[U-Boot] [PATCH v2] OMAP3: pandora: fix booting without serial attached

[U-Boot] [PATCH v2] OMAP3: pandora: fix booting without serial attached

[Grazvydas Ignotas]

When the board is booted without serial cable attached (which
is how most of them will be used) UART RX is left floating and
sometimes picks noise, which interrupts countdown and enters
U-Boot prompt instead of booting the kernel.

Fix this by setting up internal pullup on UART RX pin. This
does not prevent serial from working as the internal pullup
is weak.

Signed-off-by: Grazvydas Ignotas <notasas@gmail.com>
---
It would be nice for this to go in as a fix for 2009.11,
else users without serial cable won't be able to boot it.

 board/pandora/pandora.h |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/board/pandora/pandora.h b/board/pandora/pandora.h
index 5bfa0f9..f0ad16b 100644
--- a/board/pandora/pandora.h
+++ b/board/pandora/pandora.h
@@ -219,7 +219,8 @@ const omap3_sysinfo sysinfo = {
 	MUX_VAL(CP(UART2_RX),		(IEN  | PTD | EN  | M4)) /*GPIO_147,*/\
 								 /*UART2_RX*/\
  /*Serial Interface (Peripheral boot, Linux console, on AV connector)*/\
-	MUX_VAL(CP(UART3_RX_IRRX),	(IEN  | PTD | DIS | M0)) /*UART3_RX*/\
+ /*RX pulled up to avoid noise when nothing is connected to serial port*/\
+	MUX_VAL(CP(UART3_RX_IRRX),	(IEN  | PTU | EN  | M0)) /*UART3_RX*/\
 	MUX_VAL(CP(UART3_TX_IRTX),	(IDIS | PTD | DIS | M0)) /*UART3_TX*/\
  /*LEDs (Controlled by OMAP)*/\
 	MUX_VAL(CP(MMC1_DAT6),		(IDIS | PTD | DIS | M4)) /*GPIO_128*/\
-- 
1.5.6.3

[U-Boot] [PATCH v2] OMAP3: pandora: fix booting without serial attached

[Tom]

Grazvydas Ignotas wrote:
> When the board is booted without serial cable attached (which
> is how most of them will be used) UART RX is left floating and
> sometimes picks noise, which interrupts countdown and enters
> U-Boot prompt instead of booting the kernel.
> 
> Fix this by setting up internal pullup on UART RX pin. This
> does not prevent serial from working as the internal pullup
> is weak.
> 
> Signed-off-by: Grazvydas Ignotas <notasas@gmail.com>

Ack.
Thanks.

> ---
> It would be nice for this to go in as a fix for 2009.11,
> else users without serial cable won't be able to boot it.
> 

Wolfgang,
Can this fix be included in 2009.11 ?

Tom


>  board/pandora/pandora.h |    3 ++-
>  1 files changed, 2 insertions(+), 1 deletions(-)
> 
> diff --git a/board/pandora/pandora.h b/board/pandora/pandora.h
> index 5bfa0f9..f0ad16b 100644
> --- a/board/pandora/pandora.h
> +++ b/board/pandora/pandora.h
> @@ -219,7 +219,8 @@ const omap3_sysinfo sysinfo = {
>  	MUX_VAL(CP(UART2_RX),		(IEN  | PTD | EN  | M4)) /*GPIO_147,*/\
>  								 /*UART2_RX*/\
>   /*Serial Interface (Peripheral boot, Linux console, on AV connector)*/\
> -	MUX_VAL(CP(UART3_RX_IRRX),	(IEN  | PTD | DIS | M0)) /*UART3_RX*/\
> + /*RX pulled up to avoid noise when nothing is connected to serial port*/\
> +	MUX_VAL(CP(UART3_RX_IRRX),	(IEN  | PTU | EN  | M0)) /*UART3_RX*/\
>  	MUX_VAL(CP(UART3_TX_IRTX),	(IDIS | PTD | DIS | M0)) /*UART3_TX*/\
>   /*LEDs (Controlled by OMAP)*/\
>  	MUX_VAL(CP(MMC1_DAT6),		(IDIS | PTD | DIS | M4)) /*GPIO_128*/\

[U-Boot] [PATCH v2] OMAP3: pandora: fix booting without serial attached

[Wolfgang Denk]

Dear Tom,

In message <4AFC100C.1040001@windriver.com> you wrote:
>
> > It would be nice for this to go in as a fix for 2009.11,
> > else users without serial cable won't be able to boot it.
> 
> Wolfgang,
> Can this fix be included in 2009.11 ?

Sure - if you merge it and send a pull request, please.

Best regards,

Wolfgang Denk

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