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List:       linux-omap
Subject:    Re: [PATCH] serial: 8250: omap: Provide ability to enable/disable UART as wakeup source
From:       Vignesh R <vigneshr () ti ! com>
Date:       2018-03-29 5:44:03
Message-ID: c43b081a-a94a-fb89-d2d7-9c4947bac4a6 () ti ! com
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On Thursday 29 March 2018 04:00 AM, Tony Lindgren wrote:
> * Vignesh R <vigneshr@ti.com> [180327 12:03]:
>> Enable/Clear module level UART wakeup in UART_OMAP_WER register based on
>> return value of device_may_wakeup() in .suspend(). This allows
>> userspace to use sysfs to control the ability of UART to wakeup the
>> system from deep sleep state. Register is restored back in .startup()
>> call that happens as part of resume sequence.
>> 
>> With this patch, userspace can control UART wakeup capability via sysfs:
>> To enable wakeup capability:
>> echo enabled >   /sys/class/tty/ttyXX/device/power/wakeup
>> For disabling wakeup capability:
>> echo disabled > /sys/class/tty/ttyXX/device/power/wakeup
> 
> To avoid confusion, can you please add this to the description:
> 
> Note that the UART wakeup events configured in the 8250 hardware only
> work for idle modes that do not cut off power for the UART. For deeper
> idle states, dedicated padconf wakeirqs must be used. Or in some cases
> the UART RX pin can be remuxed to GPIO input if the GPIO block stays
> powered.
> 

That makes sense, I will add it to patch description in v2.

> I tested this briefly and the dedicated wakeirqs still work for me,
> so from that point of view:
> 
> Tested-by: Tony Lindgren <tony@atomide.com>

Thanks for testing!

-- 
Regards
Vignesh
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