[PATCH] custom PM support for 8250

[Vitaly Wool]

Greetings,
please find the patch that allows passing the pointer to custom power 
management routine (via platform_device) to 8250 serial driver.
Please note that the interface to the outer world (i. e. exported 
functions) remained the same.

Best regards,
  Vitaly
Currently 8250 serial driver doesn't have means to register custom
(i. e. board-specific) power management functions.
This patch modifies the driver to provide such facility.

 drivers/serial/8250.c       |   47 +++++++++++++++++++++++++++++++++++++------- include/linux/serial_8250.h |    4 +++
 2 files changed, 44 insertions(+), 7 deletions(-)
 
Signed-off-by: Vitaly Wool <vitalhome@xxxxxxxxxx>

Index: linux-2.6.10/drivers/serial/8250.c
===================================================================
--- linux-2.6.10.orig/drivers/serial/8250.c
+++ linux-2.6.10/drivers/serial/8250.c
@@ -2360,6 +2360,8 @@
 	uart_resume_port(&serial8250_reg, &serial8250_ports[line].port);
 }
 
+static struct uart_8250_port *uart_8250_register_port(struct uart_port *port, int *line);
+
 /*
  * Register a set of serial devices attached to a platform device.  The
  * list is terminated with a zero flags entry, which means we expect
@@ -2369,6 +2371,8 @@
 {
 	struct plat_serial8250_port *p = dev->platform_data;
 	struct uart_port port;
+	struct uart_8250_port *uart;
+	int line;
 
 	memset(&port, 0, sizeof(struct uart_port));
 
@@ -2386,7 +2390,9 @@
 		if (share_irqs)
 			port.flags |= UPF_SHARE_IRQ;
 
-		serial8250_register_port(&port);
+		uart = uart_8250_register_port(&port, &line);
+		if (!IS_ERR(uart))
+			uart->pm = p->pm;
 	}
 	return 0;
 }
@@ -2516,8 +2522,9 @@
 }
 
 /**
- *	serial8250_register_port - register a serial port
+ *	uart_8250_register_port - register a serial port
  *	@port: serial port template
+ *	@line: returned (on success) value of the line number
  *
  *	Configure the serial port specified by the request. If the
  *	port exists and is in use, it is hung up and unregistered
@@ -2526,19 +2533,20 @@
  *	The port is then probed and if necessary the IRQ is autodetected
  *	If this fails an error is returned.
  *
- *	On success the port is ready to use and the line number is returned.
+ *	On success the port is ready to use and the pointer to the 
+ *	corresponding struct uart_8250_port is returned.
  */
-int serial8250_register_port(struct uart_port *port)
+static struct uart_8250_port *uart_8250_register_port(struct uart_port *port, int *line)
 {
 	struct uart_8250_port *uart;
 	int ret = -ENOSPC;
 
 	if (port->uartclk == 0)
-		return -EINVAL;
+		return ERR_PTR(-EINVAL);
 
 	/* Avoid re-registering platform based ports if KGDB active */
 	if (port->line == kgdb8250_ttyS)
-		return -EBUSY;
+		return ERR_PTR(-EBUSY);
 
 	down(&serial_sem);
 
@@ -2560,10 +2568,35 @@
 
 		ret = uart_add_one_port(&serial8250_reg, &uart->port);
 		if (ret == 0)
-			ret = uart->port.line;
+			*line = uart->port.line;
 	}
 	up(&serial_sem);
 
+	return ret == 0 ? uart : ERR_PTR(ret);
+
+}
+
+/**
+ *	serial8250_register_port - register a serial port
+ *	@port: serial port template
+ *
+ *	Configure the serial port specified by the request. If the
+ *	port exists and is in use, it is hung up and unregistered
+ *	first.
+ *
+ *	The port is then probed and if necessary the IRQ is autodetected
+ *	If this fails an error is returned.
+ *
+ *	On success the port is ready to use and the line number is returned.
+ */
+int serial8250_register_port(struct uart_port *port)
+{
+	int ret = 0;
+	struct uart_8250_port *uart = uart_8250_register_port(port, &ret);
+
+	if (IS_ERR(uart))
+		ret = PTR_ERR(uart);
+
 	return ret;
 }
 EXPORT_SYMBOL(serial8250_register_port);
Index: linux-2.6.10/include/linux/serial_8250.h
===================================================================
--- linux-2.6.10.orig/include/linux/serial_8250.h
+++ linux-2.6.10/include/linux/serial_8250.h
@@ -24,6 +24,10 @@
 	unsigned char	iotype;		/* UPIO_* */
 	unsigned int	flags;		/* UPF_* flags */
 	unsigned int	line;		/* uart # */
+
+	/* per-port pm hook */
+	void			(*pm)(struct uart_port *port,
+				      unsigned int state, unsigned int old);
 };
 
 #endif