[Avila] GPIO 14 data output

[Ahmet Basagalar]

Tim,

Thanks for the info it is very helpful. But now I believe I can not access 
these registers from user space. Do I need to write this code in a module? 
When I try this in a regular c code, it is giving me "Segmentation Fault"

Thanks,
Ahmet

----- Original Message ----- 
From: "Tim Harvey" <tim_harvey at yahoo.com>
To: "Avila" <avila at lists.unixstudios.net>
Sent: Tuesday, August 22, 2006 4:29 PM
Subject: Re: [Avila] GPIO 14 data output
Subject: [Avila] > Ahmet,
>
> GPIO14 is configured as a PCI clock in the redboot bootloader from the 
> original Intel code for the IXP4XX boards.  You need to write your own 
> kernel mode driver for linux that disables the PCI clock functionality and 
> strobes it.  Note that it needs to be strobed quite frequently as the 
> DS1918 times out after 1.12secs so you'll probably want to strobe it every 
> 500ms or so.
>
> enable:
>   // NB: GPIO Clock Register GPCLKR is described in 12.4.7 pg 399 of the
>   //     ixp42x developers manual
>   GPCLKR_last = *IXP4XX_GPIO_GPCLKR;
>   *IXP4XX_GPIO_GPCLKR &= ~0x1ff;// clear CKL0TC/CLK0DC bits to disable 
> CLK0
>   gpio_line_config(14, IXP4XX_GPIO_OUT);
>   gpio_line_set(14, IXP4XX_GPIO_LOW);
>
> strobe:
>   gpio_line_set(14, IXP4XX_GPIO_HIGH);
>   gpio_line_set(14, IXP4XX_GPIO_LOW);
>
> Note that on the GW2347's there is a GPIO line used as a buffer enable to 
> GPIO14 that you'll have to enable.  On the GW2348's R11 needs to be 
> loaded.
>
> Tim
>
> ----- Original Message ----
> From: Ahmet Basagalar <ahmet at thebluezone.com>
> To: avila <avila at lists.unixstudios.net>
> Sent: Tuesday, August 22, 2006 2:28:13 PM
> Subject: [Avila] GPIO 14 data output
>
> Hi all,
>
> I want to use GPIO 14 to strobe the DS1819 hardware watchdog, but it is
> configured as a clock source by default. I want to change it to data 
> output
> instead of clock but I could not find so far where "GPIO Clock Control
> Register (GPCLKR)" is set. Does anybody know which piece of code I need to
> modify for this purpose?
>
> Thanks,
> Ahmet
>
>
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