From mboxrd@z Thu Jan  1 00:00:00 1970
From: Tomasz Figa <tomasz.figa@gmail.com>
Date: Sun, 16 Mar 2014 13:53:09 +0100
Subject: [U-Boot] Enabling uart 3 in arndale
In-Reply-To: <0259D8EA-B62C-4D07-8661-ED2CF6E53779@gmail.com>
References: <0259D8EA-B62C-4D07-8661-ED2CF6E53779@gmail.com>
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To: u-boot@lists.denx.de

Hi,

On 14.03.2014 09:04, armdev wrote:
> Hi,
>
> We are trying to enable the UART3 on COM18 pins of arndale board. The UART3 RXD and TXD are on pins 2 and 4 which as per the base board specification is connected as
>
> XuRXD3 : UART_3_RXD/GPA1[4] : 2
> XuTXD3 : UART_3_TXD/GPA1[5] : 4
>
> As per the public reference manual of exynos 5250, there is a register GPACON (0x1140_0000)
> Setting GPACON |= 0x0010_0000 should enable the pins, but I am not able to see any output on UART3.
>
> Can you please suggest what is the right procedure

The register is GPA1CON and its GPA1CON[4] and [5] bit fields need both 
to be set to 0x2 - see Pad Control chapter of Exynos5250 public 
datasheet. Also GPA1PUD should be reconfigured to disable default 
pull-down on both pins, again you can find details of the register in 
the datasheet.

Best regards,
Tomasz