Re: [PATCH] IIO: Adds ACPI support for ST gyroscopes

[Mika Westerberg]

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) {
+		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 */
--
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