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tty/serial/8250: use mctrl_gpio helpers 

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@googlemail.com>
Signed-off-by: Stefan Roese <sr@denx.de>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Tested-by: Yegor Yefremov <yegorslists@googlemail.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Giulio Benetti <giulio.benetti@micronovasrl.com>
Cc: Yegor Yefremov <yegorslists@googlemail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Yegor Yefremov 2019-06-20 08:24:20 +02:00 committed by Greg Kroah-Hartman
parent d99482673f
commit 4a96895f74
7 changed files with 81 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
Documentation/devicetree/bindings/serial/8250.txt
View File

@ -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>;
};

18
drivers/tty/serial/8250/8250.h
View File

@ -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);
@ -214,11 +216,25 @@ 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)

17
drivers/tty/serial/8250/8250_core.c
View File

@ -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. */

29
drivers/tty/serial/8250/8250_omap.c
View File

@ -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;

11
drivers/tty/serial/8250/8250_port.c
View File

@ -1656,6 +1656,8 @@ 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);
}
@ -1668,6 +1670,8 @@ 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);
@ -1939,12 +1943,17 @@ 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;
serial8250_rpm_get(up);
status = serial8250_modem_status(up);
serial8250_rpm_put(up);
return serial8250_MSR_to_TIOCM(status);
val = serial8250_MSR_to_TIOCM(status);
if (up->gpios)
return mctrl_gpio_get(up->gpios, &val);
return val;
}
EXPORT_SYMBOL_GPL(serial8250_do_get_mctrl);

1
drivers/tty/serial/8250/Kconfig
View File

@ -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

1
include/linux/serial_8250.h
View File

@ -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)
/*