[U-Boot] omap: overo: Disable pull-ups on camera PCLK, HS and VS signals

[U-Boot] omap: overo: Disable pull-ups on camera PCLK, HS and VS signals

[Steve Sakoman]

The level shifters used on the Caspa camera module have a 4k output
impedance. Combined with the 100uA pull-up resistors in the OMAP3,
this raises the ground level to 400mV. Adding crosstalk between the
pixel clock and the HS/VS signals on the flat cable (a ground line in
between would have been nice), logic 0 levels can raise up to 650mV.
This exceeds the camera input pins VIL maximum voltage.  This change
suggested-by Laurent Pinchart

Signed-off-by: Steve Sakoman <steve@sakoman.com>
---

diff --git a/board/overo/overo.h b/board/overo/overo.h
index 42ef1b1..915f15b 100644
--- a/board/overo/overo.h
+++ b/board/overo/overo.h
@@ -160,10 +160,10 @@ const omap3_sysinfo sysinfo = {
 	MUX_VAL(CP(DSS_DATA22),		(IDIS | PTD | DIS | M0)) /*DSS_DATA22*/\
 	MUX_VAL(CP(DSS_DATA23),		(IDIS | PTD | DIS | M0)) /*DSS_DATA23*/\
  /*CAMERA*/\
-	MUX_VAL(CP(CAM_HS),		(IEN  | PTU | EN  | M0)) /*CAM_HS */\
-	MUX_VAL(CP(CAM_VS),		(IEN  | PTU | EN  | M0)) /*CAM_VS */\
+	MUX_VAL(CP(CAM_HS),		(IEN  | PTU | DIS | M0)) /*CAM_HS */\
+	MUX_VAL(CP(CAM_VS),		(IEN  | PTU | DIS | M0)) /*CAM_VS */\
 	MUX_VAL(CP(CAM_XCLKA),		(IDIS | PTD | DIS | M0)) /*CAM_XCLKA*/\
-	MUX_VAL(CP(CAM_PCLK),		(IEN  | PTU | EN  | M0)) /*CAM_PCLK*/\
+	MUX_VAL(CP(CAM_PCLK),		(IEN  | PTU | DIS | M0)) /*CAM_PCLK*/\
 	MUX_VAL(CP(CAM_FLD),		(IDIS | PTD | DIS | M4)) /*CAM_FLD*/\
 	MUX_VAL(CP(CAM_D0),		(IEN  | PTD | DIS | M0)) /*CAM_D0*/\
 	MUX_VAL(CP(CAM_D1),		(IEN  | PTD | DIS | M0)) /*CAM_D1*/\

[U-Boot] omap: overo: Disable pull-ups on camera PCLK, HS and VS signals

[Albert ARIBAUD]

Hi Steve,

Le 30/09/2011 21:08, Steve Sakoman a ?crit :
> The level shifters used on the Caspa camera module have a 4k output
> impedance. Combined with the 100uA pull-up resistors in the OMAP3,
> this raises the ground level to 400mV. Adding crosstalk between the
> pixel clock and the HS/VS signals on the flat cable (a ground line in
> between would have been nice), logic 0 levels can raise up to 650mV.
> This exceeds the camera input pins VIL maximum voltage.  This change
> suggested-by Laurent Pinchart
>
> Signed-off-by: Steve Sakoman<steve@sakoman.com>
> ---
>
> diff --git a/board/overo/overo.h b/board/overo/overo.h
> index 42ef1b1..915f15b 100644
> --- a/board/overo/overo.h
> +++ b/board/overo/overo.h
> @@ -160,10 +160,10 @@ const omap3_sysinfo sysinfo = {
>   	MUX_VAL(CP(DSS_DATA22),		(IDIS | PTD | DIS | M0)) /*DSS_DATA22*/\
>   	MUX_VAL(CP(DSS_DATA23),		(IDIS | PTD | DIS | M0)) /*DSS_DATA23*/\
>    /*CAMERA*/\
> -	MUX_VAL(CP(CAM_HS),		(IEN  | PTU | EN  | M0)) /*CAM_HS */\
> -	MUX_VAL(CP(CAM_VS),		(IEN  | PTU | EN  | M0)) /*CAM_VS */\
> +	MUX_VAL(CP(CAM_HS),		(IEN  | PTU | DIS | M0)) /*CAM_HS */\
> +	MUX_VAL(CP(CAM_VS),		(IEN  | PTU | DIS | M0)) /*CAM_VS */\
>   	MUX_VAL(CP(CAM_XCLKA),		(IDIS | PTD | DIS | M0)) /*CAM_XCLKA*/\
> -	MUX_VAL(CP(CAM_PCLK),		(IEN  | PTU | EN  | M0)) /*CAM_PCLK*/\
> +	MUX_VAL(CP(CAM_PCLK),		(IEN  | PTU | DIS | M0)) /*CAM_PCLK*/\
>   	MUX_VAL(CP(CAM_FLD),		(IDIS | PTD | DIS | M4)) /*CAM_FLD*/\
>   	MUX_VAL(CP(CAM_D0),		(IEN  | PTD | DIS | M0)) /*CAM_D0*/\
>   	MUX_VAL(CP(CAM_D1),		(IEN  | PTD | DIS | M0)) /*CAM_D1*/\
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>

Applied to u-boot-arm/master, thanks.

Amicalement,
-- 
Albert.