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    SubjectRe: [PATCH] IIO: Adds ACPI support for ST gyroscopes
    Hi,


    On 03/25/2015 06:21 AM, Mika Westerberg wrote:
    > On Wed, Mar 25, 2015 at 02:25:05PM +0200, Mika Westerberg wrote:
    >> I think we can do the same for ACPI GpioInts so that we introduce
    >> acpi_gpio_irq_get() that translates from GpioInt to Linux IRQ
    >> numberspace. Then we can do something like below in I2C core:
    >>
    >> if (client->irq <= 0) {
    >> int irq = -ENOENT;
    >>
    >> if (dev->of_node)
    >> irq = of_irq_get(dev->of_node, 0);
    >> else if (ACPI_COMPANION(dev))
    >> irq = acpi_gpio_irq_get(ACPI_COMPANION(dev), 0);
    >>
    >> if (irq == -EPROBE_DEFER)
    >> return irq;
    >> if (irq < 0)
    >> irq = 0;
    >>
    >> client->irq = irq;
    >> }
    >>
    >> Now it has the drawback that the first GpioInt will not be available to
    >> the driver anymore (as a GPIO since it is locked) but if DT already does
    >> the same we should be fine.
    > Below patch should take care of this.
    >
    > Robert, can you try it out?
    >
    > If people think this is the right way to go forward, I'll make formal
    > patches and submit them for review.
    >
    > diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
    > index c0929d938ced..ed7c40c7b4ab 100644
    > --- a/drivers/gpio/gpiolib-acpi.c
    > +++ b/drivers/gpio/gpiolib-acpi.c
    > @@ -510,6 +510,36 @@ struct gpio_desc *acpi_get_gpiod_by_index(struct acpi_device *adev,
    > return lookup.desc ? lookup.desc : ERR_PTR(-ENOENT);
    > }
    >
    > +/**
    > + * acpi_dev_gpio_irq_get() - Find GpioInt and translate it to Linux IRQ number
    > + * @adev: pointer to a ACPI device to get IRQ from
    > + * @index: index of GpioInt resource (starting from %0)
    > + *
    > + * If the device has one or more GpioInt resources, this function can be
    > + * used to translate from the GPIO offset in the resource to the Linux IRQ
    > + * number.
    > + *
    > + * Return: Linux IRQ number (>%0) on success, negative errno on failure.
    > + */
    > +int acpi_dev_gpio_irq_get(struct acpi_device *adev, int index)
    > +{
    > + struct gpio_desc *desc;
    > + int i = 0;
    > +
    > + do {
    > + struct acpi_gpio_info info;
    > +
    > + desc = acpi_get_gpiod_by_index(adev, NULL, i, &info);
    > + if (!IS_ERR(desc)) {
    > + if (info.gpioint && i++ == index)
    > + return gpiod_to_irq(desc);
    > + }
    > + } while (!IS_ERR(desc));
    > +
    > + return -ENOENT;
    > +}
    > +EXPORT_SYMBOL_GPL(acpi_dev_gpio_irq_get);
    > +
    > static acpi_status
    > acpi_gpio_adr_space_handler(u32 function, acpi_physical_address address,
    > u32 bits, u64 *value, void *handler_context,
    > diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
    > index edf274cabe81..c12a3f24ada4 100644
    > --- a/drivers/i2c/i2c-core.c
    > +++ b/drivers/i2c/i2c-core.c
    > @@ -629,8 +629,13 @@ static int i2c_device_probe(struct device *dev)
    > if (!client)
    > return 0;
    >
    > - if (!client->irq && dev->of_node) {
    > - int irq = of_irq_get(dev->of_node, 0);
    > + if (client->irq <= 0) {
    Isn't irq 0 a valid interrupt number ? Shouldn't it be client->irq < 0 ?
    > + int irq = -ENOENT;
    > +
    > + if (dev->of_node)
    > + irq = of_irq_get(dev->of_node, 0);
    > + else if (ACPI_COMPANION(dev))
    > + irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev), 0);
    >
    > if (irq == -EPROBE_DEFER)
    > return irq;
    > diff --git a/include/linux/acpi.h b/include/linux/acpi.h
    > index 24c7aa8b1d20..826e214ab7d5 100644
    > --- a/include/linux/acpi.h
    > +++ b/include/linux/acpi.h
    > @@ -704,6 +704,8 @@ static inline void acpi_dev_remove_driver_gpios(struct acpi_device *adev)
    > if (adev)
    > adev->driver_gpios = NULL;
    > }
    > +
    > +int acpi_dev_gpio_irq_get(struct acpi_device *adev, int index);
    > #else
    > static inline int acpi_dev_add_driver_gpios(struct acpi_device *adev,
    > const struct acpi_gpio_mapping *gpios)
    > @@ -711,6 +713,11 @@ static inline int acpi_dev_add_driver_gpios(struct acpi_device *adev,
    > return -ENXIO;
    > }
    > static inline void acpi_dev_remove_driver_gpios(struct acpi_device *adev) {}
    > +
    > +static inline int acpi_dev_gpio_irq_get(struct acpi_device *adev, int index)
    > +{
    > + return -ENXIO;
    > +}
    > #endif
    >
    > /* Device properties */
    > --
    > To unsubscribe from this list: send the line "unsubscribe linux-iio" in
    > the body of a message to majordomo@vger.kernel.org
    > More majordomo info at http://vger.kernel.org/majordomo-info.html
    >

    --
    Sathyanarayanan Kuppuswamy
    Android kernel developer



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