From: Manivannan Sadhasivam <[email protected]>
Hello,
This patchset adds CTS/RTS gpio support to STM32 UART controller.
Eventhough the UART controller supports using dedicated CTS/RTS gpios,
sometimes we need to use different set of gpios for flow control.
This is necessary for the upcoming STM32MP1 based board called Stinger96
IoT-Box. On that board, a bluetooth chip is connected to one of the UART
controller but the CTS/RTS lines got swapped mistakenly. So this patchset
serves as a workaround for that hardware bug and also supports the
usecase of using any gpio for CTS/RTS functionality. As per the sugggestion
provided by Andy for v1, I've now switched to mctrl_gpio driver.
This patchset has been validated with Stinger96 IoT-Box connected to Murata
WiFi-BT combo chip.
Thanks,
Mani
Changes in v3:
* Added Andy's reviewed-by tag
* Fixed minor issues spotted by Fabrice
Changes in v2:
As per the review by Andy:
* Switched to mctrl_gpio driver instead of using custom CTS/RTS
implementation
* Removed the use of software flow control terminology.
Manivannan Sadhasivam (2):
dt-bindings: serial: Document CTS/RTS gpios in STM32 UART
tty: serial: Add modem control gpio support for STM32 UART
.../bindings/serial/st,stm32-uart.yaml | 14 +++++
drivers/tty/serial/Kconfig | 1 +
drivers/tty/serial/stm32-usart.c | 53 ++++++++++++++++++-
drivers/tty/serial/stm32-usart.h | 1 +
4 files changed, 67 insertions(+), 2 deletions(-)
--
2.17.1
From: Manivannan Sadhasivam <[email protected]>
STM32 UART controllers have the built in modem control support using
dedicated gpios which can be enabled using 'st,hw-flow-ctrl' flag in DT.
But there might be cases where the board design need to use different
gpios for modem control.
For supporting such cases, this commit adds modem control gpio support
to STM32 UART controller using mctrl_gpio driver.
Reviewed-by: Andy Shevchenko <[email protected]>
Signed-off-by: Manivannan Sadhasivam <[email protected]>
---
drivers/tty/serial/Kconfig | 1 +
drivers/tty/serial/stm32-usart.c | 53 ++++++++++++++++++++++++++++++--
drivers/tty/serial/stm32-usart.h | 1 +
3 files changed, 53 insertions(+), 2 deletions(-)
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 0aea76cd67ff..e7a6f2130684 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -1462,6 +1462,7 @@ config SERIAL_STM32
tristate "STMicroelectronics STM32 serial port support"
select SERIAL_CORE
depends on ARCH_STM32 || COMPILE_TEST
+ select SERIAL_MCTRL_GPIO if GPIOLIB
help
This driver is for the on-chip Serial Controller on
STMicroelectronics STM32 MCUs.
diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index 5e93e8d40f59..17c2f3276888 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -31,6 +31,7 @@
#include <linux/tty_flip.h>
#include <linux/tty.h>
+#include "serial_mctrl_gpio.h"
#include "stm32-usart.h"
static void stm32_stop_tx(struct uart_port *port);
@@ -510,12 +511,29 @@ static void stm32_set_mctrl(struct uart_port *port, unsigned int mctrl)
stm32_set_bits(port, ofs->cr3, USART_CR3_RTSE);
else
stm32_clr_bits(port, ofs->cr3, USART_CR3_RTSE);
+
+ mctrl_gpio_set(stm32_port->gpios, mctrl);
}
static unsigned int stm32_get_mctrl(struct uart_port *port)
{
+ struct stm32_port *stm32_port = to_stm32_port(port);
+ unsigned int ret;
+
/* This routine is used to get signals of: DCD, DSR, RI, and CTS */
- return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
+ ret = TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
+
+ return mctrl_gpio_get(stm32_port->gpios, &ret);
+}
+
+static void stm32_enable_ms(struct uart_port *port)
+{
+ mctrl_gpio_enable_ms(to_stm32_port(port)->gpios);
