[PATCH v2 0/2] serial: Add IrDA support to 8250_dw driver

[PATCH v2 0/2] serial: Add IrDA support to 8250_dw driver

[Ed Blake]

This patch set adds IrDA support to the 8250_dw driver. The first patch exposes
the set_ldisc() function in the 8250 driver so it can be overridden, and the
second patch adds a set_ldisc() function to the 8250_dw driver which enables /
disables IrDA SIR mode if supported.

v2:
  The 8250_dw set_ldisc() function no longer tries to enable/disable IrDA SIR
  mode if not supported by the hardware configuration.

Ed Blake (2):
  serial: 8250: Expose set_ldisc function
  serial: 8250_dw: Add support for IrDA SIR mode

 drivers/tty/serial/8250/8250_core.c |  3 +++
 drivers/tty/serial/8250/8250_dw.c   | 24 ++++++++++++++++++++++++
 drivers/tty/serial/8250/8250_port.c | 12 ++++++++++--
 include/linux/serial_8250.h         |  4 ++++
 include/linux/serial_core.h         |  2 ++
 5 files changed, 43 insertions(+), 2 deletions(-)

-- 
1.9.1

[PATCH v2 1/2] serial: 8250: Expose set_ldisc function

[Ed Blake]

Expose set_ldisc() function so that it can be overridden with a
platform specific implementation.

Signed-off-by: Ed Blake <ed.blake@imgtec.com>
---
 drivers/tty/serial/8250/8250_core.c |  3 +++
 drivers/tty/serial/8250/8250_port.c | 12 ++++++++++--
 include/linux/serial_8250.h         |  4 ++++
 include/linux/serial_core.h         |  2 ++
 4 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index 240a361..3ad8c80 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -830,6 +830,7 @@ static int serial8250_probe(struct platform_device *dev)
 		uart.port.handle_irq	= p->handle_irq;
 		uart.port.handle_break	= p->handle_break;
 		uart.port.set_termios	= p->set_termios;
+		uart.port.set_ldisc	= p->set_ldisc;
 		uart.port.get_mctrl	= p->get_mctrl;
 		uart.port.pm		= p->pm;
 		uart.port.dev		= &dev->dev;
@@ -1023,6 +1024,8 @@ int serial8250_register_8250_port(struct uart_8250_port *up)
 		/*  Possibly override set_termios call */
 		if (up->port.set_termios)
 			uart->port.set_termios = up->port.set_termios;
+		if (up->port.set_ldisc)
+			uart->port.set_ldisc = up->port.set_ldisc;
 		if (up->port.get_mctrl)
 			uart->port.get_mctrl = up->port.get_mctrl;
 		if (up->port.set_mctrl)
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 1bfb6fd..38c5856 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -2690,8 +2690,7 @@ static unsigned int serial8250_get_baud_rate(struct uart_port *port,
 		serial8250_do_set_termios(port, termios, old);
 }
 
-static void
-serial8250_set_ldisc(struct uart_port *port, struct ktermios *termios)
+void serial8250_do_set_ldisc(struct uart_port *port, struct ktermios *termios)
 {
 	if (termios->c_line == N_PPS) {
 		port->flags |= UPF_HARDPPS_CD;
@@ -2707,7 +2706,16 @@ static unsigned int serial8250_get_baud_rate(struct uart_port *port,
 		}
 	}
 }
+EXPORT_SYMBOL(serial8250_do_set_ldisc);
 
+static void
+serial8250_set_ldisc(struct uart_port *port, struct ktermios *termios)
+{
+	if (port->set_ldisc)
+		port->set_ldisc(port, termios);
+	else
+		serial8250_do_set_ldisc(port, termios);
+}
 
 void serial8250_do_pm(struct uart_port *port, unsigned int state,
 		      unsigned int oldstate)
diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h
index 48ec765..f350bf4 100644
--- a/include/linux/serial_8250.h
+++ b/include/linux/serial_8250.h
@@ -36,6 +36,8 @@ struct plat_serial8250_port {
 	void		(*set_termios)(struct uart_port *,
 			               struct ktermios *new,
 			               struct ktermios *old);
+	void		(*set_ldisc)(struct uart_port *,
+				     struct ktermios *);
 	unsigned int	(*get_mctrl)(struct uart_port *);
 	int		(*handle_irq)(struct uart_port *);
 	void		(*pm)(struct uart_port *, unsigned int state,
@@ -149,6 +151,8 @@ extern int early_serial8250_setup(struct earlycon_device *device,
 					 const char *options);
 extern void serial8250_do_set_termios(struct uart_port *port,
 		struct ktermios *termios, struct ktermios *old);
+extern void serial8250_do_set_ldisc(struct uart_port *port,
+				    struct ktermios *termios);
 extern unsigned int serial8250_do_get_mctrl(struct uart_port *port);
 extern int serial8250_do_startup(struct uart_port *port);
 extern void serial8250_do_shutdown(struct uart_port *port);
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 3442014..5d49488 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -123,6 +123,8 @@ struct uart_port {
 	void			(*set_termios)(struct uart_port *,
 				               struct ktermios *new,
 				               struct ktermios *old);
+	void			(*set_ldisc)(struct uart_port *,
+					     struct ktermios *);
 	unsigned int		(*get_mctrl)(struct uart_port *);
 	void			(*set_mctrl)(struct uart_port *, unsigned int);
 	int			(*startup)(struct uart_port *port);
-- 
1.9.1

[PATCH v2 2/2] serial: 8250_dw: Add support for IrDA SIR mode

[Ed Blake]

Add a set_ldisc function to enable/disable IrDA SIR mode according to
the new line discipline, if IrDA SIR mode is supported by the hardware
configuration.

