| Message ID | 1411461252-8730-1-git-send-email-jingchang.lu@freescale.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tuesday 23 September 2014 16:34:12 Jingchang Lu wrote: > This adds PM suspend/resume support for the of-serial driver > to provide power management support on devices attatched to it. > > Signed-off-by: Jingchang Lu <jingchang.lu@freescale.com> > Looks good to me, Acked-by: Arnd Bergmann <arnd@arndb.de>
Hi, This patch might have a potential issue that cause system hard hung immediately when it accesses to registers with no clock. This could happen on many chips that mainline kernel supporting with the setting "no_console_suspend=1" during suspend time. On 09/23/2014 04:34 PM, Jingchang Lu wrote: > This adds PM suspend/resume support for the of-serial driver > to provide power management support on devices attatched to it. > > Signed-off-by: Jingchang Lu <jingchang.lu@freescale.com> > --- > drivers/tty/serial/of_serial.c | 27 +++++++++++++++++++++++++++ > 1 file changed, 27 insertions(+) > > diff --git a/drivers/tty/serial/of_serial.c b/drivers/tty/serial/of_serial.c > index 27981e2..8bc2563 100644 > --- a/drivers/tty/serial/of_serial.c > +++ b/drivers/tty/serial/of_serial.c > @@ -240,6 +240,32 @@ static int of_platform_serial_remove(struct platform_device *ofdev) > return 0; > } > > +#ifdef CONFIG_PM_SLEEP > +static int of_serial_suspend(struct device *dev) > +{ > + struct of_serial_info *info = dev_get_drvdata(dev); > + > + serial8250_suspend_port(info->line); > + if (info->clk) The fix would be something like this. if (info->clk && console_suspend_enabled) > + clk_disable_unprepare(info->clk); > + > + return 0; > +} > + > +static int of_serial_resume(struct device *dev) > +{ > + struct of_serial_info *info = dev_get_drvdata(dev); > + > + if (info->clk) Ditto. Thanks, -Joseph > + clk_prepare_enable(info->clk); > + > + serial8250_resume_port(info->line); > + > + return 0; > +} > +#endif > +static SIMPLE_DEV_PM_OPS(of_serial_pm_ops, of_serial_suspend, of_serial_resume); > + > /* > * A few common types, add more as needed. > */ > @@ -271,6 +297,7 @@ static struct platform_driver of_platform_serial_driver = { > .name = "of_serial", > .owner = THIS_MODULE, > .of_match_table = of_platform_serial_table, > + .pm = &of_serial_pm_ops, > }, > .probe = of_platform_serial_probe, > .remove = of_platform_serial_remove, >
>-----Original Message----- >From: Joseph Lo [mailto:josephl@nvidia.com] >Sent: Friday, October 03, 2014 3:46 PM >To: Lu Jingchang-B35083; gregkh@linuxfoundation.org >Cc: devicetree@vger.kernel.org; arnd@arndb.de; linux- >kernel@vger.kernel.org; linux-serial@vger.kernel.org; linux-arm- >kernel@lists.infradead.org >Subject: Re: [PATCH] serial: of-serial: add PM suspend/resume support > >Hi, > >This patch might have a potential issue that cause system hard hung >immediately when it accesses to registers with no clock. This could happen >on many chips that mainline kernel supporting with the setting >"no_console_suspend=1" during suspend time. > >On 09/23/2014 04:34 PM, Jingchang Lu wrote: >> This adds PM suspend/resume support for the of-serial driver to >> provide power management support on devices attatched to it. >> >> Signed-off-by: Jingchang Lu <jingchang.lu@freescale.com> >> --- >> drivers/tty/serial/of_serial.c | 27 +++++++++++++++++++++++++++ >> 1 file changed, 27 insertions(+) >> >> diff --git a/drivers/tty/serial/of_serial.c >> b/drivers/tty/serial/of_serial.c index 27981e2..8bc2563 100644 >> --- a/drivers/tty/serial/of_serial.c >> +++ b/drivers/tty/serial/of_serial.c >> @@ -240,6 +240,32 @@ static int of_platform_serial_remove(struct >platform_device *ofdev) >> return 0; >> } >> >> +#ifdef CONFIG_PM_SLEEP >> +static int of_serial_suspend(struct device *dev) { >> + struct of_serial_info *info = dev_get_drvdata(dev); >> + >> + serial8250_suspend_port(info->line); >> + if (info->clk) >The fix would be something like this. > if (info->clk && console_suspend_enabled) > Yes, there will be, I will send a fix on this, thanks! Best Regards, Jingchang
diff --git a/drivers/tty/serial/of_serial.c b/drivers/tty/serial/of_serial.c index 27981e2..8bc2563 100644 --- a/drivers/tty/serial/of_serial.c +++ b/drivers/tty/serial/of_serial.c @@ -240,6 +240,32 @@ static int of_platform_serial_remove(struct platform_device *ofdev) return 0; } +#ifdef CONFIG_PM_SLEEP +static int of_serial_suspend(struct device *dev) +{ + struct of_serial_info *info = dev_get_drvdata(dev); + + serial8250_suspend_port(info->line); + if (info->clk) + clk_disable_unprepare(info->clk); + + return 0; +} + +static int of_serial_resume(struct device *dev) +{ + struct of_serial_info *info = dev_get_drvdata(dev); + + if (info->clk) + clk_prepare_enable(info->clk); + + serial8250_resume_port(info->line); + + return 0; +} +#endif +static SIMPLE_DEV_PM_OPS(of_serial_pm_ops, of_serial_suspend, of_serial_resume); + /* * A few common types, add more as needed. */ @@ -271,6 +297,7 @@ static struct platform_driver of_platform_serial_driver = { .name = "of_serial", .owner = THIS_MODULE, .of_match_table = of_platform_serial_table, + .pm = &of_serial_pm_ops, }, .probe = of_platform_serial_probe, .remove = of_platform_serial_remove,
This adds PM suspend/resume support for the of-serial driver to provide power management support on devices attatched to it. Signed-off-by: Jingchang Lu <jingchang.lu@freescale.com> --- drivers/tty/serial/of_serial.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+)