tx-swap OF option to stm32-usart STM32 F7/H7 usarts supports RX & TX pin swapping. Add option to turn it on. Tested on STM32MP157. Acked-by: Fabrice Gasnier Signed-off-by: Martin Devera Link: https://lore.kernel.org/r/20210328154306.22674-2-devik@eaxlabs.cz Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/stm32-usart.c | 11 ++++++++++- drivers/tty/serial/stm32-usart.h | 4 ++++ 2 files changed, 14 insertions(+), 1 deletion(-) diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index cba4f4d..4d27780 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -671,6 +671,12 @@ static int stm32_usart_startup(struct uart_port *port) if (ret) return ret; + if (stm32_port->swap) { + val = readl_relaxed(port->membase + ofs->cr2); + val |= USART_CR2_SWAP; + writel_relaxed(val, port->membase + ofs->cr2); + } + /* RX FIFO Flush */ if (ofs->rqr != UNDEF_REG) writel_relaxed(USART_RQR_RXFRQ, port->membase + ofs->rqr); @@ -789,7 +795,7 @@ static void stm32_usart_set_termios(struct uart_port *port, cr1 = USART_CR1_TE | USART_CR1_RE; if (stm32_port->fifoen) cr1 |= USART_CR1_FIFOEN; - cr2 = 0; + cr2 = stm32_port->swap ? USART_CR2_SWAP : 0; /* Tx and RX FIFO configuration */ cr3 = readl_relaxed(port->membase + ofs->cr3); @@ -1047,6 +1053,9 @@ static int stm32_usart_init_port(struct stm32_port *stm32port, stm32port->wakeup_src = stm32port->info->cfg.has_wakeup && of_property_read_bool(pdev->dev.of_node, "wakeup-source"); + stm32port->swap = stm32port->info->cfg.has_swap && + of_property_read_bool(pdev->dev.of_node, "rx-tx-swap"); + stm32port->fifoen = stm32port->info->cfg.has_fifo; res = platform_get_resource(pdev, IORESOURCE_MEM, 0); diff --git a/drivers/tty/serial/stm32-usart.h b/drivers/tty/serial/stm32-usart.h index a86773f..77d1ac0 100644 --- a/drivers/tty/serial/stm32-usart.h +++ b/drivers/tty/serial/stm32-usart.h @@ -25,6 +25,7 @@ struct stm32_usart_offsets { struct stm32_usart_config { u8 uart_enable_bit; /* USART_CR1_UE */ bool has_7bits_data; + bool has_swap; bool has_wakeup; bool has_fifo; int fifosize; @@ -76,6 +77,7 @@ struct stm32_usart_info stm32f7_info = { .cfg = { .uart_enable_bit = 0, .has_7bits_data = true, + .has_swap = true, .fifosize = 1, } }; @@ -97,6 +99,7 @@ struct stm32_usart_info stm32h7_info = { .cfg = { .uart_enable_bit = 0, .has_7bits_data = true, + .has_swap = true, .has_wakeup = true, .has_fifo = true, .fifosize = 16, @@ -268,6 +271,7 @@ struct stm32_port { int last_res; bool tx_dma_busy; /* dma tx busy */ bool hw_flow_control; + bool swap; /* swap RX & TX pins */ bool fifoen; bool wakeup_src; int rdr_mask; /* receive data register mask */ -- 2.7.4