On Thu, Jun 13, 2019 at 5:45 PM Stefan Roese <sr@xxxxxxx> wrote: > > 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. > > Use MSR / MCR <-> TIOCM wrapper functions. > > 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> > --- > v6: > - Use newly introduced TIOCM <-> MCR/MSR wrapper functions > - serial8250_in_MCR(): Don't save the already read MCR bits in TIOCM > format but "or" them later to the GPIO MCR value > - Correctly use "!up->gpios" (Andy) > - Removed Mika's reviewed by tag (because of changes) > > v5: > - Dropped a few "if (up->gpios)" checks, as the mctrl_gpio_foo() API > handles gpios == NULL (return) > - 8250_omap: Changed "IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(up->gpios, ...))" > to "up->gpios == NULL", as mctrl_gpio_to_gpiod() does not handle > gpios == NULL correctly. > > v4: > - Added Mika's reviewed by tag > - Added Johan to Cc > > 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 | 18 +++++++++++- > drivers/tty/serial/8250/8250_core.c | 17 +++++++++++ > drivers/tty/serial/8250/8250_omap.c | 29 ++++++++++--------- > drivers/tty/serial/8250/8250_port.c | 8 +++++ > drivers/tty/serial/8250/Kconfig | 1 + > include/linux/serial_8250.h | 1 + > 7 files changed, 79 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 793da2e510e0..75c7c5449461 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); > @@ -196,11 +198,25 @@ static inline int serial8250_MSR_to_TIOCM(int msr) > static inline void serial8250_out_MCR(struct uart_8250_port *up, int value) > { > serial_out(up, UART_MCR, value); > + > + if (up->gpios) > + mctrl_gpio_set(up->gpios, serial8250_MCR_to_TIOCM(value)); > } > > 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) { > + unsigned int mctrl_gpio = 0; > + > + mctrl_gpio = mctrl_gpio_get_outputs(up->gpios, &mctrl_gpio); > + mctrl |= serial8250_TIOCM_to_MCR(mctrl_gpio); > + } > + > + 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..d5bbfc8f2284 100644 > --- a/drivers/tty/serial/8250/8250_omap.c > +++ b/drivers/tty/serial/8250/8250_omap.c > @@ -141,18 +141,20 @@ 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 (!up->gpios) { > + /* > + * 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 +455,8 @@ 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 && > + !up->gpios) { > /* 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 47f0a8d01a57..bc4a5e7f7f63 100644 > --- a/drivers/tty/serial/8250/8250_port.c > +++ b/drivers/tty/serial/8250/8250_port.c > @@ -1662,6 +1662,8 @@ 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); > } > @@ -1674,6 +1676,8 @@ 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); > @@ -1944,11 +1948,15 @@ unsigned int serial8250_do_get_mctrl(struct uart_port *port) > { > struct uart_8250_port *up = up_to_u8250p(port); > unsigned int status; > + unsigned int val = 0; > > serial8250_rpm_get(up); > status = serial8250_modem_status(up); > serial8250_rpm_put(up); > > + if (up->gpios) > + return mctrl_gpio_get(up->gpios, &val); > + What happens when you have a mixed setup i.e. CTS controlled by UART but other status pins controlled by GPIO? In this case CTS status won't be returned. Do I see it right? Yegor > return serial8250_MSR_to_TIOCM(status); > } > EXPORT_SYMBOL_GPL(serial8250_do_get_mctrl); > 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 5e0b59422a68..bb2bc99388ca 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) > > /* > -- > 2.22.0 >
