* Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> [170728 03:37]: > On Thu, 2017-07-27 at 23:40 -0700, Tony Lindgren wrote: > > * yegorslists@xxxxxxxxxxxxxx <yegorslists@xxxxxxxxxxxxxx> [170727 > > 06:18]: > > > From: Yegor Yefremov <yegorslists@xxxxxxxxxxxxxx> > > > > > > This patch series aims to reintroduce the mctrl_gpio helpers for > > > 8250 > > > UARTs. > > > > > > There are some UARTs that use GPIO signals as a wakeup-sourse. > > > The first patch addresses this issue and tries to destinguish GPIO > > > usage > > > via searching for "wakeup-sourse" property. Though it must be > > > decided whether > > > this property is secure to use for this purpose. > > > > The wakeup-source part you should be able to handle pretty much > > out of box with Linux generic wakeirqs if configured. See for example > > drivers/i2c/i2c-core.c for the dev_pm_set_dedicated_wake_irq() part. > > Here are 3 cases: > 1) out-of-band interrupt (usually GPIO) which can be wake source; > 2) in-band interrupt (have not seen this for UART, though it's supported > by tty framework for a long time AFAIU); And case 2) is somewhat useless as it requires the uart to be clocked. > 3) special case when Out-of-band interrupt uses the pin in UART pool of > pins. > > We are talking here about case 3). OK at least for am335x/am437x, changing it's mode between gpio and uart use can be done with pinctrl framework with named pinctrl named modes. > > As long as the 8250 driver has runtime PM implemented > > As you remember it has not (the ugly hack which is used right now is not > correct implementation of RPM). > > > it will wake > > up the 8250 device. > > See above, in case 3) we would be able to achieve that when pin mode is > switched to GPIO and back. I don't remember if OMAP uses this approach. Yes that's needed for am335x and am437x to get a wake-up event from rx pin for example. Not needed for omap3/4/5. > > This should work just fine also with am335x gpios, just configure the > > secondary wakeup gpio interrupt using interrupts-extended in device > > tree. Typically the interrupts are named "irq" and "wakeup". And if > > the > > pin is used as gpio, you can just dev_pm_clear_wake_irq() during > > runtime. > > I think this one is not related to case 3). Hmm but it seems we already have that working for 8250_omap for omap3/4/5 where rx pin provides wakeup events when 8250_omap is in runtime suspend state. See the dev_pm_set_dedicated_wake_irq() parts in 8250_omap.c. For am335x/am437x I think the only thing missing is toggling between uart and gpio mode for the rx pin using pinctrl named modes. There's an example for am335x in omap_hsmmc.c with pinctrl_pm_select_idle_state() if that helps. But maybe you have something in case 3) that I don't follow? > > If having issues, we're still missing the wakeirq level configuration, > > the patch below should do the trick there. > > > err = request_threaded_irq(irq, NULL, > > handle_threaded_wake_irq, > > - IRQF_ONESHOT, dev_name(dev), > > wirq); > > + irq_get_trigger_type(irq) | > > IRQF_ONESHOT, > > This is not needed if you use DT or ACPI and framework (serial in this > case) checks for interrupt correctly. I think it's needed in the DT gpio interrupt case as some gpio controllers need to configure edge vs level. Regards, Tony -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
