From: Yegor Yefremov <yegorslists@xxxxxxxxxxxxxx> This patch permits the usage fo GPIOs to control the CTS/RTS/DTR/DSR/DCD/RI signals. Signed-off-by: Yegor Yefremov <yegorslists@xxxxxxxxxxxxxx> --- hanges: v2: - use newly introduced serial8250_in_MCR/serial8250_out_MCR - don't use autoRTS/CTS, if RTS pin is made via GPIO Documentation/devicetree/bindings/serial/8250.txt | 19 ++++++++++ drivers/tty/serial/8250/8250.h | 43 ++++++++++++++++++++++- drivers/tty/serial/8250/8250_core.c | 4 +++ drivers/tty/serial/8250/8250_omap.c | 31 +++++++++------- drivers/tty/serial/8250/8250_port.c | 7 +++- drivers/tty/serial/8250/Kconfig | 1 + include/linux/serial_8250.h | 1 + 7 files changed, 91 insertions(+), 15 deletions(-) diff --git a/Documentation/devicetree/bindings/serial/8250.txt b/Documentation/devicetree/bindings/serial/8250.txt index 936ab5b..f5561ac 100644 --- a/Documentation/devicetree/bindings/serial/8250.txt +++ b/Documentation/devicetree/bindings/serial/8250.txt @@ -42,6 +42,9 @@ Optional properties: - auto-flow-control: one way to enable automatic flow control support. The driver is allowed to detect support for the capability even without this property. +- {rts,cts,dtr,dsr,rng,dcd}-gpios: specify a GPIO for RTS/CTS/DTR/DSR/RI/DCD + line respectively. It will use specified GPIO instead of the peripheral + function pin for the UART feature. If unsure, don't specify this property. Note: * fsl,ns16550: @@ -63,3 +66,19 @@ Example: interrupts = <10>; reg-shift = <2>; }; + +Example for OMAP UART using GPIO-based modem control signals: + + uart4: serial@49042000 { + compatible = "ti,omap3-uart"; + reg = <0x49042000 0x400>; + interrupts = <80>; + ti,hwmods = "uart4"; + clock-frequency = <48000000>; + cts-gpios = <&gpio3 5 GPIO_ACTIVE_LOW>; + rts-gpios = <&gpio3 6 GPIO_ACTIVE_LOW>; + dtr-gpios = <&gpio1 12 GPIO_ACTIVE_LOW>; + dsr-gpios = <&gpio1 13 GPIO_ACTIVE_LOW>; + dcd-gpios = <&gpio1 14 GPIO_ACTIVE_LOW>; + rng-gpios = <&gpio1 15 GPIO_ACTIVE_LOW>; + }; diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h index 73bf57d..8e92baf 100644 --- a/drivers/tty/serial/8250/8250.h +++ b/drivers/tty/serial/8250/8250.h @@ -15,6 +15,8 @@ #include <linux/serial_reg.h> #include <linux/dmaengine.h> +#include "../serial_mctrl_gpio.h" + struct uart_8250_dma { int (*tx_dma)(struct uart_8250_port *p); int (*rx_dma)(struct uart_8250_port *p, unsigned int iir); @@ -134,12 +136,51 @@ void serial8250_em485_destroy(struct uart_8250_port *p); static inline void serial8250_out_MCR(struct uart_8250_port *up, int value) { + int mctrl_gpio = 0; + serial_out(up, UART_MCR, value); + + if (value & UART_MCR_RTS) + mctrl_gpio |= TIOCM_RTS; + if (value & UART_MCR_DTR) + mctrl_gpio |= TIOCM_DTR; + if (value & UART_MCR_OUT1) + mctrl_gpio |= TIOCM_OUT1; + if (value & UART_MCR_OUT2) + mctrl_gpio |= TIOCM_OUT2; + + mctrl_gpio_set(up->gpios, mctrl_gpio); } static inline int serial8250_in_MCR(struct uart_8250_port *up) { - return serial_in(up, UART_MCR); + int mctrl, mctrl_gpio = 0; + + mctrl = serial_in(up, UART_MCR); + + mctrl_gpio = mctrl_gpio_get_outputs(up->gpios, &mctrl_gpio); + + if (mctrl_gpio & TIOCM_RTS) + mctrl |= UART_MCR_RTS; + else + mctrl &= ~UART_MCR_RTS; + + if (mctrl_gpio & TIOCM_DTR) + mctrl |= UART_MCR_DTR; + else + mctrl &= ~UART_MCR_DTR; + + if (mctrl_gpio & TIOCM_OUT1) + mctrl |= UART_MCR_OUT1; + else + mctrl &= ~UART_MCR_OUT1; + + if (mctrl_gpio & TIOCM_OUT2) + mctrl |= UART_MCR_OUT2; + else + mctrl &= ~UART_MCR_OUT2; + + return mctrl; } #if defined(__alpha__) && !defined(CONFIG_PCI) diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c index 2f4f5ee..bfde589 100644 --- a/drivers/tty/serial/8250/8250_core.c +++ b/drivers/tty/serial/8250/8250_core.c @@ -1010,6 +1010,10 @@ int serial8250_register_8250_port(struct