+}
+
+static void stm32_disable_ms(struct uart_port *port)
+{
+ mctrl_gpio_disable_ms(to_stm32_port(port)->gpios);
}
/* Transmit stop */
@@ -626,6 +644,9 @@ static void stm32_shutdown(struct uart_port *port)
u32 val, isr;
int ret;
+ /* Disable modem control interrupts */
+ stm32_disable_ms(port);
+
val = USART_CR1_TXEIE | USART_CR1_TE;
val |= stm32_port->cr1_irq | USART_CR1_RE;
val |= BIT(cfg->uart_enable_bit);
@@ -764,6 +785,12 @@ static void stm32_set_termios(struct uart_port *port, struct ktermios *termios,
cr3 |= USART_CR3_CTSE | USART_CR3_RTSE;
}
+ /* Handle modem control interrupts */
+ if (UART_ENABLE_MS(port, termios->c_cflag))
+ stm32_enable_ms(port);
+ else
+ stm32_disable_ms(port);
+
usartdiv = DIV_ROUND_CLOSEST(port->uartclk, baud);
/*
@@ -898,6 +925,7 @@ static const struct uart_ops stm32_uart_ops = {
.throttle = stm32_throttle,
.unthrottle = stm32_unthrottle,
.stop_rx = stm32_stop_rx,
+ .enable_ms = stm32_enable_ms,
.break_ctl = stm32_break_ctl,
.startup = stm32_startup,
.shutdown = stm32_shutdown,
@@ -960,10 +988,31 @@ static int stm32_init_port(struct stm32_port *stm32port,
stm32port->port.uartclk = clk_get_rate(stm32port->clk);
if (!stm32port->port.uartclk) {
- clk_disable_unprepare(stm32port->clk);
ret = -EINVAL;
+ goto err_clk;
+ }
+
+ stm32port->gpios = mctrl_gpio_init(&stm32port->port, 0);
+ if (IS_ERR(stm32port->gpios)) {
+ ret = PTR_ERR(stm32port->gpios);
+ goto err_clk;
}
+ /* Both CTS/RTS gpios and "st,hw-flow-ctrl" should not be specified */
+ if (stm32port->hw_flow_control) {
+ if (mctrl_gpio_to_gpiod(stm32port->gpios, UART_GPIO_CTS) ||
+ mctrl_gpio_to_gpiod(stm32port->gpios, UART_GPIO_RTS)) {
+ dev_err(&pdev->dev, "Conflicting RTS/CTS config\n");
+ ret = -EINVAL;
+ goto err_clk;
+ }
+ }
+
+ return ret;
+
+err_clk:
+ clk_disable_unprepare(stm32port->clk);
+
return ret;
}
diff --git a/drivers/tty/serial/stm32-usart.h b/drivers/tty/serial/stm32-usart.h
index db8bf0d4982d..d4c916e78d40 100644
--- a/drivers/tty/serial/stm32-usart.h
+++ b/drivers/tty/serial/stm32-usart.h
@@ -274,6 +274,7 @@ struct stm32_port {
bool fifoen;
int wakeirq;
int rdr_mask; /* receive data register mask */
+ struct mctrl_gpios *gpios; /* modem control gpios */
};
static struct stm32_port stm32_ports[STM32_MAX_PORTS];
--
2.17.1
On 4/20/20 7:02 PM, [email protected] wrote:
> From: Manivannan Sadhasivam <[email protected]>
>
> STM32 UART controllers have the built in modem control support using
> dedicated gpios which can be enabled using 'st,hw-flow-ctrl' flag in DT.
> But there might be cases where the board design need to use different
> gpios for modem control.
>
> For supporting such cases, this commit adds modem control gpio support
> to STM32 UART controller using mctrl_gpio driver.
>
> Reviewed-by: Andy Shevchenko <[email protected]>
> Signed-off-by: Manivannan Sadhasivam <[email protected]>
> ---
> drivers/tty/serial/Kconfig | 1 +
> drivers/tty/serial/stm32-usart.c | 53 ++++++++++++++++++++++++++++++--
> drivers/tty/serial/stm32-usart.h | 1 +
> 3 files changed, 53 insertions(+), 2 deletions(-)
Hi Mani,
You can add my:
Acked-by: Fabrice Gasnier <[email protected]>
Thanks,
Fabrice
>
> diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
> index 0aea76cd67ff..e7a6f2130684 100644
> --- a/drivers/tty/serial/Kconfig
> +++ b/drivers/tty/serial/Kconfig
> @@ -1462,6 +1462,7 @@ config SERIAL_STM32
> tristate "STMicroelectronics STM32 serial port support"
> select SERIAL_CORE
> depends on ARCH_STM32 || COMPILE_TEST
> + select SERIAL_MCTRL_GPIO if GPIOLIB
> help
> This driver is for the on-chip Serial Controller on
> STMicroelectronics STM32 MCUs.
> diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
> index 5e93e8d40f59..17c2f3276888 100644
> --- a/drivers/tty/serial/stm32-usart.c
> +++ b/drivers/tty/serial/stm32-usart.c
> @@ -31,6 +31,7 @@
> #include <linux/tty_flip.h>
> #include <linux/tty.h>
>
> +#include "serial_mctrl_gpio.h"
> #include "stm32-usart.h"
>
> static void stm32_stop_tx(struct uart_port *port);
> @@ -510,12 +511,29 @@ static void stm32_set_mctrl(struct uart_port *port, unsigned int mctrl)
> stm32_set_bits(port, ofs->cr3, USART_CR3_RTSE);
> else
> stm32_clr_bits(port, ofs->cr3, USART_CR3_RTSE);
> +
> + mctrl_gpio_set(stm32_port->gpios, mctrl);
> }
>
> static unsigned int stm32_get_mctrl(struct uart_port *port)
> {
> + struct stm32_port *stm32_port = to_stm32_port(port);
> + unsigned int ret;
> +
> /* This routine is used to get signals of: DCD, DSR, RI, and CTS */
> - return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
> + ret = TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
> +
> + return mctrl_gpio_get(stm32_port->gpios, &ret);
> +}
> +
> +static void stm32_enable_ms(struct uart_port *port)
> +{
> + mctrl_gpio_enable_ms(to_stm32_port(port)->gpios);
> +}
> +
> +static void stm32_disable_ms(struct uart_port *port)
> +{
> + mctrl_gpio_disable_ms(to_stm32_port(port)->gpios);
> }
>
> /* Transmit stop */
> @@ -626,6 +644,9 @@ static void stm32_shutdown(struct uart_port *port)
> u32 val, isr;
> int ret;
>
> + /* Disable modem control interrupts */
> + stm32_disable_ms(port);
> +
> val = USART_CR1_TXEIE | USART_CR1_TE;
> val |= stm32_port->cr1_irq | USART_CR1_RE;
> val |= BIT(cfg->uart_enable_bit);
> @@ -764,6 +785,12 @@ static void stm32_set_termios(struct uart_port *port, struct ktermios *termios,
> cr3 |= USART_CR3_CTSE | USART_CR3_RTSE;
> }
>
> + /* Handle modem control interrupts */
> + if (UART_ENABLE_MS(port, termios->c_cflag))
> + stm32_enable_ms(port);
> + else
> + stm32_disable_ms(port);
> +
> usartdiv = DIV_ROUND_CLOSEST(port->uartclk, baud);
>
> /*
> @@ -898,6 +925,7 @@ static const struct uart_ops stm32_uart_ops = {
> .throttle = stm32_throttle,
> .unthrottle = stm32_unthrottle,
> .stop_rx = stm32_stop_rx,
> + .enable_ms = stm32_enable_ms,
> .break_ctl = stm32_break_ctl,
> .startup = stm32_startup,
> .shutdown = stm32_shutdown,
> @@ -960,10 +988,31 @@ static int stm32_init_port(struct stm32_port *stm32port,
>
> stm32port->port.uartclk = clk_get_rate(stm32port->clk);
> if (!stm32port->port.uartclk) {
> - clk_disable_unprepare(stm32port->clk);
> ret = -EINVAL;
> + goto err_clk;
> + }
> +
> + stm32port->gpios = mctrl_gpio_init(&stm32port->port, 0);
> + if (IS_ERR(stm32port->gpios)) {
> + ret = PTR_ERR(stm32port->gpios);
> + goto err_clk;
> }
>
> + /* Both CTS/RTS gpios and "st,hw-flow-ctrl" should not be specified */
> + if (stm32port->hw_flow_control) {
> + if (mctrl_gpio_to_gpiod(stm32port->gpios, UART_GPIO_CTS) ||
> + mctrl_gpio_to_gpiod(stm32port->gpios, UART_GPIO_RTS)) {
> + dev_err(&pdev->dev, "Conflicting RTS/CTS config\n");
> + ret = -EINVAL;
> + goto err_clk;
> + }
> + }
> +
> + return ret;
> +
> +err_clk:
> + clk_disable_unprepare(stm32port->clk);
> +
> return ret;
> }
>
> diff --git a/drivers/tty/serial/stm32-usart.h b/drivers/tty/serial/stm32-usart.h
> index db8bf0d4982d..d4c916e78d40 100644
> --- a/drivers/tty/serial/stm32-usart.h
> +++ b/drivers/tty/serial/stm32-usart.h
> @@ -274,6 +274,7 @@ struct stm32_port {
> bool fifoen;
> int wakeirq;
> int rdr_mask; /* receive data register mask */
> + struct mctrl_gpios *gpios; /* modem control gpios */
> };
>
> static struct stm32_port stm32_ports[STM32_MAX_PORTS];
>
Hi Greg,
On Mon, Apr 20, 2020 at 10:32:02PM +0530, [email protected] wrote:
> From: Manivannan Sadhasivam <[email protected]>
>
> Hello,
>
> This patchset adds CTS/RTS gpio support to STM32 UART controller.
