Re: [PATCH 3/6] driver: serial: omap: add prepare/complete callbackfor "no_console_suspend" case

[Sourav Poddar]

Hi Kevin,
On Thursday 18 April 2013 11:26 PM, Kevin Hilman wrote:
> Sourav Poddar<sourav.poddar@xxxxxx>  writes:
>
> > The patch adapt the serial core/driver to take care of the case when "no_console_suspend"
> > is used in the bootargs. The patch will remove dependency to set od->flags to
> > "OMAP_DEVICE_NO_IDLE_ON_SUSPEND" in serial.c(non dt case) and omap_device.c(dt case).
> >
> > Prepare and complete callbacks will ensure that clocks remain active for the console
> > uart when "no_console_suspend" is used in the bootargs.
> >
> > Signed-off-by: Sourav Poddar<sourav.poddar@xxxxxx>
> This changelog needs a rework.  The driver itself was not aware of
> od->flags and omap_device stuff in general, so it's not really
> relevant.  The driver is also not directly managing clocks, int's only
> doing runtime PM callbacks.
>
> What you want to say in the changelog is that the driver manages
> "no_console_suspend" by preventing runtime PM during the suspend path,
> which forces the console UART to stay awake.
Yes, looks to the point. Will update the changelog in the next version.
> > ---
> >   drivers/tty/serial/omap-serial.c |   20 ++++++++++++++++++++
> >   1 files changed, 20 insertions(+), 0 deletions(-)
> >
> > diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
> > index 08332f3..9ef80cf 100644
> > --- a/drivers/tty/serial/omap-serial.c
> > +++ b/drivers/tty/serial/omap-serial.c
> > @@ -1278,6 +1278,24 @@ 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);
> > +
> > +	if (!console_suspend_enabled&&  uart_console(&up->port))
> > +		pm_runtime_disable(dev);
> > +
> > +	return 0;
> > +}
> > +
> > +static void serial_omap_complete(struct device *dev)
> > +{
> > +	struct uart_omap_port *up = dev_get_drvdata(dev);
> > +
> > +	if (!console_suspend_enabled&&  uart_console(&up->port))
> > +		pm_runtime_enable(dev);
> > +}
> > +
> For compilation with !CONFIG_PM_SLEEP, you'll also need:
>
> #else
> #define serial_omap_prepare NULL
> #define serial_omap_prepare NULL
> #endif /* CONFIG_PM_SLEEP */
Ok. Will change this.
Though, just a query/proposal on this, will it be correct if we try to 
create a macro[1]
in include/linux/pm.h for prepare/complete as it is done for 
suspend/resume. ?

[1]:
#ifdef CONFIG_PM_SLEEP
#define SET_SYSTEM_SLEEP_PM_PREP_COMP_OPS(prepare_fn, complete_fn) \
        .prepare = prepare_fn, \
        .complete = complete_fn, \
#else
#define SET_SYSTEM_SLEEP_PM_PREP_COMP_OPS(prepare_fn, complete_fn)
#endif

~Sourav
> >   static int serial_omap_suspend(struct device *dev)
> >   {
> >   	struct uart_omap_port *up = dev_get_drvdata(dev);
> > @@ -1632,6 +1650,8 @@ static const struct dev_pm_ops serial_omap_dev_pm_ops = {
> >   	SET_SYSTEM_SLEEP_PM_OPS(serial_omap_suspend, serial_omap_resume)
> >   	SET_RUNTIME_PM_OPS(serial_omap_runtime_suspend,
> >   				serial_omap_runtime_resume, NULL)
> > +	.prepare        = serial_omap_prepare,
> > +	.complete       = serial_omap_complete,
> >   };
> >
> >   #if defined(CONFIG_OF)
> Kevin

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