Re: [PATCH v2 1/2] tty/serial: Add rx-tx-swap OF option to stm32-usart
On 3/1/21 11:40 PM, Martin DEVERA wrote: > On 3/1/21 11:28 AM, Fabrice Gasnier wrote: >> On 2/27/21 5:41 PM, Martin Devera wrote: >>> STM32 F7/H7 usarts supports RX & TX pin swapping. >>> Add option to turn it on. >>> Tested on STM32MP157. >>> >>> Signed-off-by: Martin Devera >>> --- >>> drivers/tty/serial/stm32-usart.c | 3 ++- >>> drivers/tty/serial/stm32-usart.h | 1 + >>> 2 files changed, 3 insertions(+), 1 deletion(-) >>> >>> diff --git a/drivers/tty/serial/stm32-usart.c >>> b/drivers/tty/serial/stm32-usart.c >>> index b3675cf25a69..3650c8798061 100644 >>> --- a/drivers/tty/serial/stm32-usart.c >>> +++ b/drivers/tty/serial/stm32-usart.c >>> @@ -758,7 +758,7 @@ 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; >> Hi Martin, >> >> Same could be done in the startup routine, that enables the port for >> reception (as described in Documentation/driver-api/serial/driver.rst) > Hello Fabrice, > > I already incorporated all your comments but I'm struggling with the one > above. > The code must be in stm32_usart_set_termios too, because CR2 is modified. Hi Martin, Yes, sure, > What is the reason to have it in startup() ? RX is enabled at both places. So the swap setting should be there too. > Is it because USART can be started without calling set_termios at all ? Yes, that's what the driver API expects: "startup(port)" ... "Enable the port for reception." Best Regards, Fabrice > Like > to reuse bootloader's last settings ? > > Thanks, Martin >
Re: [PATCH v2 1/2] tty/serial: Add rx-tx-swap OF option to stm32-usart
On 3/1/21 11:28 AM, Fabrice Gasnier wrote: On 2/27/21 5:41 PM, Martin Devera wrote: STM32 F7/H7 usarts supports RX & TX pin swapping. Add option to turn it on. Tested on STM32MP157. Signed-off-by: Martin Devera --- drivers/tty/serial/stm32-usart.c | 3 ++- drivers/tty/serial/stm32-usart.h | 1 + 2 files changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index b3675cf25a69..3650c8798061 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -758,7 +758,7 @@ 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; Hi Martin, Same could be done in the startup routine, that enables the port for reception (as described in Documentation/driver-api/serial/driver.rst) Hello Fabrice, I already incorporated all your comments but I'm struggling with the one above. The code must be in stm32_usart_set_termios too, because CR2 is modified. What is the reason to have it in startup() ? Is it because USART can be started without calling set_termios at all ? Like to reuse bootloader's last settings ? Thanks, Martin
Re: [PATCH v2 1/2] tty/serial: Add rx-tx-swap OF option to stm32-usart
On 2/27/21 5:41 PM, Martin Devera wrote:
> STM32 F7/H7 usarts supports RX & TX pin swapping.
> Add option to turn it on.
> Tested on STM32MP157.
>
> Signed-off-by: Martin Devera
> ---
> drivers/tty/serial/stm32-usart.c | 3 ++-
> drivers/tty/serial/stm32-usart.h | 1 +
> 2 files changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/tty/serial/stm32-usart.c
> b/drivers/tty/serial/stm32-usart.c
> index b3675cf25a69..3650c8798061 100644
> --- a/drivers/tty/serial/stm32-usart.c
> +++ b/drivers/tty/serial/stm32-usart.c
> @@ -758,7 +758,7 @@ 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;
Hi Martin,
Same could be done in the startup routine, that enables the port for
reception (as described in Documentation/driver-api/serial/driver.rst)
> cr3 = readl_relaxed(port->membase + ofs->cr3);
> cr3 &= USART_CR3_TXFTIE | USART_CR3_RXFTCFG_MASK | USART_CR3_RXFTIE
> | USART_CR3_TXFTCFG_MASK;
> @@ -1078,6 +1078,7 @@ static struct stm32_port
> *stm32_usart_of_get_port(struct platform_device *pdev)
> stm32_ports[id].hw_flow_control =
> of_property_read_bool (np, "st,hw-flow-ctrl") /*deprecated*/ ||
> of_property_read_bool (np, "uart-has-rtscts");
> + stm32_ports[id].swap = of_property_read_bool(np, "rx-tx-swap");
The swap option/bit is available starting with stm32f7 (e.g. not on
stm32f4).
This could be added to compatible data, e.g. as done for other
capabilities in stm32-usart.h. E.g you could add a "has_swap" in struct
stm32_usart_config, then use it at probe time:
if (cfg->has_swap)
stm32_ports[id].swap = ...;
Thanks for your patch,
Best regards,
Fabrice
> stm32_ports[id].port.line = id;
> stm32_ports[id].cr1_irq = USART_CR1_RXNEIE;
> stm32_ports[id].cr3_irq = 0;
> diff --git a/drivers/tty/serial/stm32-usart.h
> b/drivers/tty/serial/stm32-usart.h
> index cb4f327c46db..2f054e2dc0ab 100644
> --- a/drivers/tty/serial/stm32-usart.h
> +++ b/drivers/tty/serial/stm32-usart.h
> @@ -271,6 +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;
> int wakeirq;
> int rdr_mask; /* receive data register mask */
>
[PATCH v2 1/2] 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.
Signed-off-by: Martin Devera
---
drivers/tty/serial/stm32-usart.c | 3 ++-
drivers/tty/serial/stm32-usart.h | 1 +
2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index b3675cf25a69..3650c8798061 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -758,7 +758,7 @@ 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;
cr3 = readl_relaxed(port->membase + ofs->cr3);
cr3 &= USART_CR3_TXFTIE | USART_CR3_RXFTCFG_MASK | USART_CR3_RXFTIE
| USART_CR3_TXFTCFG_MASK;
@@ -1078,6 +1078,7 @@ static struct stm32_port *stm32_usart_of_get_port(struct
platform_device *pdev)
stm32_ports[id].hw_flow_control =
of_property_read_bool (np, "st,hw-flow-ctrl") /*deprecated*/ ||
of_property_read_bool (np, "uart-has-rtscts");
+ stm32_ports[id].swap = of_property_read_bool(np, "rx-tx-swap");
stm32_ports[id].port.line = id;
stm32_ports[id].cr1_irq = USART_CR1_RXNEIE;
stm32_ports[id].cr3_irq = 0;
diff --git a/drivers/tty/serial/stm32-usart.h b/drivers/tty/serial/stm32-usart.h
index cb4f327c46db..2f054e2dc0ab 100644
--- a/drivers/tty/serial/stm32-usart.h
+++ b/drivers/tty/serial/stm32-usart.h
@@ -271,6 +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;
int wakeirq;
int rdr_mask; /* receive data register mask */
--
2.11.0
