[PATCH v8 2/2] tty/serial: Add rx-tx-swap OF option to stm32-usart
From: Martin Devera <hidden>
Date: 2021-03-28 15:46:39
Also in:
linux-arm-kernel, linux-devicetree, lkml
Subsystem:
the rest, tty layer and serial drivers · Maintainers:
Linus Torvalds, Greg Kroah-Hartman, Jiri Slaby
STM32 F7/H7 usarts supports RX & TX pin swapping.
Add option to turn it on.
Tested on STM32MP157.
Signed-off-by: Martin Devera <redacted>
Acked-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
---
v8:
- rebase to the latest tty-next
v6:
- add version changelog
v4:
- delete superfluous has_swap=false
v3:
- add has_swap to stm32_usart_info (because F4 line
doesn't support swapping)
- move swap variable init from stm32_usart_of_get_port
to stm32_usart_init_port because info struct is not
initialized in stm32_usart_of_get_port yet
- set USART_CR2_SWAP in stm32_usart_startup too
v2:
- change st,swap to rx-tx-swap (pointed out by Rob Herring)
- rebase patches as suggested 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(-)
---
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 cba4f4ddf164..4d277804c63e 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 a86773f1a4c4..77d1ac082e89 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 */
--
2.11.0