| Message ID | 20190221193429.161300-1-egranata@chromium.org (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
| Series | [v3] driver: platform: Support parsing GpioInt 0 in platform_get_irq() | expand |
On Thu, Feb 21, 2019 at 8:34 PM <egranata@chromium.org> wrote: > > From: Enrico Granata <egranata@chromium.org> > > ACPI 5 added support for GpioInt resources as a way to provide > information about interrupts mediated via a GPIO controller. > > Several device buses (e.g. SPI, I2C) have support for retrieving > an IRQ specified via this type of resource, and providing it > directly to the driver as an IRQ number. > > This is not currently done for the platform drivers, as platform_get_irq() > does not try to parse GpioInt() resources. This requires drivers to > either have to support only one possible IRQ resource, or to have code > in place to try both as a failsafe. > > While there is a possibility of ambiguity for devices that exposes > multiple IRQs, it is easy and feasible to support the common case > of devices that only expose one IRQ which would be of either type > depending on the underlying system's architecture. > > This commit adds support for parsing a GpioInt resource in order > to fulfill a request for the index 0 IRQ for a platform device. > > Signed-off-by: Enrico Granata <egranata@chromium.org> > --- > Changes in v3: > - ensured that -ENOENT return from acpi_dev_gpio_irq_get is not propagated > upwards, as some drivers expect platform_get_irq to return either a valid > IRQ or -ENXIO and will break otherwise > > drivers/base/platform.c | 19 ++++++++++++++++++- > 1 file changed, 18 insertions(+), 1 deletion(-) > > diff --git a/drivers/base/platform.c b/drivers/base/platform.c > index 1c958eb33ef4d..afd8b916303e4 100644 > --- a/drivers/base/platform.c > +++ b/drivers/base/platform.c > @@ -127,7 +127,24 @@ int platform_get_irq(struct platform_device *dev, unsigned int num) > irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS); > } > > - return r ? r->start : -ENXIO; > + if (r) > + return r->start; > + > + /* > + * For the index 0 interrupt, allow falling back to GpioInt > + * resources. While a device could have both Interrupt and GpioInt > + * resources, making this fallback ambiguous, in many common cases > + * the device will only expose one IRQ, and this fallback > + * allows a common code path across either kind of resource. > + */ > + if (num == 0 && has_acpi_companion(&dev->dev)) { > + int ret = acpi_dev_gpio_irq_get(ACPI_COMPANION(&dev->dev), num); > + > + if (ret > 0 || ret == -EPROBE_DEFER) Can't 0 be a valid GPIO IRQ? > + return ret; > + } > + > + return -ENXIO; > #endif > } > EXPORT_SYMBOL_GPL(platform_get_irq); > --
On Fri, Feb 22, 2019 at 1:03 AM Rafael J. Wysocki <rafael@kernel.org> wrote: > > On Thu, Feb 21, 2019 at 8:34 PM <egranata@chromium.org> wrote: > > > > From: Enrico Granata <egranata@chromium.org> > > > > ACPI 5 added support for GpioInt resources as a way to provide > > information about interrupts mediated via a GPIO controller. > > > > Several device buses (e.g. SPI, I2C) have support for retrieving > > an IRQ specified via this type of resource, and providing it > > directly to the driver as an IRQ number. > > > > This is not currently done for the platform drivers, as platform_get_irq() > > does not try to parse GpioInt() resources. This requires drivers to > > either have to support only one possible IRQ resource, or to have code > > in place to try both as a failsafe. > > > > While there is a possibility of ambiguity for devices that exposes > > multiple IRQs, it is easy and feasible to support the common case > > of devices that only expose one IRQ which would be of either type > > depending on the underlying system's architecture. > > > > This commit adds support for parsing a GpioInt resource in order > > to fulfill a request for the index 0 IRQ for a platform device. > > > > Signed-off-by: Enrico Granata <egranata@chromium.org> > > --- > > Changes in v3: > > - ensured that -ENOENT return from acpi_dev_gpio_irq_get is not propagated > > upwards, as some drivers expect platform_get_irq to return either a valid > > IRQ or -ENXIO and will break otherwise I hope there are no other lurking ways in which this might break things... Reviewed-by: Brian Norris <briannorris@chromium.org> > > drivers/base/platform.c | 19 ++++++++++++++++++- > > 1 file changed, 18 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/base/platform.c b/drivers/base/platform.c > > index 1c958eb33ef4d..afd8b916303e4 100644 > > --- a/drivers/base/platform.c > > +++ b/drivers/base/platform.c > > @@ -127,7 +127,24 @@ int platform_get_irq(struct platform_device *dev, unsigned int num) > > irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS); > > } > > > > - return r ? r->start : -ENXIO; > > + if (r) > > + return r->start; > > + > > + /* > > + * For the index 0 interrupt, allow falling back to GpioInt > > + * resources. While a device could have both Interrupt and GpioInt > > + * resources, making this fallback ambiguous, in many common cases > > + * the device will only expose one IRQ, and this fallback > > + * allows a common code path across either kind of resource. > > + */ > > + if (num == 0 && has_acpi_companion(&dev->dev)) { > > + int ret = acpi_dev_gpio_irq_get(ACPI_COMPANION(&dev->dev), num); > > + > > + if (ret > 0 || ret == -EPROBE_DEFER) > > Can't 0 be a valid GPIO IRQ? acpi_dev_gpio_irq_get() claims: * Return: Linux IRQ number (> %0) on success, negative errno on failure. Should I trust the documentation? It seems like yes, I should: int gpiod_to_irq(const struct gpio_desc *desc) { ... /* Zero means NO_IRQ */ if (!retirq) return -ENXIO; Brian > > + return ret; > > + } > > + > > + return -ENXIO; > > #endif > > } > > EXPORT_SYMBOL_GPL(platform_get_irq); > > --
diff --git a/drivers/base/platform.c b/drivers/base/platform.c index 1c958eb33ef4d..afd8b916303e4 100644 --- a/drivers/base/platform.c +++ b/drivers/base/platform.c @@ -127,7 +127,24 @@ int platform_get_irq(struct platform_device *dev, unsigned int num) irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS); } - return r ? r->start : -ENXIO; + if (r) + return r->start; + + /* + * For the index 0 interrupt, allow falling back to GpioInt + * resources. While a device could have both Interrupt and GpioInt + * resources, making this fallback ambiguous, in many common cases + * the device will only expose one IRQ, and this fallback + * allows a common code path across either kind of resource. + */ + if (num == 0 && has_acpi_companion(&dev->dev)) { + int ret = acpi_dev_gpio_irq_get(ACPI_COMPANION(&dev->dev), num); + + if (ret > 0 || ret == -EPROBE_DEFER) + return ret; + } + + return -ENXIO; #endif } EXPORT_SYMBOL_GPL(platform_get_irq);