[PATCH 2/3][POWERPC][V2] Xilinx: of_serial support for Xilinx uart 16550.

[John Linn]

The Xilinx 16550 uart core is not a standard 16550 because it uses
word-based addressing rather than byte-based addressing. With
additional properties it is compatible with the open firmware
'ns16550' compatible binding.

This code updates the of_serial driver to handle the reg-offset
and reg-shift properties to enable this core to be used.

Signed-off-by: John Linn <john.linn at xilinx.com>
---
 Documentation/powerpc/booting-without-of.txt |   11 +++++++++++
 drivers/serial/of_serial.c                   |   15 +++++++++++++--
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/Documentation/powerpc/booting-without-of.txt b/Documentation/powerpc/booting-without-of.txt
index 87f4d84..af112d9 100644
--- a/Documentation/powerpc/booting-without-of.txt
+++ b/Documentation/powerpc/booting-without-of.txt
@@ -2539,6 +2539,17 @@ platforms are moved over to use the flattened-device-tree model.
                       differ between different families.  May be
                       'virtex2p', 'virtex4', or 'virtex5'.
 
+      iv) Xilinx Uart 16550
+
+      Xilinx UART 16550 devices are very similar to the NS16550 such that they
+      use the ns16550 binding with properties to specify register spacing and
+      an offset from the base address.
+
+      Requred properties:
+       - clock-frequency : Frequency of the clock input
+       - reg-offset : A value of 3 is required
+       - reg-shift : A value of 2 is required
+
    More devices will be defined as this spec matures.
 
 VII - Specifying interrupt information for devices
diff --git a/drivers/serial/of_serial.c b/drivers/serial/of_serial.c
index 2efb892..af9ed48 100644
--- a/drivers/serial/of_serial.c
+++ b/drivers/serial/of_serial.c
@@ -30,7 +30,7 @@ static int __devinit of_platform_serial_setup(struct of_device *ofdev,
 {
 	struct resource resource;
 	struct device_node *np = ofdev->node;
-	const unsigned int *clk, *spd;
+	const unsigned int *clk, *spd, *reg_offset, *reg_shift;
 	int ret;
 
 	memset(port, 0, sizeof *port);
@@ -48,7 +48,18 @@ static int __devinit of_platform_serial_setup(struct of_device *ofdev,
 	}
 
 	spin_lock_init(&port->lock);
-	port->mapbase = resource.start;
+
+	reg_offset = of_get_property(np, "reg-offset", NULL);
+	reg_shift = of_get_property(np, "reg-shift", NULL);
+
+	if (!reg_offset) 
+		port->mapbase = resource.start;
+	else 		
+		port->mapbase = resource.start + *reg_offset;	
+
+	if (reg_shift)
+		port->regshift = *reg_shift;
+
 	port->irq = irq_of_parse_and_map(np, 0);
 	port->iotype = UPIO_MEM;
 	port->type = type;
-- 
1.5.2.1