Re: [RFC] serial: omap-serial: Enable the UART wake-up bits always

From: Jarkko Nikula
Date: Fri Feb 04 2011 - 10:45:33 EST


On Mon, 24 Jan 2011 17:51:22 +0200
Jarkko Nikula <jhnikula@xxxxxxxxx> wrote:

> OMAP can do also dynamic idling so wake-up enable register should be set
> also while system is running. If UART_OMAP_WER is not set, then for instance
> the RX activity cannot wake up the UART port that is sleeping.
>
> This RX wake-up feature was working when the 8250 driver was used instead
> of omap-serial. Reason for this is that the 8250 doesn't set the
> UART_OMAP_WER and then arch/arm/mach-omap2/pm34xx.c ends up saving and
> restoring the reset default which is the same than value
> OMAP_UART_WER_MOD_WKUP here.
>
> Fix this by moving the conditional UART_OMAP_WER write from serial_omap_pm
> into serial_omap_startup where wake-up bits are set unconditionally.
>
> Signed-off-by: Jarkko Nikula <jhnikula@xxxxxxxxx>
> Cc: Govindraj.R <govindraj.raja@xxxxxx>
> ---
> This problem has been here since 2.6.37 when the omap-serial was switched
> into use so this patch is for 2.6.39.
> ---
For omap folks:

1. This patch is coming through tty tree
http://git.kernel.org/?p=linux/kernel/git/gregkh/tty-2.6.git;a=commit;h=78841462d72fe7038cb7ea48adecc6fc395f2dc5

2. This patch helps those boards that don't have UART RTS signal (e.g.
BeagleBoard) and thus padconf wakeup mechanism is not available.

--
Jarkko
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