uart_8250_port *up) if (up->port.flags & UPF_FIXED_TYPE) uart->port.type = up->port.type; + uart->gpios = mctrl_gpio_init(&uart->port, 0); + if (IS_ERR(uart->gpios)) + dev_dbg(uart->port.dev, "Failed to init mctrl_gpio\n"); + serial8250_set_defaults(uart); /* Possibly override default I/O functions. */ diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c index d8bd8ce..d4e7663 100644 --- a/drivers/tty/serial/8250/8250_omap.c +++ b/drivers/tty/serial/8250/8250_omap.c @@ -128,18 +128,21 @@ static void omap8250_set_mctrl(struct uart_port *port, unsigned int mctrl) serial8250_do_set_mctrl(port, mctrl); - /* - * Turn off autoRTS if RTS is lowered and restore autoRTS setting - * if RTS is raised - */ - lcr = serial_in(up, UART_LCR); - serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); - if ((mctrl & TIOCM_RTS) && (port->status & UPSTAT_AUTORTS)) - priv->efr |= UART_EFR_RTS; - else - priv->efr &= ~UART_EFR_RTS; - serial_out(up, UART_EFR, priv->efr); - serial_out(up, UART_LCR, lcr); + if (IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(up->gpios, + UART_GPIO_RTS))) { + /* + * Turn off autoRTS if RTS is lowered and restore autoRTS + * setting if RTS is raised + */ + lcr = serial_in(up, UART_LCR); + serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); + if ((mctrl & TIOCM_RTS) && (port->status & UPSTAT_AUTORTS)) + priv->efr |= UART_EFR_RTS; + else + priv->efr &= ~UART_EFR_RTS; + serial_out(up, UART_EFR, priv->efr); + serial_out(up, UART_LCR, lcr); + } } /* @@ -440,7 +443,9 @@ static void omap_8250_set_termios(struct uart_port *port, priv->efr = 0; up->port.status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS | UPSTAT_AUTOXOFF); - if (termios->c_cflag & CRTSCTS && up->port.flags & UPF_HARD_FLOW) { + if (termios->c_cflag & CRTSCTS && up->port.flags & UPF_HARD_FLOW + && IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(up->gpios, + UART_GPIO_RTS))) { /* Enable AUTOCTS (autoRTS is enabled when RTS is raised) */ up->port.status |= UPSTAT_AUTOCTS | UPSTAT_AUTORTS; priv->efr |= UART_EFR_CTS; diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c index 094763b..bdf2dc4 100644 --- a/drivers/tty/serial/8250/8250_port.c +++ b/drivers/tty/serial/8250/8250_port.c @@ -1611,6 +1611,8 @@ static void serial8250_disable_ms(struct uart_port *port) if (up->bugs & UART_BUG_NOMSR) return; + mctrl_gpio_disable_ms(up->gpios); + up->ier &= ~UART_IER_MSI; serial_port_out(port, UART_IER, up->ier); } @@ -1623,6 +1625,8 @@ static void serial8250_enable_ms(struct uart_port *port) if (up->bugs & UART_BUG_NOMSR) return; + mctrl_gpio_enable_ms(up->gpios); + up->ier |= UART_IER_MSI; serial8250_rpm_get(up); @@ -1900,7 +1904,8 @@ static unsigned int serial8250_get_mctrl(struct uart_port *port) ret |= TIOCM_DSR; if (status & UART_MSR_CTS) ret |= TIOCM_CTS; - return ret; + + return mctrl_gpio_get(up->gpios, &ret); } void serial8250_do_set_mctrl(struct uart_port *port, unsigned int mctrl) diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig index 64742a0..74cf227 100644 --- a/drivers/tty/serial/8250/Kconfig +++ b/drivers/tty/serial/8250/Kconfig @@ -6,6 +6,7 @@ config SERIAL_8250 tristate "8250/16550 and compatible serial support" select SERIAL_CORE + select SERIAL_MCTRL_GPIO if GPIOLIB ---help--- This selects whether you want to include the driver for the standard serial ports. The standard answer is Y. People who might say N diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h index 4348797..3148d6d 100644 --- a/include/linux/serial_8250.h +++ b/include/linux/serial_8250.h @@ -110,6 +110,7 @@ struct uart_8250_port { * if no_console_suspend */ unsigned char probe; + struct mctrl_gpios *gpios; #define UART_PROBE_RSA (1 << 0) /* -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html