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serial_mxc: disable new features of autobaud detection 

Bit 7 of UCR3 is described in the i.MX3x/i.MX5x/i.MX6x
reference manuals as follows:

	Autobaud Detection Not Improved-. Disables new features of
	autobaud detection (See Baud Rate Automatic Detection
        Protocol, for more details).

	0 Autobaud detection new features selected
	1 Keep old autobaud detection mechanism

On at least i.MX6DQ, i.MX6DLS and i.MX53, the "new features"
occasionally cause the receiver to get out of sync and
continuously produce received characters of '\xff'.

This patch disables the "new feature" on all boards, since
there's no support for auto-baud in U-Boot on any of them.

More details are available in this post on i.MX Community:
	https://community.freescale.com/message/403254

Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>
Tested-by: Fabio Estevam <fabio.estevam@freescale.com>
Acked-by: Stefano Babic <sbabic@denx.de>
This commit is contained in:
Eric Nelson 2014-05-14 16:58:03 -07:00 committed by Stefano Babic
parent 66ca09fc41
commit 3a56482590
1 changed files with 2 additions and 2 deletions
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4
drivers/serial/serial_mxc.c
View File

@ -77,7 +77,7 @@
#define UCR3_DSR (1<<10) /* Data set ready */
#define UCR3_DCD (1<<9) /* Data carrier detect */
#define UCR3_RI (1<<8) /* Ring indicator */
#define UCR3_TIMEOUTEN (1<<7) /* Timeout interrupt enable */
#define UCR3_ADNIMP (1<<7) /* Autobaud Detection Not Improved */
#define UCR3_RXDSEN (1<<6) /* Receive status interrupt enable */
#define UCR3_AIRINTEN (1<<5) /* Async IR wake interrupt enable */
#define UCR3_AWAKEN (1<<4) /* Async wake interrupt enable */
@ -186,7 +186,7 @@ static int mxc_serial_init(void)
while (!(__REG(UART_PHYS + UCR2) & UCR2_SRST));
__REG(UART_PHYS + UCR3) = 0x0704;
__REG(UART_PHYS + UCR3) = 0x0704 | UCR3_ADNIMP;
__REG(UART_PHYS + UCR4) = 0x8000;
__REG(UART_PHYS + UESC) = 0x002b;
__REG(UART_PHYS + UTIM) = 0x0;