From: Yegor Yefremov <yegorslists@xxxxxxxxxxxxxx> This patch permits the usage for GPIOs to control the CTS/RTS/DTR/DSR/DCD/RI signals. Changed by Stefan: Only call mctrl_gpio_init(), if the device has no ACPI companion device to not break existing ACPI based systems. Also only use the mctrl_gpio_ functions when "gpios" is available. Signed-off-by: Yegor Yefremov <yegorslists@xxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Stefan Roese <sr@xxxxxxx> Cc: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> Cc: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> Cc: Giulio Benetti <giulio.benetti@xxxxxxxxxxxxxxxx> Cc: Yegor Yefremov <yegorslists@xxxxxxxxxxxxxx> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- v3: - Only call mctrl_gpio_init(), if the device has no ACPI companion device to not break existing ACPI based systems, as suggested by Andy v2: - No change Please note that this patch was already applied before [1]. And later reverted [2] because it introduced problems on some x86 based boards (ACPI GPIO related). Here a detailed description of the issue at that time: https://lkml.org/lkml/2016/8/9/357 http://www.spinics.net/lists/linux-serial/msg23071.html This is a re-send of the original patch that was applied at that time. With patch 1/2 from this series this issue should be fixed now (please note that I can't test it on such an x86 platform causing these problems). Andy (or Mika), perhaps it would be possible for you to test this patch again, now with patch 1/2 of this series applied as well? That would be really helpful. Thanks, Stefan [1] 4ef03d328769 ("tty/serial/8250: use mctrl_gpio helpers") [2] 5db4f7f80d16 ("Revert "tty/serial/8250: use mctrl_gpio helpers"") .../devicetree/bindings/serial/8250.txt | 19 +++++++++ drivers/tty/serial/8250/8250.h | 40 ++++++++++++++++++- drivers/tty/serial/8250/8250_core.c | 17 ++++++++ drivers/tty/serial/8250/8250_omap.c | 31 ++++++++------ drivers/tty/serial/8250/8250_port.c | 9 +++++ drivers/tty/serial/8250/Kconfig | 1 + include/linux/serial_8250.h | 1 + 7 files changed, 104 insertions(+), 14 deletions(-) diff --git a/Documentation/devicetree/bindings/serial/8250.txt b/Documentation/devicetree/bindings/serial/8250.txt index 3cba12f855b7..20d351f268ef 100644 --- a/Documentation/devicetree/bindings/serial/8250.txt +++ b/Documentation/devicetree/bindings/serial/8250.txt @@ -53,6 +53,9 @@ Optional properties: programmable TX FIFO thresholds. - resets : phandle + reset specifier pairs - overrun-throttle-ms : how long to pause uart rx when input overrun is encountered. +- {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: @@ -74,3 +77,19 @@ 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 ebfb0bd5bef5..441aab94264b 100644 --- a/drivers/tty/serial/8250/8250.h +++ b/drivers/tty/serial/8250/8250.h @@ -11,6 +11,8 @@ #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); @@ -142,11 +144,47 @@ void serial8250_em485_destroy(struct uart_8250_port *p); static inline void serial8250_out_MCR(struct uart_8250_port *up, int value) { serial_out(up, UART_MCR, value); + + if (up->gpios) { + int mctrl_gpio = 0; + + if (value & UART_MCR_RTS) + mctrl_gpio |= TIOCM_RTS; + if (value & UART_MCR_DTR) + mctrl_gpio |= TIOCM_DTR; + + 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 = serial_in(up, UART_MCR); + + if (up->gpios) { + int mctrl_gpio = 0; + + /* save current MCR values */ + if (mctrl & UART_MCR_RTS) + mctrl_gpio |= TIOCM_RTS; + if (mctrl & UART_MCR_DTR) + mctrl_gpio |= TIOCM_DTR; + + 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; + } + + 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 e441221e04b9..a4470771005f 100644 --- a/drivers/tty/serial/8250/8250_core.c +++ b/drivers/tty/serial/8250/8250_core.c @@ -14,6 +14,7 @@ * serial8250_register_8250_port() ports */ +#include <linux/acpi.h> #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/ioport.h> @@ -982,6 +983,8 @@ int serial8250_register_8250_port(struct uart_8250_port *up) uart = serial8250_find_match_or_unused(&up->port); if (uart && uart->port.type != PORT_8250_CIR) { + struct mctrl_gpios *gpios; + if (uart->port.dev) uart_remove_one_port(&serial8250_reg, &uart->port); @@ -1016,6 +1019,20 @@ int serial8250_register_8250_port(struct uart_8250_port *up) if (up->port.flags & UPF_FIXED_TYPE) uart->port.type = up->port.type; + /* + * Only call mctrl_gpio_init(), if the device has no ACPI + * companion device + */ + if (!has_acpi_companion(uart->port.dev)) { + gpios = mctrl_gpio_init(&uart->port, 0); + if (IS_ERR(gpios)) { + if (PTR_ERR(gpios) != -ENOSYS) + return PTR_ERR(gpios); + } else { + uart->gpios = gpios; + } + } + 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 0a8316632d75..562ac73d9f2f 100644 --- a/drivers/tty/serial/8250/8250_omap.c +++ b/drivers/tty/serial/8250/8250_omap.c @@ -141,18 +141,21 @@ 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); + } } /* @@ -453,7 +456,9 @@ 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 2304a84eee3b..1925e62f05bf 100644 --- a/drivers/tty/serial/8250/8250_port.c +++ b/drivers/tty/serial/8250/8250_port.c @@ -1662,6 +1662,9 @@ static void serial8250_disable_ms(struct uart_port *port) if (up->bugs & UART_BUG_NOMSR) return; + if (up->gpios) + mctrl_gpio_disable_ms(up->gpios); + up->ier &= ~UART_IER_MSI; serial_port_out(port, UART_IER, up->ier); } @@ -1674,6 +1677,9 @@ static void serial8250_enable_ms(struct uart_port *port) if (up->bugs & UART_BUG_NOMSR) return; + if (up->gpios) + mctrl_gpio_enable_ms(up->gpios); + up->ier |= UART_IER_MSI; serial8250_rpm_get(up); @@ -1951,6 +1957,9 @@ unsigned int serial8250_do_get_mctrl(struct uart_port *port) serial8250_rpm_put(up); ret = 0; + if (up->gpios) + return mctrl_gpio_get(up->gpios, &ret); + if (status & UART_MSR_DCD) ret |= TIOCM_CAR; if (status & UART_MSR_RI) diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig index 296115f6a4d8..509f6a3bb9ff 100644 --- a/drivers/tty/serial/8250/Kconfig +++ b/drivers/tty/serial/8250/Kconfig @@ -8,6 +8,7 @@ config SERIAL_8250 tristate "8250/16550 and compatible serial support" depends on !S390 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 5a655ba8d273..14cd763baf78 100644 --- a/include/linux/serial_8250.h +++ b/include/linux/serial_8250.h @@ -114,6 +114,7 @@ struct uart_8250_port { * if no_console_suspend */ unsigned char probe; + struct mctrl_gpios *gpios; #define UART_PROBE_RSA (1 << 0) /* -- 2.21.0
