Re: [PATCHv4 2/5] driver: serial: omap: prevent runtime PM for "no_console_suspend"

[Sourav Poddar]

Hi Kevin,
On Friday 26 April 2013 11:58 PM, Kevin Hilman wrote:
> Sourav Poddar<sourav.poddar@xxxxxx>  writes:
>
> > The driver manages "no_console_suspend" by preventing runtime PM
> > during the suspend path, which forces the console UART to stay awake.
> >
> > Signed-off-by: Sourav Poddar<sourav.poddar@xxxxxx>
> > Reviewed-by: Felipe Balbi<balbi@xxxxxx>
> > ---
> >   drivers/tty/serial/omap-serial.c |   28 +++++++++++++++++++++++++++-
> >   1 files changed, 27 insertions(+), 1 deletions(-)
> >
> > diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
> > index 30d4f7a..eddff3c 100644
> > --- a/drivers/tty/serial/omap-serial.c
> > +++ b/drivers/tty/serial/omap-serial.c
> > @@ -161,6 +161,7 @@ struct uart_omap_port {
> >   	u32			calc_latency;
> >   	struct work_struct	qos_work;
> >   	struct pinctrl		*pins;
> > +	bool			is_suspending;
> >   };
> >
> >   #define to_uart_omap_port(p)	((container_of((p), struct uart_omap_port, port)))
> > @@ -1312,6 +1313,22 @@ static struct uart_driver serial_omap_reg = {
> >   };
> >
> >   #ifdef CONFIG_PM_SLEEP
> > +static int serial_omap_prepare(struct device *dev)
> > +{
> > +	struct uart_omap_port *up = dev_get_drvdata(dev);
> > +
> > +	up->is_suspending = true;
> > +
> > +	return 0;
> > +}
> > +
> > +static void serial_omap_complete(struct device *dev)
> > +{
> > +	struct uart_omap_port *up = dev_get_drvdata(dev);
> > +
> > +	up->is_suspending = false;
> > +}
> > +
> >   static int serial_omap_suspend(struct device *dev)
> >   {
> >   	struct uart_omap_port *up = dev_get_drvdata(dev);
> > @@ -1330,7 +1347,10 @@ static int serial_omap_resume(struct device *dev)
> >
> >   	return 0;
> >   }
> > -#endif
> > +#else
> > +#define serial_omap_prepare NULL
> > +#define serial_omap_prepare NULL
> > +#endif /* CONFIG_PM_SLEEP */
> >
> >   static void omap_serial_fill_features_erratas(struct uart_omap_port *up)
> >   {
> > @@ -1616,6 +1636,10 @@ static int serial_omap_runtime_suspend(struct device *dev)
> >   	struct uart_omap_port *up = dev_get_drvdata(dev);
> >   	struct omap_uart_port_info *pdata = dev->platform_data;
> I'd like to see a comment here about why we return error.  It's written
> in the changelog, but it deserves a comment here as well.  Something like:
>
> When using 'no_console_suspend', the console UART must not be suspended.
> Since driver suspend is managed by runtime suspend, preventing runtime
> suspend (by returning error) will keep device active during suspend.
Ok. Will add this.
> > +	if (up->is_suspending&&  !console_suspend_enabled
> > +			&&  uart_console(&up->port))
> nit: can you put the '&&' at the end of the first line, and have the
> 2nd line line up with the start of the first line?
Ok. Will modify this part.
> See other examples of similiar multi-line checks elsewhere in the
> driver.
>
> Other than those minor things, this patch is good.
>
> Then, can you repost and break this into 2 series since they can go
> independently.
>
> Patches 1-2 need to go through the serial tree (Greg), and I will queue
> up the OMAP specific changes once Greg has queued the serial core changes.
Yes, sounds good. Will break it in the next version into two series.
> Kevin

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