> Eventhough the UART controller supports using dedicated CTS/RTS gpios,
> sometimes we need to use different set of gpios for flow control.
>
> This is necessary for the upcoming STM32MP1 based board called Stinger96
> IoT-Box. On that board, a bluetooth chip is connected to one of the UART
> controller but the CTS/RTS lines got swapped mistakenly. So this patchset
> serves as a workaround for that hardware bug and also supports the
> usecase of using any gpio for CTS/RTS functionality. As per the sugggestion
> provided by Andy for v1, I've now switched to mctrl_gpio driver.
>
> This patchset has been validated with Stinger96 IoT-Box connected to Murata
> WiFi-BT combo chip.
>
Are you planning to take this series for 5.8?
Thanks,
Mani
> Thanks,
> Mani
>
> Changes in v3:
>
> * Added Andy's reviewed-by tag
> * Fixed minor issues spotted by Fabrice
>
> Changes in v2:
>
> As per the review by Andy:
>
> * Switched to mctrl_gpio driver instead of using custom CTS/RTS
> implementation
> * Removed the use of software flow control terminology.
>
> Manivannan Sadhasivam (2):
> dt-bindings: serial: Document CTS/RTS gpios in STM32 UART
> tty: serial: Add modem control gpio support for STM32 UART
>
> .../bindings/serial/st,stm32-uart.yaml | 14 +++++
> drivers/tty/serial/Kconfig | 1 +
> drivers/tty/serial/stm32-usart.c | 53 ++++++++++++++++++-
> drivers/tty/serial/stm32-usart.h | 1 +
> 4 files changed, 67 insertions(+), 2 deletions(-)
>
> --
> 2.17.1
>
On Thu, May 07, 2020 at 07:37:50PM +0530, Manivannan Sadhasivam wrote:
> Hi Greg,
>
> On Mon, Apr 20, 2020 at 10:32:02PM +0530, [email protected] wrote:
> > From: Manivannan Sadhasivam <[email protected]>
> >
> > Hello,
> >
> > This patchset adds CTS/RTS gpio support to STM32 UART controller.
> > Eventhough the UART controller supports using dedicated CTS/RTS gpios,
> > sometimes we need to use different set of gpios for flow control.
> >
> > This is necessary for the upcoming STM32MP1 based board called Stinger96
> > IoT-Box. On that board, a bluetooth chip is connected to one of the UART
> > controller but the CTS/RTS lines got swapped mistakenly. So this patchset
> > serves as a workaround for that hardware bug and also supports the
> > usecase of using any gpio for CTS/RTS functionality. As per the sugggestion
> > provided by Andy for v1, I've now switched to mctrl_gpio driver.
> >
> > This patchset has been validated with Stinger96 IoT-Box connected to Murata
> > WiFi-BT combo chip.
> >
>
> Are you planning to take this series for 5.8?
I had to wait for the DT protion to be reviewed before I could do
anything. Give me some time, if it looks ok, it will go into 5.8.
thanks,
greg k-h