Re: [RFC] serial_core: Add wake_peer uart operation

[Kiran Raparthy]

On 18 November 2014 21:55, Greg Kroah-Hartman
<gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
> On Tue, Nov 18, 2014 at 12:20:01PM +0530, Kiran Kumar Raparthy wrote:
>> From: San Mehat <san@xxxxxxxxxx>
>>
>> serial_core: Add wake_peer uart operation
>>
>> Add wake_peer which is called before starting UART TX. The idea here
>> is to provide a mechanism where we can wakeup our peer before sending
>> data.
>>
>> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
>> Cc: Jiri Slaby <jslaby@xxxxxxx>
>> Cc: linux-serial@xxxxxxxxxxxxxxx
>> Cc: linux-kernel@xxxxxxxxxxxxxxx
>> Cc: Android Kernel Team <kernel-team@xxxxxxxxxxx>
>> Cc: John Stultz <john.stultz@xxxxxxxxxx>
>> Cc: Sumit Semwal <sumit.semwal@xxxxxxxxxx>
>> Signed-off-by: San Mehat <san@xxxxxxxxxx>
>> [Kiran: Added context to commit message]
>> Signed-off-by: Kiran Raparthy <kiran.kumar@xxxxxxxxxx>
>> ---
>> This is one of the number of patches from the Android AOSP common.git tree,
>> which is used on almost all Android devices.  I wanted to submit it for review
>> to see if it should go upstream.
>>
>>  drivers/tty/serial/serial_core.c | 3 +++
>>  include/linux/serial_core.h      | 1 +
>>  2 files changed, 4 insertions(+)
>>
>> diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
>> index df3a8c7..dc45c4b 100644
>> --- a/drivers/tty/serial/serial_core.c
>> +++ b/drivers/tty/serial/serial_core.c
>> @@ -95,6 +95,9 @@ static void __uart_start(struct tty_struct *tty)
>>       struct uart_state *state = tty->driver_data;
>>       struct uart_port *port = state->uart_port;
>>
>> +     if (port->ops->wake_peer)
>> +             port->ops->wake_peer(port);
>> +
>>       if (!uart_tx_stopped(port))
>>               port->ops->start_tx(port);
>>  }
>> diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
>> index 21c2e05..219b6a3 100644
>> --- a/include/linux/serial_core.h
>> +++ b/include/linux/serial_core.h
>> @@ -66,6 +66,7 @@ struct uart_ops {
>>       void            (*set_ldisc)(struct uart_port *, int new);
>>       void            (*pm)(struct uart_port *, unsigned int state,
>>                             unsigned int oldstate);
>> +     void            (*wake_peer)(struct uart_port *);
>>
>>       /*
>>        * Return a string describing the type of the port
>
> Do you have a driver that uses this callback to submit?  I really don't
> like taking hooks that are not used in the tree, otherwise it usually
> gets removed by someone who says, "look this hook isn't being used,
> let's delete it!"
Okay,let me check and resubmit the patch which uses the callback in driver.
Thanks for the review comments.
Regards,
Kiran
>
> thanks,
>
> greg k-h
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