Thankyou for the comments.
On 08/05/13 15:34, Arnd Bergmann wrote:

On Wednesday 08 May 2013, Srinivas KANDAGATLA wrote:

quoted

From: Srinivas Kandagatla <redacted>
+*st-asc(Serial Port)
+
+Required properties:
+- compatible : Should be "st,asc".

Are there any hardware revision numbers for the asc? If there are potentially
incompatible or backwards-compatible variants, it would be good to include
the version in this string.

Unfortunately, there is no version numbering for this IP.

quoted

+- reg, reg-names, interrupts, interrupt-names	: Standard way to define device
+			resources with names. look in
+			Documentation/devicetree/bindings/resource-names.txt
+
+Optional properties:
+- st,hw-flow-ctrl	bool flag to enable hardware flow control.
+- st,force-m1		bool flat to force asc to be in Mode-1 recommeded
+			for high bit rates (above 19.2K)
+Example:
+serial@fe440000{
+    compatible    = "st,asc";
+    reg         = <0xfe440000 0x2c>;
+    interrupts     =  <0 209 0>;
+};

I would also recommed adding a way to set the default baud rate through
a property. Following the example of the 8250 driver, you should probably
call that "current-speed".

Yes, I will add this in the next version.

quoted

diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 7e7006f..346f325 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig

@@ -1484,6 +1484,25 @@ config SERIAL_RP2_NR_UARTS
 	  If multiple cards are present, the default limit of 32 ports may
 	  need to be increased.
 
+config SERIAL_ST_ASC
+	tristate "ST ASC serial port support"
+	depends on PLAT_STIXXXX
+	default y
+	select SERIAL_CORE
+	help
+	  This driver is for the on-chip Asychronous Serial Controller on
+	  STMicroelectronics STixxxx SoCs.
+	  ASC is embedded in ST COMMS IP block. It supports Rx & Tx functionality.
+	  It support all industry standard baud rates.
+
+	  If unsure, say N.

I would not make it "default y".

Yep.

quoted

+config SERIAL_ST_ASC_CONSOLE
+	bool "Support for console on ST ASC"
+	depends on SERIAL_ST_ASC
+	default y
+	select SERIAL_CORE_CONSOLE
+
 endmenu

This needs to be "depends on SERIAL_ST_ASC=y". You would get a link error
if you try to make SERIAL_ST_ASC a loadable module and SERIAL_ST_ASC_CONSOLE
built-in.

Ok, got it.

quoted

+
+static struct asc_port asc_ports[ASC_MAX_PORTS];
+static struct uart_driver asc_uart_driver;
+
+/*---- Forward function declarations---------------------------*/
+static irqreturn_t asc_interrupt(int irq, void *ptr);
+static void asc_transmit_chars(struct uart_port *);
+static int asc_set_baud(struct asc_port *ascport, int baud);
+

Please remove all forward declarations, by reordering the functions in
the way they are called.

Will do.

quoted

diff --git a/drivers/tty/serial/st-asc.h b/drivers/tty/serial/st-asc.h
new file mode 100644
index 0000000..e59f818
--- /dev/null
+++ b/drivers/tty/serial/st-asc.h
+#ifndef _ST_ASC_H
+#define _ST_ASC_H
+
+#include <linux/serial_core.h>
+#include <linux/clk.h>
+
+struct asc_port {
+	struct uart_port port;
+	struct clk *clk;
+	unsigned int hw_flow_control:1;
+	unsigned int check_parity:1;
+	unsigned int force_m1:1;
+};

Since this header file is only used in one place, just merge it into
the driver itself.

Ok, will do it.

quoted

+#define ASC_MAJOR		204
+#define ASC_MINOR_START		40

I don't know what the current policy is on allocating major/minor numbers,
but I'm sure you cannot just reuse one that is already used.

Documentation/devices.txt lists the ones that are officially assigned.
Can't you use dynamic allocation here?

	Arnd