Signed-off-by: Ed Blake <ed.blake@imgtec.com>
---
 drivers/tty/serial/8250/8250_dw.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
index 459d726..d6d41d6 100644
--- a/drivers/tty/serial/8250/8250_dw.c
+++ b/drivers/tty/serial/8250/8250_dw.c
@@ -53,6 +53,8 @@
 /* Helper for fifo size calculation */
 #define DW_UART_CPR_FIFO_SIZE(a)	(((a >> 16) & 0xff) * 16)
 
+/* DesignWare specific register fields */
+#define DW_UART_MCR_SIRE		BIT(6)
 
 struct dw8250_data {
 	u8			usr_reg;
@@ -66,6 +68,7 @@ struct dw8250_data {
 
 	unsigned int		skip_autocfg:1;
 	unsigned int		uart_16550_compatible:1;
+	unsigned int		sir_mode_supported:1;
 };
 
 static inline int dw8250_modify_msr(struct uart_port *p, int offset, int value)
@@ -254,6 +257,22 @@ static void dw8250_set_termios(struct uart_port *p, struct ktermios *termios,
 	serial8250_do_set_termios(p, termios, old);
 }
 
+static void dw8250_set_ldisc(struct uart_port *p, struct ktermios *termios)
+{
+	struct dw8250_data *data = p->private_data;
+	unsigned int mcr = p->serial_in(p, UART_MCR);
+
+	if (data->sir_mode_supported) {
+		if (termios->c_line == N_IRDA)
+			mcr |= DW_UART_MCR_SIRE;
+		else
+			mcr &= ~DW_UART_MCR_SIRE;
+
+		p->serial_out(p, UART_MCR, mcr);
+	}
+	serial8250_do_set_ldisc(p, termios);
+}
+
 /*
  * dw8250_fallback_dma_filter will prevent the UART from getting just any free
  * channel on platforms that have DMA engines, but don't have any channels
@@ -324,6 +343,7 @@ static void dw8250_quirks(struct uart_port *p, struct dw8250_data *data)
 static void dw8250_setup_port(struct uart_port *p)
 {
 	struct uart_8250_port *up = up_to_u8250p(p);
+	struct dw8250_data *data = p->private_data;
 	u32 reg;
 
 	/*
@@ -357,6 +377,9 @@ static void dw8250_setup_port(struct uart_port *p)
 
 	if (reg & DW_UART_CPR_AFCE_MODE)
 		up->capabilities |= UART_CAP_AFE;
+
+	if (reg & DW_UART_CPR_SIR_MODE)
+		data->sir_mode_supported = true;
 }
 
 static int dw8250_probe(struct platform_device *pdev)
@@ -392,6 +415,7 @@ static int dw8250_probe(struct platform_device *pdev)
 	p->iotype	= UPIO_MEM;
 	p->serial_in	= dw8250_serial_in;
 	p->serial_out	= dw8250_serial_out;
+	p->set_ldisc	= dw8250_set_ldisc;
 
 	p->membase = devm_ioremap(dev, regs->start, resource_size(regs));
 	if (!p->membase)
-- 
1.9.1

Re: [PATCH v2 0/2] serial: Add IrDA support to 8250_dw driver

[Matwey V. Kornilov]

I like this idea. OMAP UART (8250_omap) also can be switched to IrDA
mode, but I don't know anyone who use it.

2016-10-28 20:04 GMT+03:00 Ed Blake <ed.blake@imgtec.com>:
> This patch set adds IrDA support to the 8250_dw driver. The first patch exposes
> the set_ldisc() function in the 8250 driver so it can be overridden, and the
> second patch adds a set_ldisc() function to the 8250_dw driver which enables /
> disables IrDA SIR mode if supported.
>
> v2:
>   The 8250_dw set_ldisc() function no longer tries to enable/disable IrDA SIR
>   mode if not supported by the hardware configuration.
>
> Ed Blake (2):
>   serial: 8250: Expose set_ldisc function
>   serial: 8250_dw: Add support for IrDA SIR mode
>
>  drivers/tty/serial/8250/8250_core.c |  3 +++
>  drivers/tty/serial/8250/8250_dw.c   | 24 ++++++++++++++++++++++++
>  drivers/tty/serial/8250/8250_port.c | 12 ++++++++++--
>  include/linux/serial_8250.h         |  4 ++++
>  include/linux/serial_core.h         |  2 ++
>  5 files changed, 43 insertions(+), 2 deletions(-)
>
> --
> 1.9.1
>



-- 
With best regards,
Matwey V. Kornilov.
Sternberg Astronomical Institute, Lomonosov Moscow State University, Russia
119991, Moscow, Universitetsky pr-k 13, +7 (495) 9392382